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NASA Space Science

Design of Next-Gen NASA Rocket Showing Flaws 203

caffiend666 writes "According to an AP news article, NASA engineers are concerned about the design for the new rocket meant to replace the shuttle. Work on the project has revealed that the first few minutes of flight could see 'violent shaking', a serious flaw that might destroy the craft soon after launch. 'NASA officials hope to have a plan for fixing the design as early as March, and they do not expect it to delay the goal of returning astronauts to the moon by 2020. The shaking problem, which is common to solid rocket boosters, involves pulses of added acceleration caused by gas vortices in the rocket similar to the wake that develops behind a fast-moving boat.'
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Design of Next-Gen NASA Rocket Showing Flaws

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  • by the_humeister ( 922869 ) on Saturday January 19, 2008 @08:35PM (#22113812)
    ...before it's built. Seems like a non-story.
    • Reminds of this [slashdot.org]. This is akin to saying the first computer might have heating problems.
    • Re: (Score:3, Insightful)

      by khallow ( 566160 )
      I see two things that make this a story. First, the design process for the Ares 1 would be of interest to slashdot readers. Second, this is pretty far along to be dealing with an obvious flaw of the rocket's design qnd strikes me as another example of the rushed nature of this particular platform. Before this, they had to strip the Crew Exploration Vehicle (CEV) down to basics to figure out how to pare it down to the point where the Ares 1 could carry the CEV. That particular effort was because the Ares 1 i
  • so what? (Score:5, Insightful)

    by The_Rook ( 136658 ) on Saturday January 19, 2008 @08:40PM (#22113838)
    so they found a problem with a preliminary design. big deal. that's why they call it research and development.

    how long did it take to design the saturn Ib/saturn V and make sure that they'd mate well with the apollo capsule? how long did it take to come up with skylab, an orbiting lab that could be mounted on a saturn V?

    i expect it'll take about five to six years to bring the orion program to a complete first generation system.
    • Re:so what? (Score:5, Insightful)

      by Pedrito ( 94783 ) on Saturday January 19, 2008 @08:45PM (#22113864)
      Mod parent up. This is a completely ridiculous article. It's little more than a footnote on a status update of the development.
    • Re:so what? (Score:5, Insightful)

      by cyclone96 ( 129449 ) on Saturday January 19, 2008 @09:02PM (#22113966)
      Indeed. In fact, the Saturn V itself had problems with pogo oscillation [wikipedia.org], a condition that affects liquid fueled rockets and caused the center engine shutdown during the first stage of Apollo 13.
      • by delt0r ( 999393 )
        Some have even said they were lucky that the problem didn't case the loss of a vehicle. Apollo 13 pongo resulted in changes to suppress the problem in later missions.

        Personally I would prefer a longer term outlook on the space program which this current plan is not. A lot of people have this view and so are looking for reasons to criticize the program(rightly or wrongly).
    • April 1957 to July 1969 = 12 years from STARTING the Saturn project to landing on the moon.

      My biggest problem here is that they should already be flying X-vehicles. Wasn't that how progress was made? One to crash, One to fly, and One to hang up in the Smithsonian?

      Since Ares keeps getting reduced in capabilities, I'm not confident that in 2015 ( when it's scheduled to start running ) we'll actually have anything delivered, and it's going to be another Turkey.

      Step 1: Get NASA out of Manned Spaceflight.
      Step
      • Re: (Score:2, Insightful)

        by framauro13 ( 1148721 )
        The difference being that, at the time, the entire population rallied behind NASA. Our domination of the Space Race was needed to establish our position over the Soviets during the cold war. People had no problem allowing the government to pump money into a program that would prevent the Soviets from establishing a foothold above us in space.

        Unfortunately, the population doesn't have that kind of motivation (or fear) anymore. You can damn well bet though that if al-qaeda started launching men into space
        • So, I'm not sure the "Lacks Public Support" argument is applicable here. When has what "The People" want ever mattered in DC?

          Iraq a waste and more than half think it's pointless, but we've poured 500 Billion down that toilet so far.

      • Your steps 1-3 do not agree with your first sentence. NASA was the organization to go from zero to Moon in 12 years. Yet you suggest that NASA get out of manned spaceflight, in favor of (...) that has zero experience in sending people into space.

        Not sure how your #3 turns into profit, but you can continue to believe in that.
        • NASA hasn't been worth shit w.r.t. manned spaceflight since Nixon.

          And I don't really consider shuttle operations "sending people into space". That's just "sending people into low-earth-orbit."

          Sending people to Mars. That's sending people into space.
    • Re:so what? (Score:5, Insightful)

      by Antique Geekmeister ( 740220 ) on Saturday January 19, 2008 @09:24PM (#22114074)
      Mercury started launched amazingly shortly after Sputnik, in 1957 or so. Gemini launched in 1963, Saturn launched in 1967. That gives less than 10 years to build 3 generations of spacecraft and launch the third generation, successfully.

