Accelerating Future

Amazing Photo of the Recent Spacewalk Monday, Dec 18 2006 

images and space Michael Anissimov 10:04 am

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12 Responses to “Amazing Photo of the Recent Spacewalk”

1. Tom McCabe Says:
   December 18th, 2006 at 4:15 pm

   In other news, today the Flying Metal Death Trap is preparing to undock with the Flying Metal Hunk’o'Junk and return to Earth using one of the most dangerous and unreliable reentry systems yet conceived.

2. MCP2012 Says:
   December 18th, 2006 at 11:00 pm

   Beautiful pic, Michael. Spot-on comment, though, Tom! (As usual!) LOL!

3. Ben Quady Says:
   December 18th, 2006 at 11:07 pm

   “…one of the most dangerous and unreliable reentry systems yet conceived…”

   Dude, compared to what?

   Considering that the Shuttle fleet has had one catastrophic reentry failure in (rough number) 116 missions, I’d say we’re still in the “pretty damned safe and reliable” territory. If in fifty years we’re still humping up and down the well in Shuttles, well, your snark would be appropriate, if not exactly clever. In the meantime… what’s the point?

4. MCP2012 Says:
   December 18th, 2006 at 11:27 pm

   Yeah, but I’m waitin for a good, reliable, reuseable, SSTO craft to put the Shuttle out-to-pasture. (And it’ll probably come from current private sector goings-on). But, that said, true enough, the Shuttle will ferry one from Earth to orbit and back—*if* it doesn’t BLOW Up…

5. Michael Anissimov Says:
   December 19th, 2006 at 5:17 am

   Less than 1% death rate isn’t horrible, though it is awfully expensive when it blows up. The thing with space progress is that intermediary steps really do matter, in terms of keeping the spotlight on the area.

   Bringing down the cost of getting materials to orbit is a priority for risk mitigators. That’s why the Lifeboat Foundation is funding an EM launch competition:

   http://lifeboat.com/ex/em

6. Tom McCabe Says:
   December 19th, 2006 at 9:28 am

   “Dude, compared to what?”

   As compared to every other manned mission in the history of space. That includes ALL of the Mercury, Gemini, Apollo, Soyuz, Mir, and Chinese missions, not ONE of which has burned up during reentry. But don’t take my word for it- http://en.wikipedia.org/wiki/Reentry#Notable_atmospheric_reentry_mishaps

   “pretty damned safe and reliable”

   The Boeing 747 is on roughly the same order of complexity as the Shuttle, and has much of the same difficulties; high physical stresses, big tanks of explosive fuel, powerful engines, large forces of air resistance, and large pressure differences. The total failure rate of a Boeing 747 is something like one per three million flights. Granted, a Boeing’s flight isn’t as rough as the Shuttle’s, but it’s still a four orders of magnitude gap; is flying to 400 km altitude really ten thousand times as dangerous as going to 10 km? Certainly the forces acting on the craft aren’t anywhere near ten thousand times as large, and the Shuttles each have billion dollar 24/7/365 maintenace crews while the Boeings don’t.

   Even ignoring the issues of safety, the tile reentry system is very expensive, hard to maintain, and easy to break. It costs something like a hundred million dollars just to replace and repair the tiles after every flight. The idea of reusability is that you can just land the thing, refuel it, and fly it again quickly; not very feasible when the S.S.’s tiles need months of work before every flight.

   “The thing with space progress is that intermediary steps really do matter, in terms of keeping the spotlight on the area.”

   The space shuttle is a step BACKWARDS, not forwards. In comparison with the old Saturn V, the Shuttle is:

   - Less reliable. The Saturn V could have an engine out and still reach orbit (and it actually did, twice). In the Shuttle, an engine out means an abort. Similarly, the Apollo capsule had an ejection rocket to save the crew in case the Saturn blew up; the Shuttle has no such thing.
   - Less capable. It can only carry one-fifth the payload and can’t go beyond Earth orbit.
   - More expensive. The Shuttle program (not the ISS, just the Shuttle) has cost $145 billion in total and is expected to cost $172 billion by 2010; Apollo cost $135 billion in 2006 dollars. Does anyone know if Wikipedia’s figures for the Shuttle program are adjusted for inflation?
   - Pretty much useless. Tell me, can anyone remember, without looking it up, what the Columbia was doing on its last mission? Anyone?

