prb@access.digex.net (Pat) writes:  >I wrote: >>prb@access.digex.net (Pat) writes: >| >|>Given that what i described for the HST  seemed to be the SMT,   >| >|Has someone actually verified that mass is the predominant constraint on this >|mission?  You seem to be assuming it without giving supporting evidence.    >Someone from NASA posted that there were very significant mass margins >on the HST re-boost mission.  A while back i had asked why not carry >the EDO pallet up,  and the answer was the mass margins were tight enough, they weren't even carrying extra suits.  So how much mass is saved by not burning the OMS?  That's the critical question. My data shows that the OMS engines hold 10,900 kg of propellant.  Of that, a  substantial fraction is going to be used for the first OMS burn, the reentry burn and the reserve.  So Pat, tell us how much fuel the altitude change is going to take, and how much the EDO pallet, BUS-1 and extra parts are going mass.  If you can make the numbers work out, _then_ I'll be interested.  After you show us that it can be done, then tell us how much the EDO pallet, BUS-1 and extra equipment is going to cost.    >|>WHy not do this? >| >|>	Quick Test  Goldins philosophjy  of faster cheaper, better. >| >|>Build a real fast Space TUg,  to handle the re-boost  of the HST  using >|>clean Cryo fuels,  and get it ready before the  HST mission. >| >|Pat, this would be slower, more expensive and worse.    >Where's wingo when you need him:-) >COme on.   Knock that S**T off.  >YOu forget,  that during skylab,  they did  overnight mission planning >for the repair EVA's.   Also during thexD    >Intelsat Mission,   they did overnight  WETF simulations. >I somehow think they could train up a new  EVA in  8 months.  First, while astronauts certainly have done EVAs with minimal planning, that was because they _had_ to.  They don't like to do that as a general rule.  Second, remember why they had to improvise during Intelsat 6?  They were trying to attach a motor to a piece of hardware that wasn't designed to do that.   Trying to shortcut the training is only going to make a repeat more likely.  Third, they don't have eight months.  They have however much time is left  after someone comes up with a plan, shows it can work and gets it approved. You may think I have a pessimistic attitude.  I think it's realistic.  I'm not saying that the engineering task is impossible (few engineering tasks are).   What I'm saying is that this is neither cost effective nor feasible under NASA management.  >And as for building hardware,  anything can  be built if you want it >bad enough.  >YOu forget,  the  BUS 1  is already built.  all they'd ahve to do >is soup it up, even test it  on a delta mission.  "All they have to do is soup it up?"  Just what does that mean?    >Don't get into this mode of  negativism.   besides,  at the rate >missions slip,   the Discovery won't launch on this mission until >March.  that's almost a year.  >|More Expensive:  Your proposal still requires the shuttle to do everything it >|was going to do execpt fire the OMS.  In addition, you've added significant >|extra cost for a new piece of complex hardware.  >Ah,  but how much more expensive is the Second HST servicing mission.  The second servicing mission is a contingency.  You have neither shown that it would be necessary without your plan nor that it would be unnecessary with your plan.    >YOu forget,  there is a bum FGS,  the Solar array electronics, are >getting hinky  and there is still 8 months until the servicing mission.  No, Pat, I haven't forgotten.  >If the SMT can avoid a second servicing mission that's $500 million >saved.  No Pat.  That's $500 million minus the cost of the new hardware, minus the cost of the extra struff you want to bring along, minus development and mangement  costs, minus extra operating costs.  TANSTAAFL.  >|According to a GAO report on the OMV I have before me, there are >|only two currently planned missions that could use such a vehicle -- HST and >|AXAF.  Since AXAF has since been scaled back and HST can rely on the shuttle, >|there doesn't seem to be any need for your vehicle.  >Of course,  there wasn't any need for the Saturn  V  after apollo too.  I'm sure that if you reread this you'll see that your argument is falacious.  >as for the problems with the aperture door,  I am sure they can >work out some way to handle  that.  Maybe a Plug  made from >Frozen ice.?   it'll keep out any contamination, >yet sublime away  after teh boost.  Pat, not only is this messy and less reliable than a device that's _made_ to  perform this task, it also ignores the point.  There is a desire to have  astronauts available so that if the door fails to open, something can be done about it.  Unless you can provide a very reliable way of reopening the door, you haven't solved the problem.