Japan Funds Three Paths to a Cleaner Orbit: Inspect, Maneuver and Deorbit

Astroscale, Pale Blue and BULL are attacking orbital debris from three directions: approach and inspect dangerous dead objects, give active satellites the power to maneuver, and make end-of-life deorbiting routine.

TOKYO. There is no single technology that “cleans up space.” Orbital debris is a systems problem. Operators need to prevent collisions while satellites are alive, remove spacecraft from useful orbits when their missions end, inspect large dead objects before anyone attempts to capture them and, in the hardest cases, physically remove objects that can no longer help themselves.

Japan’s Ministry of Education, Culture, Sports, Science and Technology, MEXT, took another step toward building that technology stack on October 2. A special stage-gate review under the ministry’s SBIR Phase 3 fund examined three space-debris projects and approved additional funding for all three: Astroscale Japan, Pale Blue and BULL.

The projects attack different points in the debris life cycle. Astroscale is developing a spacecraft that can approach and inspect large defunct satellites. Pale Blue is building propulsion systems that give small satellites the ability to maneuver away from collisions and deorbit at the end of their missions. BULL is developing a passive membrane device that increases atmospheric drag and pulls spacecraft down without relying on propulsion.

The industrial stakes are rising because the orbital environment is changing quickly. European Space Agency statistics updated July 31, 2026 list about 47,080 objects routinely tracked by surveillance networks. Statistical models estimate roughly 68,450 objects larger than 10 centimeters, 1.5 million between 1 and 10 centimeters and about 230 million between 1 millimeter and 1 centimeter. Not all are debris, and not all present the same risk, but collisions can generate thousands of additional fragments.

Astroscale: before debris can be removed, it has to be approached safely

The largest of the three programs is Astroscale’s mission to image and diagnose large defunct satellites from close range. Its Phase 1 grant ceiling was ¥2.69 billion and its Phase 2 ceiling ¥6.31 billion. The latest review adds ¥250 million to Phase 2.

The spacecraft, ISSA-J1—In-situ Space Situational Awareness – Japan 1—is scheduled for launch in 2027. Astroscale says it will approach and inspect two Japanese satellites that were launched in the 2000s and are now out of service. In 2025 the company signed a launch agreement with India’s NewSpace India Limited for a PSLV flight.

Close inspection is not a trivial camera mission. A dead satellite is a “non-cooperative object”: it does not transmit useful navigation data for a servicing vehicle, cannot hold its attitude on command and may be tumbling. Its condition may also have changed after years of radiation, thermal cycling and impacts.

That makes rendezvous and proximity operations, or RPO, foundational. A servicing spacecraft must find the target, estimate its relative motion, approach without collision and maintain a safe geometry. Astroscale Japan President and Managing Director Hideki “Eddie” Kato leads the Japanese subsidiary carrying out the SBIR work.

ADRAS-J turned proximity operations into flight heritage

ISSA-J1 is not starting from zero. Astroscale’s ADRAS-J spacecraft, operated under Phase I of JAXA’s Commercial Removal of Debris Demonstration, or CRD2, launched in February 2024 and approached a real Japanese H-IIA upper stage roughly 11 meters long, 4 meters in diameter and about 3 tonnes in mass.

During the mission, ADRAS-J conducted stationary and fly-around observations at a distance of about 50 meters, approached to roughly 15 meters from the payload attach fitting region and demonstrated collision-avoidance functions. In March 2026 Astroscale announced that ADRAS-J had begun lowering its own orbit at the end of operations.

The follow-on spacecraft, ADRAS-J2, is being developed under JAXA’s CRD2 Phase II to go beyond inspection: it is intended to capture the same rocket upper stage and remove it from orbit. JAXA’s Phase II contract with Astroscale is worth about ¥13.2 billion including tax, with launch targeted for fiscal 2027.

CRD2 and MEXT’s SBIR are separate programs, but together they show a deliberate progression from approach, to inspection, to capture and deorbit.

