April 20, 2021

Privately-funded mission takes off to begin space debris cleanup trials


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The ELSA-d mission’s servicer and chaser satellites (bottom and top) during ground testing last year. Credit: Astroscale

A commercial mission developed by the Japanese company Astroscale rocketed into space on a Russian Soyuz launcher Monday with 37 other payloads, ready to kick off an orbital “dance” with two small spacecraft demonstrating how satellite sweepers might one day drag junk out of orbit.

The privately-funded mission is a pathfinder for future satellites that could roam busy orbital traffic lanes to link up with old pieces of space junk and drive them back into Earth’s atmosphere.

The End-of-Life Services by Astroscale demonstration mission, known as ELSA-d, will use two small satellites launched in tandem to perform a series of trials in low Earth orbit around 340 miles (550 kilometers) above the planet.

The ELSA-d satellites launched into orbit aboard a Russian Soyuz booster Monday at 2:07:12 a.m. EDT (0607:12 GMT) from the Baikonur Cosmodrome in Kazakhstan.

Sporting an unusual white and blue paint scheme to mark the upcoming 60th anniversary of the first human spaceflight mission, the Soyuz-2.1a rocket deployed a Fregat upper stage in space, which fired its engine several times over four hours to inject 38 small and medium-size international satellites into three different orbits.

The biggest payload on-board Monday’s launch was the South Korean CAS500 1 Earth observation satellite. Four commercial Earth-imaging satellites from the Japanese company Axelspace and dozens of smaller commercial and research missions also launched Monday.

Read our preview story for details on all the satellites on Monday’s commercial mission, which was managed by GK Launch Services, a division of the government-owned Russian space company Glavkosmos.

Astroscale’s ELSA-d mission was one of the larger satellites on the mission, and it was one of the last payloads deployed from the Fregat upper stage. Tokyo-based Astroscale confirmed the ELSA-d spacecraft was healthy and unfurled its power-generating solar panels after separation from the Fregat in orbit.

“Great start!” tweeted Nobu Okada, founder and CEO of Astroscale.

A Soyuz-2.1a rocket lofted the Astroscale ELSA-d mission and 37 other small satellites Monday. Credit: GK Launch Services

The larger of the two ELSA-d satellites, designated the “Servicer” spacecraft, launched connected with a “Client” satellite. The two spacecraft will separate from each other before commencing their experiments.

Using on-board navigation aids, the two satellites will dock and undock several times over the course of the six-month demonstration mission, simulating an approach to a stable piece of space junk and then practicing for a docking with a tumbling object in orbit. The satellites will use magnets to connect with each other in space.

ELSA-d is the first commercial mission to demonstrate technologies to remove space junk from orbit. The satellites have a combined mass of about 423 pounds, or 192 kilograms. The Servicer was built by Astroscale in Japan and the Client was manufactured by Surrey Satellite Technology Ltd. in the United Kingdom.

“This mission is really going to be the first demonstration mission that demonstrates capabilities of removal from end-to-end, from the capture, detumble, to the lowering of the orbit of the client, so it’s pretty monumental for us. We’re very excited,” said Mike Lindsay, Astroscale’s chief technology officer.

Astroscale employees in Hartwell, England, will oversee ELSA-d’s operations after launch. The UK Space Agency licensed the first-of-its-kind mission.

Founded in 2013, Astroscale has nearly 200 employees distributed in offices in Japan, the United Kingdom, the United States, Israel, and Singapore. The company has raised $191 million in capital to help jump-start its operations.

ELSA-d’s Servicer satellite has all the smarts to perform the complex navigation, rendezvous, and docking maneuvers required to link up with the Client. The smaller Client spacecraft, standing in for an old satellite or rocket body needing help getting out of orbit, has a ferromagnetic plate that serves as a docking target for the Servicer. It’s painted with a pattern of shapes to help the Servicer determine its range and motion relative to the Client.

“The servicer has all the remote sensing capabilities to assess the tumble rate, the condition of the client, the attitude control and the orbit control to do the rate matching and docking maneuvers,” Lindsay said earlier this month in a presentation at the LRA Institute’s Space Disposal and Debris Mitigation Conference.

“The Servicer will be using a magnetic capture device,” Lindsay said. “We like this idea because we can simplify the robotic interface … We have a magnetic interface there, so it tolerates a lot of additional error, translation error, and rotation and angular. So it’s a really robust capture system, which is really key for when you’re trying to dock with a client that is not necessarily controlling its own attitude.”

