Liquid Hydrogen in Orbit: Orbital Operations Raises $8.8M to Build “Loitering” Cryogenic Space Vehicle

Aerospace startup Orbital Operations has closed an $8.8 million seed round to develop Astraeus, a high-thrust orbital vehicle that stores liquid hydrogen (LH₂) and liquid oxygen (LOX) in space for long durations—enabling rapid-response maneuvers and mission persistence measured in years, not days. The raise was reported by SpaceNews and includes a detailed technical roadmap centered on active cooling to achieve zero-boil-off storage on orbit. (SpaceNews, FinSMEs, orbitalops.tech)

https://spacenews.com/orbital-operations-raises-seed-round-for-orbital-vehicle-using-liquid-hydrogen-fuel/

Backers include Initialized Capital (lead) with participation from Harpoon Ventures, DTX Ventures, Rebel Fund, TRAC VC, Karman Ventures, and investor Immad Akhund. Founders Ben Schleuniger (CEO) and Ross Doherty—alumni of Relativity—say Astraeus will combine a ~10,000 lbf engine with active cryogenic management to keep LH₂ near 20 K and LOX near 90 K, preventing boil-off that typically forces venting and limits on-orbit life to a day or two. (Payload, FinSMEs)

“What we’re really looking to provide for the U.S. Space Force is the third-stage rocket that can stay out in orbit indefinitely… The only way to do that is to add this active cooling cycle to the tanks as well,” said CEO Ben Schleuniger. He added, “This is a counterspace weapon,” emphasizing non-kinetic “degradation” options like high-power microwave or spoofing over destructive approaches. (Payload)

According to the company, Astraeus targets ~10 km/s of delta-v, enabling staging in LEO with rapid repositioning to target orbits. Orbital Operations plans engine test-stand work and a terrestrial demo of long-term cryogenic cooling; the firm is also exploring refueling pathways, including water electrolysis and cryogenic transfers, to support reusable on-orbit operations. (Payload, orbitalops.tech)

Hydrogen Aerospace: Why Zero-Boil-Off Matters for Space & Aviation

Hydrogen offers the highest specific impulse among chemical propellants, but on-orbit thermal inputs (sunlight/radiation) quickly heat tanks, causing LH₂/LOX to boil off. Historically the workaround has been venting, which wastes propellant and caps mission endurance. Orbital Operations’ active cooling and integrated radiative heat rejection aim to hold cryogens at setpoints—turning LH₂ from a short-lived upper-stage propellant into a persistent, on-orbit energy store. That approach, long discussed for vehicles like ULA’s Centaur, has not been demonstrated on-orbit with true zero-boil-off—making Astraeus a potential first. (Payload, orbitalops.tech)

Defense & Commercial Use Cases for Hydrogen in Space Mobility

Orbital Operations positions Astraeus for space domain awareness, deterrence, and rapid interception, while also flagging commercial roles: asset repositioning, life extension, and end-of-life services. The seed funding will expand the Long Beach, CA footprint and accelerate engine and cryogenic demonstrations in collaboration with national security partners. (FinSMEs, orbitalops.tech)

For more information

https://www.orbitalops.tech/ (orbitalops.tech)

(Top image: Credit — Orbital Operations)

FAQ: Hydrogen Aviation & Orbital Hydrogen Vehicles

1. What makes liquid hydrogen attractive for space and aviation propulsion?

   1. LH₂ has the highest chemical specific impulse, delivering more thrust per unit mass than kerosene or methane. The tradeoff is cryogenic complexity (≈20 K storage) and low density, demanding larger insulated tanks and active thermal control—especially in space where boil-off is mission-limiting. (Payload, orbitalops.tech)

2. How does zero-boil-off (ZBO) change the economics of hydrogen systems?

   1. ZBO reduces propellant losses, enabling longer mission durations and higher utilization of assets. Over time, less propellant wastage and fewer refueling launches can lower $ per maneuver and total lifecycle costs for on-orbit services.

3. What’s novel about Orbital Operations’ approach to LH₂ management?

   1. Active cooling cycles plus integrated radiative cooling routed through propulsion hardware—rather than large, separate radiators—seek to cut dry mass and complexity while maintaining cryogens at setpoints for years. (orbitalops.tech)

4. Is the Astraeus vehicle reusable?

   1. The company describes Astraeus as refuelable and designed for long-term persistence in orbit (e.g., via water electrolysis or cryogenic transfer), which underpins reusability and improved economics for multi-mission use. (orbitalops.tech)

5. How does on-orbit hydrogen storage relate to hydrogen aviation (AAM/eVTOL)?

   1. Both domains wrestle with cryogenic storage, insulation, and boil-off. Lessons from orbital ZBO (materials, heat exchangers, turbomachinery) can inform liquid hydrogen aircraft designs, from regional to AAM scales, where compact, efficient thermal systems and refueling logistics are crucial.

6. What are typical storage temperatures for LH₂ and LOX—and why do they matter?

   1. About 20 K for LH₂ and 90 K for LOX. Straying above these setpoints risks pressure rise and venting; precise thermal control is central to safety and endurance. (Payload)

7. What mission types benefit most from hydrogen’s high performance?

   1. High-delta-v tasks—rapid intercepts, plane changes, cislunar transfers, or multi-target servicing—reward hydrogen’s Isp, especially when ZBO enables standby loiter without propellant loss. (Payload)

8. Are non-kinetic counterspace options realistic for a hydrogen vehicle?

   1. Yes. Persistent maneuverability lets a vehicle position and deter while carrying non-kinetic payloads (e.g., high-power microwave, electronic attack/spoofing), aligning with operators’ interest in reversible effects over debris-creating impacts. (Payload)

9. What are the main technical risks for on-orbit LH₂?

   1. Thermal runaway, insulation degradation, micro-meteoroid/fragment impacts, and transient heat loads during maneuvers. Robust fault detection, redundant cooling loops, and tank health monitoring are key mitigations—areas Astraeus’ ground demos aim to validate. (Payload, orbitalops.tech)

10. Who invested in Orbital Operations and how might that shape development?

    1. The seed was led by Initialized Capital, joined by Harpoon Ventures, DTX Ventures, Rebel Fund, TRAC VC, Karman Ventures, and Immad Akhund—a mix of deep-tech and defense-savvy capital that typically accelerates government contracting and dual-use scaling. (FinSMEs)

11. How soon could zero-boil-off hydrogen be demonstrated on-orbit?

    1. The company is first building a terrestrial demonstrator and engine test stand; timelines point to near-term ground validation, with on-orbit ZBO the longer-pole milestone that would mark a first-of-kind operational capability if achieved. (Payload)

12. Did prior stages consider active cooling for cryogens?

    1. Yes—concepts were discussed for stages like ULA’s Centaur, but on-orbit demonstrations of full ZBO with LH₂ remain unrealized; Astraeus explicitly targets that gap. (Payload)

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Sources: SpaceNews (Jeff Foust), Payload, FinSMEs, and Orbital Operations’ official site. (SpaceNews, Payload, FinSMEs, orbitalops.tech)