Pale Blue: make the satellite capable of avoiding trouble—and leaving

The second strategy is preventive. Pale Blue, founded in 2020 and based in Kashiwa, Chiba Prefecture, develops compact electric-propulsion systems for small satellites. Its representative director is Jun Asakawa.

Under the SBIR project, the company is developing an ultra-small water ion thruster and a Hall thruster for collision avoidance and end-of-life deorbiting. Its Phase 1 grant ceiling was ¥1.58 billion. Phase 2 was initially capped at ¥1.17 billion and was raised to ¥1.96 billion after a June 2026 stage-gate review.

The program also illustrates how government-funded development can change course when engineering evidence changes. Pale Blue originally planned a water-propellant Hall thruster. A September 2025 stage-gate review approved a change of propellant for the Hall-thruster portion from water to xenon. The official project title was consequently changed from “water ion thruster and water Hall thruster” to “water ion thruster and Hall thruster.”

In September 2025, Pale Blue said its PBI water-ion engine had operated successfully in orbit, which the company described as the first orbital operation of a water ion engine. It has separately announced that its PBH-100 compact Hall thruster, aimed at roughly 50-to-200-kilogram satellites, is planned for an in-orbit demonstration in 2027.

The debris logic is straightforward. A satellite with propulsion can maneuver away from conjunctions during its useful life and lower its orbit when the mission is over. Every spacecraft that disposes of itself successfully is one less object that a future removal vehicle might have to chase.

BULL: use the atmosphere as the brake

BULL’s approach is simpler in principle and deliberately independent of propulsion. Its HORN Post-Mission Disposal device is installed before launch. At the end of a mission, it deploys a large membrane, increasing drag against the trace atmosphere in low Earth orbit and accelerating orbital decay.

BULL’s Phase 1 grant ceiling was ¥1.47 billion and Phase 2 was capped at ¥1.31 billion. The October review adds ¥260 million to Phase 2.

Unlike many debris-mitigation concepts, HORN already has a recent in-orbit demonstration behind it. HORN-L and HORN-R launched aboard H3 Flight 6 on June 12, 2026. BULL reported successful deployment of membranes with planned areas of about 20 square meters and 10 square meters, respectively. Orbital data showed both objects descending faster than a similar comparison spacecraft, while space-based optical images confirmed deployment.

HORN-L went further. BULL reported that it reentered Earth’s atmosphere on August 27 UTC, 76 days after launch. A comparison spacecraft at roughly the same starting altitude near 560 kilometers remained close to that altitude while HORN-L steadily descended.

The commercial proposition is a kind of fail-safe. A propulsion system is useful only if enough of the spacecraft remains alive to command and power it. A properly designed passive disposal system can provide a second path to deorbit if the main spacecraft fails.

Why now: around 10 payloads launched per day

ESA’s 2026 Space Environment Report says more than 300 launches placed over 4,000 new payloads into orbit in 2025—roughly 10 payloads per day. More than three intact objects, such as satellites and rocket bodies, were also reentering Earth’s atmosphere each day on average.

The danger is not simply “too many satellites.” Active spacecraft that can maneuver and coordinate can coexist more safely than inert objects that cannot. The risk grows where dead payloads, old rocket stages and fragments accumulate in heavily used altitude bands.

ESA notes that below about 600 kilometers the environment is increasingly busy but still dominated by maneuverable satellites. Between roughly 600 and 1,100 kilometers, decades of legacy debris create a more difficult environment. Above 1,100 kilometers, natural decay can take centuries.

From the Kessler warning to an engineering industry

The long-term physics of the problem has been understood for decades. In 1978, NASA scientist Donald Kessler and Burton Cour-Palais described how collisions in a sufficiently dense orbital population could generate fragments that create still more collisions. The scenario became known as the Kessler syndrome.