Demonstrating the Servicer can dock with a tumbling spacecraft is a critical part of the ELSA-d mission. With few exceptions, all of the failed satellites and spent rocket stages in orbit were never designed to be serviced or receive a visiting spacecraft. They have no docking ports, and most are uncontrolled, drifting and tumbling as they circle the planet hundreds to thousands of miles up.

This infographic illustrates the problem of space debris in orbit. Credit: ESA / UNOOSA

As of December, the European Space Agency said there were about 26,000 objects in orbit regularly tracked and catalogued by space surveillance networks. About 90% of those objects were no longer functioning, according to ESA.

Astroscale’s ground team will shepherd the ELSA-d mission through progressively more complex maneuvers later this year.

“The first demonstration is we separate the Client, we hold the Client steady, and we just demonstrate a cooperative docking maneuver,” Lindsay said. “It should be relatively straightforward.”

“The next demonstration is we release the client, and the Client goes into a simulated natural tumbling motion. This is not really known by the Servicer. So the servicer will start its mission by assessing the tumble rates of the client,” Lindsay said. “It uses the fiducial pattern on the docking plate to aid the determination of rates, and it uses that pattern again to help guide the docking. So the Servicer will do this rate matching.”

When it comes to space debris removal, this is where the rubber hits the road. Engineers designing a removal mission are unlikely to know the state of the piece of space junk until the satellite gets close.

“We call this the dance, where it matches the tumble rate, finds the docking plate, and then docks with it and stabilizes the Client,” Lindsay said.

“And the final demonstration is we will release the client and separate enough to essentially lose the client from the Servicer’s standpoint,” Lindsay said. “We, of course, know where the client is on the ground, and it’s well within the instrument capabilities on the Servicer.

The servicing spacecraft will locate its companion and close in for docking.

“It’s critical to demonstrate because of the population of debris objects that are on-orbit,” said Clare Martin, Astroscale’s executive vice president of programs and operations. “A lot of those are rocket bodies. They are tumbling objects and they’re not going to be able to control their attitude as we try to approach and dock with them.”

“Once you have that relative motion zeroed out between Servicer and Client, then things get a lot easier,” Lindsay said. “You can better assess the condition of the client. You’re looking at a steady point for docking, and any sort of contact that is made, you’re minimizing the shocks, potential torques, to the combined system.

“Once we have those rates zeroed out, the magnetic approach is a single degree of freedom,” Lindsay said. “We don’t need to have a multi-degree of freedom robotic arm to carry out this mission. So ELSA-d is kind of simplifying the docking as much as possible, but maturing the dance operations, which is going to be key for all future missions.”

With ELSA-d’s third and final docking complete, Lindsay said spacecraft will go into a “passive decay orbit” to allow atmospheric drag to pull it back into Earth’s atmosphere, well within 25 years, the guideline for space missions to ensure they don’t become a source of new space junk.

Lindsay said the ever-increasing rate of launches, putting up thousands of satellites in mega-constellations like SpaceX’s Starlink, OneWeb, and other planned broadband internet networks, is forcing the entire space industry to look at the space debris problem.

“The utilization of space, the assets that are being put in orbit, is increasing at exponential rates,” Lindsay said. “Where are the remediation technologies — the investment there? Where is the policy to support sustainability? It’s trailing, so what can we do about that?”

There’s better space situational awareness, getting a better picture of what the risks are and better assess the situation,” he said. “Only when you understand the situation can you fix and understand how the factors play against each other, can you really start to think about remediation, and how do we solve the problem going forward.

“Active debris removal has to be a major part of the equation,” Lindsay said. “Large debris objects pose a risk by themselves, but then if they become smaller pieces, it becomes even more of a risk.”

More launch companies are setting aside fuel in their rockets to deorbit spent upper stages once they deploy their payloads. SpaceX plans to drop its Starlink satellites out of orbit at the end of their lives, and OneWeb is placing a ferromagnetic plate similar to the one on the ELSA-d mission on all of its internet satellites, setting them up for future debris removal missions.

“We really need to be planning our satellites for end-of-life scenarios, planning ahead of time to prepare your satellite such that it can be captured or having a backup plan,” Lindsay said. He said it’s important to ensure “that deorbit can be achieved in both nominal and off-nominal cases if there’s a failure. Getting it out of orbit quickly is important.”

