Author: Sarah Frazier

NASA’s Lunar Flashlight operations team continues to work on remedying the CubeSat’s underperforming propulsion system. They developed a method to get one of the CubeSat’s four thrusters to deliver more thrust; however, the small spacecraft will need additional, more consistent thrust in the next few days to reach its revised target orbit.

Devised by team members at NASA’s Jet Propulsion Laboratory in Southern California, Georgia Tech, and the agency’s Marshall Space Flight Center in Huntsville, Alabama, the new method involves trying to clear the thruster fuel lines of suspected obstructions by increasing fuel pump pressure far beyond the system’s operational limit while opening and closing the system’s valves. After some improvement with one spacecraft thruster, the team is now attempting this method on the other three thrusters. This has resulted in limited success, with the remaining thrusters inconsistently producing some increased levels of thrust.

The CubeSat is currently beyond the Moon’s orbit, more than half a million miles from Earth and looping back toward our planet. To carry out monthly flybys of the lunar South Pole to look for surface ice inside permanently shadowed craters, the team needs to nudge Lunar Flashlight into a trajectory that will allow it to arrive in the required Earth-Moon orbit. They need more reliable thrust for the next few days to achieve that goal.

The mission’s miniaturized propulsion system is a technology demonstration that has never been flown in space before. Technology demonstrations are high-risk, high-reward endeavors intended to push the frontiers of space technology. The lessons learned from these challenges will help to inform future missions that advance this technology.

The other systems aboard Lunar Flashlight continue to perform well.

Lunar Flashlight is funded by the Small Spacecraft Technology program based at NASA’s Ames Research Center in Silicon Valley and within NASA’s Space Technology Mission Directorate.

Teams are continuing work to place NASA’s Lunar Flashlight CubeSat in an orbit that would allow flights over the Moon’s South Pole. The opportunity to place Lunar Flashlight in such an orbit extends through the end of April.

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.

The other systems aboard Lunar Flashlight continue to perform well and the mission has successfully completed all of its technology objectives, paving the way for future low-cost planetary exploration.

The mission’s miniaturized propulsion system is a technology demonstration that has never been flown in space before. Technology demonstrations are high-risk, high-reward endeavors intended to push the frontiers of space technology. The lessons learned from these challenges will help to inform future missions that further advance this technology.

“Though we hoped the propulsion system would perform perfectly, encountering and responding to these issues is an expected part of a technology demonstration mission like this,” said Justin Treptow, deputy program executive for the Small Spacecraft Technology program in NASA’s Space Technology Mission Directorate. “Flight testing, evaluating, and troubleshooting this system all help fulfill the mission’s primary objective to explore the actual in-space performance of this novel propulsion system.”

Lunar Flashlight is funded by the Small Spacecraft Technology program based at NASA’s Ames Research Center in Silicon Valley and within NASA’s Space Technology Mission Directorate.

NASA’s Lunar Flashlight CubeSat launched on Dec. 11, 2022, to demonstrate several new technologies with a stretch science goal of detecting surface ice at the Moon’s South Pole. Shortly into Lunar Flashlight’s journey, the mission operations team discovered three of its four thrusters were underperforming.

Among the steps taken to analyze the issue and find possible solutions, the mission performed tests to determine whether the one fully functional thruster could provide adequate thrust to guide the spacecraft into its planned orbit. To that end, team members at NASA’s Jet Propulsion Laboratory in Southern California and Georgia Tech devised a creative maneuvering technique using one thruster: The spacecraft was spun at a rate of 6 degrees per second, or one revolution per minute, around its directed axis. Then the thruster was fired while commanding the spacecraft to remain pointed in the right direction. There was potential after 20 days, these mini-trajectory correction maneuvers would guide Lunar Flashlight to its planned near-rectilinear halo orbit around the Moon.

The team successfully completed quite a few 10-minute sequences on the single thruster, but soon after, that thruster also experienced a rapid loss in performance, and it became clear that the thrust being delivered was not enough to make it to the planned orbit.

The NASA JPL and Georgia Tech team is developing a new plan to get to the Moon. Because achieving an optimal near-rectilinear halo orbit appears unlikely, the Lunar Flashlight team decided to attempt lunar flybys using any remaining thrust the propulsion system can deliver. This new attempt is designed to get the CubeSat into high Earth orbit, which includes periodic flybys of the lunar South Pole once a month to collect data. The team plans to begin maneuvers on Thursday, and, if successful, the expected first science pass will now be in June.

While Lunar Flashlight faces significant challenges in its goal of getting to the Moon, testing its new propulsion system in space fulfills one of the mission’s objectives and will support future technology development. The mission’s miniaturized propulsion system is a technology demonstration that has never been flown in space before. Technology demonstrations are high-risk, high-reward endeavors intended to push the frontiers of space technology. The lessons learned from these challenges will help to inform future missions that further advance this technology.

The 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.

Lunar Flashlight is funded by the Small Spacecraft Technology program in NASA’s Space Technology Mission Directorate.