CEV PDQ

"Herb Schaltegger" wrote in
message .com...
On Sat, 14 May 2005 11:13:08 -0500, Jeff Findley wrote
(in article ):

f we do improve EVA suits to make EVA easier, then, and only then, we
can
actually start planning on using more EVA's to do assembly. Agreed?

Agree with "can." Absolutely do NOT agree with "should." There are
better, more efficient and much less expensive (in terms of resources
used v. available) ways to design for assembly without EVA.

Then I think we agree.

If, and only if, better EVA suits are developed, then the engineers need to
run their risk/cost-benefit analyses for the next bit of assembly they want
to do and decide what's the cheapest, easiest, lowest risk way to go. At
this point, the engineers might find that doing more EVA's is cheaper than
trying to completely automate the assembly tasks.

After all, we can't assume that automated assembly won't similarly progress
while improvements are made to make EVA's easier.

Jeff
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"Herb Schaltegger" wrote in
message .com...
Yep. The problem is there's no money being allocated for improved EVA
capabilities right now, and until those capabilities are achieved
(somehow), designing to use them is dangerous at best, foolhardy at
worst, and unlikely to succeed in any case.

Then this is another example of short sighted planning on NASA's part. It's
this sort of planning that's got us completely relying on the Russians for
our ISS crew escape vehicle (Soyuz).

Unfortunately, the current shuttle/ISS EMU's are completely unsuited to
Martian surface EVA. If we get people to Mars, but can't do any EVA's then
I'd consider the entire program to be a failure. If we can't do EVA's on
Mars, then why send people to Mars at all?

Jeff
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On Sat, 14 May 2005 09:31:07 +0800, in a place far, far away, "Neil
Gerace" made the phosphor on my monitor glow in
such a way as to indicate that:

Sounds like: Our goal is not to stamp out WMDs, but to be the only
country
that has them.

What's wrong with that?

Because the USA government (any one, not just the current one) is not
necessarily more trustworthy than any other country's government.

Really? Not more than, say North Korea's?

On Wed, 11 May 2005 16:11:34 -0500, in a place far, far away, Pat
Flannery made the phosphor on my monitor glow in
such a way as to indicate that:



Rand Simberg wrote:


Which nation would you prefer to be dominant in outer space?



I would prefer no nation to be dominant in outer space, the same way I
would prefer no nation to be dominant in Antarctica.
Space should be treated like Antarctica or the open oceans, not under
the thumb of one nation.

Sorry to break it to you, but the US is dominant in the open oceans.
And most of the world is better off for it.

On Thu, 12 May 2005 09:56:36 -0500, in a place far, far away, Herb
Schaltegger made the
phosphor on my monitor glow in such a way as to indicate that:

But in the cases mentioned, the planning and training done on the ground
turned out to be worth little to nothing. On top of that, the equipment and
procedures didn't work so well. Only because we had people in EVA suits
were we able to complete those missions.


You're just as guilty as Rand of missing the point, which is (again!)
PLANNED EVA ASSEMBLY IS A BAD IDEA!

We understand your point Herb. WE JUST DISAGREE WITH IT! And putting
it in all caps with a bang on the end doesn't make it more valid, or
more persuasive.

"Dave Michelson" wrote in message
news:ARDhe.1355611$Xk.501451@pd7tw3no...
Derek Lyons wrote:

Define 'considerable'. Enough such that EVA durations as demonstrated
were reaching the effective life of the suit? Enough such that EVA
durations as demonstrated were placing the astronauts in an unsafe
enviroment?

- "Pete Conrad noted that the suits were more worn after 8 hr of surface
activity that their training suits were after 100 hr and further
reported that their EMS were worn through the outer layer and into the
Mylar® multi-layer insulation above the boot. One or two additional EVAs
could have resulted in a pressure failure in the Apollo 12 EMS."

And we all know that pressure failure of your EMS is a *bad thing*.

- "The ability of the EMS to be resealed after EVA was also compromised
by dust on the suit seals. The Apollo 12 astronauts experienced higher
than normal suit pressure decay due to dust in fittings. Pete
Conrad’s suit, which was tight before the first EVA, developed a leak
rate of 0.15 psi/min after it, and rose to 0.25 psi/min after the second
EVA. Since the safety limit was set at 0.30 psi/min, it is doubtful
whether a third EVA could have been performed, had it been scheduled."