7. Randy Roach Says:
   December 19th, 2006 at 1:08 pm

   OK, you had one Orbiter destroyed on re-entry, but this was not due to failure of the Thermal Protection System as designed. It was due to management signing off on flying the Orbiter even when they knew chunks of foam were flying off and strking the wing, rather than fixing the problem. It was a managment failure, not an engineering failure.

   The comparison of the Space Shuttle to a 747 is ludicrous. The four engines of a Boeing 747 produce 188,000 pounds of thrust at takeoff. The Shuttle produces 7.3 million pounds and shakes the stack like a paint mixer. Yeah, they both carry “explosive fuel” but the Shuttle’s fuel includes 383,066 gallons of cryogenic hydrogen at -423 F. vs. max of 63,500 gallons of jet fuel. Powerful engines? Does the exhaust of the 747 leave the engine at Mach 5 and 6,000 F ?

   There is a huge difference between crusing at 565 MPH and achieving orbital velocity near 17, 500 MPH. Is it a thousand times harder? Yes it is. Ask Burt Rutan.

   Is the Thermal Protection System too expensive and difficult to maintain? Yes, although it has evolved over the years with new materials such as thermal blankets replacing tiles in many areas. Overall, cost of shuttle processing has dropped about 40%.

   Now, I’m a big fan of the Saturn V, having personally witnessed every single launch, manned and unmanned. Being within five miles of a Saturn launch is literally a religious experience. Saturn had a perfect success rate, enormous capacity, and killing it was a crime. You and I, as well as current NASA Administrator Mike Griffin, are in complete agreement that dismantling the Apollo infrastructure was a mistake, and that we’ve been on the wrong course for 30 years.

   I don’t think that you can say the Shuttle is useless though. It does have many unique capabilities. Don’t blame a lack of direction and focus on the vehicle.

   You should be happy to know that when the Shuttle is retired in 2012, it will be replaced by hardware much like Apollo-Saturn. The Orion spacecraft will be a capsule similar in shape to Apollo, but larger. It will be resusable but have a replaceable, one-time-use heat shield. Orion will be launched on the Ares 1, which consists of a 1st stage based on a Shuttle SRB, and a second stage with an engine derived from a Saturn J-2. An unmanned heavy lift vehicle, the Ares 5, will be developed to once again provide Saturn-class capabilities for Moon and Mars missions. It’s Back To The Future.

8. Tom McCabe Says:
   December 19th, 2006 at 1:48 pm

   “but this was not due to failure of the Thermal Protection System as designed”

   The Thermal Protection System’s function is to protect the spacecraft from reentry. To perform this function, it must necessarily be able to withstand the various stresses of liftoff, including small bits of debris. Even if we had found the damage while in orbit, we couldn’t have really done much- the Shuttle only had so many days of supplies and the things are damnably difficult to repair on the ground let alone on-orbit.

   “It was a managment failure, not an engineering failure.”

   If the damn thing breaks, that’s an engineering failure. It the thing is broken and we go ahead and use it anyway, that’s a management failure. The engineering failure pretty much doomed the astronauts no matter what management did.

   “188,000 pounds of thrust at takeoff. The Shuttle produces 7.3 million pounds and shakes the stack like a paint mixer.”

   Yes, but the Shuttle is also heavier and therefore more durable. The relevant ratio here is thrust-to-dry mass, since the dry mass is the mass that must support the force of the engines. It’s .64 for the Boeing and .085 for the shuttle. So yes, there is a big gap, but your figures are highly misleading.

   “383,066 gallons of cryogenic hydrogen at -423 F. vs. max of 63,500 gallons of jet fuel.”

   Both are explosive enough to blow up the entire vehicle if mixed with oxygen and ignited. And your figures are again misleading, because LH2 is much less dense than jet fuel; in terms of mass, the quantities are roughly equal.