      NASA has known that the Space Shuttle flies like a duck-taped cow since well before its first launch in 1981, since it was designed by committees lobbying wildly to have different components manufactured in different states to get Congressional approval and for many other political, rather than engineering, reasons. Development of replacement spacecraft has been hindered by funding, similar lobbying stupidity, and the unwillingness to admit that rockets have to be built and tested rather than modeled to death for decades before actually trying anything.

      Private industry has already shown a far more capable design, when the Ariadne won the X-Prize. But NASA is blocking its development for numerous political reasons, not engineering reasons. You cannot expect NASA to do anything in real development and admit that complex craft are going to crash in the design and testing phase, and treats it as an acceptable risk rather than a political nightmare. And their current leadership is too politically hidebound to do anything profoundly innovative: it would interfere with the "5 year plans" of their contracts with Boeing and other manufacturers.
    • Mod parent up to 6 (Score:2, Insightful)

      by Shandalar ( 1152907 )
      This is a non-story. Rockets explode during their development.
  • Holy cow! (Score:5, Insightful)

    by ruiner13 ( 527499 ) on Saturday January 19, 2008 @08:40PM (#22113840) Homepage
    You mean they didn't get the design of a prototype exactly right on the first try? Amateurs! Seriously though, where is the news here?
    • by Anonymous Coward on Saturday January 19, 2008 @09:23PM (#22114066)

      Yeah, how pathetic to run into problems already. It's not rocket science, guys.

    • Re: (Score:3, Interesting)

      by hey! ( 33014 )
      Well, the problem as I see it is that the prototype design has diverged so far from the original concept.

      The idea was that by using Shuttle components that are (a) in production and (b) have proven safe in their current designs, then (c) by configuring them in a way that avoids known problems, you end up with a safe and economical vehicle much faster.

      The problem is that it might not be so simple. The first concept was a Shuttle solid rocket booster for the first stage, an second stage powered by a Shuttle
  • by quanticle ( 843097 ) on Saturday January 19, 2008 @08:42PM (#22113850) Homepage

    If anyone else has read Diane Vaughan's Challenger Launch Decision [amazon.com], he or she will know that launch schedule pressure from upper management was a leading cause of the rationalization of risk that NASA undertook to justify flying with known Shuttle desgign flaws. Hopefully, in this case, the NASA senior managers are not applying the same mindless schedule pressures that leads to quick fixes and mindless workarounds at the expense of long term safety.

    • From http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster [wikipedia.org]

      Forecasts for January 28 predicted an unusually cold morning, with temperatures close to 31 F (0.5 C), the minimum temperature permitted for launch. The low temperature had prompted concern from engineers at Morton Thiokol, the contractor responsible for the construction and maintenance of the shuttle's SRB. At a teleconference which took place on the evening of January 27, Thiokol engineers and managers discussed the weather conditions with NASA managers from Kennedy Space Center and Marshall Space Flight Center. Several engineers--most notably Roger Boisjoly, who had voiced similar concerns previously--expressed their concern about the effect of the temperature on the resilience of the rubber O-rings that sealed the joints of the SRBs. They argued that if the O-rings were colder than 53 F (approximately 11.7 C), there was no guarantee the O-rings would seal properly. This was an important consideration, since the O-rings had been designated as a "Criticality 1" component--meaning their failure would destroy Challenger and its crew. They also argued that the low overnight temperatures would almost certainly result in SRB temperatures below their redline of 40 F. However, they were overruled by Morton Thiokol management, who recommended that the launch proceed as scheduled.

      It wasn't just a problem at NASA, it was a wrong culture in the companies surrounding NASA.

  • by ueltradiscount ( 1195109 ) on Saturday January 19, 2008 @08:45PM (#22113862)

    How is it that astronauts managed to land on the moon in 1969 but the next mission to get people to the moon will take until 2020? With today's engineering tech - CFD software, advanced materials science, VR simulation, rapid prototyping technology - and lots of commercial sattelites shot into space every year, it should be much easier to get people to the moon and back safely than it must have been in the 60s. Unless of course that landing was faked as some people allege.
    • Re:Moon landing 1969 (Score:5, Interesting)

      by Tablizer ( 95088 ) on Saturday January 19, 2008 @08:54PM (#22113922) Journal
      How is it that astronauts managed to land on the moon in 1969 but the next mission to get people to the moon will take until 2020? With today's engineering tech...

      Basically they spent more in the 60's relative to today's budget to speed up the process. We're taking a slower, cheaper route this time.
             
    • Re: (Score:3, Interesting)

      Brilliant! I mean we have more computers nowadays! Computers everywhere means easier everything! That's some solid logic! Never mind the political atmosphere, what with its shoe string budgets and extreme shifts in public opinion. Never mind that there is no immediate, short term goal to be accomplished by expanding space travel. The fact that people haven't been truly interested in the long term benefits or concerned at all, really, with space exploration is completely irrelevant when compared to the amoun
    • Re: (Score:3, Insightful)

      by Bruce Perens ( 3872 ) *

      With today's engineering tech - CFD software, advanced materials science,...

      Well, if you exercise, has all that technology made you able to lift heavier weights than you might have in 1960? Generally not. Indeed, we are going back to the sort of design used in 1969 instead of the more sophisticated shuttle design. They had great technology for this particular problem back then. But they also had William Proxmire, architect of what is arguably the most stupid decision in the history of mankind: the turn bac

      • Oh, the technology used is older than that! Werner von Braun was one of the core designers of the 1960 spacecraft of the USA, and he helped build the V-2 rockets for the Germans in World War II. And the problems predate Proxmire's campaign against federally funded research.

        There are certainly material changes, and computer changes, that could enormously benefit space craft. Computers have shrunk incredibly and draw less power, GPS and other navigational techniques have improved enormously and could be used.
      • Re: (Score:2, Interesting)

        Was it really a conscious decision by one demonizable person, or a prevalent attitude?

        To have abandoned a heavy-lift capability like Saturn V, to have dumped such precious knowledge into the equivalent of a junkyard... I think it betrays the attitude that scientific knowledge, however amazing its accomplishments may have been, was considered disposable! And it goes without saying that the people who sweated it out, most visibly the test pilots and astronauts that helped test and prove those technologies (e
      • by MrKaos ( 858439 )

        But they also had William Proxmire, architect of what is arguably the most stupid decision in the history of mankind: the turn back from pioneering space.
        Was that the Golden Fleece thing? I would have liked to do the "measured the length of airline hostess's buttock" project, I mean whoever thought of the project *SHOULD* be the president, what an absolute legend of an idea - sheer genius.
  • by ThreeGigs ( 239452 ) on Saturday January 19, 2008 @08:51PM (#22113912)
    It's a harmonic vibration issue apparently, and these are generally solved quite easily. Adding or removing stiffness, a spiral wrap of an energy dissipating elastomer, isolation mounts, ading or removing mass (or simply moving mass around)... doesn't look like it's a severe issue at this early of the design stage. Someone's just being alarmist.
    • by corsec67 ( 627446 ) on Saturday January 19, 2008 @08:57PM (#22113944) Homepage Journal
      Actually the way I read it is the problem is in the gas inside the solid booster having turbulence that leads to vibrations. Thus it isn't dependent on the structure of the booster, but on the way the fuel inside it is shaped, at ignition and during the burn.

      But, I am not a rocket scientist.
      • by ThreeGigs ( 239452 ) on Saturday January 19, 2008 @09:08PM (#22113994)
        Yes, it's the gas that causes it, which would ordinarily just be a rumble. However, the frequency of the rumble apparently matches one of the harmonics of the rocket casing or motor, which causes a nasty bit of positive feedback.

        Much like bouncing in the middle of a board. Changing the frequency of the input force means you won't go as high, changing the mass (lighter or heavier person) means the resonant frequency changes, making the board out of something stiffer or less stiff changes the optimum rate of bouncing...etc.
        • The problem with your simple fix (you are correct about the problem assessment) is this: Rockets change dramatically during flight.

          When you are trying to avoid having a resonate frequency in a wide range of spectrum and your device goes from a hundred thousand pounds spread evenly to a few thousand pounds almost entirely at the top, you have a more difficult challenge then mere stiffness and structural changes can easily fix.
      • You're right - this is much less a structural issue and has more to do with the complex aerothermodynamics going on inside the combustion chamber. What I am surprised no one has mentioned is how much this risk is mitigated by the fact that the first stage of the Ares I is simply a 5-segment version of the space shuttle's solid rocket boosters. This is exactly why you re-use technology when appropriate. In this case, we have a very good understanding of the performance and characteristics of this solid ro
    • by syousef ( 465911 )
      So long as they don't do what they have already done with the shuttle:

      1) Build a flawed machine, with safety standards specified
      2) Gradually remove the safeguards, kill some people in the process.
      3) Wind up delaying with repeated patch jobs to the flawed design (instead of doing a proper redesign). Re-instate or intensify safeguards that aren't going to fix the issue.
      4) Continue to launch despite seeing ongoing problems.

      They need to either get this right and kill no one in the first few HUNDRED launches of
      • Re: (Score:3, Insightful)

        by willfe ( 6537 )

        They need to either get this right and kill no one in the first few HUNDRED launches of the vehicle (if it's not superseded by then) or convince people that if we do incur a few deaths they are the price that has to be paid.

        They've succeeded completely in the second count there -- in 120 launches, 14 human lives have been lost in two accidents (one on launch, one during reentry). Hundreds of humans have taken over a hundred trips into space on the shuttle, and the vehicle has killed only a handful of them

        • by syousef ( 465911 )
          They haven't succeeded. I said few hundred launches. Not 100 launches. Not a few thousand people. When the risk is riduced to a fraction of a percent (similar to what airline travel is today) there will be less reason to argue based on safety that humans shouldn't attempt space travel. 14 lives in 120 launches isn't good enough. If your local airline carried those odds you'd not use it.
          • When the risk is riduced to a fraction of a percent (similar to what airline travel is today) there will be less reason to argue based on safety that humans shouldn't attempt space travel. 14 lives in 120 launches isn't good enough. If your local airline carried those odds you'd not use it.

            Sure, if an airline carried those odds I wouldn't use it to go on holiday. But these aren't the general public going on their summer break - they are a relatively small group of astronauts who understand and accept the r
    • Re: (Score:3, Insightful)

      by khallow ( 566160 )

      In other words, these are solved by *adding mass*. In a rocket optimized for low mass and a fixed size payload (like the Ares 1 is), removing mass just isn't an option. As I understand it, the resonance mode is due to the payload, the SRB on the bottom, and the coupling between the two masses. If you cut down either one, the coupling would be able to dampen vibration more (there's less energy that needs to be dissipated). I don't know if the SRB has a sharp peak at this frequency. If the vibrations induced

  • by Bruce Perens ( 3872 ) * <bruce@perens.com> on Saturday January 19, 2008 @09:01PM (#22113960) Homepage Journal
    Solid Rocket Boosters are sort of like strapping yourself to a firecracker. We can't have liquid ones?
    • Re: (Score:2, Insightful)

      by cbcanb ( 237883 )
      Because liquid ones aren't made by a certain company in a certain state. It's all politics.

      Had any sense prevailed, we'd be sticking a capsule on top of an existing booster -- Atlas 5 or Delta 4 -- and being done with it.
    • by segedunum ( 883035 ) on Saturday January 19, 2008 @09:52PM (#22114238)

      Solid Rocket Boosters are sort of like strapping yourself to a firecracker. We can't have liquid ones?
      You could have liquid ones, but they take an awful lot of development to get right. NASA, and US institutions in general, typically don't like them because of the danger involved (the Soviets have had some major disasters with liquid fuels). The only people who really did get liquid fuels to be fairly safe and reliable were the British and their Blue Streak (HTP was used after the failure of LOX - impractical in an ICBM), Black Arrow and Black Knight projects:

      http://en.wikipedia.org/wiki/Blue_streak [wikipedia.org]
      http://en.wikipedia.org/wiki/Black_Arrow [wikipedia.org]

      These rockets were a departure from everything else around, and used Hydrogen Peroxide as an oxidiser - cheap, readily available and works well at normal temperatures and pressure. Most considered the fuel to be too hazardous, and a Hydrogen Peroxide fuelled torpedo allegedly sank the Kursk (probably not sensible on a submarine), but the British developed ways to handle it safely and efficiently. To this day, no one else has tried this method and its pretty advanced rocketry even forty years on. It certainly gets rid of the dangerous handling of liquid oxygen, which has to be kept ultra cool and under controlled cryogenic conditions.

      After a textbook final launch, the project was cancelled. Given the need for commercial satellite launches over the past few decades, the mind boggles as to how cheap and useful this could have been if developed further. The British, as per usual, decided that simply reusing the Scout solid fuelled rocket would be cheaper. Go figure.
      • by rijrunner ( 263757 ) on Sunday January 20, 2008 @03:08AM (#22115628)
        LOX is routinely handled by thousands of industrial facilities in the US alone. Its properties are well known and it has been used safely for over a century.

            Liquid boosters have been used safely on dozens of rocket types. They have been used safely to launch crewed capsules. Liquid rocket engines are commercially available. (In fact, every single crewed American vehicle has had liquid fuels as their main source of energy. The SRB's on the Shuttle are booster assist and the only Gemini to fly on a solid was an unmanned test capsule).

            What we are seeing here is a departure from decades of development. Solids have been considered unsafe for manned flight for decades as they are not able to be throttled in flight. Once lit, they burn to exhaustion. They have uneven burn characteristics due to uneven mixing of the propellants. No solid casing has ever been put in a load of this magnitude. (The SRB's on the Shuttle never carried the full weight of the shuttle and they were axially loaded as opposed to have the load directly along the case). There is no engine shutdown in an SRB.

          Arguing that liquids would take a lot of development to get right is a bit misleading as it is just as much a statement to be made for SRB's.

          The whole Shuttle-derived stuff is crap. These are essentially new engines along with a new booster design and they should have had a design competition and weigh the relative merits of various design proposals. This was a fiat decision made by Griffin when he came into office. There was no technical justification. No weighing of options. Even the sizing of the Orion is extremely questionable.
        • LOX is routinely handled by thousands of industrial facilities in the US alone. Its properties are well known and it has been used safely for over a century.

          That doesn't make it any better, safer or cheaper to produce, store and handle unfortunately. Why is a foam insulation coating needed on the shuttle's main fuel tank, what routinely hits the shuttle on take-off and what caused Columbia's destruction?

          These are essentially new engines along with a new booster design and they should have had a design com

      • Re: (Score:3, Insightful)

        by khallow ( 566160 )

        Liquid hydrogen and hypergolics (chemicals that spontaneously burn when mixed) tend to be rather dangerous for different reasons. Hydrogen leaks and can cause explosive conditions under the right concentrations. Hypoergolics often are corrosive or environmentally dangerous. For example, a popular mix is fuming nitric acid and hydrazine (which is highly toxic and can decompose releasing a lot of energy).

        To this day, no one else has tried this method and its pretty advanced rocketry even forty years on. It

      • by smoker2 ( 750216 )
        You didn't read the links did you ?
        Blue Streak didn't use H2O2, it used LOX and Kerosene.

        Eventually the project was cancelled because of its lack of credibility as a deterrent. Some considered the cancellation of Blue Streak to be not only a blow to British military-industrial efforts, but also to Commonwealth ally Australia, which had its own vested interest in the project.

        The missiles used liquid oxygen and kerosene propellants. Whilst the vehicle could be left fully laden with 20+ tonnes of kerosene,

        • You didn't read the links did you ? Blue Streak didn't use H2O2, it used LOX and Kerosene.

          How about you read what was written rather than jumping in to criticise? :-

          ...and their Blue Streak (HTP was used after the failure of LOX - impractical in an ICBM)

          Blue Streak was a failure because they copied the Americans usage of LOX - a failure in an ICBM you want to launch in seconds pretty much. By the time they had really looked at HTP as the right option it was all too late and the Blue Streak was cancelle

      • ALL of our early missiles from the 50's were liquid based. All of our space program has been liquid based. Mercury was based on Atlas. Gemini was based on Titans. Apollo used the Mighty Saturn V. ALL of these engines were liquid based. Some are kerosine/LOX, and others are Hydrogen/LOX. The main boost of the Shuttle is based on the SSME. The main boost of the Ares V will be liquid. Likewise, even spacex's engines are liquid based. The brits abanded their missles and their launch systems BECAUSE they had so
    • Not really (Score:3, Informative)

      by WindBourne ( 631190 )
      IANARS, but these do not blow up. Heck even the challenger did not blow up. A seal popped open that allowed the exhaust to hit the fuel tank. The simple fact is that these are VERY safe. It has only several issues; The mix is hard to get right. Considering that it is the same mix that has gone into all 120+ x 2 shuttles, I am not too worried. The second is that once lit, there is no stopping it, and there is no throttling it (other than building it into the mix). This is not like strapping yourself to a fir
  • by Anonymous Coward
    The first Saturn V rockets for the Apollo program had a similar problem with pogo oscillations. http://www.time.com/time/magazine/article/0,9171,902216,00.html [time.com] . Engineers were able to solve the problem back then, I'm sure they can come up with solutions again.
    • Re: (Score:3, Interesting)

      by cyclone96 ( 129449 )
      Interesting article. It was written just after the Apollo 6 [wikipedia.org] unmanned test of the Saturn V in 1968.

      The mission went quite poorly. 2 engines failed on the second stage, and the third stage engine failed to restart in orbit. Parts fell off the shroud, too.

      Still, NASA went ahead and launched the next Saturn V with a crew to the moon (Apollo 8). Another unmanned test was not performed to "save about $280 million and avoid further delays in its program to place U.S. astronauts on the moon in 1969". This has of
    • by TheHawke ( 237817 ) <rchapin@NOSPam.stx.rr.com> on Saturday January 19, 2008 @09:44PM (#22114194)
      Saturn V multi-engine pogo effects were solved by buffering the fuel supply with super-critical helium cells and adjusting the guidance system for smoother steering impulses.

      A single solid propellant pogo on the other hand, is more complicated due to fact that you have variances in the solid, no matter how precise the mix is. The Japanese have been tangling with this for some time with success and failures, more failures are recorded though. Go with a clustered booster kit, then would be able to counter most of the pogo with each booster's own vibration frequency.

      A Delta-Style cluster kit would resolve this problem and give a higher delta-v impulse to the stack as a whole. The ticklish part would be man-rating the stack with the added solids. One solution would be to stagger the cluster's firing as to maximize the dampening effects. This would add a safety factor in case there's a failure in the cluster at any stage, the opposing elements would be jettisoned along with the failed unit. Then the second stage would simply burn longer to make the orbit, or a contingency plan would kick in, with maximum of life safety.
      • (Since you would probably get this...)

        A simpler solution is possible! Simply use a pogo buffer, inserted between the propellant cores and the nozzle throat.

        Now, admitedly, it would need to be much larger - since we are buffering a gas here. So picture this: we have the 150 ft x 10 ft core on top of a 40 ft wide sphere, which is attached to the nozzle...

        Hm - maybe that wouldn't get through congress...
  • Yeah, well... (Score:4, Interesting)

    by jd ( 1658 ) <imipakNO@SPAMyahoo.com> on Saturday January 19, 2008 @09:10PM (#22114008) Homepage Journal
    This might be part of why other organizations are looking more at combination liquid/solid engines, in addition to the greater control provided. For many decades now, organizations - NASA included - have worked on replacing the first stage rocket completely with a turbine-assisted ramjet. TAR engines are much more efficient than rockets, the main difficulties are in building one large enough, building large enough bypasses for the engine to work efficiently at high speeds, and at the same time building a turbine large enough for the engine to work well stationary.

    When stationary, the air must have a net velocity in excess of 400 mph for the engine to retain efficiency - which a turbine can easily do if there are no other complications. Eventually, the turbine gets in the way, hence the need for a really good bypass system. White Knight avoided the need for TAR by having the first stage as an actual aircraft, but a conventional aircraft isn't going to be capable of carrying the weight needed for true orbital flight, let alone interplanetary flight. Affordable space flight is probably going to require TAR engines.

