Editing Lunar orbit rendezvous (section)

=== Advocacy ===
[[File:John C. Houbolt - GPN-2000-001274.jpg|thumb|[[John Houbolt]] explains Lunar orbit rendezvous]]
Dr. [[John Houbolt]] would not let the advantages of LOR be ignored. As a member of Lunar Mission Steering Group, Houbolt had been studying various technical aspects of [[space rendezvous]] since 1959 and was convinced, like several others at [[Langley Research Center]], that LOR was not only the most feasible way to make it to the Moon before the decade was out, it was the only way. He had reported his findings to [[NASA]] on various occasions but felt strongly that the internal task forces (to which he made presentations) were following arbitrarily established "ground rules." According to Houbolt, these ground rules were constraining NASA's thinking about the lunar mission—and causing LOR to be ruled out before it was fairly considered.<ref name=":0" />

In November 1961, Houbolt took the bold step of skipping proper channels and writing a nine-page private letter directly to associate administrator [[Robert C. Seamans]]. "Somewhat as a voice in the wilderness," Houbolt protested LOR's exclusion. "Do we want to go to the Moon or not?" the Langley engineer asked. "Why is Nova, with its ponderous size simply just accepted, and why is a much less grandiose scheme involving rendezvous ostracized or put on the defensive? I fully realize that contacting you in this manner is somewhat unorthodox," Houbolt admitted, "but the issues at stake are crucial enough to us all that an unusual course is warranted."{{sfnp|Tennant|2009}}{{sfnp|Hansen|1995}}

It took two weeks for Seamans to reply to Houbolt's letter. The associate administrator agreed that "it would be extremely harmful to our organization and to the country if our qualified staff were unduly limited by restrictive guidelines." He assured Houbolt that NASA would in the future be paying more attention to LOR than it had up to this time.

[[File:Comparison of Lander Sizes - Direct vs LOR.gif|thumb|Comparison of lunar lander sizes, from an early Langley study]]
In the following months, NASA did just that, and to the surprise of many both inside and outside the agency, LOR quickly became the front runner. Several factors decided the issue in its favor. First, there was growing disenchantment with the idea of [[direct ascent]] due to the time and money it was going to take to develop a {{convert|50|ft|m|adj=on}} diameter [[Nova (rocket)|Nova rocket]], compared to the {{convert|33|ft|m|adj=on}} diameter [[Saturn V]]. Second, there was increasing technical apprehension over how the relatively large spacecraft demanded by Earth-orbit rendezvous would be able to maneuver to a soft landing on the Moon. As one NASA engineer who changed his mind explained: <blockquote>The business of eyeballing that thing down to the Moon really didn't have a satisfactory answer. The best thing about LOR was that it allowed us to build a separate vehicle for landing.</blockquote>

The first major group to change its opinion in favor of LOR was [[Robert R. Gilruth|Robert Gilruth]]'s Space Task Group, which was still located at Langley but was soon to move to Houston as the [[Lyndon B. Johnson Space Center|Manned Spacecraft Center]]. The second to come over was [[Wernher von Braun]]'s team at the  [[Marshall Space Flight Center]] in [[Huntsville, Alabama]]. These two powerful groups, along with the engineers who had originally developed the plan at Langley, persuaded key officials at NASA Headquarters, notably Administrator [[James E. Webb|James Webb]], who had been holding out for direct ascent, that LOR was the only way to land on the Moon by 1969. Webb approved LOR in July 1962.{{sfnp|Witkin|1962}} The decision was officially announced at a press conference on July 11, 1962.{{sfnp|NASA|1962|p=1}} President Kennedy's science adviser, [[Jerome Wiesner]], remained firmly opposed to LOR.{{sfnp|Nelson|2009|pp=209–210}}<ref name=":0">{{Cite web|url=https://www.nasa.gov/centers/langley/news/factsheets/Rendezvous.html|title=The Rendezvous That Was Almost Missed: Lunar Orbit Rendezvous and the Apollo Program – NASA|date=December 1992|website=www.nasa.gov|language=en|id=Fact Sheet NF175|access-date=2017-03-20|archive-date=2020-12-23|archive-url=https://web.archive.org/web/20201223201720/https://www.nasa.gov/centers/langley/news/factsheets/Rendezvous.html|url-status=dead}}<!-- This NASA Facts was prepared by the NASA Langley Research Center Office of Public Affairs, with the assistance of Dr. James R. Hansen, author of ''Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917–1958'' --></ref>