   “Does the exhaust of the 747 leave the engine at Mach 5 and 6,000 F ?”

   I honestly don’t know; if you have the figures, please tell me. If you use the 747’s specific impulse to calculate the exhaust velocity, it comes out to around 15,000 m/s, allowing for the fact that most of the fuel by mass is oxygen.

   “There is a huge difference between crusing at 565 MPH and achieving orbital velocity near 17, 500 MPH.”

   Please tell me what difference you have in mind so I can respond more thoroughly.

   “Is it a thousand times harder? Yes it is. Ask Burt Rutan.”

   Burt Rutan seems to have made it harder than need be for PR’s sake. He uses N2O and rubber for fuel, requiring the development of an entire new engine instead of using one off-the-shelf, and a “shuttlecock” reentry mechanism instead of cheap, reliable ablative shields or simple insulation (SS1’s reentry was nowhere near as bad as an orbital vehicle’s).

   And as measured in cost, it sure as hell isn’t a thousand times more expensive to build an airplane than a spaceship. SpaceX’s Falcon 1 costs $6 million to buy, while a Cessna capable of carrying roughly the same payload costs $200-300 thousand.

   “I don’t think that you can say the Shuttle is useless though. It does have many unique capabilities.”

   Like? Please tell me what these “unique capabilities” are compared to the 40-year-old Gemini spacecraft.

   “Don’t blame a lack of direction and focus on the vehicle.”

   A lack of direction and focus was the NASA administration’s decision; the necessary result is a vehicle with no destination and no function.

   “You should be happy to know that when the Shuttle…”

   I knew all this two years ago, and I still don’t trust the US government.

9. Randy Roach Says:
   December 20th, 2006 at 2:22 pm

   I’m really just playing devil’s advocate here, but what the heck, it’s fun!

   I say Shuttle safety is mostly a management problem.

   The Columbia Accident Investigation Board report says “Despite original design requirements that the External Tank not shed debris, and the corresponding design requirement that the Orbiter not receive debris hits exceeding a trivial amount of force, debris has impacted the Shuttle on each flight. Over the course of 113 missions, foam-shedding and other debris impacts came to be regarded more as a turnaround or maintenance issue, and less as a hazard to the vehicle and crew.”

   They were aware that the TPS was fragile and so the Shuttle’s design requirement was that there be no debris from the ET. The ET did not meet the design requirment but for a number of reasons management decided not to fix it. Now, you can say that the ET had an engineering problem in that it didn’t meet specs, but the TPS performed as designed.

   If I decide I can drive my car with the tires half-inflated because “hey, I’ve driven it a hundred times and nothing happened”, and then have an accident when a tire comes off the rim, did the tires fail? No, because I didn’t use them as they were engineered to be used.

   Your comparison of the Shuttle and the 747 concerned their relative saftey and the opinion that spaceflight shouldn’t be that much more dangerous than commercial flight.

   My figures concerning thrust, exhaust velocity etc. were simply to illustrate that the enviromental stresses on the Shuttle are considerably higher than experienced by a conventional aircraft. The dynamic pressure, vibration, and temperature variations, with all the energy required to get any vehicle going at orbital velocity (and stopped again) are pretty intense and you are in a dangerous flight regime.

   It’s interesting that you think Burt Rutan used a hybrid engine “for PR’s sake” when in fact it was for safety’s sake. Both oxidizer and fuel can be stored without special precautions; they will not react with each other until provided with a significant source of heat; and the nitrous oxide is self-pressurizing so you just need simple valves and not complex, prone to failure turbopumps.

   The purpose of the “shuttlecock” system is also safety. The vehicle will automatically align itself “belly down” on reentry without pilot input (or the need for a reaction control system) and the high drag reduces heating.

   Unfortunately neither of these innovations can be scaled up to use in an orbital vehicle. I can’t wait to see how Burt tackles that problem.