    (Other alternative launch-assist methods include using linear accelerators - basically strap the rocket onto something akin to a bullet train and then get the train up to the critical speed, or using a very powerful gas cannon to fire the rocket into the air at the critical speed. The first would likely end up more expensive to operate than a TAR, the latter would require a very sophisticated multi-charge arrangement if it is to avoid killing everyone onboard, but might end up being another viable method.)

    One thing I think can be said for certain - by 2020, no sane engineer will be designing launch vehicles for space that use a rocket first stage. I'll give it a 40/60 chance that by 2020 commercial space flight will have surpassed NASA in terms of cost-per-unit-mass-launched, and 20/80 that hobbyist space flight will have done likewise. If NASA persists in long-outmoded next-gen launch vehicles, then somewhere in the 2030-2050 timeline, NASA will be redundant. Government-run organizations make sense for bleeding-edge work because that is generally too expensive for everyone else. However, once everyone passes said Government agency's technology, it has no value or merit. To have value for money, NASA should be working on systems that will become bleeding-edge in 2020, not what were bleeding-edge in 1920. R&D is the expensive work, everything else is meccano tech.

    • Re:Yeah, well... (Score:5, Interesting)

      by DerekLyons ( 302214 ) <fairwater.gmail@com> on Saturday January 19, 2008 @09:34PM (#22114134) Homepage

      For many decades now, organizations - NASA included - have worked on replacing the first stage rocket completely with a turbine-assisted ramjet.

      No, NASA gave it up years ago - as it simply doesn't work. The turbines are too heavy, useful for too small a portion of the flight profile, etc... etc...
       
       

      Other alternative launch-assist methods include using linear accelerators - basically strap the rocket onto something akin to a bullet train and then get the train up to the critical speed, or using a very powerful gas cannon to fire the rocket into the air at the critical speed.

      Two more ideas that don't work, despite years of fanboy cheerleading for them. Among other large drawbacks - you still need to get a substantial portion (99%+) of the required velocity from rockets, but the weight of the structure needed to withstand these methods of 'assisting' means a rocket launched this way is actually larger and heavier than one that launched in a conventional fashion.
      • by MrKaos ( 858439 )
        At the risk of being seen as a fan bouy, what about Space elevators? Surely research into solving the materials issues to make this happen should be a priority, I'm specifically referring to the creation of funding for nano-fibre ribbon research.

        At the very least will this generation of launchers facilitate construction of an S.E. Will the heavy lift vehicles be able to carry enough into L.E.O for the initial spool segment. I mean realistically without S.E technology is there any point to building chemi

        • by jd ( 1658 )
          ...it's less about the specific solution and more about the fact that commercial efforts to exploit high-altitude and space flight are edging past NASA in their research into alternative technologies -- and far more yet about the fact that NASA's top research at the moment is a blended-wing body aircraft that they'd already got just about as far with in 2000 when they cancelled it. Yes, BWB and waveriders are tough, but NASA is a self-imposed decade behind where they damn well should be. A decade in which e
          • by MrKaos ( 858439 )

            I doubt the Australians were doing nothing after the USA got their scramjet tests in,

            Dood, I am Australian, I love this country - but lets be realistic, we are hardly in the space race. I have little doubt that the CSIRO scramjet research was contributed under some trade agreement to the U.S. We did a lot of rocket development here (a little known fact that Australia has/had the largest Air Force base in the world, something like 5000kms) for the Brit's and the U.S but that's about all. I'd love it if w

  • by segedunum ( 883035 ) on Saturday January 19, 2008 @09:22PM (#22114060)
    Seriously, this was known about forty years ago and are called pogo oscillations. They are generally disastrous, and they were the cause of Apollo 13's fifth engine shut down after liftoff.

    In general, I'm pretty non-plussed by NASA's moon landing attempts. Their design is basically Apollo rehashed plus forty years (fifty years if it actually launches - pretty depressing), the vast majority of it isn't reusable (I haven't got a clue how they can call it a shuttle replacement) and it really doesn't get us any further forwards in terms of making getting into space easier, safer and something that can be done on a regular basis.
    • Re: (Score:3, Informative)

      by Chairboy ( 88841 )
      Nope, Pogo oscillation was caused by compression waves that affected pump volume in liquid fueled rockets. This was solved in the SSME for the Shuttle by adding a chamber along the fuel feed that acted like a capacitor. Transient pressure waves would back fill the chamber, then the other side of the wave would suck it out. Constant flow, no pogo.

      This is a solid rocket, it's a different problem.
      • by MrKaos ( 858439 )

        Constant flow, no pogo.

        Sounds like an advertisement for colonic irrigation.

      • Nope, Pogo oscillation was caused by compression waves that affected pump volume in liquid fueled rockets.
        Yes, true, as this is a solid fuelled rocket. However, the effect is pretty much the same - resonance of some kind.
    • Re: (Score:3, Funny)

      by khallow ( 566160 )

      (I haven't got a clue how they can call it a shuttle replacement)
      They reuse most of the supply chain/political kickback system.
    • Re: (Score:2, Insightful)

      by maxume ( 22995 )
      Wait, you think the shuttle is reusable?

