NYT Editorial: NASA's Predicament

Jorge R. Frank wrote:
John Doe wrote in :


In terms of pretending that CEV can participate in a Mars mission, this
is utter rubbish. All it would do is act as a crew ferry between earth
and the staging area in LEO where the mars ship would be assembled.
[...]

If that's true we're up to three uses (not one) for the CEV for a Mars
mission, in case you're counting.

I guess the article by Buzz Aldrin in the December 2005 Popular
Mechanics passed him over.

BTW, can someone expand on the semi-cycler idea? The references I
found by googling were all of the "put in shopping cart" variety, with
the exception of a few very vague descriptions.

/dps

Kelly McDonald kellymcdonald@ wrote:

Didn't Zond make use of the skip-rentry profile during the unmanned
test missioned?




Yeah, and it was one big skip also- clean from the Indian Ocean into the
Soviet Union.

Pat

Henry Spencer wrote:


Correct. Zond was designed for a skip reentry, and at least one of the
tests (I forget exactly) demonstrated it.


They were all (of the actual Soyuz-derived L-1 design that is) supposed
to do it, but only Zond 6, 7, and 8 succeeded in doing it. The skip took
the Zond 6 and 7 spacecraft clean from the Antarctica to over the Soviet
Union, with touchdown being only 16 km. from its launch site at
Baikonur in the case of Zond 6:
http://www.astronautix.com/details/zond6810.htm
Zond 7 was less precise and came down 50 km. from its aim point of Kustani.
Zond 8 came in over the North pole and skipped to a landing site in the
Indian Ocean; this was going to be the preferred landing trajectory for
the returning L-3 LOK capsule for the Soviet manned lunar landing
program as it allowed the returning spacecraft's trajectory to be
fine-tuned by the Soviet tracking stations in the northern hemisphere,
allowing the skip maneuver to be adjusted targeted for a precise landing.
The south polar approach meant a landing on ground inside the Soviet
Union, but the landing point was very imprecise due to the lack of
tracking stations in the southern hemisphere.

Coming back from beyond LEO,
you definitely want to do a lifting reentry -- a purely ballistic reentry
at such speeds is really brutal


Peaking at 20 G's in the case of Zond 5.
Ouch.

Pat

Henry Spencer wrote:
No, Apollo was good enough even without the skip. If memory serves --
references aren't handy -- Apollo landing error was no more than a few
kilometers. That doesn't matter a whole lot if you're coming down
somewhere like White Sands. And we could probably do somewhat better now,
with better guidance hardware.

When you consider Soyuz's landing performance, is it really realistic to
expect a capsule to ALWAYS land with sufficient precision to target some
area in the USA landmass ? *If* the USA flew Soyuz, would it allow it
to land on continental USA based on its current landing precision
statistics ?


If CEV is to be doing more than a couple of camping trips to the moon,
isn't it safe to assume that there might eventually be some landing
mishaps that might put the capsule off-target for its landing over the
course of the lifetime of that CEV ?

Henry Spencer wrote:

No, Apollo was good enough even without the skip. If memory serves --
references aren't handy -- Apollo landing error was no more than a few
kilometers. That doesn't matter a whole lot if you're coming down
somewhere like White Sands. And we could probably do somewhat better now,
with better guidance hardware.



Maybe they will install some sort of a steerable parachute or parafoil
system like the X-38 ISS lifting body rescue craft was going to use.
This would also aid in dealing with crosswinds at landing, which caused
some Soyuz to get dragged around until they jettisoned their chutes.

Pat

On Fri, 6 Jan 2006 11:52:03 -0600, Pat Flannery wrote
(in article ):

Maybe they will install some sort of a steerable parachute or parafoil
system like the X-38 ISS lifting body rescue craft was going to use.

That's not really the plan, according to the ESAS documents. Three
large-diameter parachutes + airbags for terminal descent, preceded by
pilot and drogue chutes at higher altitude.

--
Herb

There ain't no such thing as a free lunch.
~ RAH

Pat Flannery wrote:


Yeah, and it was one big skip also- clean from the Indian Ocean into
the Soviet Union.


Or at least that's what I thought- actually it was clean from Antarctica
to the Soviet Union, which is a mighty big skip indeed.

Pat

John Doe wrote:

*If* the USA flew Soyuz, would it allow it
to land on continental USA based on its current landing precision
statistics ?



You could land it here in North Dakota without much chance of anything
going wrong due to the flatness and sparse population of the state. In
fact, our state is designated as an emergency Soyuz landing area.
In the continental US , any desert area would make a fairly safe landing
zone provided it wasn't too mountainous.

Pat


If CEV is to be doing more than a couple of camping trips to the moon,
isn't it safe to assume that there might eventually be some landing
mishaps that might put the capsule off-target for its landing over the
course of the lifetime of that CEV ?



Besides ground landings the Soyuz is also designed to be able to safely
land at sea if necessary.
It would be surprising if the CEV didn't have a similar capability, and
that opens up a lot more of the Earth's surface as a emergency landing area.

Pat

On Fri, 6 Jan 2006 16:07:31 -0600, Pat Flannery wrote
(in article ):

It would be surprising if the CEV didn't have a similar capability,

It will.

(*Ahem - Read the ESAS report, damn it! No, there are no simian test
flights planned, but you shouldn't let that stop you. ;-) *)

--
Herb

There ain't no such thing as a free lunch.
~ RAH

Herb Schaltegger wrote:

That's not really the plan, according to the ESAS documents. Three
large-diameter parachutes + airbags for terminal descent, preceded by
pilot and drogue chutes at higher altitude.


Then they had better make sure they detach immediately on touchdown, as
getting dragged around at sea is one thing, on dry land quite another.
They had also better hope that they don't encounter severe side wind
during landing, as I don't know how the airbags are going to react to
hitting the ground while traveling at twenty or thirty mph sideways.
I think the Russians may detach them manually, as they had a bad
experience during tests of a unmanned Soyuz where the parachutes
separated at several thousand feet in the air.

Pat