Category Archives: Space

Space

Ares Woes Ongoing

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Av Week has a fairly detailed technical description of the thrust oscillation problem:

“Conservative” calculations of the potential frequency and amplitude of a thrust oscillation that could occur in the first stage as it nears burnout, and of the way that vibration links to the rest of the vehicle, suggest that it could set up a resonance that would damage critical components and harm the crew (AW&ST Dec. 10, 2007, p. 60).

A thrust-oscillation “focus team,” convened in November 2007, has since calculated that the problem may not be as severe as it appeared earlier in the fall. But the work continues under a looming March deadline, set so designers on both the launch vehicle and Orion can start work in earnest on mitigating the effect, if necessary, before preliminary design review (PDR) at the end of the summer.

“That gives us a good view of the problem with what we see as how big the risk is, [along with] what are the right mitigation strategies for any residual risk left, so that going into PDR we have a good handle on it and we’re designing for it,” says Garry Lyles, an experienced launch vehicle engineer at Marshall who heads the focus team. “You’re not waiting downstream of the [PDR] to start designing your system to accommodate the oscillation.”

Emphasis mine. If it “may not be,” it also “may be.” This goes beyond risk (which is quantifiable), into uncertainty, which by definition is not, and that’s an unhappy place for an engineer to be. They continue with the “may not be” language.

…the focus team has since calculated that the problem may not be as severe as originally feared. Nominally the oscillation frequency of a five-segment booster is 12 Hz. (compared with 15 Hz. for the four-segment version). But after that it gets complicated. Translating RSRM ground-test data into accurate forcing function figures and the stack’s response to that force is extremely difficult, particularly since the upper-stage and Orion designs remain immature and oscillation data are based on ground tests.

They can do flight tests on a Shuttle SRB, but that still won’t tell them how a five-segment motor will behave (though it will give them better data with which to model it). But as it notes, there’s no way to model the dynamic structural behavior of the stack, because they don’t have enough fidelity in the design. They are risking going into a program, spending billions more, without certain knowledge that they’ll have a viable system until they’re well along in the development, at which point they might find out that they have to essentially start over from scratch.

…if the problem doesn’t go away with more data and more refined calculations, or can’t be fixed with propellant redesign, then isolation pads and other mechanical fixes probably will add weight to the overall vehicle. Making it work could eat into the weight margins held at various levels of the Ares I and Orion programs (AW&ST Dec. 10, 2007, p. 52).

Although the problem isn’t fully understood, none of the NASA engineers involved in solving it sees it as a show-stopper.

“I hope this is the worst we’ve got to deal with,” says NASA Administrator Michael Griffin.

Well, apparently, they’re not allowed to see it as a show stopper. People get fired for pointing out that the emperor is naked.

As Dr. Laura says, hope has no power, Mike. It is not a plan. And there are numerous other solutions.

Space, Space Education, Space History

Remembering Challenger

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This weekend, I met a young woman, now attending law school in Ann Arbor, who was in diapers when it happened. To her, it’s ancient unremembered history, just as the Eisenhower administration is to me (though I at least study it, unlike most of my age cohorts). It made me feel old. We have a generation, though, about ten years older than her, now in their thirties, for whom it was probably the most traumatic event of their young lives. The comments are closed on my post from six years ago, but anyone who wants to post remembrances can do it here, with the caveat that I still haven’t completely recovered from my recent MT upgrade (still hoping that someone who knows it will volunteer to help), so you can use them, but they will time out. Don’t expect to get a response after submitting the comment. Just back up after a while, and refresh the page to see it.

I’m particularly interested in how the event changed your perception of the Shuttle, and the space program in general, if at all, per my previous thoughts.

Space, Space History

Twenty-Two Years

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This is a week of space anniversaries. Yesterday was forty-one years since the Apollo fire that killed three astronauts on the launch pad as horrified technicians watched during a ground test. Thursday will be the fiftieth anniversary of the launch of the first US satellite, Explorer I. Friday will be five years since the Columbia disintegrated over the otherwise quiet morning skies of Texas.

But today is the twenty-second anniversary of the destruction of the Space Shuttle Challenger, an event that traumatized the nation as millions of schoolchildren watched the first “teacher in space” go up in a fireball on live television. I’ll never forget the date because it was then (as it remains) coincident with the anniversary of my birth.