      Getting into space isn't going to get a whole lot easier or cheaper for a long time. Maybe ever. It's the physics that are the problem.
    • Re: (Score:3, Informative)

      Seriously, this was known about forty years ago and are called pogo oscillations. They are generally disastrous, and they were the cause of Apollo 13's fifth engine shut down after liftoff.

      They're "generally disastrous" only in the sense that they'll destroy the craft if they aren't addressed. Apollo solved the problem by essentially adding a big bellows to the fuel supply feed, allowing the pressure pulses to be damped instead of allowing the fuel flow to resonate. The Space Shuttle main engines have similar dampers in place, and their design was based on data acquired during Apollo.

      In general, I'm pretty non-plussed by NASA's moon landing attempts. Their design is basically Apollo rehashed plus forty years (fifty years if it actually launches - pretty depressing), the vast majority of it isn't reusable (I haven't got a clue how they can call it a shuttle replacement) and it really doesn't get us any further forwards in terms of making getting into space easier, safer and something that can be done on a regular basis.

      Your observation shows a shocking lack of perspective. Just because the design has a capsule on top doe

  • Same old Griffin (Score:3, Interesting)

    by 0123456 ( 636235 ) on Saturday January 19, 2008 @09:26PM (#22114086)
    ""I hope no one was so ill-informed as to believe that we would be able to develop a system to replace the shuttle without facing any challenges in doing so," NASA administrator Michael Griffin said in a statement to The Associated Press."

    Well, duh, the whole point of the 'shuttle-derived' Stick design was that it was supposed to be safe to fly and fast and cheap to develop because the shuttle technology would avoid these kind of 'challenges'.

    But instead of building a capsule that could fly on the shuttle-derived launcher they've expanded it into an orbital RV which requires major changes to the launcher design to have any chance of reaching orbit.
  • "... similar to the wake that develops behind a fast-moving boat."

    Only different. Without water. Or a propeller. And no gasoline. Or a steering wheel...forget about steering - really.
  • of course not (Score:4, Interesting)

    by sentientbrendan ( 316150 ) on Saturday January 19, 2008 @10:12PM (#22114336)
    >they do not expect it to delay the goal of returning astronauts to the moon by 2020.

    of course not, what's going to delay going to the moon again by 2020 is the fact that congress has no intention whatsoever of paying for that, and no one, not even Bush takes the program seriously.

    Why are they wasting money on programs that are going to be thrown right out the window, never to be heard of again, as soon as the next president takes office?
  • Last year the 'problem' was that the Orion spacecraft was too heavy, and NASA was criticized on this forum. That was quickly and quietly solved, though the solution was not as widely reported inn the press. Ares I will use the largest solid rocket motor ever fired. Let the engineers work. If they can launch a space shuttle 120x using motors only 20% smaller, I think they can get the larger one working safely without the oversight of the New York Times.

    • by 0123456 ( 636235 )
      "That was quickly and quietly solved"

      Exactly how was Orion's Bloat 'quickly and quietly solved'? Last I heard they'd had to switch from land landing to water landing because it was already too heavy to launch with no prospect for future weight growth, and then discovered the slight problem of not being able to land if they had to abort early in the launch.

      And, even then, it was still too heavy.

      The simple fact is that they're building far too big a capsule, and every other problem stems from that. That's led
      • by dbIII ( 701233 )

        Exactly how was Orion's Bloat 'quickly and quietly solved'?

        Get the flight crew under 1.5 metres in height and under 50kg in weight and you can make the capsule a lot smaller and lighter. Orion? Sorry ... that was the Rocket Girls anime from 2007.

  • The first couple minutes really suck. Those SRB's shake bad. Once they burn out, the ride is really smooth. Solid rockets are that way, I am sorry, but you can't have fuel moving up the tube and the flame following it and have a smooth ride. Think of the solid fuel, it doesn't move, only the pressure. The farther it moves up the more the pressure changes here and there. POGO is something else. That is more from liquid fuel sloshing around, not presenting and even pressure. As the fuel is falling it adds m
  • Nuclear Rockets (Score:5, Interesting)

    by serutan ( 259622 ) <snoopdougNO@SPAMgeekazon.com> on Saturday January 19, 2008 @11:06PM (#22114642) Homepage
    I wish NASA would put more effort into developing gaseous core nuclear rocket engines. There was a nuclear engine project in the late 60s using a solid core reactor, but gaseous core reactors have not been thoroughly explored. Whereas solid reactors melt above about 3500C, a "light bulb" type of reactor consisting of a hollow quartz bulb with a cloud of gaseous nuclear fuel confined in the center could operate at 25000 C, radiating in the ultraviolet range instead of heat per se. In an engine based on this type of reactor, hydrogen flowing past the outside of the bulb would be superheated and expelled as rocket exhaust. No chemical combustion, no radioactive emissions, just heat transfer.

