Astronomy:Apollo 21

"Apollo 21" is an apocryphal reference to an eleventh crewed Moon landing mission of NASA's Apollo program. Apollo contracted for the construction of fifteen Saturn V launch vehicles used to launch the Apollo spacecraft to the Moon, and achieved the first crewed landing with the sixth one (Apollo 11), leaving nine for follow-on lunar missions, through Apollo 20. However, budget cuts caused NASA to cancel the last three missions, ending the lunar program after Apollo 17. One Saturn V was used to launch the Skylab space station, and parts of the other two became museum displays.

An "Apollo 21" lunar landing mission appears in three twenty-first-century works of fiction.

Possible origin

The Apollo program used a Saturn V to launch the first crewed test of the complete Apollo spacecraft, consisting of the Apollo Command/Service Module and a separate Apollo Lunar Module landing craft in a low Earth orbit, on the Apollo 9 mission. However, the original plan for this test would have used two launches of the smaller Saturn IB Earth-orbital launch vehicle: the first would launch the crew in the Command/Service Module, followed shortly by a second, uncrewed launch of the Lunar Module, with which the crew would rendezvous in orbit. Some people have speculated that tentative plans of an "Apollo 21" might have been made assuming availability of the extra Saturn V that would have left, although by the time NASA resumed planning crewed missions using this numbering sequence (defined on April 24, 1967), the dual-Saturn IB plan had been replaced with the single Saturn V. There is no evidence NASA ever planned an eleventh Moon landing mission.

External links

• The Laika's Dream, Apollo 21 (Space Must be the Place)