NASA engineers continue to struggle to save the Flashlight lunar probe

In an update today, NASA reports that engineers continue to troubeshoot the failure of the experimental thrusters on the Lunar Flashlight cubesat, in an effort to improvise a way to get the probe into lunar orbit.

Shortly after launch on Dec. 11, 2022, the operations team for NASA’s Lunar Flashlight determined that three of the four CubeSat’s thrusters were underperforming. This cast doubt on whether the mission could complete its stretch science goal of detecting surface ice at the Moon’s South Pole. After analyzing the situation, team members at NASA’s Jet Propulsion Laboratory and Georgia Tech arrived at a creative maneuvering technique that would use the one fully-functioning thruster to get into planned orbit. But when attempting the modified maneuvers in January, that thruster also experienced a rapid loss in performance and the team determined that Lunar Flashlight would likely be unable to reach its planned near-rectilinear halo orbit around the Moon.

After further troubleshooting, the operations team has been working on ways to restore partial operation of one or more thrusters to keep the spacecraft within the Earth-Moon system. They have had some success but continue to try new things to clear the suspected obstructions in the thruster fuel lines. They have until the end of April to generate the required thrust to preserve the opportunity to allow for monthly flybys of the lunar South Pole.

Though it increasingly appears Lunar Flashlight will not make lunar orbit, the mission is not a failure, since it was first and foremost an engineering mission testing a variety of new cubesat technologies, including the failed thrusters. Their failure and the efforts by engineers to recover them is important data for developing better cubesat thrusters on future such planetary probes.

Engineers struggle to salvage Lunar Flashlight cubesat

Because of thruster failures shortly after its December 11, 2022, NASA’s technology test lunar orbiter cubesat Lunar Flashlight has been unable to reach its planned orbit around the Moon.

Instead, first engineers have attempted an improvisation with the one thruster that had not initially failed, and when that did not work are now hoping to instead use the Earth’s gravity to shift its present path so that it will periodically fly over the Moon’s south pole, when it could possible still use its lasers reflectometer to gather data in the permanently shadowed craters there.

[Other than the thrusters, t]he rest of the CubeSat’s onboard systems are fully functional, and the mission recently successfully tested its four-laser reflectometer. This mini-instrument is the first of its kind and is designed and calibrated to seek out surface ice inside the permanently shadowed craters at the Moon’s South Pole.

As a engineering test satellite, everything that has happened has been to the good, as it has allowed these engineers to push this cutting edge cubesat technology to the limit.

Lunar Flashlight cubesat in trouble

The mission of NASA’s test cubesat Lunar Flashlight is now threatened because of a problem with its experimental thrusters that use what the agency labels a new “green” propellant.

The spacecraft, called Lunar Flashlight, launched last month on a mission to seek out water ice on the moon. The probe was also expected to test a new “green” propellant during its four-month voyage to the moon, but its thrusters have a problem, NASA said on Thursday (Jan. 12). “While the smallsat is largely healthy and communicating with NASA’s Deep Space Network, the mission operations team has discovered that three of its four thrusters are underperforming,” NASA wrote in an update. “Based on ground testing, the team thinks that the underperformance might be caused by obstructions in the fuel lines that may be limiting the propellant flow to the thrusters.”

Engineers are now devising a plan to fire the thrusters longer and more frequently to make up for the lower thrust. If successful, the cubesat will enter its planned lunar orbit in about four months, where it will use infrared lasers to search for ice in the permanently shadowed craters at the lunar poles while testing a variety of other new technologies.