- "Another indicator is that all of the environmental sample and gas
sample seals failed because of dust. By the time they reached earth the
samples were so contaminated as to be worthless."

- "Gauge dials were so scratched up during the Apollo 16 mission as to
be unreadable."

- "Harrison Schmitt’s sun shade on his face plate was so scratched that
he could not see out in certain directions, and the cover gloves worn by
the Apollo 17 astronauts when they were working the core drill were so
worn through after drilling core samples after only two EVAs that they
were removed and discarded at the beginning of the third."

Much has been written in these groups about the wear and tear, but if
we are going to use it as quantifiable measurment, then we need to
quantify it.

http://gltrs.grc.nasa.gov/reports/20...005-213610.pdf

Most of the above deals with the horribly abrasive lunar soil. Hopefully
this won't be an issue on Mars (due to wind erosion wearing down sharp edges
of Martian soil). However, the plan is to go to the Moon first, so this
issue must be dealt with if we want to truly explore the moon, not just
repeat the "flags and footprints" experience of Apollo.

But when you get to Mars, you run into the issue of the cooling system on
the Apollo/Shuttle suits not working due to the thin atmosphere. Also, you
run straight into weight issues since Martian gravity is far higher than
lunar gravity. In other words, the "state of the art" EVA technology we
have today, is completely unsuitable for Martian surface EVA's.

This is why I keep saying that I think NASA ought to be working on better
EVA equipment now.
If we get to Mars and can't do surface EVA's, why in the hell would we be
spending billions on *manned* missions to Mars in the first place? If we
can't do Martian surface EVA's, just send big robotic sample return missions
instead.

Jeff
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"Pat Flannery" wrote in message
...


Charles Buckley wrote:



I suspect that the exposure of particulate matter of the size
of lunar dust is going to be a significant problem and the
whole chemistry and how it effects people and equipment is
pretty much completely unknown.


Although the winds will mean that Martian dust has been ground down to
less jagged forms than that of the Moon, I note there is real concern
about how chemically active it is when it comes to a person coming in
contact with it via either inhalation or simply handling it.

But on Mars, the "state of the art" Apollo/Shuttle suits cooling systems
won't work. The even bigger problem would be their weight in Martian
gravity, which is far stronger than lunar gravity. And that is ignoring
"routine" maintenance issues with the current suit designs.

There are many reasons that today's EVA suits are unsuitable for Martian
surface EVA.

Jeff
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On Fri, 13 May 2005 18:01:51 -0500, in a place far, far away, Herb
Schaltegger made the
phosphor on my monitor glow in such a way as to indicate that:


Either you are honestly blind to the possibility that EVAs are only hard
because we haven't focused enough attention to the problem, or you are
dishonestly pretending that EVAs will always be hard.

Neither. Please work on your reading comprehension skills.

On the other hand, I don't wish NASA to halt CEV architecture design
for the five years that'll be necessary for someone to create and test
your hypothetical "not hard" EVA hardware, techniques and procedures.

I do. I also want them to wait until they've reduced the costs of
getting into orbit.

On Sun, 15 May 2005 08:06:27 GMT, in a place far, far away,
(Derek Lyons) made the phosphor on my monitor glow
in such a way as to indicate that:

Nobody has suggested, except in
your strawmen, that we stop, or slow down, or anything to current
plans - but rather that we look to future needs and goals rather than
being bogged down by what was impossible yesterday.

Actually, I would suggest that.

On Sat, 14 May 2005 15:39:25 -0500, in a place far, far away, Herb
Schaltegger made the
phosphor on my monitor glow in such a way as to indicate that:

You do realize that the CEV program is using an iterative (spirals)
approach, not the traditional waterfall (parallel design of *everything*
needed) approach that Apollo used?

Yep. The problem is there's no money being allocated for improved EVA
capabilities right now

Not true. I think that one of the Millenium Challenge prizes is the
development of a vastly improved high-pressure glove.