NASA tests dual mode propulsion CubeSat ahead of launch

Spacecraft propulsion traditionally relies on volatile fuels and separate, bulky systems for different types of maneuvering in space. NASA is working to change that. Engineers at NASA’s Marshall Space Flight Center in Huntsville, Alabama, recently completed a series of environmental and physical tests on a new small satellite designed to make spaceflight safer and more efficient.

The ASCENT (Advanced Spacecraft Energetic Non-Toxic) Propulsion Dual Mode mission is a flight demonstration of a spacecraft about the size of a large shoebox. The mission will test a single, integrated propulsion system that uses a common fuel tank to feed two types of engines.

Typically, spacecraft carry two separate propulsion systems to navigate: a high-thrust chemical system for rapid movements like entering orbit, and a low-thrust electric system for efficient, slow maneuvers like maintaining a position. This requires multiple fuel tanks and heavy plumbing, which take up valuable space and add weight.

The spacecraft being developed uses a single nontoxic propellant called ASCENT. By feeding both a high-thrust combustion engine and low-thrust electrospray thrusters from one central tank, the spacecraft saves mass and volume. For future missions, this means more room for scientific instruments and the ability to launch on smaller, less expensive rockets.

Bringing this concept to flight requires collaboration across the country. NASA Marshall manages the mission, while the spacecraft relies on electrospray thrusters developed by the Massachusetts Institute of Technology, a chemical propulsion module built by Plasma Processes and a spacecraft bus integrated by the Georgia Institute of Technology.

“There are a lot of odds and ends, and a lot of small challenges and some big ones,” said Nehemiah Williams, the demonstration’s project manager at NASA Marshall. “But ensuring the functionality of the propulsion system across all these different teams is what makes the mission successful.”

Before a spacecraft can safely operate in the harsh environment of low Earth orbit, it must pass a battery of tests on the ground. Over the past few months, the engineering team at Marshall has put the flight hardware through its paces inside the center’s Small Spacecraft Servicing and Integration Lab.

To verify the integrity of the unified propulsion system, engineers performed a pressurized helium leak test of the spacecraft inside a vacuum chamber. The test confirmed that its seals worked as intended. Because the system uses a single tank of ASCENT propellant to feed two types of thrusters, sealed fuel lines and valves are vital to the mission’s safety and success.

The team also subjected the spacecraft to thermal vacuum testing. Space is an unforgiving environment with no air and extreme temperature swings. By placing the spacecraft inside a specialized vacuum chamber that mimics these conditions, engineers can check whether the electronics, thrusters and mechanical systems will operate normally in orbit.

The spacecraft also underwent a spin test. Like a car tire, a spacecraft needs to be balanced. The test measures the spacecraft’s mass properties and center of gravity. This validates the CubeSat’s ability to fly stably and maintain the correct attitude, allowing its antennas to communicate with Earth and its solar panels to catch the sun’s rays.

With the environmental and physical testing complete, the mission is entering its final stages of preparation. The team will complete the final system checks, integrate the spacecraft’s solar arrays and ship the hardware to its launch destination.

The ASCENT Propulsion Dual Mode mission is scheduled to launch no earlier than Oct. 1 as a payload aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California.

Once deployed into an orbit about 325 miles (520 kilometers) above Earth, the spacecraft will begin a nine-month mission. After an initial checkout period, the operations team will execute short chemical and electric maneuvers. If successful, the spacecraft will spend several months performing multiple orbit-raising and lowering maneuvers, alternating between its high-thrust and low-thrust engines to prove the dual-mode concept works in space.

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Swati Mestri

Swati Mestri holds a bachelor’s degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space.

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Andrew Zinin

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