This is starting to repeat like a broken record ... From Spaceflight Now, yet another Dragon delay:
The target launch date for SpaceX's first test flight to the International Space Station is now no earlier than late April, the company announced Thursday, as the California-based firm and NASA continue extensive software testing to prove the Dragon spacecraft can safely approach the 450-ton orbiting complex.
"SpaceX is continuing to work with NASA to set a new target date for launch, expected to be late April," SpaceX said in a statement. "The primary driver for the schedule continues to be the need to conduct extensive software testing. This is a challenging mission, and we intend to take every necessary precaution in order to improve the likelihood of success."
There are two problems I have heard of. One is related to DOD requirements for the self-destruct system. Apparently DOD (like NASA) doesn't provide a complete specification, but reviews each design with which it is presented. The DOD review of the first Falcon 9 launch took some time and to have any chance of approval SpaceX was required to use a range safety system that has been in use for many years, which blows up the entire booster. This was probably a good idea in the 1950's, when the only way to tell which way a rocket was going was to watch the exhaust trail, but today almost every other launch site in the world uses a safer and much less expensive system that simply shuts down the engines. The next launch was to have added additional payloads in the "trunk" section behind the capsule, and moved parts of the self-destruct system, and apparently the DOD decided not to approve the minor change.
ReplyDeleteAnother problem seems to be a disagreement over testing and documentation requirements for the electronics. NASA normally requires a lot of testing and documentation on individual components, before they are assembled into systems. SpaceX apparently did their testing only on the completed systems, which they presumably had the freedom to do under the Space Act Agreement, but when it came time to actually dock with the ISS NASA would not approve it.
Deciding who is actually correct in these situations is a challenge. One could test forever but then the rocket will be too expensive to compete in the world market. But if you cut too many corners you may miss a problem and the vehicle may blow up.
There's no simple answer. Paperwork is not what keeps you alive in space, and (as Hi-Shing Chan eloquently demonstrates in "Space Launch Vehicle Reliability") even if you test forever you may not find every possible problem until a few vehicles are actually flown and some blow up. Judgement and vision are essential components, and cannot be built to spec.
Dan, thank you for the insight ... I'm sure this must be very frustrating for SpaceX. There was a report after last September's House space committee meeting that Elon Musk mused in the hallway afterwards about going his own way.
ReplyDeleteAt the same time, I think all parties concerned realize how important this is. With Russia's program suffering so many failures, the U.S. really needs this to go right. It's not just for cargo but also for crew, but the SpaceX game plan is to fly Dragon for three years as cargo to get experience for its crew flights circa 2015.
Someone on CollectSpace.com posted a link to this editorial cartoon from 1960:
http://i106.photobucket.com/albums/m246/SkyMan58/SpaceRelated/41108_339.jpg
It was mocking NASA for Mercury launch delays. But here we are fifty years later and no one cares. I suspect it will be the same with SpaceX.
In the Mixed Blessings category, it's actually encouraging to see that SpaceX is willing to slip its launch dates rather than rush ahead hellbent on meeting schedules, with the all-too-common rationale that nothing can wrong because so far nothing has gone wrong. We've lost two shuttles because of magical managerial thinking, and it's surely time to show we've learned something.
ReplyDeleteThat said, I hope knowledgable high level folks at SpaceX are keeping really good track of what sorts of actions and plans lead to unproductive and expensive delays and which turn out to have been sensible in retrospect. I'm increasingly thinking of space programs as a venue for improving project management -- and God knows, space isn't the only business that could be improved.
Mike, interesting comment about using commercial as a model for project management. Back in the 1960s, NASA (and specifically the Apollo program) were held up as examples of good business management. In retrospect, now we know it was due to billions of taxpayer dollars thrown at the project. No one would seriously believe today that NASA is a good example of project management.
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