In November 1961, Houbolt took the bold step of skipping proper channels and writing a 9-page private letter directly to incoming Associate Administrator Dr. Robert C. Seamans. Describing himself somewhat melodramatically “as a voice in the wilderness,” Houbolt protested LOR’s exclusion from the NASA debate on the Apollo mission profile. “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.” Houbolt clearly saw that the giant Nova rocket and the expensive and complex Earth orbit rendezvous plan were clearly not a realistic option–especially if the mission was to be accomplished anywhere close to President Kennedy’s timetable. While conducting a rendezvous in orbit around the Moon was going to be a challenge, the weight, cost and savings of using LOR were obvious once one realized that LOR was not fundamentally much more difficult than Earth orbit rendezvous. This insights, and Houbolt’s brave and energetic advocacy of it, made all the difference.
It’s just a shame that they didn’t do earth-orbit rendezvous as well with smaller vehicles. We could have avoided the Saturn V and the Apollo Cargo Cult.
RIP. He was highlighted in some Apollo documentaries, and I think he was portrayed in that HBO series on Apollo.
RIP.
As a related question, could someone please explain to me the reasoning against Earth Orbit Rendezvous? The explanation I’ve seen is “It was judged too technically challenging” and that makes no sense to me, because I can’t see why rendezvous in earth orbit would be harder than rendezvous in lunar orbit, which they did use. As the quoted part mentions, LOR had great advantages for a moon mission, so why, exactly, if you can do it in lunar orbit, would it be hard to do it in LEO? Assuming you had a launch capability for each component (SM/CM, LEM, TLI stage) why would earth orbit assembly (simple docking) be so hard? Heck, they did some of that for Apollo; the LEM launched under the service module, so had to be repositioned and docked with the command module after the TLI burn. Then, of course, they had to do LOR as well after lunar ascent.
I don’t see how EOR instead of the S5 (which took a lot of time to develop) would have delayed the lunar landing? It might have even accelerated it, as it would have eased the mass constraints on the LEM.
I think you mixing up LOR’s LEM and separate command/service module with EOR. EOR was the same as direct ascent (one vehicle all the way), but launched into orbit on two rockets instead of one giant one. Once the two had mated in Earth orbit, the one moon ship would go out, enter lunar orbit, decelerate and land, and then blast off for Earth return. There would be no CSM in lunar orbit to meet it, so the fuel for returning to Earth would have to be carried all the way to the lunar surface and back up. This meant the lander would have to be very large and heavy.
Yes, and one of problems with EOR was that you would need to launch two rockets in a very short time frame, which they felt increased the odds of failure.
That may well have been the belief at the time, but it’s not necessarily true. It certainly isn’t if you use storable propellant for TLI or for unmanned launches, say for propellant or a mostly empty lander, because in that case the payload can go first and doesn’t boil off. This removes the time pressure on a cryogenic transfer stage. Crew is more difficult without a space station, because it’s not reasonable to expect a crew to spend two weeks in LEO before departing to the moon. The simplest solution might have been to use a storable transfer stage for the crew, possibly also used as crasher stage for the lander.
Automated docking would indeed have been a challenge, but the Soviets had mastered it by 1967. I think the US could have done so too, and that it would have been simpler than building the Saturn V.
Yeah. But you could do EOR/LOR. The problem is the dual launch architecture. It increases the possibility something will go wrong and at the time automated docking was considered a hard problem to solve.
Sorry, I garbled that. By EOR, I meant assemble the lunar vehicle in earth orbit; basically launch the CM, SM, and LEM on one launcher, and the TLI stage on a second.
The LEM wouldn’t be the CM – it’d still need to do LOR. I wasn’t thinking of EOR instead of LOR.
@ Thomas; yep, it’d require two launches in a short timeframe. That would be a challenge, but my hope was it’d be less of one (fiscally as well) then building the Saturn5.
@ Godzilla; yep, EOR/LOR is what I meant but I wrote it fuzzily. 🙂 Why automated docking though? Just launch the CM/SM first, dock it to the LEM, then dock it to the TLI stage when it gets there. About the only problem I see with doing this with Apollo hardware is docking the CM/SM aft-first to the TLI stage; the CM windows wouldn’t allow a view that way, and I don’t think they had flight-practical closed circuit TV capabilities way back then. The only workaround I can think of short of a redesign is to do the docking of the TLI stage and the CM/SM/Lem stack from the LEM, using its thrusters. (the LEM did have a window facing in the appropriate direction, but… now I think about it, the CM/SM would still be in the way of what they needed to see.
One important fact that gets left out of the official histories (which were written by the winners): Houbolt was not trying to “save Apollo.” He was arguing for Lunar Gemini, which was a Langley program.
NASA accepted the LOR idea, but wouldn’t let the Gemini do it. The Gemini “bug” (greatly enlarged) became the Apollo LEM.
Had NASA allowed GeminI to go ahead, instead of protecting Apollo, they might have gotten to the Moon more cheaply and sooner. Whether it would have been cheap enough to make a difference (i.e., avoid cancelation) is unknowable, of course.
Very interesting. Even back then pork was a driving factor behind architecture decisions.