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Utility of the Lunar Landing Training Vehicle

Commentary Copyright © 1995 by Eric M. Jones.
All rights reserved.
Last revised 24 September 2007

The following discussion is largely derived from my 1991 discussions with Gene Cernan and Jack Schmitt.

Schmitt - "As I recall, everybody was eventually supposed to go through LLTV training, but they were barely able to qualify all of the Commanders. All of us did get helicopter training as a precursor to the LLTV."

Cernan - "The reasoning behind giving only Commanders LLTV training, as best I can remember, was a combination of time, cost, and, quite frankly, safety. All the lunar module pilots wanted to fly the LLTV, strictly from a piloting point of view. When I was a lunar module pilot, I wanted to fly it. But, because we didn't have plans to land on Apollo 10, there wasn't any point in either Tom Stafford or I training in the LLTV; and, even for the actual landing missions, quite frankly, there was no need for LMP LLTV training. It would have been nice gravy to put on a chicken fried steak if the LMPs could have flown it as well as the Commanders; but, in reality, there was no need. There were two people to train for each flight anyway: the Commander and the Back-up Commander; and that pretty much took up all the time that was available. There were also some very real safety issues. We started out with four training vehicles, I believe, and we ended up with one. Joe Algranti (a NASA test pilot) ejected out of the first one. He was heading our aircraft operation before Neil ever flew the LLTV. And then two other people had to eject. So I was the last to fly the last one. It was a very unstable vehicle."

In all, Bell Aerosystems, Buffalo, NY built five LM trainers of this type for NASA. Two were an early version called the Lunar Landing Research Vehicle ( LLRV ). Neil Armstrong was flying LLRV-1 on May 6, 1968 when it went out of control. He ejected safely and the vehicle crashed. A later version was called the Lunar Landing Training Vehicle or LLTV and three were built. Two of these were lost in crashes on December 8, 1968 (LLTV-1 piloted by Algranti) and January 29, 1971 (piloted by Stuart M. Present). Both pilots ejected safely. The LLTV was a more accurate LM simulator and Gene is correct in saying that only one (NASA vehicle 952) was available for Apollo 17 training.

Cernan - "The LLTV gave us training in the critical final phases of the descent, from 500 to 700 feet on down. It had a J85 jet engine which, basically, maintained a constant thrust - based upon the weight of the vehicle - and took away 5/6th of the weight. That put you in a simulated lunar one-sixth gravity environment. You had sets of RCS thrusters, just like the lunar module, to control attitude; but, in addition, you had two other, vertically-mounted, hydrogen-peroxide-fueled 'lift' rockets that were capable of handling the extra one-sixth of the weight above the five-sixth that the J85 removed. They let you control how fast you went up or went down. To fly a descent, you'd use the lift rockets to fly yourself up to about five hundred feet. Then you'd start a forward trajectory and pick a landing point a few thousand feet down a runway. The key was to practice, and to get familiar with the dynamics of a six-degree-of-freedom machine. The more experience you got, the more you could displace yourself; or you'd give yourself errors; or, as you developed proficiency, instead of flying right straight down the runway, you could move over in the grass somewhere and put yourself in a position where errors were established before you started."

"The LLTV was inherently less stable than the LM itself; and we also had to contend with gusts of wind that could cause problems. But, LLTV training was very valuable because it really put your tail out on the line. It was not a simulator you could make a mistake in and then reset. If you made a mistake, you busted your ass, quite frankly. It also really brought home the uniqueness of the problems that you get with six degrees of freedom. By six degrees of freedom, I mean that not only could you roll, pitch, and yaw the vehicle and change your thrust direction because of the main engine, you could also use the RCS thrusters and move it laterally up, laterally down, laterally left, laterally right, laterally fore, or laterally aft. You had a combination of all those things to do when you landed a lunar module, and that is why the LLTV was so realistic. It was a great training device, one of a kind and probably never will be seen or used again. The 'flying bridge'. The ugliest thing in the world; but it was an ingenious idea and an ingenious design, and I don't know how else you could have ever put yourself in a one-sixth gravity flying environment, with rocket engines, here on Earth, and still have six degrees of freedom. Helicopters are just vertical flying machines, and they were nothing like this at all."

Also used in training and in the development of the landing systems was the Lunar Landing Research Facility - shown here with Neil standing in front of the LM mock-up. The facility consisted of a large, overhead gantry which allowed the cable-suspended LM mock-up to be moved forward and down - or up and back - in response to pilot input. The figure consists of a set of multiple exposures showing the mock-up as it comes in for a landing. A view from behind and one from the side show the vehicle approaching touchdown. Note that the 'craters' are painted on the flat tarmac. Both images are frames captured by Ken Glover from a 16mm film of a training session by either Neil or Buzz in late June 1969.

In 2002, I was reminded that the Apollo 15 Training Log shows that, on 24-25 March 1970, Jack was at Langley AFB using the LLRF. Although the Apollo 15 Prime and Back-up crews were not announced until 27 March 1970, the training log shows Jack's first Apollo 15 training session was a LM Radar Briefing on 27 October 1969. Dick Gordon, the Back-up Commander, didn't join Jack in training until 3 April 1970, following the conclusion of the Apollo 12 PAO tour.

Schmitt, from a 2002 e-mail - "As I remember, that was my only use of the LLRF at Langley and I had several runs during those two days. Originally, LMPs also were going to check out in the LLTV. Development and test delays and having the LLTV operational long enough to train CDRs, however, prevented this from happening."

"Al Shepard told me in January 1970 that I would soon be assigned to a back-up crew and that I should start stealing some simulator time. I had already been doing this for many months and just increased the level of activity to scheduling time whenever the MSC or KSC, CSM or LM simulators were available. In fact, this was the reason that I was at KSC rather than Houston right after Apollo 13 launched - the simulators were available. That meant that when the Apollo 13 explosion occurred, I immediately began to work with the KSC simulator operators to develop and test navigation and engine burn procedures we thought 13 would need as well as test those developed at MSC."

"The simulator operators at both MSC and KSC were great and spent a lot of time with me as I learned the various systems and subsystems as they were presented in the two cabins. I also scheduled a lot of time with the contractor training personnel that understood the details of the various CSM and LM systems. I worked alone until Dick Gordon, Vance Brand and I began to work as a crew, probably after Apollo 13 returned, the 12 crew was free of post-flight activities, and the Apollo 15 prime and back-up crews were assigned internally. April 1970 sounds about right as my memory is that we trained for 15 months for the July 1971 launch of Apollo 15."

Note added 13 December 2005: Journal Contributor Brian Lawrence adds that, based on unconfirmed but seemingly plausible postings to sci.space.history, "In December 1966 Deke Slyton assigned six guys to do the initial testing of the LLRV. They were the CDRs and LMPs of the early crews who might have been assigned to flights with an LM. They were Borman/Anders, Conrad/Williams, and Armstrong/Aldrin. Williams made one - possibly two - flights in February 1967 before the training was put on hold for a year. He died in an aircraft accident in October 1967. Starting in February 1968 the other five men got their chance. When Neil ejected from LLRV #1 (6 May 1968), he had made 21 flights while Pete had made 13. The other three (Borman, Anders, Aldrin) had made 18 flights between them. When flights resumed in June 1969, there was no time for any of the LMPs to fly the vehicle."

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