Rivals are rising to challenge the dominance of SpaceX

SpaceX is a space launch juggernaut. In just two decades, the company has managed to edge out former aerospace heavyweights Boeing, Lockheed, and Northrop Grumman to gain near-monopoly status over rocket launches in the US; it accounted for 87% of the country’s orbital launches in 2024, according to an analysis by SpaceNews. Since the mid-2010s, the company has dominated NASA’s launch contracts and become a major Pentagon contractor. It is now also the go-to launch provider for commercial customers, having lofted numerous satellites and five private crewed spaceflights, with more to come. 

Other space companies have been scrambling to compete for years, but developing a reliable rocket takes slow, steady work and big budgets. Now at least some of them are catching up. 

A host of companies have readied rockets that are comparable to SpaceX’s main launch vehicles. The list includes Rocket Lab, which aims to take on SpaceX’s workhorse Falcon 9 with its Neutron rocket and could have its first launch in late 2025, and Blue Origin, owned by Jeff Bezos, which recently completed the first mission of a rocket it hopes will compete against SpaceX’s Starship. 

Some of these competitors are just starting to get rockets off the ground. And the companies could also face unusual headwinds, given that SpaceX’s Elon Musk has an especially close relationship with the Trump administration and has allies at federal regulatory agencies, including those that provide oversight of the industry.

But if all goes well, the SpaceX challengers can help improve access to space and prevent bottlenecks if one company experiences a setback. “More players in the market is good for competition,” says Chris Combs, an aerospace engineer at the University of Texas at San Antonio. “I think for the foreseeable future it will still be hard to compete with SpaceX on price.” But, he says, the competitors could push SpaceX itself to become better and provide those seeking access to space with a wider array of options..

A big lift

There are a few reasons why SpaceX was able to cement its position in the space industry. When it began in the 2000s, it had three consecutive rocket failures and seemed poised to fold. But it barreled through with Musk’s financial support, and later with a series of NASA and defense contracts. It has been a primary beneficiary of NASA’s commercial space program, developed in the 2010s with the intention of propping up the industry. 

“They got government contracts from the very beginning,” says Victoria Samson, a space policy expert at the Secure World Foundation in Broomfield, Colorado. “I wouldn’t say it’s a handout, but SpaceX would not exist without a huge influx of repeated government contracts. To this day, they’re still dependent on government customers, though they have commercial customers too.”

SpaceX has also effectively achieved a high degree of vertical integration, Samson points out: It owns almost all parts of its supply chain, designing, building, and testing all its major hardware components in-house, with a minimal use of suppliers. That gives it not just control over its hardware but considerably lower costs, and the price tag is the top consideration for launch contracts. 

The company was also open to taking risks other industry stalwarts were not. “I think for a very long time the industry looked at spaceflight as something that had to be very precise and perfect, and not a lot of room for tinkering,” says Combs. “SpaceX really was willing to take some risks and accept failure in ways that others haven’t been. That’s easier to do when you’re backed by a billionaire.” 

What’s finally enabled international and US-based competitors to emerge has been a growing customer base looking for launch services, along with some investors’ deep pockets. 

Some of these companies are taking aim at SpaceX’s Falcon 9, which can lift as much as about 20,000 kilograms into orbit and is used for sending multiple satellites or the crewed Dragon into space. “There is a practical monopoly in the medium-lift launch market right now, with really only one operational vehicle,” says Murielle Baker, a spokesperson for Rocket Lab, a US-New Zealand company.

Rocket Lab plans to take on the Falcon 9 with its Neutron rocket, which is expected to have its inaugural flight later this year from NASA’s Wallops Flight Facility in Virginia. The effort is building on the success of the company’s smaller Electron rocket, and Neutron’s first stage is intended to be reusable after it parachutes down to the ocean. 

Another challenger is Texas-based Firefly, whose Alpha rocket can be launched from multiple spaceports so that it can reach different orbits. Firefly has already secured NASA and Space Force contracts, with more launches coming this year (and on March 2 it also became the second private company to successfully land a spacecraft on the moon). Next year, Relativity Space aims to loft its first Terran R rocket, which is partially built from 3D-printed components. And the Bill Gates–backed Stoke Space aims to launch its reusable Nova rocket in late 2025 or, more likely, next year.

Competitors are also rising for SpaceX’s Falcon Heavy, holding out the prospect of more options for sending massive payloads to higher orbits and deep space. Furthest along is the Vulcan Centaur rocket, a creation of United Launch Alliance, a joint venture between Boeing and Lockheed Martin. It’s expected to have its third and fourth launches in the coming months, delivering Space Force satellites to orbit. Powered by engines from Blue Origin, the Vulcan Centaur is slightly wider and shorter than the Falcon rockets. It currently isn’t reusable, but it’s less expensive than its predecessors, ULA’s Atlas V and Delta IV, which are being phased out. 

Mark Peller, the company’s senior vice president on Vulcan development and advanced programs, says the new rocket comes with multiple advantages. “One is overall value, in terms of dollars per pound to orbit and what we can provide to our customers,” he says, “and the second is versatility: Vulcan was designed to go to a range of orbits.” He says more than 80 missions are already lined up. 

Vulcan’s fifth flight, slated for no earlier than May, will launch the long-awaited Sierra Space Dream Chaser, a spaceplane that can carry cargo (and possibly crew) to the International Space Station. ULA also has upcoming Vulcan launches planned for Amazon’s Kuiper satellite constellation, a potential Starlink rival.

Meanwhile, though it took a few years, Blue Origin now has a truly orbital heavy-lift spacecraft: In January, it celebrated the inaugural launch of its towering New Glenn, a rocket that’s only a bit shorter than NASA’s Space Launch System and SpaceX’s Starship. Future flights could launch national security payloads. 

Competition is emerging abroad as well. After repeated delays, Europe’s heavy-lift Ariane 6, from Airbus subsidiary Arianespace, had its inaugural flight last year, ending the European Space Agency’s temporary dependence on SpaceX. A range of other companies are trying to expand European launch capacity, with assistance from ESA.

China is moving quickly on its own launch organizations too. “They had no less than seven ‘commercial’ space launch companies that were all racing to develop an effective system that could deliver a payload into orbit,” Kari Bingen, director of the Aerospace Security Project at the Center for Strategic and International Studies, says of China’s efforts. “They are moving fast and they have capital behind them, and they will absolutely be a competitor on the global market once they’re successful and probably undercut what US and European launch companies are doing.” The up-and-coming Chinese launchers include Space Pioneer’s reusable Tianlong-3 rocket and Cosmoleap’s Yueqian rocket. The latter is to feature a “chopstick clamp” recovery of the first stage, where it’s grabbed by the launch tower’s mechanical arms, similar to the concept SpaceX is testing for its Starship.

Glitches and government

Before SpaceX’s rivals can really compete, they need to work out the kinks, demonstrate the reliability of their new spacecraft, and show that they can deliver low-cost launch services to customers. 

The process is not without its challenges. Boeing’s Starliner delivered astronauts to the ISS on its first crewed flight in June 2024, but after thruster malfunctions, they were left stranded at the orbital outpost for nine months. While New Glenn reached orbit as planned, its first stage didn’t land successfully and its upper stage was left in orbit. 

SpaceX itself has had some recent struggles. The Federal Aviation Administration grounded the Falcon 9 more than once following malfunctions in the second half of 2024. The company still shattered records last year, though, with more than 130 Falcon 9 launches. It has continued with that record pace this year, despite additional Falcon 9 delays and more glitches with its booster and upper stage. SpaceX also conducted its eighth Starship test flight in March, just two months after the previous one, but both failed minutes after liftoff, raining debris down from the sky.

Any company must deal with financial challenges as well as engineering ones. Boeing is reportedly considering selling parts of its space business, following Starliner’s malfunctions and problems with its 737 Max aircraft. And Virgin Orbit, the launch company that spun off from Virgin Galactic, shuttered in 2023.

Another issue facing would-be commercial competitors to SpaceX in the US is the complex and uncertain political environment. Musk does not manage day-to-day operations of the company. But he has close involvement with DOGE, a Trump administration initiative that has been exerting influence on the workforces and budgets of NASA, the Defense Department, and regulators relevant to the space industry. 

Jared Isaacman, a billionaire who bankrolled the groundbreaking 2021 commercial mission Inspiration4, returned to orbit, again via a SpaceX craft, on Polaris Dawn last September. Now he may become Trump’s NASA chief, a position that could give him the power to nudge NASA toward awarding new lucrative contracts to SpaceX. In February it was reported that SpaceX’s Starlink might land a multibillion-dollar FAA contract previously awarded to Verizon. 

It is also possible that SpaceX could strengthen its position with respect to the regulatory scrutiny it has faced for environmental and safety issues at its production and launch sites on the coasts of Texas and Florida, as well as scrutiny of its rocket crashes and the resulting space debris. Oversight from the FAA, the Federal Communications Commission, and the Environmental Protection Agency may be weak. Conflicts of interest have already emerged at the FAA, and the Trump administration has also attempted to incapacitate the National Labor Relations Board. SpaceX had previously tried to block the board from acting after nine workers accused the company of unfair labor practices.

