Apollo 17 Oral History Interview Excerpts . ... At about three meters, you got a contact light, that little probe hits the surface, tells you you're close, you better shut the engine down, because if you don't shut it down and you land with the descent engine running full-blast at high power, like it was at that point in time, the backpressure could explode the Lunar Module. ... Read Gene Cernan's oral history transcript: http://www.jsc.nasa.gov/history/oral_histories/CernanEA/cernanea.pdf . ...