Friday, July 8, 2011
Today, hopefully, Atlantis will launch and it will be the final mission for the Space Shuttle Program.
The biggest problem with the Space Shuttle was it worked good enough.
When it was originally conceived there was supposed to be 20 shuttles that would rotate through with a launch every two weeks. This would lower the cost per launch dramatically as their would always be a shuttle in space, one being prepped, one being reconditioned after the mission. So even though NASA would have a much bigger workforce, there would be no downtime.
Two things killed that plan. Budget cuts forced NASA to only have 4 shuttles. So they hoped for a launch every month.
Unfortunately, the shuttle wasn't quite reliable enough for that schedule. However it was reliable enough to ensure the space program could go on. If it were a little less reliable it would have been scrapped earlier and replaced with something more reliable. If it were reliable enough to hold the once a month schedule America could have built its own space station in the 90s and open up new markets in space. That would force congress to give space exploration a bigger budget and NASA would have to build a new space craft.
Since the Space Shuttle was “good enough” all our space missions revolved around a few launches every year.
It also wasn't the safest design. Placing the crew next to the engines, instead of on top of them, was riskier but not so risky to stop the program.
2 out of roughly 100 missions ended in disaster, 2%. That is good enough odds for most people wanting to go in space. I'd take those odds. But it meant huge redesigns to try and give better odds. If it had been less safe, a safer replacement would have been made. If it were safer there would have been more missions per year. The Space Shuttle was “Safe Enough” to keep flying.
It was also expensive, half a billion dollars per launch. If it were more expensive it would be worth going back to the drawing board and coming up with a new one. If it were less expensive there would be more launches and more things done in space giving NASA a powerful reason to build a successor.
In the end it was “Cheap Enough” to keep the program going.
The problem of having the Space Shuttle being “Good Enough” at everything is in building a replacement its hard to justify taking the next small step in improvement. If the Space Shuttle can do 4 to 8 missions a year, it's tough to justify spending billions to replace it with one that can do 8 to 12 missions a year. So any replacement had to have a two week turnaround time. That would be a remarkable feat.
Having the Space Shuttle being “Safe Enough” meant a replacement needed to be as safe as an airplane. Something that is probably impossible.
Having the Shuttle being “Cheap Enough” to fly meant it was hard to justify building a new craft that had a 20% saving or $100 million per launch. So any replacement needed to have huge cost savings.
The Space Shuttle was a remarkable machine, but it was cursed by being good enough not to justify building a replacement but not so great that a true successor could be built.
With the end of the Space Shuttle program new spacecraft can be built that are slightly better, not so much better that they are impossible.
Getting the odds of disaster down to 1 in 100 is doable and insurable. $150,000 per flight per passenger in insurance.
One launch per month is doable.
Getting launch costs down 20% per ton. Is doable.
Perfect is the enemy of good as perfect is impossible. With the end of the Space Shuttle program we can look to build a better spacecraft instead of trying the impossible and building the perfect spacecraft.
So goodbye Space Shuttle, if you were a little better or a little worse you would have been replaced years ago. If congress is willing your retirement will lead to a slightly better replacement and that will lead to a fantastic future.
By Darrell B. Nelson author of I KILLED THE MAN THAT WASN'T THERE