In article ,
says...

Jeff Findley wrote:

In article ,
says...

Anthony Frost wrote:

In message
Jeff Findley wrote:

This has changed somewhat recently. Reportedly SpaceX is the one who
shelved development of Dragon V2 vertical landing. The reasons for this
aren't terribly clear, but there are hints from SpaceX that this is
because they've decided to change the (Mars) landing mode of their
(eventual) Mars vehicle.

Also apparently NASA weren't happy about cargo flights being used for
testing powered landings.


Why would they care? They get their cargo on the way up, not the way
down.


Because Dragon is the only way that NASA can get things like EMUs back
to earth for refurbishment. There have been articles on how few
functioning EMUs are left. Sorry for the word-wrap on the cites:


But most flights aren't carrying those (or anything else) back down.
So why is NASA apparently being obstructionist about landing the
'empties' propulsively?

I suspect that it's mostly the pointy haired bosses at NASA being
"cautious", not the engineers raising concerns. They've had it hammered
into their heads that "Failure is not an option", even though that's not
at all what was meant by that phrase during Apollo 13.

Like you said, if they lost a capsule or two (as long as it didn't carry
something critical to be refurbished like an EMU), it's not like it
would impact ISS safety in any way.


I think it's funny that NASA lets astronauts ride on Soyuz,
which relies on power at landing on dirt for them to survive, yet is
being obstructionist to safety certify Dragon V2 for fully powered
landings on dirt.

That's the rumor. Another rumor says Dragon V2 propulsive landings are
being dropped because SpaceX is going to be changing its landing mode
for Mars missions. I'm not sure how much stock I put in that, but we'll
just have to wait and see. SpaceX isn't afraid to change directions
when something isn't working out or when another more promising approach
surfaces.


Well, they could get smaller by removing the outer ring of engines.
That would reduce thrust to 1/4 of the original concept, which is
about four times what a Falcon Heavy delivers. But is that big enough
to support a real Mars colony?

Good question. A better question might be does a BFR that's only good
for Mars make economic sense when NASA is setting its sights on lunar
orbit and might very well buy launches since SLS is going to have an
abysmally low flight rate (at most twice per year).

Jeff
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