SpaceX did not respond to MIT Technology Review’s requests for comment for this story.

“I think there’s going to be a lot of emphasis to relieve a lot of the regulations, in terms of environmental impact studies, and things like that,” Samson says. “I thought there’d be a separation between [Musk’s] interests, but now, it’s hard to say where he stops and the US government begins.”

Regardless of the politics, the commercial competition will surely heat up throughout 2025. But SpaceX has a considerable head start, Bingen argues: “It’s going to take a lot for these companies to effectively compete and potentially dislodge SpaceX, given the dominant position that [it has] had.”

Ramin Skibba is an astrophysicist turned science writer and freelance journalist, based in the Bay Are

Europe is finally getting serious about commercial rockets

Europe is on the cusp of a new dawn in commercial space technology. As global political tensions intensify and relationships with the US become increasingly strained, several European companies are now planning to conduct their own launches in an attempt to reduce the continent’s reliance on American rockets.

In the coming days, Isar Aerospace, a company based in Munich, will try to launch its Spectrum rocket from a site in the frozen reaches of Andøya island in Norway. A spaceport has been built there to support small commercial rockets, and Spectrum is the first to make an attempt.

“It’s a big milestone,” says Jonathan McDowell, an astronomer and spaceflight expert at the Harvard-Smithsonian Center for Astrophysics in Massachusetts. “It’s long past time for Europe to have a proper commercial launch industry.”

Spectrum stands 28 meters (92 feet) tall, the length of a basketball court. The rocket has two stages, or parts, the first with nine engines—powered by an unusual fuel combination of liquid oxygen and propane not seen on other rockets before, which Isar says results in higher performance—and the second with a single engine to give satellites their final kick into orbit.

The ultimate goal for Spectrum is to carry satellites weighing up to 1,000 kilograms (2,200 pounds)  to low Earth orbit. On this first launch, however, there are no satellites on board, because success is anything but guaranteed. “It’s unlikely to make it to orbit,” says Malcolm Macdonald, an expert in space technology at Strathclyde University in Scotland. “The first launch of any rocket tends not to work.”

Regardless of whether it succeeds or fails, the launch attempt heralds an important moment as Europe tries to kick-start its own private rocket industry. Two other companies—Orbex of the UK and Rocket Factory Augsburg (RFA) of Germany—are expected to make launch attempts later this year. These efforts could give Europe multiple ways to reach space without having to rely on US rockets.  

“Europe has to be prepared for a more uncertain future,” says Macdonald. “The uncertainty of what will happen over the next four years with the current US administration amplifies the situation for European launch companies.”

Trailing in the US’s wake 

Europe has for years trailed behind the US in commercial space efforts. The successful launch of SpaceX’s first rocket, the Falcon 1, in 2008 began a period of American dominance of the global launch market. In 2024, 145 of 263 global launch attempts were made by US entities—and SpaceX accounted for 138 of those. “SpaceX is the benchmark at the moment,” says Jonas Kellner, head of marketing, communications, and political affairs at RFA. Other US companies, like Rocket Lab (which launches from both the US and New Zealand), have also become successful, while commercial rockets are ramping up in China, too.

Europe has launched its own government-funded Ariane and Vega rockets for decades from the Guiana Space Centre, a spaceport it operates in French Guiana in South America. Most recently, on March 6, the European Space Agency (ESA) launched its new heavy-lift Ariane 6 rocket from there for the first time. However, the history of rocket launches from Europe itself is much more limited. In 1997 the US defense contractor Northrop Grumman air-launched a Pegasus rocket from a plane that took off from the Canary Islands. In 2023 the US company Virgin Orbit failed to reach orbit with its LauncherOne rocket after a launch attempt from Cornwall in the UK. No vertical orbital rocket launch has ever been attempted from Western Europe.

Isar Aerospace is one of a handful of companies hoping to change that with help from agencies like ESA, which has provided funding to rocket launch companies through its Boost program since 2019. In 2024 it awarded €44.22 million ($48 million) to Isar, Orbex, RFA, and the German launch company HyImpulse. The hope is that one or more of the companies will soon begin regular launches from Europe from two potential sites: Isar’s chosen location in Andøya and the SaxaVord Spaceport on the Shetland Islands north of the UK, where RFA and Orbex plan to make their attempts. 

“I expect four or five companies to get to the point of launching, and then over a period of years reliability and launch cadence [or frequency] will determine which one or two of them survives,” says McDowell.

a test on the launchpad of a rocket engine

ISAR AEROSPACE

Unique advantages

In their initial form these rockets will not rival anything on offer from SpaceX in terms of size and cadence. SpaceX sometimes launches its 70-meter (230-foot) Falcon 9 rocket multiple times per week and is developing its much larger Starship vehicle for missions to the moon and Mars. However, the smaller European rockets can allow companies in Europe to launch satellites to orbit without having to travel all the way across the Atlantic. “There is an advantage to having it closer,” says Kellner, who says it will take RFA one or two days by sea to get its rockets to SaxaVord, versus one or two weeks to travel across the Atlantic.

Launching from Europe is useful, too, for reaching specific orbits. Traditionally, a lot of satellite launches have taken place near the equator, in places such as Cape Canaveral in Florida, to get an extra boost from Earth’s rotation. Crewed spacecraft have also launched from these locations to reach space stations in equatorial orbit around Earth and the moon. From Europe, though, satellites can launch north over uninhabited stretches of water to reach polar orbit, which can allow imaging satellites to see the entirety of Earth rotate underneath them.

Increasingly, says McDowell, companies want to place satellites into sun-synchronous orbit, a type of polar orbit where a satellite orbiting Earth stays in perpetual sunlight. This is useful for solar-powered vehicles. “By far the bulk of the commercial market now is sun-synchronous polar orbit,” says McDowell. “So having a high-latitude launch site that has good transport links with customers in Europe does make a difference.”

Europe’s end goal

In the longer term, Europe’s rocket ambitions might grow to vehicles that are more of a match for the Falcon 9 through initiatives like ESA’s European Launcher Challenge, which will award contracts later this year. “We are hoping to develop [a larger vehicle] in the European Launcher Challenge,” says Kellner. Perhaps Europe might even consider launching humans into space one day on larger rockets, says Thilo Kranz, ESA’s program manager for commercial space transportation. “We are looking into this,” he says. “If a commercial operator comes forward with a smart way of approaching [crewed] access to space, that would be a favorable development for Europe.”

A separate ESA project called Themis, meanwhile, is developing technologies to reuse rockets. This was the key innovation of SpaceX’s Falcon 9, allowing the company to dramatically drive down launch costs. Some European companies, like MaiaSpace and RFA, are also investigating reusability. The latter is planning to use parachutes to bring the first stage of its rocket back to a landing in the sea, where it can be recovered.

“As soon as you get up to something like a Falcon 9 competitor, I think it’s clear now that reusability is crucial,” says McDowell. “They’re not going to be economically competitive without reusability.”

The end goal for Europe is to have a sovereign rocket industry that reduces its reliance on the US. “Where we are in the broader geopolitical situation probably makes this a bigger point than it might have been six months ago,” says Macdonald.

The continent has already shown it can diversify from the US in other ways. Europe now operates its own successful satellite-based alternative to the US Global Positioning System (GPS), called Galileo; it began launching in 2011 and is four times more accurate than its American counterpart. Isar Aerospace, and the companies that follow, might be the first sign that commercial European rockets can break from America in a similar way.

“We need to secure access to space,” says Kranz, “and the more options we have in launching into space, the higher the flexibility.”

Should we be moving data centers to space?

Last week, the Florida-based company Lonestar Data Holdings launched a shoebox-size device carrying data from internet pioneer Vint Cerf and the government of Florida, among others, on board Intuitive Machines’ Athena lander. When its device lands on the moon later this week, the company will be the first to explicitly test out a question that has been on some technologists’ minds of late: Maybe it’s time to move data centers off Earth?

After all, energy-guzzling data centers are springing up like mushrooms all over the world, devouring precious land, straining our power grids, consuming water, and emitting noise. Building facilities in orbit or on or near the moon might help ameliorate many of these issues. 

For Steve Eisele, Lonestar’s president and chief revenue officer, a big appeal of putting data storage on the moon is security. “Ultimately, the moon can be the safest option where you can have a backup for your data,” Eisele says. “It’s harder to hack; it’s way harder to penetrate; it’s above any issues on Earth, from natural disasters to power outages to war.”

Lonestar’s device is equipped with eight terabytes of storage, about as much as a high-end laptop. It will last for just a couple of weeks before lunar night descends, temperatures plummet, and solar power runs out. But the company expects that to be enough time to test practicalities like downloading and uploading data and verifying secure data transfer protocols.

And it has bigger plans. As early as 2027, the company aims to launch a commercial data storage service using a bunch of satellites placed in the Earth-moon Lagrange point L1, a gravitationally stable point 61,350 kilometers above the moon’s surface. There, the spacecraft would have a constant view of Earth to allow continuous data access.

