In article om,
says...

On 14-08-25 13:48, Jeff Findley wrote:

If given the choice between a gliding landing on a runway in a lifting
body or propulsive vertical landing, I'd personally choose the vertical
landing. But I'm not the NASA Astronaut Office who's been landing
gliders for decades, so they may have another preference.

Can you elaborate on your preference ?

Both techniques involve a "only one shot to land". And contrary to the
unar landers where the crew are in control o craft for minutes and see
descent slowing down etc, the capsules are in free fall (with
parachutes) with engines firing only at last minute to slow down to
landing speed. Miss that and you land rather hard.

Actually on Dragon V2, parachutes are there only for a backup landing
method (i.e. launch abort which uses Super Draco fuel to escape the
booster would leave no fuel reserve for propulsive landing). On a
normal landing, Dragon V2 lands by firing the Super Draco engines.

But your point is still valid. There is only enough fuel for "one shot
to land". I don't think it's designed for extended hover.

In a glider scenario, I suspect the crew have much more time to get into
a controlled approach and failing this, they can bail out if they
realise the landing will fail.

Lifting bodies tend to have horrible L/D ratios, like the shuttle, so
they'll suffer many of the same problems. Bailing out of the shuttle
was only an option if you were still very, very high up in the air. The
thing flew like a brick and there simply wasn't time to bail out at "the
last minute". Remember the M2-F2 lifting body crash which was used in
the opening sequence of The Six Million Dollar Man? Not a good day for
lifting bodies.

However, I guess from the hot re-entry phase, a capsule gains advantages
over a glider whose attitude must remain within a very narrow set fo
acceptable numbers of face total destruction. A capsule is more
forgiving and self adjusting.

Depends on the details. Dragon V2 and CST-100 will both fly hypersonic
lifting reentries similar to that of a lifting body. The advantage of
the lifting body during hypersonic reentry is that it can have higher
hypersonic L/D than a capsule and therefore more cross-range and lower G
loading during that phase of the flight. But you have to temper that
with the fact that the lifting body needs to hit a long runway with a
precise speed, altitude, and heading, where the capsule can come down on
pretty much any flat surface, or even water, in an emergency.

In short, the pilot of the lifting body has many more variables to
contend with and if things go bad near the runway, there is no time to
bail out and I don't believe Dream Chaser will have e-seats (which carry
with them their own dangers).

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer