Slashdot Mirror
"Father of the Space Shuttle" George Mueller Dies At 97 (washingtonpost.com)
The Washington Post reports that long-time NASA engineer and administrator George Mueller died on October 12 of congestive heart failure, at 97. Mueller had a hand in NASA programs as Associate Administrator of the NASA Office of Manned Space Flight going back to the Apollo program, but not only as an administrator: he played a large role in the design of Skylab, and in lobbying for the Space Shuttle; this last earned him the (sometimes disputed) nickname of "Father of the Space Shuttle." During his Apollo days, Mueller became well known for his insistence on "all-up" testing, rather than incremental, per-component tests. From the Washington Post's story:
As applied to the space program, [all-up testing] implied specifically such techniques as the testing of all three stages of the giant Saturn V booster rocket while they were coupled together and with a payload attached to boot. It was reported that the scheme had its doubters, among them such leading lights of rocketry as Wernher von Braun. But in time, the forceful Dr. Mueller proved persuasive enough to overcome all such reservations, and it was “all up” for the mammoth Saturn V, the launch vehicle upon which NASA pinned its hopes of sending Americans to the moon.
At least when it came to solid boosters.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
The problem comes when you want to test the first stage of your rocket in flight. It needs to be tested in an environment as close as possible to a real launch. You either spend a lot of money building a fake second and third stage, or you put a real second stage on top. That also has to be tested in an environment as close as possible to a real launch. So you spend a lot of money building a fake third stage, or you put a real third stage on top. Then you need a realistic payload. So you might as well put a real spacecraft on top.
So long as there's a good chance of the first stage working, you probably save money and time in the long run by just launching the whole thing. You can test whichever stages work, and you don't have to spend money building fake stages.
I work at KSC and here is the issue. Sometime just creating the relevant environment is more expensive then just having a test flight. For example to simulate the aerodynamic and vibration loads on a rocket stage are near impossible. We will shake the avionics or even whole spacecraft. But nobody has a shaker big enough for a whole stage so you need to test it in flight. And for example on the Saturn V are you just going to test the first stage? Then you need to simulate the rest of the vehicle weight, cg, and aerodynamic loads. At that point its just easier to use the second and third stage.
I love Jesus, except for his foreign policy.
uh, no. the spacecraft is usually the most expensive part of the launch, especially if it's a man-rated craft.
A Saturn V launch cost about $2,000,000,000 in today's money. So adding another test flight to test the spacecraft after you've already tested the Saturn V would add $2,000,0000,000 to the development cost.
Usually, you need a mixture of approaches to get things to work. Idealism in software engineering, or in engineering, works about as well as idealism in politics, ie it doesnt really, it misses key points. But, in both areas, it's much easier to create a platform on idealism, and so people who propose one single idealistic viewpoint often do quite well.
In practice, in software engineering, saying 'all tests must be automated, 100%', misses that some things are really hard to test automatically, but can be tested by hand quite simply. Similarly for creating test harnesses, mocking, which this article is the hardware-engineering equivalent for. Sometimes it's easier to mock, and do real 'unit-testing', and sometimes it isnt, and insisting that every project, and every part of every project, uses the exact uniform standard, might not always work as well as it looks like it will in the Powerpoint presentation :-P
MSFC has a "shaker" big enough. A whole Saturn V rocket, and then later a Space Shuttle, were tested in the dynamic test stand here.