Editing Apollo 13 (section)

== Training and preparation ==
[[File:Lovell deploying the flag.jpg|thumb|upright|Lovell practices deploying the flag]]

The Apollo&nbsp;13 prime crew undertook over 1,000 hours of mission-specific training, more than five hours for every hour of the mission's ten-day planned duration. Each member of the prime crew spent over 400 hours in simulators of the CM and (for Lovell and Haise) of the LM at KSC and at Houston, some of which involved the flight controllers at Mission Control.{{sfn|Apollo 13 Press Kit|1970|p=104}} Flight controllers participated in many simulations of problems with the spacecraft in flight, which taught them how to react in an emergency.<ref name = "Cass 1" />  Specialized simulators at other locations were also used by the crew members.{{sfn|Apollo 13 Press Kit|1970|p=104}}

The astronauts of Apollo 11 had minimal time for geology training, with only six months between crew assignment and launch; higher priorities took much of their time.{{sfn|Phinney|2015|p=100}} Apollo 12 saw more such training, including practice in the field, using a CAPCOM and a simulated backroom of scientists, to whom the astronauts had to describe what they saw.{{sfn|Phinney|2015|pp=103–104}} Scientist-astronaut [[Harrison Schmitt]] saw that there was limited enthusiasm for geology field trips. Believing an inspirational teacher was needed, Schmitt arranged for Lovell and Haise to meet his old professor, [[California Institute of Technology|Caltech]]'s [[Leon Silver|Lee Silver]]. The two astronauts, and backups Young and Duke, went on a field trip with Silver at their own time and expense. At the end of their week together, Lovell made Silver their geology mentor, who would be extensively involved in the geology planning for Apollo&nbsp;13.{{sfn|Phinney|2015|pp=107–111}} [[Farouk El-Baz]] oversaw the training of Mattingly and his backup, Swigert, which involved describing and photographing simulated lunar landmarks from airplanes.{{sfn|Phinney|2015|p=134}} El-Baz had all three prime crew astronauts describe geologic features they saw during their flights between Houston and KSC; Mattingly's enthusiasm caused other astronauts, such as Apollo 14's CMP, Roosa, to seek out El-Baz as a teacher.{{sfn|Phinney|2015|pp=141–142}}

Concerned about how close Apollo 11's LM, ''Eagle'', had come to running out of propellant during its lunar descent, mission planners decided that beginning with Apollo&nbsp;13, the CSM would bring the LM to the low orbit from which the landing attempt would commence. This was a change from Apollo 11 and 12, on which the LM made the burn to bring it to the lower orbit. The change was part of an effort to increase the amount of hover time available to the astronauts as the missions headed into rougher terrain.{{sfn|Harland|1999|p=53}}

The plan was to devote the first of the two four-hour lunar surface [[extravehicular activity|extravehicular activities]] (EVAs) to setting up the [[Apollo Lunar Surface Experiments Package]] (ALSEP) group of scientific instruments; during the second, Lovell and Haise would investigate [[Cone (crater)|Cone crater]], near the planned landing site.{{sfn|Orloff & Harland|2006|p=363}} The two astronauts wore their spacesuits for some 20 walk-throughs of EVA procedures, including sample gathering and use of tools and other equipment. They flew in the "[[Reduced-gravity aircraft|Vomit Comet]]" in simulated microgravity or lunar gravity, including practice in donning and doffing spacesuits. To prepare for the descent to the Moon's surface, Lovell flew the [[Lunar Landing Research Vehicle|Lunar Landing Training Vehicle]] (LLTV) after receiving helicopter training.{{sfn|Apollo 13 Press Kit|1970|p=105}} Despite the crashes of one LLTV and one similar Lunar Landing Research Vehicle (LLRV) prior to Apollo 13, mission commanders considered flying them invaluable experience and so prevailed on reluctant NASA management to retain them.<ref>{{cite web|last=Jones|first=Eric M.|title=Lunar Landing Training Vehicle NASA 952|date=April 29, 2006|access-date=January 4, 2021|url=https://history.nasa.gov/alsj/LLTV-952.html|publisher=[[NASA]]|work=Apollo Lunar Surface Journal}}</ref>