The policy response initially emphasized prevention: avoid releasing objects during normal operations, passivate spacecraft and upper stages so stored fuel or batteries do not explode, reduce collision probability and dispose of spacecraft after their missions. Those principles were later reflected in the Inter-Agency Space Debris Coordination Committee guidelines and the United Nations Committee on the Peaceful Uses of Outer Space debris-mitigation guidelines.

But prevention cannot remove the large dead objects already in orbit. ESA’s 2026 report states that even improved mitigation is not enough to halt long-term growth in the debris population under current conditions; active removal is also required to stop collisions among existing objects from feeding a runaway cycle.

The old 25-year disposal rule is becoming five years

For years, the standard benchmark for low-Earth-orbit disposal was to leave the protected region within 25 years after mission completion. As constellation traffic grows, that expectation is tightening. ESA’s 2026 report describes a broader transition from a 25-year to a five-year post-mission disposal target in low Earth orbit.

That shift changes the economics. If regulators, launch providers, insurers and major satellite customers increasingly require fast disposal, thrusters and passive deorbit systems stop looking like optional environmental add-ons and begin to look like ordinary spacecraft subsystems.

This is where Pale Blue and BULL may have the clearest near-term business case. Instead of waiting for governments to pay to remove abandoned spacecraft, the cost of responsible disposal can be designed into a mission before launch.

Japan is also trying to build an on-orbit services market

JAXA is explicit that CRD2 is not only an environmental project. Its stated goal is to use debris removal as the starting point for new space businesses and help Japanese companies capture emerging markets.

The technology stack can extend well beyond cleanup. RPO can support inspection, repair, relocation, life extension and eventually refueling. Propulsion designed for collision avoidance can also support station-keeping and orbital transfer. Passive disposal devices can become mission-assurance equipment if primary spacecraft systems fail.

Seen that way, the three SBIR projects are not three competing versions of the same machine. They are complementary pieces of orbital infrastructure: know what is there, give active satellites mobility, and make sure failed or retired systems do not stay forever.

The missing business model: who pays to remove someone else’s dead satellite?

The largest unresolved question is economic. A defunct satellite does not have a budget. A spent rocket stage does not sign a service contract. The cost must ultimately be borne by an owner, launching state, operator, insurer, government or future users of the orbital environment.

There are also legal limits. A space object does not automatically become ownerless simply because it stops functioning. Physical capture or relocation raises questions of authorization, ownership, liability and consent. Commercial removal therefore requires not only robotics but contractual and governmental arrangements around each target.

That may make inspection of clearly identified customer assets, or mitigation hardware fitted before launch, easier to commercialize than removal of legacy objects. Active debris removal remains both the most technically demanding and institutionally complex part of the market.

Stage-gate funding is a test, not a verdict

MEXT’s SBIR Phase 3 program deliberately divides projects into stages. Additional public funding follows reviews rather than arriving as one unconditional award. The October 2 decision means all three programs have cleared another funding decision; it does not establish that the technologies will become profitable or even complete every planned demonstration.

Astroscale still has to launch ISSA-J1 and demonstrate safe approaches to two large dead satellites. Pale Blue must turn thruster performance into reliable, manufacturable products that satellite builders will buy. BULL must show that HORN can scale across different spacecraft masses, geometries and orbital regimes while meeting launch and mission safety requirements.

The final measure of success for Japan will not be the amount of subsidy spent or even the number of spacecraft launched. It will be whether satellites spend less unnecessary time in orbit, dangerous objects are removed and fragmentation events become less likely.

Low Earth orbit looks vast from the ground. Operationally useful orbital bands are not. Objects cross them at relative velocities of kilometers per second. Now that communications, navigation, weather forecasting, disaster monitoring and security depend on spacecraft, keeping those bands usable is no longer a niche environmental cause. It is infrastructure maintenance.

Japan’s latest SBIR decision shows that the country is beginning to treat orbital sustainability exactly that way: as a chain of practical technologies for inspection, avoidance and disposal.