Faster Cars and Smellier Air

Government is not perfect. But properly managed, it can harness our collective genius in times of challenge.

Government investment brought us the Internet, put us on the Moon, and built a system of trails and highways that reach from one end of this country to the other. New investments like these in energy technology can save us from global climate change and from our dangerous dependence on foreign oil. The money we spend will also put Americans to work and help jump start our stalled economy.

http://my.barackobama.com/page/content/newenergy

It’s Election Day in the United States, everybody. Let’s do this.

Josh has a new article up about “spacediving”. The enormous speeds we ordinarily associate with atmospheric re-entry result from de-orbiting. If you just go straight up and straight down, re-entry speeds are reduced to the point where spacediving ceases to be impossible and becomes merely gonzo-stupid.

Proceeding from this premise, the beryllium heat shield on Alan Shepherd’s Freedom 7 Mercury Spaceship must have been fairly over-designed. Freedom 7’s non-orbital, ballistic trajectory reached a top altitude of 187 kilometers (116.5 miles). If you dropped an anvil from this height through a vacuum, it would hit the ground at about 1,755 meters per second (5,758 feet per second.) Of course, in Earth’s atmosphere the anvil would reach terminal velocity before achieving this speed.

15 minutes and 22 seconds after blast-off, Freedom 7 splashed down 486 kilometers (302 miles) from its launch pad. That corresponds to an average Eastward velocity in the same ballpack as our idealized anvil — about 527 meters per second (1,730 miles per second.)

Cringely has a surprising article this week about the use of giant kites to harvest electricity from the wind. The hardest part of flying a kite is launching it, and I’m a little hazy on how they plan to get these monsters off the ground, where the windspeed is modest. But the proponents think they can generate electricity for the game-changing price of 0.5 cents a kilowatt hour. Forget windmills, this price beats coal. Reportedly, the Google People are involved, which suggests this is science fiction rather than fantasy.

It’s gratifying to see somebody draft aerospace engineering to fight global warming. I’m reading an interesting book, Break Through: From the Death of Environmentalism to the Politics of Possibility, which suggests that efforts to reduce global poverty can also help combat global warming. The conventional wisdom says that economic progress will result in more industry and therefore more pollution. The authors of Break Through argue convincingly that nations must escape poverty before they feel secure enough to focus on environmental issues and expend the kind of resources necessary to really secure rain forests and reduce greenhouse gas emissions. The authors advocate a new Apollo project (again with the aerospace engineering!) to jumpstart large-scale clean technologies that we can share with them and, of course, use ourselves.

I’ll keep riding my bike to work, but this is good stuff.

Now that Discovery is happily back safe and sound, it’s hard not to be dissapointed about another ginormous chunk of foam detaching from its external fuel tank after everyone worked so hard to prevent it.

There were some successes here. Notably, the repair process worked well. The centerpiece of this success was Canadarm, the newly-extended remote manipulator arm contributed by our friends to the north.

I agree with astronaut Scott J. Horowitz and others that the design of the shuttle is simply too complicated. If you amortize the total cost of the program, each launch burns about a billion dollars, and human resources account for much of it.

There is really no effective way to test the shuttle. Other manned rocket systems are launched dozens of times without people in them before they are considered safe. Only the pieces of the shuttle can be tested. As Richard Feynman pointed out in the Challenger investigation chapter of his excellent book, when you assemble 100 components that each are 99% reliable, you should expect the resulting machine to be less than 36.6% (0.99 ^ 100) reliable. The only ways around this problem are to use fewer components, or to rigorously test the finished assembly.

When considered against the initial goal of routine access to space, one has to conclude that the space shuttle program has not been a success. In the near future, a return to more conventional rocket technology is appropriate. However, we can’t drop the ball developing the promising scramjet technology. If we ever have spaceships like the kind they have in Firefly, they’re going to use scramjets. We should take all the money we save by scrapping the next generation space shuttle and invest heavily in non-military scramjet research. And, of course, continue the highly successful unmanned exploration programs to Mars and the outer solar system.