It wasn’t obvious to many at the time, but that event was the beginning of the end of the Space Shuttle program, then less than five years old, with its first flight having occurred on April 12th, 1981. Prior to that flight, there had still been plans (that some thought fantasies, due to budget restrictions and ongoing problems of turnaround time) of twenty-four flights a year (including a couple per year out of Vandenberg AFB in California). The catastrophe was a splash of cold water in the face of those who had held out hopes for the Shuttle in terms of meeting its original promises of routine, affordable, safe access to orbit. Those promises had caused people (like those in the L5 Society) to dream of space stations, and space manufacturing, and ultimately, space colonies.

After the disaster, many realized that if those dreams were to come true, they would have to be by some means other than the Shuttle (a realization that some later took one step further and decided that NASA itself was unlikely to be of much help in achieving the goals, particularly since it continued to flout the law, and had no interest in them whatsoever). But the program went on, because it was all NASA had for manned spaceflight, and it maintained jobs in the districts of politically powerful congressmen and senators. Though there had been disillusionment about the promise of the program, there was no political will to replace it. The few (misguided) attempts (NASP, X-33, SLI, OSP) to replace it all floundered or failed. The latter two morphed from one to the other. The program thus struggled along with four orbiters, and a low flight rate, with occasional fleet stand downs due to endemic problems, such as hydrogen leaks at the interface, or other concerns.

But the final blow was struck five years ago this coming Friday, with the loss of Columbia. The fleet was down to three birds, and unlike the case after the loss of Challenger, no structural spares had been procured with which to build a new one, and the tooling for them had long since been scrapped. So the decision was finally made, almost seventeen years after the loss of the first orbiter, to end the program.

Unfortunately, what is planned to replace it, Ares 1/Orion, will be little improvement, and in some ways a major step backwards. It will launch even fewer crew than Shuttle, and while the Shuttle was a heavy-lift vehicle capable of delivering twenty tons to the space station, the new system will deliver little payload other than crew. It will have minimal ability to return payloads and no ability to return the types of payloads that the Shuttle could. It will likely cost as much or more per launch, particularly when having to amortize the development costs, which had been long sunk for the Shuttle, and it’s unlikely to launch much, if any, more often. We will go from a system that could deliver a few government employees (along with a couple dozen tons of paylad) into space a few times a year, at a cost of hundreds of millions of dollars per flight to a system that can deliver fewer government employees (with essentially no paylad) into space a few times a year, at a cost of hundreds of millions of dollars per flight. The only saving grace is that, in theory, it can also deliver people to the moon, and it may be somewhat safer.

But the Shuttle started out with a dream: of dozens of flights per year, of low costs per flight, of many flights for many purposes, some of which would be privately funded for private purposes. In canceling most launch vehicle technology development, and returning to a horrifically expensive concept from the 1960s, NASA has in essence officially declared that dream dead.

Fortunately, investors don’t take NASA as seriously as they used to, and the dream now lives on in the form of new private companies, determined to open up the heavens to all of us, and not just a few civil servants. If we hadn’t lost the Challenger over two decades ago, the Columbia loss might have been seen as an anomaly in an otherwise-successful program. As in 1986, it might have simply been replaced (albeit at great expense) with the structural spares that were earlier used to build Endeavor, and the program might still be lumbering on, keeping us trapped in low earth orbit, and continuing to crush the dreams of those who believe that we can do better. If that loss back then was a necessary catalyst to ultimately end the program and spur on efforts to do better privately, even if delayed, then perhaps the sacrifice of the Challenger crew will, in the long run of history, be viewed as not for naught.

Space, Technology and Society

The Radiation Problem

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A solution?

They started with two common food preservatives–the same stuff, BHA and BHT, that keeps Wonder Bread fresh for weeks–as a means to carry away free radicals before they can cause harm.

But for the food preservatives to become effective, the scientists needed a way to get them inside cells.

That’s where carbon nanotubes, single layers of carbon atoms curved into tiny cylinders, came in handy. The research team attached the food preservatives to the nanotubes, which, because of their size, provided a perfect vehicle for traversing the body’s arteries and entering cells.

Tour said he began his research with the goal of finding a drug to protect astronauts on long-duration space missions from the radiation to which they are exposed outside Earth’s atmosphere.