Other companies have similar aspirations. The US space company Axiom, best known for organizing short trips to the International Space Station for private astronauts, intends to launch a prototype server to the station in the coming months. By 2027, the firm wants to set up a computing node in low Earth orbit aboard its own space station module. 

A company called Starcloud, based in Washington state, is also betting on the need to process data in space. The company, which raised an $11 million round in December and more since then, wants to launch a small data-crunching satellite fitted with Nvidia GPUs later this year. 

Axiom sees an urgent need for computing capacity in space beyond simply providing an untouchable backup for earthly data. Today’s growing fleets of Earth- and space-observing satellites struggle with bandwidth limitations. Before users can glean any insights from satellite observations, the images must be downlinked to ground stations sparsely scattered around the planet and sent over to data centers for processing, which leads to delays.

“Data centers in space will help expedite many use cases,” says Jason Aspiotis, the global director of in-space data and security at Axiom. “The time from seeing something to taking action is very, very important for national security and for some scientific applications as well. A computer in space would also save costs that you need to bring all the data to the ground.”

But for these data centers to succeed, they must be able to withstand harsh conditions in space, pull in enough solar energy to operate, and make economic sense. Enthusiasts say the challenges are more tractable than they might appear—especially if you take into account some of the issues with data centers on Earth.

Better in space?

The current boom in AI and crypto mining is raising concerns about the environmental impact of computing infrastructure on Earth. Currently, data centers eat up around 1% or 2% of the world’s electricity. This number could double by 2030 alone, according to a Goldman Sachs report published last year. 

Space-tech aficionados think orbiting data centers could solve the problem.

“Data centers on Earth need a lot of power to operate, which means they have a high carbon footprint,” says Damien Dumestier, a space systems architect at the European aerospace conglomerate Thales Alenia Space. “They also produce a lot of heat, so you need water to cool them. None of that is a problem in space, where you have unlimited access to solar power and where you can simply radiate excess heat into space.”

Dumestier, who led an EU-funded study on the feasibility of placing large-scale IT infrastructure in Earth’s orbit, also sees space as a more secure option than Earth for data transportation and storage. Subsea fiber-optic cables are vulnerable to sabotage and natural disasters, like the undersea volcanic eruption that cut Tonga off from the web for two weeks.

High above Earth, data centers connected with unhackable laser links would be much harder to cut off or penetrate. Barring antisatellite missiles, space-based nuke explosions, or interceptor robots, these computing superhubs would be nigh untouchable. That is, except for micrometeorites and pieces of space debris, which spacecraft can dodge and, to some extent, be engineered to withstand. 

Outside of Earth’s protective atmosphere, the electronic equipment would also be exposed to energetic particles from the sun, which could damage it over time. Axiom plans to tackle the problem by using hardened military equipment, which Aspiotis says survives well in extreme environments. Lonestar thinks it could avoid the harsh radiation near the moon by ultimately placing its data centers in lava tubes under the lunar surface.

Then there is the matter of powering these facilities. Although solar power in Earth’s orbit is free and constantly available, it’s never previously been harvested in amounts needed to power data infrastructure at the scale existing on Earth. 

The Thales Alenia Space study, called ASCEND (an acronym for “advanced space cloud for European net zero emission and data sovereignty”), envisions orbiting data platforms twice as large as the International Space Station, the largest space structure built to date. The server racks at the heart of the ASCEND platforms would be powered by vast solar arrays producing a megawatt of power, equivalent to the electricity consumption of about 500 Western households. In comparison, the solar panels on the ISS produce only about one-quarter that amount—240 kilowatts at full illumination.

Launch costs—and the environmental effects of rocket launches—also complicate the picture. For space-based data centers to be an environmental win, Dumestier says, the carbon footprint of rocket flights needs to improve. He says SpaceX’s Starship, which is designed to carry very large loads and so could be cheaper and more efficient for each kilogram launched, is a major step in the right direction—and might pave the way for the deployment of large-scale orbital data centers by 2030. 

Aspiotis echoes those views: “There is a point in the not-too-distant future where data centers in space are as economical as they are on the ground,” he says. “In which case do we want them on the ground, where they are consuming power, water, and other kinds of utilities, including real estate?”

Domenico Vicinanza, an associate professor of intelligent systems and data science at Anglia Ruskin University in the UK, tempers the optimism, however. He says that moving data centers to space en masse is still a bit of a moonshot. Robotic technologies that could assemble and maintain such large-scale structures do not yet exist, and hardware failures in the harsh orbital environment would increase maintenance costs. 

“Fixing problems in orbit is far from straightforward. Even with robotics and automation, there are limits to what can be repaired remotely,” Vicinanza says. “While space offers the benefit of 24-7 solar energy, solar flares and cosmic radiation could damage sensitive electronic equipment and current electronics, from mainstream microchips to memories that are not built and tested to work in space.”

He also notes that any collisions could further crowd Earth orbit with space debris. “Any accidental damage to the data center could create cascading debris, further complicating orbital operations,” he says.

But even if we don’t move data centers off Earth, supporters say it’s technology we will need to expand our presence in space. 

“The lunar economy will grow, and within the next five years we will need digital infrastructure on the moon,” Eisele says. “We will have robots that will need to talk to each other. Governments will set up scientific bases and will need digital infrastructure to support their needs not only on the moon but also for going to Mars and beyond. That will be a big part of our future.”

Nokia is putting the first cellular network on the moon

Later this month, Intuitive Machines, the private company behind the first commercial lander that touched down on the moon, will launch a second lunar mission from NASA’s Kennedy Space Center. The plan is to deploy a lander, a rover, and hopper to explore a site near the lunar south pole that could harbor water ice, and to put a communications satellite on lunar orbit. 

But the mission will also bring something that’s never been installed on the moon or anywhere else in space before—a fully functional 4G cellular network. 

Point-to-point radio communications, which need a clear line of sight between transmitting and receiving antennas, have always been a backbone of both surface communications and the link back to Earth, starting with the Apollo program. Using point-to-point radio in space wasn’t much of an issue in the past because there never have been that many points to connect. Usually, it was just a single spacecraft, a lander, or a rover talking to Earth. And they didn’t need to send much data either.

“They were based on [ultra high frequency] or [very high frequency] technologies connecting a small number of devices with relatively low data throughput”, says Thierry Klein, president of Nokia Bell Labs Solutions Research, which was contracted by NASA to design a cellular network for the moon back in 2020. 

But it could soon get way more crowded up there: NASA’s Artemis program calls for bringing the astronauts back to the moon as early as 2028 and further expanding that presence into a permanent habitat in 2030s. 

The shift from mostly point-to-point radio communications to a full-blown cell network architecture should result in higher data transfer speeds, better range, and increase the number of devices that could be connected simultaneously, Klein says. But the harsh conditions of space travel and on the lunar surface  make it difficult to use Earth-based cell technology straight off the shelf. 

Instead, Nokia designed components that are robust against radiation, extreme temperatures, and the sorts of vibrations that will be experienced during the launch, flight, and landing. They put all these components in a single “network in a box”, which contains everything needed for a cell network except the antenna and a power source.

“We have the antenna on the lander, so together with the box that’s essentially your base station and your tower”, Klein says. The box will be powered by the lander’s solar panels.

During the IM-2 mission, the 4G cell network will allow for communication between the lander and the two vehicles. The network will likely only work for a few days— the spacecraft are not likely to survive after night descends on the lunar surface. 

But Nokia has plans for a more expansive 4G or 5G cell network that can cover the planned Artemis habitat and its surroundings. The company is also working on integrating cell communications in Axiom spacesuits meant for future lunar astronauts. “Maybe just one network in a box, one tower, would provide the entire coverage or maybe we would need multiple of these. That’s not going to be different from what you see in terrestrial cell networks deployment”, Klein says. He says the network should grow along with the future lunar economy. 

Not everyone is happy with this vision. LTE networks usually operate between 700 MHz and 2.6 GHz, a region of the radiofrequency spectrum that partially overlaps with frequencies reserved for radio astronomy. Having such radio signals coming from the moon could potentially interfere with observations.

“Telescopes are most sensitive in the direction that they are pointing–up towards the sky”, Chris De Pree, deputy spectrum manager at the National Radio Astronomy Observatory (NRAO) said in an email. Communication satellites like Starlink often end up in the radio telescopes’ line of sight. A full-scale cell network on the moon would add further noise to the night sky. 

There is also a regulatory hurdle that must be worked around. There are radio bands that have been internationally allocated to support lunar missions, and the LTE band is not among them. “Using 4G frequencies on or around the moon is a violation of the ITU-R radio regulations”, NRAO’s spectrum manager Harvey Liszt explained in an email.

To legally deploy the 4G network on the moon, Nokia received a waiver specifically for the IM-2 mission. “For permanent deployment we’ll have to pick a different frequency band,” Klein says. “We already have a list of candidate frequencies to consider.” Even with the frequency shift, Klein says Nokia’s lunar network technology will remain compatible with terrestrial 4G or 5G standards.

