In article <C6BBow.IH9@news.cso.uiuc.edu> jbh55289@uxa.cso.uiuc.edu (Josh Hopkins) writes: >prb@access.digex.net (Pat) writes: | |>Given that what i described for the HST  seemed to be the SMT,   and given |>the mass amrgins on the discovery mission  is tight enough that  spacewalking |>has to be carefully constrained.....  No EDO pallets,  no spare Suits, |>no extra MMU's.    | |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.  |>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.   | |Slower:  The shuttle mission is scheduled to go up in December.  That's less |than eight months away.  There is no way you could build new hardware, retrain |and reschedule the EVA's in that time. |  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 theøÄ    Intelsat Mission,   they did overnight  WETF simulations. I somehow think they could train up a new  EVA in  8 months.  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.  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.  YOu forget,  there is a bum FGS,  the Solar array electronics, are getting hinky  and there is still 8 months until the servicing mission.  The time for the space walks are growing rapidly.  THis was orignally planned out as 3 spacewalks,  now they are at 5 EVA's  with 3 reserve walks.  If the SMT can avoid a second servicing mission that's $500 million saved.  If the Weight savings,  means they  can sit on orbit  for 30 Days. and  handle any contingency  problems,  that's quite a savings.  | |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.  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.