Henry Spencer

“In the long run, it's impossible to make progress without sometimes having setbacks, although people who get lucky on their first attempt sometimes forget this.”

“NASA has never had a problem finding capable people to be astronauts. NASA's problem was, and still is, finding ways to cut the list of capable applicants down to a manageable length.”

“In the first few years, it was at least plausible to come in in the morning and read all the Usenet traffic that had come in, and 15 minutes later be off doing something useful.”

“As plans for the first lunar landing started to be made, nobody had really thought about who would be out first.”

“Testing a parachute drop of a heavy object is not simple.”

“If your goal is to change the world, you can't start by doing things the same old way because it sells better.”

“Speaking of photography, while the Apollo 8 crew shot hundreds of photos, there was one that got everybody's attention: a blue-and-white Earth rising over a gray moonscape.”

“Sure, there were hopes that Constellation's systems could later be adapted to support more ambitious goals. But Apollo had those hopes, too. It didn't work in 1970, and it wasn't going to work in 2020.”

“The communications delays between Earth and Mars can be half an hour or more, so the people on the ground can't participate minute by minute in Mars surface activities.”

“Claiming that solid rockets are necessary for a heavy-lift launcher is obvious nonsense.”

“On the technical side, Apollo 8 was mainly a test flight for the Saturn V and the Apollo spacecraft. The main spacecraft system that needed testing on a real lunar flight was the onboard navigation system.”

“It's true that Apollo 10's lander was overweight. Late in the craft's development, it became clear that its ballooning weight was endangering the whole mission.”

“Since SpaceX's very beginnings, they have talked about recovering and reusing at least the first stages of their rockets.”

“Reusable rockets promise much easier testing because you should usually get them back, and you can debug as you go rather than having to get everything perfect the first time.”

“The Apollo programme of the 1960s had some weight problems, too; in particular, the lunar lander needed some fairly drastic weight-reduction work.”

“The demise of Constellation is not the death of a dream. It's just the end of an illusion.”

“SpaceX does seem to have had a run of bad luck, with its first three launches all failing.”

“Whether solid rockets are more or less likely to fail than liquid-fuel rockets is debatable. More serious, though, is that when they do fail, it's usually violent and spectacular.”

“Is manned space exploration important? Yes - not least because it simply works much better than sending robots.”

“Spaceflight, especially in the Mercury spacecraft, clearly wasn't going to be much like flying an airplane.”