Quotes from Henry Spencer

Rocket engines generally are simpler than jet engines, not more complicated.

Large solid rockets have never been a very good way to build launchers that might have crews on top, especially because of the problems in getting the crew away from a failing launcher.

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

Progress requires setbacks; the only sure way to avoid failure is not to try.

Altruism is a fine motive, but if you want results, greed works much better.

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

Not until the space shuttle started flying did NASA concede that some astronauts didn't have to be fast-jet pilots. And at that point, sure enough, women started becoming astronauts.

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

In a small spacecraft, it was hard for the other two guys to sleep when the on-duty man was talking to Mission Control regularly.

An experienced designer with more freedom to act might have realised that there was just too much optimism in the Ares I concept: that a shuttle SRB was simply too small as a first stage for a rocket carrying the relatively heavy Orion spacecraft.

Trying to build a spaceship by making an aeroplane fly faster and higher is like trying to build an aeroplane by making locomotives faster and lighter - with a lot of effort, perhaps you could get something that more or less works, but it really isn't the right way to proceed.

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.

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.

Foul-ups in testing are not uncommon, especially when the test setup is being tried for the first time.

The Moon may not be quite as appealing as Mars, but it's still a complex and poorly understood world, with many questions still unanswered.

Historically, the U.S.'s big launchers fly seldom enough that their costs are dominated by annual upkeep of facilities and staff, not by the actual cost of each launch. The expensive part is maintaining the launch capability, not actually conducting launches.

Programming graphics in X is like finding the square root of PI using Roman numerals.

Those who do not understand UNIX are condemned to reinvent it -- badly.

We're thinking about upgrading from SunOS 4.1.1 to SunOS 3.5.

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.

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.

Liquid oxygen is one of the cheapest manufactured substances on Earth. In large quantities, it costs pennies per kilogram - cheaper than milk or beer.

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.

The key virtue of orbital assembly is that it eliminates the tight connection between the size of the expedition and the size of the rockets used to launch it.