“The removal of hazardous space debris is not only environmentally important but is also a huge commercial opportunity for the UK, with companies like Astroscale leading the way in demonstrating how we can make space safer for everyone,” said Amanda Solloway, the UK’s science minister.

“I am proud the UK Government not only helped make this mission a reality but is Europe’s largest investor in helping with space clean-up,” Solloway said in a statement. “As we build back better, we will continue to drive growth by investing in the technologies that have made today’s breakthrough possible.”

This infographic illustrates the series of in-orbit demonstrations planned on the ELSA-d mission. Credit: Astroscale

The ELSA-d mission’s technology trials will try to make space debris removal closer to reality, but there are other hurdles for company’s like Astroscale that want to make money doing it.

“The problem is three-fold, and we work on all aspects of that,” Martin said. “The technology is one aspect. It is something that we all enjoy doing. But we focus also on policy and regulation.”

She said Astroscale is working with governments and industry “to both educate and support the establishment of responsible policy to encourage sustainable space.”

“The third aspect is of course business case,” Martin said.

The U.S. Space Force’s vice chief of space operations said earlier this month that the military would be interested in buying debris removal services if they were commercially available.

“We’re actively engaging with the Space Force in order to educate them on our capabilities and services, and the fact that we’re a fully established U.S. company,” Martin said, referring to Astroscale’s Colorado-based business unit focused on the U.S. market.

“Everybody is probably more reliant on space than they ever realized,” Martin said. “People are now much more aware that space isn’t just the purview of the elite. It’s actually something that is relied upon in everyday life. And therefore … taking the responsible steps to make sure that it’s a resource that’s available for a very long time to come is absolutely vital for us.”

Getting international policymakers and entrenched industrial interests to buy in on debris removal is “obviously a big challenge,” Lindsay said.

“Everyone can see the long-term issue but not everyone wants to invest in the short-term solution,” he said. “We need to inform the policies in order to support our activities. We need to be able to license the type of activities that we wish to do, and a lot of this is kind of new and unfamiliar to certain license processes. So we have to kind of work with various entities to kind of pioneer some of the solutions.”

Lindsay said decision-makers are starting to recognize the space debris problem, and introducing designs to allow satellites to be robotically serviced after launch. Lockheed Martin said earlier this year said it was looking at upgrading future GPS satellites for servicing in orbit.

“The notion of launching something that could potentially be serviced is something that’s really starting to take hold,” Lindsay said. “No longer are you sending something up into space that will never be touched again. This is a good thing toward sustainability if we start designing more satellites and launching our satellites with this in mind, thinking long term, across all orbits.”

The ferromagnetic docking plate flown on OneWeb satellites, and on the ELSA-d Client spacecraft, is as simple as it comes, Lindsay said.

“It’s completely passive on the client side, low mass, low profile, it has three bolts on it,” he said. “You just put it on there and now you have a backup plan.”

Artist’s illustration of the ELSA-d servicer and chaser satellites. Credit: Astroscale

Astroscale’s ELSA-d mission follows a pioneering mission named RemoveDebris, which launched from the International Space Station in 2018 and demonstrated the use of a net and a harpoon to capture simulated space junk. Astroscale will take the next step in debris removal experiments with an attempt to dock with a tumbling satellite in orbit.

Another small Astroscale satellite is scheduled for launch in late 2022 to survey a disused Japanese rocket upper stage in low Earth orbit, collecting information on the rocket’s condition before a future mission might go capture it and drag it back into the atmosphere to burn up. That mission is a public-private partnership with Japan’s space agency.

The rocket stage survey mission will validate technologies to inspect space junk before attempting to move in for docking.

Astroscale is also planning a mission that could launch as soon as 2023 to extend the life of a customer satellite in geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) over the equator. The life extension mission is similar to the Mission Extension Vehicle developed by Northrop Grumman.

The first MEV mission accomplished the first docking between two commercial satellites in 2020, when it linked up with an aging Intelsat communications satellite and took over propulsion duties. The docking allowed Intelsat to keep operating the satellite even though it was about to run out of fuel.

Other companies, such as ClearSpace in Switzerland, are also pursuing the debris removal market. ClearSpace won a European Space Agency contract last year to develop a demonstration mission for launch in 2025 to remove an old Vega rocket adapter from orbit.

“Within 10 years, on-orbit servicing, including debris removal will become a routine work in space to make sure space is sustainable and safe,” Okada said.

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Follow Stephen Clark on Twitter: @StephenClark1.


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