rewrite this title Satellites With Never-Ending Batteries Are Coming | Metaverse Planet

A new system eliminating dependence on traditional fuels generates propulsion by collecting sparse air in VLEO and converting it into plasma. The SabreSat, only 100 cm long, can theoretically remain at an altitude of 150 km for up to seven years, multiplying surveillance capacity. The US Department of Defense‘s research arm, DARPA, is pushing boundaries in space by moving the Very Low Earth Orbit (VLEO) Otter satellite program to the production stage. Florida-based company Redwire announced it won a $44 million contract to transition to Phase 2 of the Otter program.

Redwire had also won the prime contract for Otter last year, tasked with developing a VLEO satellite capable of using an air-breathing electric propulsion system to stay in orbit without relying on a fixed amount of fuel.

VLEO covers altitudes between 90 and 450 kilometers. This region is relatively uncrowded compared to Low Earth Orbit and geosynchronous orbit altitudes, primarily because there is much more atmospheric drag on objects at that height. This necessitates more frequent use of propulsion systems to maintain orbit, which limits the lifespan of satellite missions in VLEO.

A System Generating Energy from Air

According to the explanation on DARPA‘s Otter program webpage, “Otter aims to enable extended satellite operations at VLEO altitudes by harvesting ambient low-density air, ionizing and accelerating the resulting ion flow, thus using a nearly limitless source of propellant.”

Redwire states that this system uses the very scarce air existing at VLEO altitudes to convert it into plasma in an ionization chamber. Charged particles can then be ejected from the spacecraft as a propulsive force without the need for onboard gas. Since there is no need for onboard fuel, such satellites can be built smaller and lighter, theoretically lasting much longer than the lifespan of a device dependent on traditional fuels.

However, building such systems is not easy. If successful, Redwire‘s design will be the first of its kind to reach orbit.

As Redwire notes, VLEO missions have certain advantages due to being closer to the ground, such as improved sensor perception, lower latency, and increased ability to revisit specific points on Earth. Additionally, VLEO operations offer an ideal environment for used satellites and space debris at the lowest altitudes to de-orbit in just hours or days rather than remaining in space for years.

SabreSat Preparing for Flight

The design selected for the Otter program is a surprisingly small, drone-like device named SabreSat by Redwire, measuring only 100 cm in length. As designed, this device is expected to last up to seven years at altitudes of approximately 150 km. SabreSat is designed for various missions such as intelligence gathering, surveillance and reconnaissance, communication, navigation, and scientific research.

However, it is not clear whether Redwire has yet built a functional SabreSat or VLEO air-breathing electric thruster. DARPA also mentions on the Otter program page that recreating VLEO conditions in ground test facilities is difficult. Therefore, the launch of a functional SabreSat will be the first moment the company has the opportunity to test its design in the field.

According to DARPA, the Otter program will conclude with an “orbiting wind tunnel” demonstration of SabreSat‘s electric propulsion technology lasting more than a year. Ground tests of Redwire‘s thruster and air intake technology must also be conducted so that the obtained data can be compared with information gathered from orbital operations.

In addition to developing SabreSat for DARPA‘s Otter program, Redwire is also working with the European Space Agency (ESA) to develop its own VLEO platform, Phantom. However, unlike the drone-style device designed for DARPA, Phantom resembles a more traditional satellite, has a shorter lifespan, and lacks air-breathing capability.

Furthermore, Redwire is working with Deepsat to develop a network of VLEO Earth observation satellites. This contract was signed just this July, and it is unclear at what stage the project is.

It is also not yet clear when DARPA intends to launch Redwire‘s Otter spacecraft. According to solicitation documents from 2023, DARPA envisions the program lasting four years. Considering Redwire received its initial contract in 2024, Otter may not take to the skies before 2027.

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