But the test results in mice, which were given the drug 30 minutes before a blast of radiation, were so impressive that Tour thought the drug might have much broader potential.

I hope that the real promise is for deep space travel, not for a nuclear war. We need to do everything we can to avoid the latter, but if not, this will help as well.

Political Commentary, Space

What I’d Like To See A Presidential Candidate Say About Space

Of either party.

“I fully support the president’s Vision for Space Exploration. I believe that we should expand our presence beyond low earth orbit, and establish a human civilization into the solar system, going to the moon, the asteroids, Mars and points beyond, which is what the vision was in its essence. However, I’m extremely disappointed in the implementation of it to date by NASA, and if elected, I pledge to revisit the Aldridge Report, which required that the vision be fully integrated with the commercial sector and that it support national security goals, and restructure it in order to do so.”

One could obviously expand on it in detail, but that’s what’s missing from the debate, in my opinion.

Political Commentary, Space

What I’d Like To See A Presidential Candidate Say About Space

Of either party.

“I fully support the president’s Vision for Space Exploration. I believe that we should expand our presence beyond low earth orbit, and establish a human civilization into the solar system, going to the moon, the asteroids, Mars and points beyond, which is what the vision was in its essence. However, I’m extremely disappointed in the implementation of it to date by NASA, and if elected, I pledge to revisit the Aldridge Report, which required that the vision be fully integrated with the commercial sector and that it support national security goals, and restructure it in order to do so.”

One could obviously expand on it in detail, but that’s what’s missing from the debate, in my opinion.

Political Commentary, Space

What I’d Like To See A Presidential Candidate Say About Space

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Of either party.

“I fully support the president’s Vision for Space Exploration. I believe that we should expand our presence beyond low earth orbit, and establish a human civilization into the solar system, going to the moon, the asteroids, Mars and points beyond, which is what the vision was in its essence. However, I’m extremely disappointed in the implementation of it to date by NASA, and if elected, I pledge to revisit the Aldridge Report, which required that the vision be fully integrated with the commercial sector and that it support national security goals, and restructure it in order to do so.”

One could obviously expand on it in detail, but that’s what’s missing from the debate, in my opinion.

Space

The Unveiling

There’s very little news in Virgin’s announcement today, except for the pretty picture and the schedule. Many more questions are left unanswered than answered. There’s a little more, but not much more info at the New York Times (registration required). The Times piece has an error, calling SpaceShipTwo SpaceShipOne.

Are they really claiming that they’re going to start SS2 flights in June? Or just White Knight 2? And if SS2 flies in June, how many flights will there be with ballast for the propulsion system (i.e., simply drop tests) and at what point will it first fire the rocket motor? I ask because, despite Scaled’s fine for not properly training its employees in the handling of nitrous oxide, there has been no announcement as to the cause of last July’s accident. Do they know? If not, have they moved forward with engine development anyway? Or have they switched gears and gone to a different propulsion system? Seems like a pretty tight schedule, if so.

I think that they could learn a lot and start test flying the airframe this summer, assuming it’s well enough along, and perhaps they’re betting on the come when it comes to the powerplant to meet that schedule. Finally, I wonder what Burt thinks about the announcement?

Jeff Foust has more thoughts. The dual cabin design of WK2 is interesting. I wonder if that’s for additional passenger revenue?

[Update a little later]

A lot of posts and links over at Clark Lindsey’s place (not a permalink).

[Update at 5 PM EST]

Alan Boyle has more details, with some comments from Virgin. But none on propulsion. As I suspected, the initial flights for SS2 will be drop tests (naturally), which can go forward without engines.

And Alan has pretty mixed response from his commenters, some of whom sound like morons. At least I don’t have to worry about that until I get my comments fixed, which is turning out to be a much bigger deal than I thought it would. Again, if there’s an MT doctor in the house, email me at the address in the upper left corner.

[Evening update]

Clark Lindsey has more info. As I was guessing, the flight tests this summer will be WK2, not SS2, and Burt still says they don’t know what happened or what they’ll do about propulsion. That’s not good if they want to be in operations in ’09. He surely must have some options in mind. I’d recommend going with a liquid, from XCOR or someone else, and dumping the hybrid, which adds ops cost, and whose safety is overrated. But we’ll see.