And that means that if you happened to bring your smartphone to the moon, and it somehow survived both the trip and the brutal lunar conditions, it should work on the moon just like it does here on Earth. “It would connect if we put your phone on the list of approved devices”, Klein explains. All you’d need is a lunar SIM card.

The dream of offshore rocket launches is finally blasting off

Want to send something to space? Get in line. The demand for rides off Earth is skyrocketing, pushing even the busiest spaceports, like Florida’s Kennedy Space Center, to their operational limits. Orbital launches worldwide have more than doubled over the past four years, from about 100 to 250 annually. That number is projected to spiral further up this decade, fueled by an epic growth spurt in the commercial space sector.

To relieve the congestion, some mission planners are looking to the ocean as the next big gateway to space. China has sent more than a dozen space missions from ocean platforms since 2019, most recently in January 2025. Italy’s space program has announced it will reopen its ocean launchpad off the coast of Kenya, while German space insiders envision an offshore spaceport in the North Sea. In the US, the idea of sea launches has attracted attention from heavyweights like SpaceX and inspired a new startup called the Spaceport Company

Launching rockets from offshore platforms like barges or oil rigs has a number of advantages. For one thing, it dramatically expands potential locations to lift off from, especially along the equator (this provides rockets with a natural speed boost because, thanks to geometry, the equator moves faster than the poles). At the same time, it is potentially safer and more environmentally friendly, placing launches further from population centers and delicate ecosystems. 

Ocean launches have taken place on and off for decades. But the renewed interest in offshore spaceports raises a host of questions about the unique regulatory, geopolitical, and environmental trade-offs of sea-based launches. It also offers a glimpse of new technologies and industries, enabled by a potentially limitless launch capacity, that could profoundly reshape our lives.

“The best way to build a future where we have dozens, hundreds, or maybe thousands of spaceports is to build them at sea,” says Tom Marotta, CEO and founder of the Spaceport Company, which is working to establish offshore launch hubs. “It’s very hard to find a thousand acres on the coast over and over again to build spaceports. It’s very easy to build the same ship over and over again.”

The saga of sea launches

The vision of oceanic spaceports is almost as old as rocketry itself. The first large rocket to take off from sea was a V2, the notorious missile developed by Germany in World War II and subsequently adopted by the United States, which the US Navy launched from the aircraft carrier USS Midway south of Bermuda on September 6, 1947. 

As it turned out, the inaugural flight was a bit of a mixed bag. Neal Casey, an 18-year-old technician stationed on the Midway, later recalled how the missile tilted dangerously starboard and headed toward  the vessel’s own command center, known as the island.

“I had no problem tracking the rocket,” said Casey, according to the USS Midway Museum. “It almost hit the island.”

Despite this brush with disaster, the test was considered a success because it proved that launching rockets from sea platforms was technically feasible. That revelation enabled the proliferation of missile-armed vessels, like warships or submarines, that have prowled the sea ever since.

Of course, missiles are designed to hit targets on Earth, not venture into space. But in the early 1960s Robert Truax, an American rocketry engineer, began pursuing a spectacular vision: the Sea Dragon. 

Standing nearly 500 feet tall, it would have been by far the biggest rocket in history, towering over the Apollo Program’s Saturn V or SpaceX’s Starship. No launchpad on land could withstand the force of its liftoff. A rocket this gargantuan could only be launched from a submerged position beneath the sea, rising out of the water like a breaching whale and leaving whirlpools swirling in its wake.

Truax proposed this incredible idea in 1963 while he was working at the rocket and missile manufacturer Aerojet General. He was even able to test a few small prototypes, including the Sea Bee, which was fired from under the waters of San Francisco Bay. Though the Sea Dragon never became a reality, the concept captured the imaginations of space dreamers for decades; most recently, it was depicted bursting from the ocean in the Apple+ series For All Mankind.  

Truax was eerily prescient about many future trends in spaceflight, and indeed, various governments and private entities have developed offshore launch platforms to take advantage of the flexibility offered by the seas.

“The most wanted launching sites are close to the equator,” says Gerasimos Rodotheatos, an assistant professor of international law and security at the American University in the Emirates who has researched sea-based launches. “Many countries there are hard to deal with because of political instability or because they don’t have the infrastructure. But if you’re using a platform or a vessel, it’s easier to select your location.”

Another major advantage is safety. “You’re far away from cities,” Rodotheatos adds. “You’re far away from land. You’re minimizing the risk of any accidents or any failures.”

For these reasons, rockets have intermittently lifted off from sea for nearly 60 years, beginning with Italy’s Luigi Broglio Malindi Space Center, a retrofitted oil rig off the coast of Kenya that launched orbital missions from the 1960s to the 1980s and may soon reopen after a nearly 40-year hiatus. 

Sea Launch, a multinational company founded in 1995, launched dozens of missions into orbit from the LP Odyssey, another repurposed drilling rig. The company might still be in business if Russia had not annexed Crimea in 2014, a move that prompted the venture—a partnership between Russia, Ukraine, the United States, and Norway—to shutter later the same year. 

The saga of Sea Launch proved that offshore launches could be commercially profitable, but it also exposed gray areas in international marine and space law. For instance, while Sea Launch was a venture between four spacefaring nations, it registered its rig and vessels to Liberia, which has been interpreted as a flag of convenience. Such strategies could present the opportunity for companies or other entities to evade certain labor laws, tax obligations, and environmental regulations.  

“Some states are very strict on the nationality and transparency of ownership, and other states less strict,” says Alla Pozdnakova, a professor of law at the University of Oslo’s Scandinavian Institute for Maritime Law, who has researched sea-based launches. “For now, it seems that it hasn’t been really that problematic because the United States, for example, would require that if you’re a US citizen or a US company, then you have to apply for a license from the US space authorities, regardless of where you want to launch.”

But if the US imposes strict oversight on launches, other nations might apply different standards to licensing agreements with launch providers. “I can imagine that some unauthorized projects may become possible simply because they are on the seas and there is no real authority—by contrast to land-based space launches—to supervise those kinds of launches,” Pozdnakova says.

Boeing, which managed Sea Launch, was fined $10 million in 1998 by the US Department of State for allegedly sharing information about American defense technology with its foreign partners in violation of the Arms Export Control Act. In addition to the legal and national security risks posed by Sea Launch, Pacific Island nations raised concerns to the United Nations in 1999 that the company’s offshore rockets could damage the environment by, for instance, creating oil slicks from unused fuel in discarded boosters. 

The complex issues that offshore spaceports raise for international law, environmental protection, and launch access have never been more relevant. SpaceX, which is famous for pioneering offshore rocket landings, has also flirted with sea-based launches. The company went so far as to purchase two oil rigs for $3.5 million apiece in 2020. They were renamed Deimos and Phobos after the two moons of Mars.

“SpaceX is building floating, superheavy-class spaceports for Mars, moon & hypersonic travel around Earth,” SpaceX CEO Elon Musk posted on Twitter (when it was still Twitter) in 2020. 

SpaceX eventually abandoned this project and sold the rigs, though Gwynne Shotwell, its president and COO, said in 2023 that sea-based launches were likely to be part of the company’s future. SpaceX did not respond to a request for comment. 

The company might need to move launch operations offshore if it wants to carry through on its aspirations for Starship, which is the most powerful rocket ever developed and the keystone of SpaceX’s future plans to send humans to the moon and Mars. “We have designed Starship to be as much like aircraft operations as we possibly can get it,” she said at a conference in 2023, according to SpaceNews. “We want to talk about dozens of launches a day, if not hundreds of launches a day.” 

The environmental impact of launching hundreds of rockets a day, either from sea or land, is not known. While offshore launches pose fewer direct risks to local environments than land launches, very little is understood about the risks that rocket emissions and chemical pollution pose to the climate and human health at current levels, much less exponentially higher ones. 

“It’s hard to deny that launching or emitting anything further from people is usually better,” says Sebastian Eastham, the senior lecturer in sustainable aviation at Imperial College London, who studies aerospace emissions and their environmental impacts. “But when we say that we’re concerned about the emissions, it is incomplete to say that we’re not launching near people, so people aren’t going to be affected.”

“I really hope that we find out that the impacts are small,” he continues. “But because you have this very rapid growth in launch emissions, you can’t sample now and say that this is representative of what it’s going to be like in five years. We’re nowhere near a steady state.”

In other words, rocket launches have been largely overlooked as a source of greenhouse-gas emissions and air pollution, simply because they have been too rare to be considered a major contributor. As space missions ramp up around the world, experts must aim to constrain the impact on climate change, the ozone layer, and pollution from spent parts that burn up in the atmosphere

The McDonald’s of spaceports

Offshore launches are almost routine in China, where companies like Galactic Energy, Orienspace, and the China Aerospace Science and Technology Corporation have expanded orbital liftoffs from barges. (None of these companies responded to a request for comment.) 

