Re: Ares alternatives? "NASA renegades"


"Jochem Huhmann" <joh@xxxxxxx> wrote in message
news:m2iqok5dma.fsf@xxxxxxxxxxxxxxxxxxxx
John Doe <jdoe@xxxxxxx> writes:

Having a good launcher will help reduce the number of launches needed to
assemble a mars expedition. (whether set as one ship or as 2 ships, you
still need to send that mass to LEO and assemble it in one or two chunks
before sending it.

But if you want to launch that on current EELV's you will deliver at
most 10 to 15 tons of equipment with one launch (since every single
payload will need power and engines and fuel and more). Add to this the
needed crews to assemble non-trivial stuff which you also have to launch
and you end up with dozens or more launches, not two or three. This is
just not practical.

This is how ISS has been assembled. So ISS isn't practical? Don't you
think lessons have been learned from ISS which would make in orbit assembly
easier for future projects?

You'll have to launch modules that are assembled and
tested on the ground and which don't need any manual work to join them.

Not true. Mir and ISS have shown otherwise.

You most certainly don't want to assemble a heat-shield for a Mars
lander from a dozen different pieces launched seperately.

Why not? Not all previously flown heat shields have been one piece. The
shuttle is one example of this. The re-flown Gemini and TKS reentry vehicle
both had hatches in the base of their heat shields and they both worked
fine.

You probably
even don't want to assemble the structure and tanks and engines and
pressure vessel and airlock and other equipment for a moon lander this
way.

Just how much do you think an *empty* lunar lander needs to weigh? If you
fill the tanks in LEO using a fuel depot, you can launch a much bigger
lander than you might think.

Jeff
--
"Many things that were acceptable in 1958 are no longer acceptable today.
My own standards have changed too." -- Freeman Dyson


.

Relevant Pages

  • Re: Is the space station a dead end project?
    ... to get near enough the station to be berthed to a CBM hatch in just a ... that if Ares/Orion continues that we would see Orion flights to ISS. ... It's also concievable that you could launch an Orion minus its pressurized ... This will do nothing to prepare NASA for how to assemble hardware in LEO ...
    (sci.space.station)
  • Re: 10 meter diameter CaLV
    ... Depends on how easy the assembly is and it depends on the price differential between the HLV needed to launch the ground assembled vehicle when compared to the cost to launch the pieces which are assembled in LEO. ... The shuttle/ISS experience is hardly a shining example of how to do in orbit assembly "right", but there are lessons to be learned there which could make a next generation vehicle much easier to assemble in LEO. ... I'd like to see a compromise for the lunar program baselined using existing EELV's, rather than having NASA build yet another extremely large, extremely low flight rate launch vehicle that does absolutely nothing for the launch industry in terms of lowering launch costs. ...
    (sci.space.policy)
  • Re: 10 meter diameter CaLV
    ... to the cost to launch the pieces which are assembled in LEO. ... a next generation vehicle much easier to assemble in LEO. ... I really think Griffin's NASA would go ...
    (sci.space.policy)
  • Re: Ares alternatives? "NASA renegades"
    ... needed crews to assemble non-trivial stuff which you also have to launch ... This is how ISS has been assembled. ... How many years are you willing to take to assemble your spacecraft? ...
    (sci.space.shuttle)
  • Re: Ares alternatives? "NASA renegades"
    ... assemble a mars expedition. ... (whether set as one ship or as 2 ships, ... But if you want to launch that on current EELV's you will deliver at ...
    (sci.space.shuttle)