Also, there was no provision for docking with the lunar module. He oversaw the development of the lunar module propulsion systems. The system's sole intention was to project the illusion of piloting the Lunar Module. TRW used this same injector for the Descent Propulsion System on Apollo's Lunar Module. Armstrong and Aldrin undock in the Lunar Module and attempt the landing. Such shields were used on the Apollo Service Module and Lunar Module descent stage. Armstrong said, "I'm going to step off the LM [lunar module] now". Its role was analogous to the American Apollo Lunar Module (LM). He would then command the fourth, a medium Earth orbit mission with a lunar module. The ascent stage of the Apollo Lunar Module "Snoopy" was jettisoned into a heliocentric orbit. He also served as backup lunar module pilot for Apollo 17. The landing radar on the Apollo Lunar Module combined both CW radar types. The descent stage of the Lunar Module remains at the original point of landing. Essentially the equivalent of the EECOM for the lunar module. Any roving vehicle would have to fit on the same lunar module as the astronauts.