But at the moment, sea-based launches are limited to small rockets that can deploy payloads of a few thousand pounds to orbit. No ocean spaceport is currently equipped to handle the world’s most powerful rockets, like SpaceX’s Falcon Heavy, which can deliver more than 140,000 pounds to orbit. There are also currently no public plans to invest in sea-based infrastructure for heavy-lift rockets, but that may change if smaller offshore spaceports prove to be reliable and affordable options.

“All the activities now are based on off-the-shelf technologies,” Rodotheatos says, meaning facilities like oil rigs or barges. “If one company makes an investment to design and implement a floating platform from zero, specifically fitted for that purpose, I expect to see a big change.” 

Tom Marotta founded the Spaceport Company in 2022 with a similar long-term vision in mind. After working both for the space company Astra and on the regulatory side at the Federal Aviation Administration’s Office of Commercial Space Transportation, Marotta observed what he calls a “spaceport bottleneck” that had to be addressed to keep pace with the demands of the commercial space sector.  

To that end, the Spaceport Company procured a former US Navy training vessel, named the Once in a Lifetime after the Talking Heads song, as its first launchpad. The company is currently serving customers for suborbital space missions and missile tests, but its broader vision is to establish a network of scalable orbital spaceports across the ocean.

“We want to be the McDonald’s of spaceports, and build a model that can be repeated and copied-and-pasted all around the world,” Marotta says.

Marotta sees boundless applications for such a network. It could expand launch capacity without threatening coastal ecosystems or provoking pushback from local communities. It could serve as a reliable backup option for busy spaceports on land. It could give nations that normally don’t have access to spaceflight an affordable option for their own launch services. 

“Many nations want their own sovereign orbital launch capability, but they don’t want to spend a billion dollars to build a launchpad that might only be used once or twice,” Marotta says. “We see an opportunity there to basically give them a launchpad on demand.”

Marotta also has another dream in mind: ocean platforms could help to enable point-to-point rocket travel, capable of transporting cargo and passengers anywhere on Earth in under 90 minutes.

“You’re going to need dedicated and exclusive use of rockets off the coasts of major cities to serve that point-to-point rocket travel concept,” Marotta says. “This is science fiction right now, but I would not be surprised if in the next five years we see [organizations], particularly the military, experimenting with point-to-point rocket cargo.” 

Offshore launches currently represent a small tile in the global space mosaic, but they could dramatically change our lives in the coming decades. What that future might look like, with all of its risks and benefits, depends on the choices that companies, governments, and the public make right now.

Becky Ferreira is a science reporter based in Ithaca, NY. She writes the weekly Abstract column for 404 Media and is the author of the upcoming book First Contact, about the search for alien life.

How the Rubin Observatory will help us understand dark matter and dark energy

MIT Technology Review Explains: Let our writers untangle the complex, messy world of technology to help you understand what’s coming next. You can read more from the series here.

We can put a good figure on how much we know about the universe: 5%. That’s how much of what’s floating about in the cosmos is ordinary matter—planets and stars and galaxies and the dust and gas between them. The other 95% is dark matter and dark energy, two mysterious entities aptly named for our inability to shed light on their true nature. 

Cosmologists have cast dark matter as the hidden glue binding galaxies together. Dark energy plays an opposite role, ripping the fabric of space apart. Neither emits, absorbs, or reflects light, rendering them effectively invisible. So rather than directly observing either of them, astronomers must carefully trace the imprint they leave behind. 

Previous work has begun pulling apart these dueling forces, but dark matter and dark energy remain shrouded in a blanket of questions—critically, what exactly are they?

Enter the Vera C. Rubin Observatory, one of our 10 breakthrough technologies for 2025. Boasting the largest digital camera ever created, Rubin is expected to study the cosmos in the highest resolution yet once it begins observations later this year. And with a better window on the cosmic battle between dark matter and dark energy, Rubin might narrow down existing theories on what they are made of. Here’s a look at how.

Untangling dark matter’s web

In the 1930s, the Swiss astronomer Fritz Zwicky proposed the existence of an unseen force named dunkle Materie—in English, dark matter—after studying a group of galaxies called the Coma Cluster. Zwicky found that the galaxies were traveling too quickly to be contained by their joint gravity and decided there must be a missing, unobservable mass holding the cluster together.

Zwicky’s theory was initially met with much skepticism. But in the 1970s an American astronomer, Vera Rubin, obtained evidence that significantly strengthened the idea. Rubin studied the rotation rates of 60 individual galaxies and found that if a galaxy had only the mass we’re able to observe, that wouldn’t be enough to contain its structure; its spinning motion would send it ripping apart and sailing into space. 

Rubin’s results helped sell the idea of dark matter to the scientific community, since an unseen force seemed to be the only explanation for these spiraling galaxies’ breakneck spin speeds. “It wasn’t necessarily a smoking-gun discovery,” says Marc Kamionkowski, a theoretical physicist at Johns Hopkins University. “But she saw a need for dark matter. And other people began seeing it too.”

Evidence for dark matter only grew stronger in the ensuing decades. But sorting out what might be behind its effects proved tricky. Various subatomic particles were proposed. Some scientists posited that the phenomena supposedly generated by dark matter could also be explained by modifications to our theory of gravity. But so far the hunt, which has employed telescopes, particle colliders, and underground detectors, has failed to identify the culprit. 

The Rubin observatory’s main tool for investigating dark matter will be gravitational lensing, an observational technique that’s been used since the late ’70s. As light from distant galaxies travels to Earth, intervening dark matter distorts its image—like a cosmic magnifying glass. By measuring how the light is bent, astronomers can reverse-engineer a map of dark matter’s distribution. 

Other observatories, like the Hubble Space Telescope and the James Webb Space Telescope, have already begun stitching together this map from their images of galaxies. But Rubin plans to do so with exceptional precision and scale, analyzing the shapes of billions of galaxies rather than the hundreds of millions that current telescopes observe, according to Andrés Alejandro Plazas Malagón, Rubin operations scientist at SLAC National Laboratory. “We’re going to have the widest galaxy survey so far,” Plazas Malagón says.

Capturing the cosmos in such high definition requires Rubin’s 3.2-billion-pixel Large Synoptic Survey Telescope (LSST). The LSST boasts the largest focal plane ever built for astronomy, granting it access to large patches of the sky. 

The telescope is also designed to reorient its gaze every 34 seconds, meaning astronomers will be able to scan the entire sky every three nights. The LSST will revisit each galaxy about 800 times throughout its tenure, says Steven Ritz, a Rubin project scientist at the University of California, Santa Cruz. The repeat exposures will let Rubin team members more precisely measure how the galaxies are distorted, refining their map of dark matter’s web. “We’re going to see these galaxies deeply and frequently,” Ritz says. “That’s the power of Rubin: the sheer grasp of being able to see the universe in detail and on repeat.”

The ultimate goal is to overlay this map on different models of dark matter and examine the results. The leading idea, the cold dark matter model, suggests that dark matter moves slowly compared to the speed of light and interacts with ordinary matter only through gravity. Other models suggest different behavior. Each comes with its own picture of how dark matter should clump in halos surrounding galaxies. By plotting its chart of dark matter against what those models predict, Rubin might exclude some theories and favor others. 

A cosmic tug of war

If dark matter lies on one side of a magnet, pulling matter together, then you’ll flip it over to find dark energy, pushing it apart. “You can think of it as a cosmic tug of war,” Plazas Malagón says.

Dark energy was discovered in the late 1990s, when astronomers found that the universe was not only expanding, but doing so at an accelerating rate, with galaxies moving away from one another at higher and higher speeds. 

“The expectation was that the relative velocity between any two galaxies should have been decreasing,” Kamionkowski says. “This cosmological expansion requires something that acts like antigravity.” Astronomers quickly decided there must be another unseen factor inflating the fabric of space and pegged it as dark matter’s cosmic foil. 

So far, dark energy has been observed primarily through Type Ia supernovas, a special breed of explosion that occurs when a white dwarf star accumulates too much mass. Because these supernovas all tend to have the same peak in luminosity, astronomers can gauge how far away they are by measuring how bright they appear from Earth. Paired with a measure of how fast they are moving, this data clues astronomers in on the universe’s expansion rate. 

Rubin will continue studying dark energy with high-resolution glimpses of Type Ia supernovas. But it also plans to retell dark energy’s cosmic history through gravitational lensing. Because light doesn’t travel instantaneously, when we peer into distant galaxies, we’re really looking at relics from millions to billions of years ago—however long it takes for their light to make the lengthy trek to Earth. Astronomers can effectively use Rubin as a makeshift time machine to see how dark energy has carved out the shape of the universe. 

“These are the types of questions that we want to ask: Is dark energy a constant? If not, is it evolving with time? How is it changing the distribution of dark matter in the universe?” Plazas Malagón says.

If dark energy was weaker in the past, astronomers expect to see galaxies grouped even more densely into galaxy clusters. “It’s like urban sprawl—these huge conglomerates of matter,” Ritz says. Meanwhile, if dark energy was stronger, it would have pushed galaxies away from one another, creating a more “rural” landscape. 

