national security space

Redwire’s SabreSat platform for national security missions in very low Earth orbit (VLEO). Credit: Redwire

Redwire Corporation, a company based in Jacksonville, has secured a DARPA Phase 2 contract, valued at $44 million, to continue its work on the Otter Very Low Earth Orbit (VLEO) mission. This mission focuses on the development and in-orbit demonstration of an air-breathing electric propulsion (ABEP) system designed to sustain spacecraft operation in VLEO.

What Is VLEO And Why Go There?

Very Low Earth Orbit, which spans altitudes between roughly 90 and 450 kilometers (~56 to ~280 miles), presents a challenging environment for satellites due to significant atmospheric drag. This drag typically requires satellites operating in this region to carry a considerable amount of propellant for frequent orbit maintenance, limiting their operational lifespan. Shorter lifespans ultimately translates to “more expensive” and by creating satellites that last longer, Redwire plans to offer better value to its customers.

“VLEO represents an exciting new frontier for defense, intelligence, and communications missions. Through our work with DARPA, we are accelerating the development of cutting-edge capabilities that will define the future of this domain,” said Tom Campbell, President, Space Missions at Redwire in a press release. “With Otter and our SabreSat platform, we are delivering higher-performance missions at lower altitudes: improving sensor perception and proximity to targets of interest, increasing revisit, reducing latency, and redefining mission resilience.”

The Otter program aims to overcome this limitation by utilizing ABEP electric propulsion technology. This system is designed to harvest the low-density air present in the upper atmosphere, which is then ionized and accelerated to generate thrust. This approach provides a virtually unlimited propellant supply, theoretically enabling smaller, lighter satellites to remain in VLEO for extended periods without relying on stored fuel.

Redwire’s Proposed Solution

Redwire’s spacecraft for the Otter mission is built on its proprietary SabreSat Orbital Drone platform. The final stage of this project involves manufacturing and delivering the spacecraft for launch, followed by an orbital flight demonstration lasting over one year. During this test, the mission will characterize the performance of the air-breathing electric propulsion system and collect data for comparison with ground-test results, helping refine future VLEO satellite designs.

Operating closer to Earth offers several potential advantages for applications such as communications, intelligence, and surveillance. These benefits include lower latency for data transmission, improved sensor perception due to closer proximity to targets, and higher-resolution Earth observation. Furthermore, debris at VLEO altitudes is naturally cleared relatively quickly by atmospheric drag, reducing the long-term risk of space debris accumulation.

The Otter program is a multi-year effort that seeks to transition this novel propulsion technology from concept to operational capability, setting a precedent for persistent, long-duration missions in this orbital regime.

No launch date or launch provider were provided. This is a technology that ultimately could lead to many satellites in operation, so it is well worth keeping an eye on.

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blue origin 9x4 flight
Blue Origin New Glenn 9X4 in flight. Credit: Blue Origin

It has been a big week for Blue Origin, first with the second launch of New Glenn, the successful landing of the first stage. As they were moving the first stage of last week’s New Glenn flight, the company casually made three major announcements today in one press release: a new, supersized New Glenn for megapayloads, ramping up the power output of its BE-4 and BE-3U engine used on the second stage of the current New Glenn, as well as the 9X4. It might be a while for the megarocket to be on the launch pad, but the engine advancements start arriving on the next New Glenn flight, NG-3.

Evolving Quickly

The first major upgrade is a boost in engine performance across both stages. The seven BE 4 engines on the booster will now deliver about 4.5 million pounds of thrust, up from 3.9 million. On the stand, BE 4 has already hit 625,000 pounds of thrust with its current propellant setup and is on track to reach 640,000 later this year. Subcooling the propellant raises the engine’s output well above its previous 550,000 pound level.

The upper stage is getting a similar lift. Its pair of BE 3U engines will move from a planned 320,000 pounds of thrust to roughly 400,000 over the next few flights. BE 3U has already shown 211,658 pounds on the test stand.

These performance gains directly support customers already booked to fly on New Glenn to low Earth orbit, the Moon, and farther than that. Other vehicle updates include a reusable fairing for a higher flight tempo, a redesigned tank that lowers manufacturing cost, and a new thermal protection system that can be reused and cuts turnaround time.

Blue Origin said in their press release today that the improvements and upgrades will be phased into upcoming New Glenn missions beginning with NG-3.  

Super-Heavy: The New Glenn 9X4

On the right, the New Glenn 9×4 variant. It will be taller than a Saturn V and the SLS Block 1 rockets. Credit: Blue Origin

The next significant step in the evolution of the New Glenn program is a new super-heavy rocket. Called New Glenn 9×4, a nod to the engine layout on each stage, it targets missions that need more lift and higher performance. It can place more than 70 metric tons into low Earth orbit, over 14 metric tons directly into geosynchronous orbit, and more than 20 metric tons on a translunar trajectory. The 9×4 will also carry a wider 8.7 meter fairing.

Both the 9×4 and the current 7×2 version will operate in parallel, giving customers more flexibility across mission types, from mega-constellations to lunar and deep space work to national security needs such as Golden Dome or larger NSSL payloads.

Presumably, the new variant will also be built at Blue Origin’s factory in Exploration Park across from the Kennedy Space Center Visitors Center.

No mission or date for the upgraded rocket was given.

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