Discover DARPA’s Otter Satellite Program as it breaks ground in VLEO advancements with cutting-edge insights from Redwire.
The Defense Advanced Research Projects Agency (DARPA), known as the U.S. Department of Defense’s research powerhouse, is set to redefine space exploration. Recently, the Very Low Earth Orbit (VLEO) Otter satellite program has witnessed a massive leap with Florida-based Redwire securing a substantial $44 million contract to push this initiative into its next phase.
Previously, Redwire was also awarded the primary contract for Otter, marking the beginning of its mission to invent a satellite system capable of enduring in VLEO using air-breathing electric propulsion, thereby eschewing traditional fuel usage. In terms of altitude, VLEO spans between 90 and 450 km, a relatively uncrowded region due to higher atmospheric resistance, which necessitates more frequent propulsion, traditionally limiting the mission duration in this orbit.
Innovation in Space Propulsion
The air-breathing propulsion system as envisioned by DARPA aims to allow satellites at these altitudes to function using the sparse atmospheric air. This air is ionized and accelerated, providing an almost limitless fuel source. Redwire explains that this innovative technique harnesses the scant air at VLEO altitudes into plasma, ejecting charged particles to create propulsion without the need for a propellant. This breakthrough could mean lighter, more compact satellites with potentially longer service durations compared to their fuel-reliant counterparts.
SabreSat Ready for the Skies
The innovative design chosen for Otter is a compact drone-like satellite dubbed SabreSat, stretching only 100 cm. Built to last up to seven years at 150 km altitudes, SabreSat is designed to perform a wide range of tasks such as intelligence, surveillance, reconnaissance, communication, and scientific research. However, building these complex systems comes with challenges; it’s yet to be seen if Redwire has successfully created a working SabreSat or its propulsion system. This satellite’s launch will be pivotal in assessing the design under real-world conditions.
Throughout its mission, SabreSat will demonstrate its electric propulsion capabilities in a year-long “orbital wind tunnel.” Current efforts include ground testing of propulsion and air intake technologies, essential for cross-comparing with orbital operation data. Parallelly, Redwire is collaborating with the European Space Agency (ESA) on a VLEO project named Phantom and partnering with Deepsat for a VLEO Earth observation satellite network. While specific launch dates remain undecided, with DARPA’s program slated for four-year completion, the Otter spacecraft might debut around 2027.