Researchers will be able to use Rubin’s maps of dark matter and the 3D distribution of galaxies to plot out how the structure of the universe changed over time, unveiling the role of dark energy and, they hope, helping scientists evaluate the different theories to account for its behavior. 

Of course, Rubin has a lengthier list of goals to check off. Some top items entail tracing the structure of the Milky Way, cataloguing cosmic explosions, and observing asteroids and comets. But since the observatory was first conceptualized in the early ’90s, its core goal has been to explore this hidden branch of the universe. After all, before a 2019 act of Congress dedicated the observatory to Vera Rubin, it was simply called the Dark Matter Telescope. 

Rubin isn’t alone in the hunt, though. In 2023, the European Space Agency launched the Euclid telescope into space to study how dark matter and dark energy have shaped the structure of the cosmos. And NASA’s Nancy Grace Roman Space Telescope, which is scheduled to launch in 2027, has similar plans to measure the universe’s expansion rate and chart large-scale distributions of dark matter. Both also aim to tackle that looming question: What makes up this invisible empire?

Rubin will test its systems throughout most of 2025 and plans to begin the LSST survey late this year or in early 2026. Twelve to 14 months later, the team expects to reveal its first data set. Then we might finally begin to know exactly how Rubin will light up the dark universe. 

Vera C. Rubin Observatory: 10 Breakthrough Technologies 2025

WHO

US Department of Energy’s SLAC National Accelerator Laboratory, US National Science Foundation

WHEN

6 months

The next time you glance up at the night sky, consider: The particles inside everything you can see make up only about 5% of what’s out there in the universe. Dark energy and dark matter constitute the rest, astronomers believe—but what exactly is this mysterious stuff? 

A massive new telescope erected in Chile will explore this question and other cosmic unknowns. It’s named for Vera Rubin, an American astronomer who in the 1970s and 1980s observed stars moving faster than expected in the outer reaches of dozens of spiral galaxies. Her calculations made a strong case for the existence of dark matter—mass we can’t directly observe but that appears to shape everything from the paths of stars to the structure of the universe itself. 

Explore the full 2025 list of 10 Breakthrough Technologies.

Soon, her namesake observatory will carry on that work in much higher definition. The facility, run by the SLAC National Accelerator Laboratory and the US National Science Foundation, will house the largest digital camera ever made for astronomy. And its first mission will be to complete what’s called the Legacy Survey of Space and Time. Astronomers will focus its giant lens on the sky over the Southern Hemisphere and snap photo after photo, passing over the same patches of sky repeatedly for a decade. 

By the end of the survey, this 3.2-gigapixel camera will have catalogued 20 billion galaxies and collected up to 60 petabytes of data—roughly three times the amount currently stored by the US Library of Congress. Compiling all these images together, with help from specialized algorithms and a supercomputer, will give astronomers a time-lapse view of the sky. Seeing how so many galaxies are dispersed and shaped will enable them to study dark matter’s gravitational effect. They also plan to create the most detailed three-dimensional map of our Milky Way galaxy ever made. 

If all goes well, the telescope will snap its first science-quality images—a special moment known as first light—in mid-2025. The public could see the first photo released from Rubin soon after. 

The Vera C. Rubin Observatory is ready to transform our understanding of the cosmos

High atop Chile’s 2,700-meter Cerro Pachón, the air is clear and dry, leaving few clouds to block the beautiful view of the stars. It’s here that the Vera C. Rubin Observatory will soon use a car-size 3,200-megapixel digital camera—the largest ever built—to produce a new map of the entire night sky every three days.

Generating 20 terabytes of data per night, Rubin will capture fine details about the solar system, the Milky Way, and the large-scale structure of the cosmos, helping researchers to understand their history and current evolution. It will capture rapidly changing events, including stellar explosions called supernovas, the evisceration of stars by black holes, and the whiz of asteroids overhead. Findings from the observatory will help tease apart fundamental mysteries like the nature of dark matter and dark energy, two phenomena that have not been directly observed but affect how objects in the universe are bound together—and pushed apart.  

Rubin is the latest and most advanced entrant into the illustrious lineage of all-sky surveyors—instruments that capture, or survey, the entire sky, over and over again. Its first scientific images are expected later this year. In a single exposure, Rubin will capture 100,000 galaxies, the majority invisible to other instruments. A quarter-­century in the making, the observatory is poised to expand our understanding of just about every corner of the universe.  

The facility will also look far outside the Milky Way, cataloguing around 20 billion previously unknown galaxies and mapping their placement in long filamentary structures known as the cosmic web.

“I can’t think of an astronomer who is not excited about [Rubin],” says Christian Aganze, a galactic archeologist at Stanford University in California.

The observatory was first proposed in 2001. Then called the Large-Aperture Synoptic Survey Telescope (LSST), it grew out of an earlier concept for an instrument that would study dark matter, the enigmatic substance making up 85% of the matter in the universe. LSST was later reenvisioned to focus on a broader set of scientific questions, cataloguing the night sky over the course of a decade. Five years ago, it was renamed in honor of the late American astronomer Vera Rubin, who uncovered some of the best evidence in favor of dark matter’s existence in the 1970s and ’80s. 

During operations, Rubin will point its sharp eyes at the heavens and take a 30-second exposure of an area larger than 40 full moons. It will then swivel to a new patch and snap another photo, rounding back to the same swath of sky after about three nights. In this way, it can provide a constantly updated view of the universe, essentially creating “this huge video of the southern sky for 10 years,” explains Anais Möller, an astrophysicist at the Swinburne University of Technology in Melbourne, Australia.

a man in a clean room suit shines a light at a device that spans the room.
A view of the back of the Rubin Observatory’s massive LSST camera, which boasts six filters designed to capture light from different parts of the electromagnetic spectrum.
SPENCER LOWELL
diagram of light hitting an exploded view of mirrors and lenses
1) Secondary mirror (M2); 2) Lenses; 3) Primary Mirror (M1); 4) Tertiary mirror (M3)
GREG STEWART/SLAC NATIONAL ACCELERATOR LABORATORY/NSF/DOE/RUBIN OBSERVATORY/AURA

To accomplish its work, Rubin relies on an innovative three-mirror design unlike that of any other telescope. Its primary mirror is actually made up of two separate surfaces with different curvatures. The outer section, 8.4 meters wide, captures light from the universe and reflects it onto a 3.4-meter-wide secondary mirror located above it. This bounces the light back onto the inner part of the primary, which stretches five meters across and is considered a tertiary mirror, before being reflected into a digital camera. The compact configuration allows the enormous instrument to be powerful but nimble as it shifts around to take roughly 1,000 photos per night. 

“It has five seconds to go to the next position and be ready,” says Sandrine Thomas, the deputy director for the observatory’s construction and project scientist for the telescope. “Meaning that it doesn’t move. It doesn’t vibrate. It’s just rock solid, ready to take the next image.” 

Technicians reinstall a cover on the secondary telescope mirror, to protect it before installation.
The observatory’s three mirrors and the housing of the LSST camera are mounted on a structure called the Telescope Mount Assembly. The assembly has been carefully engineered for stability and precision, allowing the observatory to track celestial objects and carry out its large-scale survey of the sky.
The primary and tertiary telescope mirrors are positioned below a chamber at the Rubin Observatory that is used to apply reflective coatings.
A view of the Telescope Mount Assembly from above, through the observatory’s protective dome shutter.

Rubin’s 3,000-kilogram camera is the most sensitive ever created for an astronomical project. By stacking together images of a piece of sky taken over multiple nights, the telescope will be able to spot fainter and fainter objects, peering deeper into the cosmos the longer it operates. 

Each exposure creates a flood of data, which has to be piped via fiber-optic cables to processing centers around the world. These use machine learning to filter the information and generate alerts for interested groups, says Möller, who helps run what are known as community brokers, groups that design software to ingest the nightly terabytes of data and search for interesting phenomena. A small change in the sky—of which Rubin is expected to see around 10 million per night—could point to a supernova explosion, a pair of merging stars, or a massive object passing in front of another. Different teams will want to know which is which so they can aim other telescopes at particular regions for follow-up studies. 

The focal plane of the LSST has a surface area large enough to capture a portion of the sky about the size of 40 full Moons. Its resolution is so high that you could spot a golf ball from 24 km (15 miles) away.

clusters of galaxies
Matter in the universe can warp and magnify the light from more distant objects. The Rubin Observatory will use this phenomenon, called gravitational lensing, to study dark matter— an as-yet-unidentified substance that makes up most of the universe’s matter.
ESA, NASA, K. SHARON/TEL AVIV UNIVERSITY AND E. OFEK/CALTECH

With its capacity to detect faint objects, Rubin is expected to increase the number of known asteroids and comets by a factor of 10 to 100. Many of them will be objects more than 140 meters in diameter with orbits passing near Earth’s, meaning they could threaten our world. And it will catalogue 40,000 new small icy bodies in the Kuiper Belt, a largely unexplored region beyond Neptune where many comets are born, helping scientists better understand the structure and history of our solar system. 

