Luminary 69 rev. 2 might well have been able to land Lunar Module 5, Eagle, the first LM that was light enough *structurally* to have the propellant margins needed to fly the landing mission. LM-4 was too heavy with a proper flight load of propellant so that would have been incredibly risky. Had mission managers decided they wanted Apollo 10 to do the landing (and there was at least one) they would have had to wait for LM-5 and launch in July anyway. By then the whole program was on a roll. They had ramped up to a launch cadence of about every two months that would have gotten them three shots at a landing before 1969 was finished.

Also, the crew landing procedures and simulations were still being worked out to give them sufficient confidence to do the big thing (landing) and may not have been ready for flight in May. The commander of Apollo 10, Tom Stafford, with Low, Gilruth, and Maynard finally decided it was really worthwhile to test out the rest of the whole landing plan, including descent orbit insertion and then rendezvous, so that the only new thing Apollo 11 would have to do would be land and take off. It was a good decision!

Great video and cool work. Just wish Ron Burkey and his Virtual AGC website was given more props.

Okay, let's call the computer program that does the docking by itself the autopilot. What I should probably call the thing that turns target attitudes and/or attitude rates into thruster firings is an Attitude Control System (ACS). So the autopilot figures out from sensors where it is relative to the docking port and maneuvers along a predetermined path at various target rates by issuing pointing and translating commands. The ACS takes those commands and figures out which of the 12 available thrusters to fire based on the current mass of the spacecraft and the torque and translation vectors the thrusters can provide. If the autopilot crapped out, the astronauts would manually figure out the path and issue pointing and translating commands which the ACS would execute. The sim we get to play with does not have an attitude hold mode (something the real spacecraft's ACS should have) and so that part of it is harder than the real thing. If the ACS crapped out as well, the crew would be screwed, as would we be (with less serious consequence).

That's a good point. I think the onboard computer does the actual docking maneuver with the crew watching. If they have to take over, they can by flying it manually, as in the sim. My point is that the attitude control during that manual flying is mediated by the computer as well, such as an attitude hold mode, where the crew commands attitude rates then commands an attitude stop which the autopilot holds. Full manual, like controlling which thruster fires directly, is probably (nearly) impossible.

This sim is cute and gives you some idea of what docking is like, but is probably much harder than flying the real thing. The attitude of the real spacecraft would be held, within a tight deadband, by the autopilot. In other words, you should be able to maneuver to a pointing angle then stop without worrying that you'll move away from it. The dynamics are also very much simplified and don't reflect the weird drifting in height (radial direction) as you move (accelerate) in against the velocity direction.

So now Bridenstine wants to take what NASA stands for and make it stand for anything else? The US Army could do the same with their uniforms. Make them like NASCAR outfits with logos and stuff (just as bright though, so they stand out). Judges could logo up their robes so we know who's paying for justice. We already pay for something that is supposed to stand for what is best in us, pushing at the final frontier. If the endeavor is not worth it, selling ads for chump change will make that clear.

In any combination of Boeing, Sierra Nevada, SpaceX, or Lockheed Martin vehicles, we'll get up there with people fairly soon and in modern spacecraft that will be able to do useful things for the next few decades. What we do with them then and how much it will cost is the key question. The NASA program is stuck in pork that traps its potential so we may well lose the Space Station. Not many really care about it anyway, other than those who work on it. Those companies that are innovating for cost, certainly SpaceX, perhaps Sierra Nevada and Boeing, could make the NASA program moot. The Russian problem of access to the ISS might accelerate the non-NASA New Space regime slightly, but it will happen. If our national space program can take advantage of this new capability, if the politics of supporting old players dies, we could be in for an exciting future of human space exploration. That might still happen if human spaceflight becomes a mostly private affair. We'll know in a few years.

If we have the capacity to change the fundamental dynamic, right now, why would we want to increase nuclear? Efficiency will much more cheaply get us where we need to go in the short term and profit-driven developments in wind/solar/"renewables" will get us where we need to be in 30-50 years. The nuclear option is idiotically expensive and a step away from distributed power generation. We can't afford it!

handy_vandal's last line is the whole answer: Mindset. Google "carol dweck" mindset. Change your mindset and you don't have to pose the question.

Who wants to make a big deal about this "secret" information? Old guys that want some reflected glory. Now I am NOT talking about the overwhelming number of Apollo folks who have managed to keep their memories close to the events and are very willing to share them. But even there, conflation and haziness often combine to set the history just a little wrong. You need primary sources. Documents from the time period are best.

The linked story is a great example of why you should never listen to what old men remember about great events and their (often "heroic") part in them. At no time did NASA need some graduate student from MIT to help them with a Guidance 101 type problem on Apollo 13. The difficulty was in getting the Lunar Module prepped quickly enough to make a small burn that would get them on a free return trajectory, the same type used on the previous four Apollo missions to the moon. Apollo 13 was the first to use a less safe trajectory so they could visit a more interesting place, Fra Mauro. There were always many ways out of a pickle and abort guidelines had been carefully developed for different phases of the mission. At the point of Apollo 13's explosion, a direct abort going straight back was never possible, not least because their big engine was in the now dead Service Module. Free return was the only option. There *was* a very famous "hippy" type guy at the MIT Instrumentation Lab, Don Eyles, who was responsible for much of the Lunar Module's landing program. On Apollo 14 he was instrumental in solving a problem that would have prevented that landing and he did get official recognition for it and there are pictures of him with his long hair and mustache. So that's another part of the Gizmodo crap article that is wrong. As far as the photos of the Apollo 11 astronauts on the moon go, there were about three pictures taken by Aldrin with Armstrong only incidentally in the frame. The shot with the flag is definitely of Aldrin, as you can see Armstrong taking the picture in the 16mm film taken from the Lunar Module window. Aldrin, unconsciously or deliberately, never took a proper picture of his fellow crew member and commander. It was only after Apollo 12 that a photo specialist at the Houston space center suggested red armbands for the commander to distinguish him in the photos and Jim Lovell, the Apollo 13 commander, never got to show them off, alas.