   It’s also interesting that you used Falcon 1 as an example, since SpaceX’s Falcon 1 cost 6.7 million dollars and blew up 25 seconds after launch due to a corroded nut. Cheap access to space continues to elude us.

   You really want to compare Shuttle to Gemini? Shuttle can haul 63,500 pounds of payload into orbit then: provide power, cooling and telemetry. Shuttle can deploy, retrieve, assemble, checkout, troubleshoot, repair or service those payloads. Shuttle provides a shirt-sleeve environment for up to seven crewmembers on missions exceeding 16 days.

   Gemini can keep two astronauts alive for up to two weeks and test docking and rendezvous techniques. It flew 10 times.

   The lack of direction for our national space policy came from the White House, not NASA Administrators. Do you think any NASA Administrator had the power to say “We’re going to expand human presence in space, starting with a return to the Moon”? They can advise, but the White House sets the policy they must implement. (Feel free to blame Sean O’Keefe though - damn bean counter!).

   The Nixon White House is responsible for the Space Shuttle. The Shuttle was just one part of NASA’s grand plan. Nixon cut everything but the Shuttle. To get approval from various potential users the Shuttle had to become all things to all people. Fully reusable designs were thrown out for the initially cheaper but ultimately costly design we see today.

   They say an elephant is a mouse designed by committee, and that’s pretty much how the Shuttle cam into being.

   As for trusting the government, I trust only that politicians are interested in maintaining their power. I think one of the key reasons NASA has chosen to build new vehicles from Shuttle-derived hardware is to mitigate the loss of current Shuttle-related jobs. Congress-critters won’t want to risk losing any of that pork so they’ll continue to support NASA at around it’s current funding, which by the way is only 6/10 of 1% of the federal budget.

10. Tom McCabe Says:
    December 20th, 2006 at 4:40 pm

    “I say Shuttle safety is mostly a management problem.”

    Neither of the two disasters could realistically have been predicted in advance, because the damn thing has so many flaws that they were too busy trying to stop a hundred other things from killing it.

    “They were aware that the TPS was fragile and so the Shuttle’s design requirement was that there be no debris from the ET.”

    Okay, then, I admit that the TPS didn’t violate its original specifications during Columbia. The problem, then, is that the original specifications didn’t call for a more durable system.

    “when a tire comes off the rim, did the tires fail? No, because I didn’t use them as they were engineered to be used.”

    Columbia is more like “the tires blew because I hit a pebble in the ground, and the tires weren’t designed to cope with pebbles.” It may not be a breach of the original specifications, but come on, any realistic tire system has to be able to deal with pebbles.

    “oxidizer and fuel can be stored without special precautions;”

    Kerosene and LOX don’t normally require special precautions. Kerosene will simply burn without exploding in roughly the same manner as rubber if ignited, and LOX, of course, won’t burn at all. Although LOX can boil off and create enough pressure to burst the tank, this equally applies to N2O and any other chilled gas.

    “they will not react with each other until provided with a significant source of heat;”

    This applies to every fuel except hypergols, which are not used in any ground launch, to my knowledge, due to low ISP.

    Oh, and N2O is thermodynamically unstable and can violently decompose or even explode if detonated. http://en.wikipedia.org/wiki/Nitrous_oxide#Safety

    “and the nitrous oxide is self-pressurizing so you just need simple valves and not complex, prone to failure turbopumps.”

    The same thing applies to LOX! LOX will pressurize itself due to boiloff even faster than N2O will, and it’s not my fault if Rutan realized this (I do give him credit here) and NASA didn’t.

    “The vehicle will automatically align itself “belly down” on reentry without pilot input (or the need for a reaction control system)”

    Yes, and it also requires that you be able to move half the vehicle into a different orientation, requiring dozens of motors, gears, levers, and God knows what else, which not only can fail but also add weight. I’ll take the RCS system.

    “I can’t wait to see how Burt tackles that problem.”

    Burt doesn’t have an orbital vehicle, except possibly as a drawing on some design board.

