Is In-Space Maneuvering Tech on the Cusp of a Breakthrough?

In the next half-century, a plethora of tech sectors currently stationed here on Earth are poised to move up to space, and the U.S. government and its commercial partners want to be at the forefront. From pharmaceutical development in microgravity to the manufacture of new minerals, to space tourism, to military superiority, the promise of – and investment in – space technologies has never been higher.

For all of this to become reality, satellite operators must be able to service and refuel their spacecraft in orbit. For decades, this sounded like sci-fi, but several U.S. government efforts could successfully demonstrate these capabilities in the next five years.

In 2022, the White House released a report named the “In-Space Servicing, Assembly, and Manufacturing National Strategy,” which laid out key strategies and goals to support commercial activities for satellite servicing and life extension. Those goals include establishing and adopting standards to promote growth in the field, and improving collaboration among the United States government among its own agencies, and its international partners.

In the two years since the report’s release, the Defense Department and NASA have prepared a slew of programs meant to test out various elements of sustainable in-space maneuvering, with the priority placed on autonomous refueling of satellites. Stakeholders say the outcome of these programs will have significant implications for national security operations in space, as well as the development of new economies among the stars.

The Space Force in particular is focusing heavily on in-space refueling capabilities, with a goal of fielding successful technologies within the next five years. There have been a number of significant developments in recent months.

In January, the service’s Space Systems Command announced it selected Northrop Grumman’s passive refueling module (PRM) as its first “preferred” refueling interface standard, meaning it is approved for use on any future satellites looking to be refueled. Service officials have noted that other companies’ interfaces are also under review for approval as a preferred interface standard.

Northrop Grumman began development on the PRM in 2021. As of this article’s writing, it will be integrated on the Mission Robotic Vehicle (MRV), a new spacecraft built for on-orbit servicing missions expected to launch in 2025, developed in partnership with the Defense Advanced Research Projects Agency (DARPA) and Northrop Grumman’s subsidiary SpaceLogistics. It is also contracted to fly on a currently undisclosed operational Space Force mission in the 2025 timeframe, per the company.

Proving out the concept of in-space refueling will provide space with a key strategic capability that other military domains have enjoyed for ages – maneuverability.

But it’s also a “wickedly hard mission,” says Lauren Smith, program manager for In-Space Refueling at Northrop Grumman.

“Imagine if you had an aircraft that consumed all of its fuel, and you had no means of refueling it,” says Smith. “You would throw it away, and it would also make you think really differently about how you fly that aircraft, if you knew that your fuel was a finite resource. You might not want to deviate from your plans. You might be concerned about expending fuel to do something unexpected, because you're really trying to conserve that fuel.

“This might sound like a silly thought experiment, but it's a fairly accurate picture of how we currently operate our satellites in space today,” she continues.

Refueling in space requires an “orchestrated dance” of sophisticated rendezvous and docking capabilities, fuel transfer, and a smart mission design, adds Smith. “If this doesn't go right, you risk generating space debris and potentially damaging that valuable asset, that client vehicle that you were intending to refuel.”

Previous missions focused on in-space refueling have either been experimental or demonstrative, says Dallas Kasaboski, a principal analyst with NSR, an Analysys Mason company, citing examples such as the recently launched ADRAS-J active debris removal mission by Astroscale, which was developed in partnership with the Japanese Aerospace Exploration Agency (JAXA).

In recent years, commercial companies have worked to overcome the technical challenges for on-orbit maneuvering, supported through increased investment, Kasaboski says.

“In the past, this was a barely-considered notion, but the dramatic increase in satellites launched, and expected to be launched, as part of satellite constellations, has raised concern,” he adds.

Last year, the Space Force awarded Astroscale US a new contract worth $25.5 million to design and deliver a refueling satellite. The Astroscale Prototype Servicer for Refueling (APS-R) is envisioned as a “launch-ready” spacecraft about the size of a gas pump, that can carry and provide hydrazine fuel to the client satellite without any interruption to operations. It’s scheduled to be delivered in 2026. Astroscale US has committed $12 million in private funding to APS-R, and is working with the Southwest Research Institute to design the satellite bus, and with Orbit Fab to provide the refueling interfaces.

