"There was no mass or power available in the LESS for an Inertial Measurement Unit to measure acceleration and tell the astronauts where they were, where they were going or how fast they would be getting there, or even for a radar altimeter to show altitude above the lunar surface."
https://en.wikipedia.org/wiki/Lunar_Escape_Systems
"There was no mass or power available in the LESS for an Inertial Measurement Unit to measure acceleration and tell the astronauts where they were, where they were going or how fast they would be getting there, or even for a radar altimeter to show altitude above the lunar surface."