NASA Pinpoints Clogged Propellant Lines as the Cause of Lunar Flashlight’s End

NASA recently pinpointed the cause of the Lunar Flashlight mission’s end—clogged propellant lines. The primary research objective of the mission was to design and create a prototype instrument that could measure the local concentrations of hydrogen, water, and other volatile elements on the Moon.

The Earth-based team controlling the mission initially believed that all was working smoothly until an issue with the craft’s attitude control system was detected. But after further investigation, they found that the clogged lines were the result of an accidental liquid spatter during ground handling prior to launch. The incident had gone undetected until now, and it was eventually concluded that the clogged lines were the most likely cause of the mission’s demise.

The Lunar Flashlight mission was launched in May 2017 and was designed to fly on a low trajectory over craters and ancient lava fields to measure the local concentrations of hydrogen and other volatile elements. The instrument, which was designed and built at NASA’s Langley Research Center in Hampton, Virginia, included five subsystems including a visible and near-infrared imaging system, a yaw control system, a power system, an instrument data processing system, and a rocket motor system. The mission had planned for lunar sampling at least four times during its flight.

NASA researchers from the mission found that the clogged propellant lines obviously affected the mission performance and ultimately caused it to end earlier than planned. Mission scientists speculated that the foreign material in the lines caused an imbalance in the rocket motor, resulting in a reduced performance and earlier termination of the mission.

This incident serves as a reminder of the importance of prelaunch checks and a check for cleanliness of propellants lines. NASA engineers now plan to make servicing the propellant lines more accessible so that prelaunch checks can be done more easily.

The Lunar Flashlight mission was the first of its kind in attempting to measure the local concentrations of hydrogen and other volatile elements on the moon. It’s unfortunate that it ended prematurely due to some bad luck. Nevertheless, this incident proves that even experienced engineers can make mistakes and reminds us that we need to take extra precautions in order to ensure mission safety.