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brobof

brobof also uses the worldhandle of  Dave Lermit and is a Gemini by trade. A confirmed Space enthusiast from an early age:  Science Fact or Science Fiction it is all grist to his mill. brobof has one criteria: if it doesn’t have Rocket Ships or Rayguns it ain’t worth watching!

2 comments

  1. Thanks for your comment on my comment at NASA WATCH. It’s apposite. I’ll reserve judgment on whether it’s a whole adequate rebuttal however — I’m not seeing a bunch of comments there or elsewhere proclaiming that Obama’s space policies are more likely than others to lead to colonizing the solar system; mostly folks who approve of them simply are pleased that Obama’s plans aren’t Mike Griffins.

    Oh well. Truthfully, I suspect Obama’s Space Policy is written on the winds. Proclaiming a Plan of any sort that isn’t going to be affected by economics and technological change and the actions of other nations is a waste of energy.

    But I might be wrong.

    Nice to see your blog. I’ll have to come back.

    -ms


  2. To Brobof / Dave Lermit

    This is a very belated reply since I was working on a deadline when my article came out. I thought your comments on my article on Space Tugs (NASAwatch 6-13-2010 – already buried in their archives), as well as the useful links you provided, were very helpful. No one can pay attention to or see all of the relevant output all of the time.

    I agree that both a common docking system and a permanent module mating system should be agreed on. I have not studied the details of the current docking systems, but I agree it is an important issue. One part of it that has been rarely mentioned is the issue of sudden stress on docking or mating joints, caused by unexpected thrust, collisions, etc., which could damage or rupture them, killing anyone inside. Therefore there should also be an international standard for placing connection points on the outside of modules to connect bracing struts between modules which are permanently mated to further protect them from such accidents.

    I was aware of the risk of attaching a propellant depot to the station, (which could cause stress or damage to docked or mated modules in case of a fuel leak or other accident). The depot I had in mind is a small one, sized only large enough to handle station re-boosting needs and the re-supply of the space tug (which would need relatively little propellant to recover nearby objects). Any large depot such as would be required to support LEO to lunar or escape velocity missions could not be attached to the station. That is why I mentioned the venting safety system.

    I am avoiding hypergolics for (1) the toxic risk they pose to ground crews and (2) an accident could cause a much bigger problem than mere venting. Dad’s work with the Agena program showed him the risks of UDMH and RFNA getting together when they are not supposed to.

    I am very much in favor of using an existing or proposed stage or module to create a space tug or depot.

    Using venting propellants directly at low pressure to keep the space station in its proper orbit seems a possibly wasteful method rather than actually using them to power a rocket engine at intervals. Ultra-insulation can be combined with solar powered re-condensation equipment to keep the propellants from boiling off. The possible alternative of running a very small rocket engine most of the time using the venting propellants introduces a high degree of operational complexity and risk and would need to be turned off during spacewalks, dockings, etc.

    The budget is tight for alternate, new and programs directly applicable to beyond LEO exploration only because the politicos want to keep the current jobs in the current locations. This means endless and wasteful production of expendable vehicles. My strategy was to use the surplus labor pool to work on projects that directly advance exploration capabilities even if they would not be used immediately, and to select projects that would more clearly show the administrations intent to develop beyond LEO exploration capabilities. Here I am focusing on development of IN-space vehicles and equipment and technology for them.

    This issue is different for HLV development since private companies are already working on their own HLV designs, and the government (by “choosing” a design), may well end up with a much more costly design to operate. What it could do is do neutral work that could apply to all HLV designs. I do not want to see continued use of solids since launch prices will never come down if we don’t switch to re-usable liquids.

    The opponents claim that it is impossible to build a light enough power plant to run the VASIMR as an effective interplanetary or cis-lunar transport vehicle. Solar panels are getting more efficient and lighter every day, (more to advance the Cause of space solar also). We have also not really tried to design an effective nuclear-reactor-based power source for decades. They are however, testing Stirling cycle based isotope-powered systems for outer solar system missions. I do not know if the power to weight of these is high enough.

    You are welcome to correspond with me via my email address. I am working on a paper on Mars Logistics for presentation at the upcoming Mars Soc. Convention. I am currently interested in any comments on the problem of landing large, re-usable ferry vehicles on Mars, as well as the minimum mass of a vehicle that can land and carry habitats of at least 20 tons inside it. I assume that this would be about 100 tons minimum including cargo.

    John Strickland
    Austin,TX



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