“We have never had such a big telescope imaging so wide and so deep.”

Anais Möller, astrophysicist, Swinburne University of Technology, Melbourne, Australia

Beyond our solar system, Rubin will see telltale flickers that signal exoplanets passing in front of their parent stars, causing them to briefly dim. It should also find thousands of new brown dwarfs, faint objects between planets and stars in size, whose positions in the Milky Way can provide insight into how the environments in which stars are born affect the size and type of objects that can form there. It will discover never-before-seen dim dwarf galaxies orbiting our own and look closely at stellar streams, remnant trails of stars left behind when the Milky Way tore other, similar galaxies apart.

The facility will also look far outside the Milky Way, cataloguing around 20 billion previously unknown galaxies and mapping their placement in long filamentary structures known as the cosmic web. The gravitational pull of dark matter directly affects the overall shape of this web, and by examining its structure, cosmologists will glean evidence for different theories of what dark matter is. Rubin is expected to observe millions of supernovas and determine their distance from us, a way of measuring how fast the universe is expanding. Some researchers suspect that dark energy—which is causing the cosmos to expand at an accelerated rate—may have been stronger in the past. Data from more distant, and therefore older, supernovas could help bolster or disprove such ideas and potentially narrow down the identity of dark energy too.  

An overhead view of the observatory.
SPENCER LOWELL

In just about every way, Rubin will be a monumental project, explaining the near-universal eagerness for those in the field to see it finally begin operations. 

“We have never had such a big telescope imaging so wide and so deep,” says Möller. “That’s an incredible opportunity to really pinpoint things that are changing in the sky and understand their physics.”  

Adam Mann is a freelance space and physics journalist who lives in Oakland, California.

The world’s next big environmental problem could come from space

Early on a Sunday morning in September, a team of 12 sleep-deprived, jet-lagged researchers assembled at the world’s most remote airport. There, on Easter Island, some 2,330 miles off the coast of Chile, they were preparing for a unique chase: a race to catch a satellite’s last moments as it fell out of space and blazed into ash across the sky.

That spacecraft was Salsa, one of four satellites that were part of the European Space Agency (ESA) Cluster constellation. Salsa and its counterparts had been studying Earth’s magnetic field since the early 2000s, but its mission was now over. Months earlier, the spacecraft had been set on a spiral of death that would end with a fiery disintegration high up in Earth’s atmosphere about a thousand miles away from Easter Island’s coast.

Now, the scientists were poised to catch this reentry as it happened. Equipped with precise trajectory calculations from ESA’s ground control, the researchers took off in a rented business jet, with 25 cameras and spectrometers mounted by the windows. The hope was that they’d be able to gather priceless insights into the physical and chemical processes that occur when satellites burn up as they fall to Earth at the end of their missions.

Researchers were able to monitor the reentry of Cluster Salsa from a rented business jet.

This kind of study is growing more urgent. Some 15 years ago, barely a thousand satellites orbited our planet. Now the number has risen to about 10,000, and with the rise of satellite constellations like Starlink, another tenfold increase is forecast by the end of this decade. Letting these satellites burn up in the atmosphere at the end of their lives helps keep the quantity of space junk to a minimum. But doing so deposits satellite ash in the middle layers of Earth’s atmosphere. This metallic ash can harm the atmosphere and potentially alter the climate. Scientists don’t yet know how serious the problem is likely to be in the coming decades.

The ash from the reentries contains ozone-damaging substances. Modeling studies have shown that some of its components can also cool down Earth’s stratosphere, while others can warm it. Some worry that the metallic particles could even disrupt Earth’s magnetic field, obscure the view of Earth-observing satellites, and increase the frequency of thunderstorms.

“We need to see what kind of physics takes place up there,” says Stijn Lemmens, a senior analyst at ESA who oversaw the campaign. “If there are more [reentering] objects, there will be more consequences.”

A community of atmospheric scientists scattered all over the world is awaiting results from these measurements, hoping to fill major gaps in their understanding. 

The Salsa reentry was only the fifth such observation campaign in the history of spaceflight. The previous campaigns, however, tracked much larger objects, like a 19-ton upper stage from an Ariane 5 rocket.  

Cluster Salsa, at 550 kilograms, was quite tiny in comparison. And that makes it of special interest to scientists, because it’s spacecraft of this general size that will be increasingly crowding Earth orbit in the coming years.

The downside of mega-constellations

Most of the forecasted growth in satellite numbers is expected to come from satellites roughly the same size as Salsa: individual members of mega-constellations, designed to provide internet service with decent speed and latency to anyone, anywhere.

SpaceX’s Starlink is the biggest of these. Currently consisting of about 6,500 satellites, the fleet is expected to mushroom to more than 40,000 at some point in the 2030s. Other mega-constellations, including Amazon Kuiper, France-based E-Space, and the Chinese projects G60 and Guowang, are in the works. Each could encompass several thousand satellites, or even tens of thousands. 

Mega-constellation developers don’t want their spacecraft to fly for two or three decades like their old-school, government-funded counterparts. They want to replace these orbiting internet routers with newer, better tech every five years, sending the old ones back into the atmosphere to burn up. The rockets needed to launch all those satellites emit their own cocktail of contaminants (and their upper stages also end their life burning up in the atmosphere).

The amount of space debris vaporizing in Earth’s atmosphere has more than doubled in the past few years, says Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who has built a second career as a leading space debris tracker..

“We used to see about 50 to 100 rocket stages reentering every year,” he says. “Now we’re looking at 300 a year.” 

In 2019, some 115 satellites burned up in the atmosphere. As of late November, 2024 had already set a new record with 950 satellite reentries, McDowell says.

The mass of vaporizing space junk will continue to grow in line with the size of the satellite fleets. By 2033, it could reach 4,000 tons per year, according to estimates presented at a workshop called Protecting Earth and Outer Space from the Disposal of Spacecraft and Debris, held in September at the University of Southampton in the UK.

Crucially, most of the ash these reentries produce will remain suspended in the thin midatmospheric air for decades, perhaps centuries. But acquiring precise data about satellite burn-up is nearly impossible, because it takes place in territory that is too high for meteorological balloons to measure and too low for sounding instruments aboard orbiting satellites. The closest scientists can get is remote sensing of a satellite’s final moments.

Changing chemistry

None of the researchers aboard the business jet turned scientific laboratory that took off from Easter Island in September got to see the moment when Cluster Salsa burst into a fireball above the deep, dark waters of the Pacific Ocean. Against the bright daylight, the fleeting explosion appeared about as vivid as a midday full moon. The windows of the plane, however, were covered with dark fabric (to prevent light reflected from inside to skew the measurements), allowing only the camera lenses to peek out, says Jiří Šilha, CEO of Slovakia-based Astros Solutions, a space situational awareness company developing new techniques for space debris monitoring, which coordinated the observation campaign.

“We were about 300 kilometers [186 miles] away when it happened, far enough to avoid being hit by any remaining debris,” Šilha says. “It’s all very quick. The object reenters at a very high velocity, some 11 kilometers [seven miles] per second, and disintegrates 80 to 60 kilometers above Earth.”

nfographic that describes the reentry of the first of four Cluster satellites

ESA

The instruments collected measurements of the disintegration in the visible and near-infrared part of the light spectrum, including observations with special filters for detecting chemical elements including aluminum, titanium, and sodium. The data will help scientists reconstruct the satellite breakup process, working out the altitudes at which the incineration takes place, the temperatures at which it occurs, and the nature and quantity of the chemical compounds it releases.

The dusty leftovers of Cluster Salsa have by now begun their leisurely drift through the mesosphere and stratosphere—the atmospheric layers stretching at altitudes from 31 to 53 miles and 12 to 31 miles, respectively. Throughout their decades-long descent, these ash particles will interact with atmospheric gases, causing mischief, says Connor Barker, a researcher in atmospheric chemical modeling at University College London and author of a satellite air pollution inventory published in early October in the journal Scientific Data

Satellite bodies and rocket stages are mostly made of aluminum, which burns into aluminum oxide, or alumina—a white, powdery substance known to contribute to ozone depletion. Alumina also reflects sunlight, which means it could alter the temperature of those higher atmospheric layers.

“In our simulations, we start to see a warming over time of the upper layers of the atmosphere that has several knock-on effects for atmospheric composition,” Barker says. 

For example, some models suggest the warming could add moisture to the stratosphere. This could deplete the ozone layer and could cause further warming, which in turn would cause additional ozone depletion.

The extreme speeds of reentering satellites also produces “a shockwave that compresses nitrogen in the atmosphere and makes it react with oxygen, producing nitrogen oxides,” says McDowell. Nitrogen oxides, too, damage atmospheric ozone. Currently, 50% of the ozone depletion caused by satellite burn-ups and rocket launches comes from the effects of nitrogen oxides. The soot that rockets produce alters the atmosphere’s thermal balance too.

