Engineers are troubleshooting engines on the Cubesat, which launched last month to search for water ice on the Moon. It’s the latest in a series of technical issues among small satellites recently launched to the moon and beyond.

In a January 12 update, NASA’s Jet Propulsion Laboratory reported that three of the four engines on the Cubesat Lunar Flashlight were either not working or were producing less thrust than expected. One explanation, according to JPL, was that having obstructions in the lines supplying fuel to the engines reduced the amount of fuel reaching the engines and therefore the thrust they produced.

Spacecraft controllers plan to run the engines for extended periods of time, hoping it will help clear any obstructions. If the engines cannot be restarted, project managers are considering alternative approaches that will allow the spacecraft to reach the moon and complete its mission. The spacecraft will need to begin daily maneuvers in February before it can orbit the moon in about four months.

Moonlight is designed to enter an almost linear halo orbit similar to that used by the CAPSTONE cube satellite, which arrived at the Moon in November, and the approaching Lunar Gateway. Cubesat’s orbit will take it 15 kilometers above the surface at the South Pole, where it will use lasers to search for water ice that may exist on the surface.

The Cubesat propulsion system uses a “green” fuel called Advanced Spacecraft Energy Non-Toxic (ASCENT), formerly known as AF-M315E. The fuel was successfully demonstrated on NASA’s Green Propellant Infusion Mission launched in 2019, but the Lunar Flashlight is the first time ASCENT has been used on a mission beyond Earth orbit.

A switch from the Lunar Flashlight propulsion system during its development to one provided by the Georgia Institute of Technology caused the cubic satellite to lose its initial launch capability as an additional payload during the Space Launch System’s first mission, Artemis 1. It was delivered to NASA for installation on the rocket by the fall of 2021, and the Lunar Flashlight propulsion system was not ready in time. Instead, NASA provided a joint launch, eventually launching the spacecraft in a Falcon 9 along with Japan’s ispace’s Hakuto-R lunar lander on December 11.

Artemis 1 was launched on 16 November with 10 cubic satellites as secondary payload. Many experienced serious problems at launch. One example is LunaH-Map, a NASA-funded cube satellite designed to go into orbit again in search of water ice. The electric motor has a problem with a valve magic that threatens its ability to orbit the moon.

Craig Hardgrove, the mission’s chief inspector, said in mid-December that engineers believed heating the valve would allow the valve to open and resume normal engine operation. The mission has until mid-January to repair the engine so the spacecraft can orbit around the moon, after which it will consider an asteroid transit instead, he said. Several other cube satellites reported problems or failed to communicate with Earth at all. There are no obvious technical issues to associate with cube satellites.