    Check out this interesting article [nuclearspace.com], part 10 of a series, about a hypothetical design for a non-polluting, 100% reusable nuclear rocket based on the Saturn V form factor. Using existing engineering apart from the gaseous core reactor, it could lift 1000 tons of payload into orbit (6 times the capacity of the proposed single-use Ares 5 cargo rocket, and 30 times that of the shuttle), and then return 1000 tons of cargo to a powered vertical landing. No expendable fuel tanks, no solid booster recovery, just a big old Flash Gordon style rocketship. This is heavy lifting power that could take up a space hotel or moon base in one shot. It could power enormous ships to Mars in 3 months, not merely to explore but to colonize, carrying hundreds of people at a time, hundreds of tons of equipment and supplies, and highly effective radiation shielding.

    I know it's the "N" word, but this rocket wouldn't be a nuclear disaster waiting to happen. If such a ship crashed or exploded and released its entire nuclear fuel load into the atmosphere, the nuclides released would be 1% of what came out of a single 1950s bomb test (and there were many of those).
    • I support the idea of nuclear rocketry, in theory.

      Let's however get back from engineering dreamland and take a cold hard look at political reality. Anything with the word "nuclear" in it scares the shit out of the vast majority of people. Most people seem to be convinced that every nuclear device is a potential nuclear weapon waiting to go off, and that any nuclear accident will inevitably result in thousands of deaths and an area the size of Texas rendered uninhabitable.

      I am perfectly well aware that

      • Exactly, thank you Cold War and Chernobyl/Three Mile Island for scaring the ever living bejesus out of most people when it comes to the word nuclear.
    • Comment removed based on user account deletion
  • The problem of NASA is that it always want to make it non-Russian. While Russians just make it practical and scientific. That is why the Shuttle has got its crazy shape and the crew cabin is below the towering tank. As a result junk falls down on the Shuttle crew capsule.

    With this new rocket we see the same idiotic non-scientific design. The rocket will be unstable folks. You know it, we know it. Make it look like Soyuz. Nothing will happen, but lives will be saved.

    You proved the world that you can live

  • by FleaPlus ( 6935 ) on Sunday January 20, 2008 @05:53AM (#22116044) Journal
    Over at Transterrestrial Musings aerospace engineer Rand Simberg has some pretty interesting thoughts on this issue. A quote:

    http://www.transterrestrial.com/archives/010396.html#010396 [transterrestrial.com]

    What exactly is the issue? The problem is that any structure has a resonant frequency at which it naturally vibrates. If you excite the structure at that frequency, you can develop a positive-feedback system that will literally shake it apart (the Tacoma Narrows Bridge is the classic example).

    Solid rocket motors don't run particularly smoothly (compared to well-designed or even poorly designed liquids) and large solid motors provide a very rough ride. Everyone who has ever ridden the Shuttle to orbit has commented on how much smoother the ride gets after staging the SRBs.

    Now, one way to mitigate this is to damp it out with a large mass. The Shuttle does this by its nature, because even though it has two of the things, they are not directly attached to the orbiter--they are attached to a large external tank with one and a half million pounds of liquid propellants in it, and it can absorb a lot of the vibration. Moreover, the large mass has a frequency that doesn't resonate with the vibration.

    As I understand it (and I could be wrong, and I'm not working Ares, but this is based on discussions, many off the record and all on background with insiders on the program), there is a very real concern that the upper stage on top of the SRB in "the Stick" will be excited at a resonant frequency, but that even if not, the stage will be too small to damp the vibrations of the huge SRB below.

    If this is the case, there is no simple solution. You can't arbitrarily change the mass of the upper stage--that is determined by the mission requirement. Any solution is going to involve damping systems independent of the basic structure that are sure to add weight to a launch vehicle that is already, according to most reports, underperforming. Or it will involve beefing up the structure of the upper stage and the Orion itself so that they can sustain the acoustic vibration loads. In the case of the latter, it is already overweight, with low margins.

    So this constitutes a major program risk, that could result in either cancellation, or a complete redesign (that no longer represents the original concept, because the problem is fundamentally intrinsic to it).

    Now, let's take apart the response a little:

    Thrust oscillation is...a risk. It is being reviewed, and a mitigation plan is being developed. NASA is committed to resolve this issue prior to the Ares I Project's preliminary design review, currently scheduled for late 2008.

    The problem is that NASA can "commit" to resolve it until the cows come home, but if it's not resolvable, it's not resolvable. They can't rescind the laws of physics, and we're approaching a couple of anniversaries of times when they attempted to do that, with tragic results.

    Now this next part is (to put it mildly) annoying:

    NASA has given careful consideration to many different launch concepts (shuttle-derived, evolved expendable launch vehicle, etc.) over several years. This activity culminated with release of the Exploration Systems Architecture Study in 2005. Since then, the baseline architecture has been improved to decrease life cycle costs significantly.

    NASA's analysis backs up the fact that the Ares family enables the safest, least expensive launch architecture to meet requirements for missions to the International Space Station, the moon and Mars. NASA is not contemplating alternatives to the current approach.


    The problem is that NASA didn't give "careful consideration" to the previous analyses after Mike Griffin came in. As far as can be determined, all of the analysis performed under Admiral Steidle's multiple CE&R contracts, performe

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