Astroscale US first began exploring refueling technology to support its own vision of providing a number of missions in orbit, from life extension of satellites, inspection, on-orbit assembly, and debris removal, says Jack Deasy, vice president of business development and advanced systems, Astroscale.

The subsidiary of Japan-based Astroscale is currently building an initial life extension vehicle for Geostationary (GEO) satellites, designed to perform services including station holding and attitude control via robotic servicing arms, along with inclination correction and orbit relocation. Via the Life Extension In-Orbit (LEXI) servicer program, Astroscale US developed technologies that then became relevant to APS-R, like advanced rendezvous and docking capabilities, he notes.

While the business case for LEXI closes without a refueling capability, “it's much more interesting if we can do even more missions with the single servicer,” Deasy adds.

Meanwhile, the Air Force Research Laboratory and the Space Force are leading the Tetra-5 experiment, which aims to demonstrate hydrazine refueling in Geostationary Orbit (GEO) in the 2025 timeframe.

During the mission, the Tetra-5 spacecraft developed by Orion Space Systems will connect with an Orbit Fab-supplied fuel depot using the latter’s Rapid Attachable Fluid Transfer Interface (RAFTI), hosted on an Impulse Space satellite. The program, worth $44.5 million, recently completed a critical design review.

One in-space servicing demonstration – NASA’s Orbital Servicing and Manufacturing (OSAM-1) mission – was just terminated after nearly a decade of development, demonstrating that the path to in-space servicing is not easy.

On March 1, the agency announced its decision to cancel the OSAM-1 mission after a monthslong project review “due to continued technical, cost, and schedule challenges, and a broader community evolution away from refueling unprepared spacecraft.” The program began in 2015, and aimed to successfully refuel the aging Landsat 7 Earth Observation satellite, then added another mission to demonstrate robotic assembly capabilities.

NASA had contracted Maxar to deliver the OSAM-1 space vehicle, along with two robotic servicing arms and the company’s Space Infrastructure Dexterous Robot (SPIDER) payload. The goal was for OSAM-1 to demonstrate a number of firsts, by robotically and autonomously performing a rendezvous with a satellite that was not built for satellite servicing, and also refuel that satellite, Mike Fox, senior director of civil business development at Maxar Technologies said in an interview prior to NASA’s cancellation announcement.

“It really charts a path toward future missions like commercial LEO [Low-Earth Orbit] constellations, where you're going to want a large robotic arm to minimize the number of, or even avoid, extravehicular activities” that require an astronaut to service the spacecraft, he said.

An Office of the Inspector General report published last October assessed the program would exceed its current $2.05 billion cost and its scheduled 2026 launch date. It attributed the delays to Maxar, stating that the company “underestimated the scope and complexity of the work, lacked full understanding of NASA technical requirements, and were deficient in necessary expertise.”

Maxar, for its part, disputed the report’s findings in a response that same month, stating among other critiques that the OIG did not meaningfully engage with Maxar over the course of the audit, and failed to take external factors, such as the COVID-19 pandemic, into account regarding the cost and schedule overruns. Maxar declined to provide a response to the program’s cancellation in a March 5 email.

Refueling an unprepared satellite – meaning a satellite that was not made specifically to be refueled – had never been performed before, and is “already on the horizon of what is achievable in space,” notes NSR’s Kasaboski.

“To add an assembly component to the mission more than doubled the original projected cost,” he adds. “In space, complications are magnified; needing an extra part or extending a mission in the slightest results in consequences far more costly, timely, and difficult than here on Earth.”

The ‘Dynamic Space Operations’ Doctrine

The KC-135 Stratotanker aircraft, introduced in 1957, gave the US Air Force the ability to refuel jets in midair, ensuring that pilots could traverse lengthy distances with great speed and precision. It became a necessary element for any modern air campaign.