    “and blew up 25 seconds after launch due to a corroded nut”

    The Falcon 1 used aluminium nuts, which are actually more expensive than steel; steel would not have corroded. (http://en.wikipedia.org/wiki/Falcon_1#First_flight_failure)

    “Shuttle can haul 63,500 pounds of payload into orbit then:”

    Okay, this isn’t something Gemini could do, but it could be done with the Saturn V, Delta IV Heavy, Atlas Heavy, and I believe some Titan variations.

    “provide power, cooling and telemetry.”

    Gemini had all of these.

    “Shuttle can deploy,”

    A BDB can deploy a payload. Hell, the Vanguard rockets “deployed” their payload in 1958.

    “retrieve,”

    Satellite retrieval is uneconomical for the vast majority of satellites, because in addition to launching it again, you have to launch the retrieval mission as well. Data return can be done with radio, sample return can be done with heat shields, and build costs aren’t usually much greater than launch costs. So yes, it can do it, but there usually isn’t much point.

    “assemble,”

    Assemble means to put two things together into one thing, something that any EVA guy with maneuverability and the right equipment could do. Assembly of spacecraft was actually first demonstrated during Gemini.

    “checkout,”

    Really? Please tell me what potential problems can be spotted with a space shuttle that can’t be spotted with an ordinary EVA. And why this “checking out” didn’t work with Columbia.

    “troubleshoot,”

    Any kind of troubleshooting in space is almost invariably done via Houston. Troubleshooting started with the very first Mercury orbital mission (http://en.wikipedia.org/wiki/Mercury-Atlas_6)

    “repair”

    The only case I can remember of the S.S. repairing something was the HST in 1993. Granted, that would have been difficult to do with Gemini; however, a leftover Apollo capsule or the planned Orion spacecraft wouldn’t have any problems I can see.

    Oh, and the Skylab space station was repaired by astronauts operating out of a leftover Apollo capsule in 1973.

    “service”

    The Skylab space station was “serviced” by leftover Apollo spacecraft in 1973.

    “Shuttle provides a shirt-sleeve environment for up to seven crewmembers on missions exceeding 16 days.”

    Okay, that’s 112 person-days; Skylab 4 logged 249 without resupply.

    “The lack of direction for our national space policy came from the White House, not NASA Administrators.”

    President Lyndon Johnson pretty much ignored space, and we completed the Apollo project. President George H. Bush made a grand committment and then failed to follow through, and it got canceled. President W. Bush made a grand committment and then failed to follow through, and it still doesn’t look like it’ll be canceled even three years later. Realistically, fault lays with the NASA admins who didn’t try and cut costs, Congresses that didn’t provide enough funding, and an apathetic public; the White House has had little to do with it.

    “Do you think any NASA Administrator had the power to say “We’re going to expand human presence in space, starting with a return to the Moon”?”

    They have the power to say pretty much anything they want, and Webb was very successful at getting funding for Apollo even if he didn’t start the project.

    “The Nixon White House is responsible for the Space Shuttle.”

    Yes, but rather indirectly. He, after all, never proposed, designed, funded, or built the thing.

    “Nixon cut everything but the Shuttle.”

    If I may remind you of the US Constitution, all requests for government spending must be made through the House, not the presidency.

11. MCP2012 Says:
    December 28th, 2006 at 4:18 pm

    Thanks, Tom, for reminding us of the specifications of the U.S. Constitution. Everyone who frequents this site would do well to study the constitution (get the copy from the federal printing office…it’s only $4 [unless they’ve gone-up in price since last time I checked…] and well worth it). As for studies and commentary on the meaning and specifications of the constitution, see Thomas M. Cooley, *General Principles of Constitutional Law*, 2nd Ed., Randy Barnett, *Restoring the Lost Constitution* (Princeton U. Pr), and Michael Badnarik, *Good To Be King: The Foundation of our Constitutional Freedom*.

    One needn’t be a narrow libertarian to be a Lockean constitutionalist. Check-out those works…you’ll be glad you did…

12. Phreekoid Says:
    September 14th, 2007 at 1:58 pm

    Hey! I can see my place from here! Te Wai Pounamu is its name in the native Maori. I live near that beaky bit on top left….

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