Re: Someone to defend the Stick?


Scott Lowther wrote:
> Alex Terrell wrote:
>
> >>I've discussed this with the relevant people at ATK. The HLLV sans upper
> >>stage can insert the ET, SSME's and 130,000 lbs of *stuff* into 220 NM
> >>easterly orbit. Woo! Super-Skylab, done wet-lab style. Personally, I'd
> >>love to see a good chunk of that 130,000 lbs be Bigelow modules
> >>
> >>
> >>
> >That would be nice. Why only 60 tons though? The current system puts
> >over 100 tons into LEO.
> >
> >
> Remember, that 130Klbs of payload *with* the ET and SSME's. It's clearly
> not optimised; an optimal system would stage off the ET early and use a
> smaller OMS-type system for orbit circularization.
>
Thanks - is that what the Shuttle OMS does? Do you know how much delta
V it gives?

I guess for a moon shot it might be optimal to fire the Earth Departure
Stage before orbital velocity is reached.

> >I think the key points are still:
> >1. NASA could benefit from an HLV (100t to LEO), so the Shuttle derived
> >HLV could be justified.
> >2. There is no requirement for 30-40 tons to LEO, so there is need for
> >the Stick.
> >
> >
>
> Except that it appears that there *is* a requirement for 30 or so tons,
> to get a *complete* CEV to orbiot. That means not only capsule, but SM
> as well.
>
A 30 ton vehicle sounds more useful. However, if this is the
requirement for a low Earth Orbit CEV, then the CEV design is wrong.
Apollo SM/CM stack was under 30 tons, and that went to the moon and
back, and was stuffed with 60s technology including 60s electronics. It
also reentered with twice the energy of a LEO CEV.

For LEO operations, CEV + SM should be less than 20 tons.

The only situation where I can see the stick being useful is for
1. A lunar orbital mission, with no landing. Even for that it's a bit
on the light side.
2. Landing cargo on the moon, where it would be able to land 4 tons.
But for this, an HLV landing 14 tons is much better.

I suppose salvo launches could be arranged, with EO rendez-vous, but
that adds further complexity.

.

Relevant Pages

  • CEV launch - Stick or HLV?
    ... NASA is proposing the stick to launch the CEV. ... back, requires a CEV of about 24 tons, and about 6 tons of return fuel. ... this needs an LEO capability of 75 tons - way ...
    (sci.space.policy)
  • Re: Someone to defend the Stick?
    ... but this equals reliance upon foreign powers. ... They've already flown with 20 tons, which is enough for a CEV mission ... to LEO, or a resupply mission to ISS. ...
    (sci.space.policy)
  • Re: ESAS "1.5 EOR" Architecture Finished?
    ... And if there is the slightest chance that having a crew aboard ... You are talking over 35 tons to LEO and 30 tons to ISS if done right. ... Such a rocket might exceed 14 tons to LEO. ...
    (sci.space.policy)
  • Re: Someone to defend the Stick?
    ... >Apollo or CEV. ... what is a LEO CEV for? ... I am suspecting that there won't be separate LEO and Lunar CEVs. ... well below 4 tons. ...
    (sci.space.policy)
  • Re: Launch costs seem irrelevant
    ... >would need about 25 times 14 tons on the lunar surface. ... >about 2,500 tons in LEO with cryogenics, or 3,000 tons in LEO with ... >Suppose Mr Musk transforms launch operations, and does LEO for 1c per ...
    (sci.space.policy)