Now, as Defense Department officials cite the growing threat of “great power competition” between the U.S., China, and Russia as an incentive to invest heavily in space capabilities, leaders are betting that on-orbit refueling will provide them with the same advantage in the space domain.

Space Force leaders have been emphatic in their need to mature in-space refueling capabilities now. Over a year ago, the newest military branch established a new mission area dedicated to on-orbit capabilities, dubbed the Space Access, Mobility, and Logistics program.

Lt. Gen. John Shaw, the deputy commander of U.S. Space Command, has said in several public appearances that the service needs a refueling solution in place within five years to support missions requiring extensive maneuverability.

The command is working toward a new doctrine Shaw has described as “dynamic space operations,” which would pivot away from the traditional approach of minimizing satellite maneuvering to limit fuel expenditures.

Daniel Faber, CEO and co-founder of Orbit Fab, says the urgency from the Space Force to field in-space servicing capabilities is palpable.

“If you want to prevail in a conflicted environment, you need mobility,” he notes. “That is the history of conflict, and the Space Force gets that, and they're aggressively trying to move these timelines as fast as they can.”

To GEO, and Beyond

A recent report by Analysys Mason forecasts over $18 billion cumulative revenues to be generated from in-orbit satellite services, with life extension – including refueling – to account for one third of that amount between 2023-2033. After national security missions, the manufacturing and launch sectors are likely the next focus area, says NSR’s Kasaboski.

“Space debris mitigation would be higher on this list, if the legal structure and commercial viability here were better-defined,” he says. He calls the FCC’s 2022 ruling that satellite operators must deorbit LEO-dwelling spacecraft within five years – rather than 25 years – as a “good first step,” along with the promise of projects like the JAXA/Astroscale partnership, or the European Space Agency’s (ESA) Clearspace-1 mission.

But the framework of this new ruling remains unclear. “Will it be an enforced, integrated aspect of future satellite mission design, or an option that will only be taken up when forced to?” Kasaboski wonders.

For now, the programs focused on sustainable maneuvering in space are geared toward satellites in GEO. But once the technology is proven, industry players see opportunities for their technologies to support missions in other orbits including LEO and cislunar, as well as deep space.

The management of megaconstellations in LEO could benefit from more sustainable maneuvering in space, says Deasy, from Astroscale.

He says the company is seeing interest from the U.S. government in terms of inspection missions for LEO-based satellites, which can help operators better understand malfunctions or other on-orbit anomalies.

DARPA kicked off a new study late last year called the 10-Year Lunar Architecture Capability Study (LunA-10), intended to explore the technologies required to build an integrated, sustainable commercial lunar infrastructure.

Colorado-based CisLunar Industries is on contract for the first phase of the study, which kicked off last December and will run for seven months. The company is developing a “modular space foundry” that would repurpose space debris and inactive satellites into metal feedstock and building materials, and possibly even propellant for a future lunar ecosystem, says Gary Calnan, the company’s co-founder and CEO.

That business plan only works if the in-space refueling capabilities now being demonstrated by companies like Northrop Grumman and Astroscale are successful. “There's a lot of different pieces of the puzzle that are key to enabling this whole in-space economy,” he says.

Before the U.S. Space Force was established in 2019, senior Air Force officials were already considering a future where the military could preposition cargo bases in orbit, modeled upon SpaceX deliveries to the International Space Station. Gen. Carlton Everhart, the then-chief of the service’s Air Mobility Command, envisioned setting up such bases within the next decade.

The U.S. may not quite be sending hardware and supplies to sit up in space quite yet, but policymakers, government officials, and industry partners are building the foundation for that potential reality.

Orbit Fab COO Adam Harris, for example, says the company’s long-term goal is to become the industrial chemical supplier to the expanding space industry, providing the hardware, the service, and the fuel itself.

Right now, those customers are largely in GEO, but Orbit Fab sees opportunity in the International Space Station replacement program, or supporting NASA’s Artemis moon exploration mission, he adds.

The technology and know-how to refuel and service satellites is here, Harris continues. “And in 2025, we have a demonstration to show that it can be done.” VS