In some ways, high-altitude atmospheric pollution is nothing new. Every year, about 18,000 tons of meteorites vaporize in the mesosphere. Even 10 years from now, if all planned mega-constellations get developed, the quantity of natural space rock burning up during its fall to Earth will exceed the amount of incinerated space junk by a factor of five.

That, however, is no comfort to researchers like McDowell and Barker. Meteorites contain only trace amounts of aluminum, and their atmospheric disintegration is faster, meaning they produce less nitrogen oxide, says Barker. 

“The amount of nitrogen oxides we’re getting [from satellite reentries and rocket launches] is already at the lower end of our yearly estimates of what the natural emissions of nitrogen oxides [from meteorites] are,” said Barker. “It’s certainly a concern, because we might soon be doing more to the atmosphere than naturally occurs.”

The annual amount of alumina from satellite reentries is also already approaching that arising from incinerated meteorites. Under current worse-case scenarios, the human-made contribution of this pollutant will be 10 times the amount from natural sources by 2040.

Impact on Earth?

What exactly does all this mean for life on Earth? At this stage, nobody’s certain. Studies focusing on various components of the air pollution cocktail from satellite and rocket activity are trickling in at a steady rate. 

Barker says computer modeling puts the current contribution of the space industry to overall ozone depletion at a minuscule 0.1%. But how much this share will grow 10, 20, or 50 years from now, nobody knows. There are way too many uncertainties in this equation, including the size of the particles—which will affect how long they will take to sink—and the ratio of particles to gaseous by-products.

“We have to make a decision, as a society, whether we prioritize reducing space traffic or reducing emissions,” Barker says. “A lot of these increased reentry rates are because the global community is doing a really good job of cleaning up low-Earth-orbit space debris. But we really need to understand the environmental impact of those emissions so we can decide what is the best way for humanity to deal with all these objects in space.”

A ground antenna captured radar data of some of the final moments of the ESA satellite Aeolus, as it reentered Earth’s atmosphere in July 2023.
FRAUNHOFER FHR

The disaster of 21st-century climate change was set in motion when humankind began burning fossil fuels in the mid-19th century. Similarly, it took 40 years for chlorofluorocarbons to eat a hole in Earth’s protective ozone layer. The contamination of Earth by so-called forever chemicals—per-and polyfluoroalkyl substances used in manufacturing nonstick coatings and firefighting foams—started in the 1950s. Researchers like McDowell are concerned the story may repeat yet again.

“Humanity’s activities in space have now gotten big enough that they are affecting the space environment in a similar way we have affected the oceans,” McDowell says. “The problem is that we’re making these changes without really understanding at what stage these changes will become concerning.”

Previous observation campaigns mostly analyzed the physical disintegration of reentering satellites. With the Cluster constellation, scientists hope to begin unraveling the chemical side of this elusive process. For researchers like Barker, that means finally getting data that could validate and further improve their models. The Cluster constellation will provide three more opportunities to fill the blanks in this environmental puzzle when the siblings of Salsa reenter in 2025 and 2026. 

“The great thing with Cluster is that we have four satellites that are identical and that we know every detail about,” says Šilha. “It’s a scientist’s dream, because we can repeat the experiment and learn from every previous campaign.”

What’s next for NASA’s giant moon rocket?

MIT Technology Review’s What’s Next series looks across industries, trends, and technologies to give you a first look at the future. You can read the rest of them here.

NASA’s huge lunar rocket, the Space Launch System (SLS), might be in trouble. As rival launchers like SpaceX’s Starship gather pace, some are questioning the need for the US national space agency to have its own mega rocket at all—something that could become a focus of the incoming Trump administration, in which SpaceX CEO Elon Musk is set to play a key role.

“It’s absolutely in Elon Musk’s interest to convince the government to cancel SLS,” says Laura Forczyk from the US space consulting firm Astralytical. “However, it’s not up to him.”

SLS has been in development for more than a decade. The rocket is huge, 322 feet (98 meters) tall, and about 15% more powerful than the Saturn V rocket that took the Apollo astronauts to the moon in the 1960s and 70s. It is also expensive, costing an estimated $4.1 billion per launch.

It was designed with a clear purpose—returning astronauts to the moon’s surface. Built to launch NASA’s human-carrying Orion spacecraft, the rocket is a key part of the agency’s Artemis program to go back to the Moon, started by the previous Trump administration in 2019. “It has an important role to play,” says Daniel Dumbacher, formerly a deputy associate administrator at NASA and part of the team that selected SLS for development in 2010. “The logic for SLS still holds up.”

The rocket has launched once already on the Artemis I mission in 2022, a test flight that saw an uncrewed Orion spacecraft sent around the moon. Its next flight, Artemis II, earmarked for September 2025, will be the same flight but with a four-person crew, before the first lunar landing, Artemis III, currently set for September 2026.

SLS could launch missions to other destinations too. At one stage NASA intended to launch its Europa Clipper spacecraft to Jupiter’s moon Europa using SLS, but cost and delays saw the mission launch instead on a SpaceX Falcon Heavy rocket in October this year. It has also been touted to launch parts of NASA’s new lunar space station, Gateway, beginning in 2028. The station is currently in development.

NASA’s plan to return to the moon involves using SLS to launch astronauts to lunar orbit on Orion, where they will rendezvous with a separate lander to descend to the surface. At the moment that lander will be SpaceX’s Starship vehicle, a huge reusable shuttle intended to launch and land multiple times. Musk wants this rocket to one day take humans to Mars.

Starship is currently undergoing testing. Last month, it completed a stunning flight in which the lower half of the rocket, the Super Heavy booster, was caught by SpaceX’s “chopstick” launch tower in Boca Chica, Texas. The rocket is ultimately more powerful than SLS and designed to be entirely reusable, whereas NASA’s rocket is discarded into the ocean after each launch.

The success of Starship and the development of other large commercial rockets, such as the Jeff Bezos-owned firm Blue Origin’s New Glenn rocket, has raised questions about the need for SLS. In October, billionaire Michael Bloomberg called the rocket a “colossal waste of taxpayer money”. In November, journalist Eric Berger said there was at least a 50-50 chance the rocket would be canceled.

“I think it would be the right call,” says Abhishek Tripathi, a former mission director at SpaceX now at the University of California, Berkeley. “It’s hard to point to SLS as being necessary.”

The calculations are not straightforward, however. Dumbacher notes that while SpaceX is making “great progress” on Starship, there is much yet to do. The rocket will need to launch possibly up to 18 times to transfer fuel to a single lunar Starship in Earth orbit that can then make the journey to the moon. The first test of this fuel transfer is expected next year.

SLS, conversely, can send Orion to the moon in a single launch. That means the case for SLS is only diminished “if the price of 18 Starship launches is less than an SLS launch”, says Dumbacher. SpaceX was awarded $2.9 billion by NASA in 2021 for the first Starship mission to the moon on Artemis III, but the exact cost per launch is unknown.

The Artemis II Core Stage moves from final assembly to the VAB at NASA’s Michoud Assembly Facility in New Orleans, July, 6, 2024.

MICHAEL DEMOCKER/NASA

NASA is also already developing hardware for future SLS launches. “All elements for the second SLS for Artemis II have been delivered,” a NASA spokesperson said in response to emailed questions, adding that SLS also has “hardware in production” for Artemis III, IV, and V.

“SLS can deliver more payload to the moon, in a single launch, than any other rocket,” NASA said. “The rocket is needed and designed to meet the agency’s lunar transportation requirements.”

Dumbacher points out that if the US wants to return to the moon before China sends humans there, which the nation has said it would do by 2030, canceling SLS could be a setback. “Now is not the time to have a major relook at what’s the best rocket,” he says. “Every minute we delay, we are setting ourselves up for a situation where China will be putting people on the moon first.”

President-elect Donald Trump has given Musk a role in his incoming administration to slash public spending as part of the newly established Department of Government Efficiency. While the exact remit of this initiative is not yet clear, projects like SLS could be up for scrutiny.

Canceling SLS would require support from Congress, however, where Republicans will have only a slim majority. “SLS has been bipartisan and very popular,” says Forczyk, meaning it might be difficult to take any immediate action. “Money given to SLS is a benefit to taxpayers and voters in key congressional districts [where development of the rocket takes place],” says Forczyk. “We do not know how much influence Elon Musk will have.”

It seems likely the rocket will at least launch Artemis II next September, but beyond that there is more uncertainty. “The most logical course of action in my mind is to cancel SLS after Artemis III,” says Forczyk.

Such a scenario could have a broad impact on NASA that reaches beyond just SLS. Scrapping the rocket could bring up wider discussions about NASA’s overall budget, currently set at $25.4 billion, the highest-funded space agency in the world. That money is used for a variety of science including astrophysics, astronomy, climate studies, and the exploration of the solar system.

“If you cancel SLS, you’re also canceling the broad support for NASA’s budget at its current level,” says Tripathi. “Once that budget gets slashed, it’s hard to imagine it’ll ever grow back to present levels. Be careful what you wish for.”