LSAM and an unmanned CEV in lunar orbit?

(Yes, an old thread, but I'm behind...)

In article .com,
TVDad Jim wrote:
What are the risks of having an unpiloted CEV in orbit, rather than
leaving a pilot onboard while the LSAM lands?
How have these risks changed since the days of manned lunar CSMs? Is it
just better automation available?

Remember that the basic design concepts for Apollo were set at a time when
unmanned spacecraft failed more often than they succeeded. So it had a
three-man crew so they could work three shifts and always have somebody
watching the dials (a crew of three turned out to be convenient for the
LOR mission, but that wasn't the original motive), and there were plans
for preliminary lunar-orbit reconnaissance flights in case Ranger and
Surveyor were total failures (which seemed a serious possibility, given
what a disaster area the early Rangers were).

The technologies of telemetry and telecommand (and confidence in them)
improved *enormously* in just a few years. Even in 1969, there wasn't
really any compelling need to leave one guy in orbit, were it not that the
hardware and procedures were already built around it. Having him do
surface photography and such was a bonus, added because he was there
anyway and he might as well do something useful -- there was nothing in
that which couldn't have been automated easily, by then.

How do four astronauts on the Moon make it a "better" mission than
three astronauts on the Moon? It sounds like a lot of ballast (both in
body mass and support materiel) to land and re-launch.

The point of the whole exercise is doing things on the surface. A guy in
orbit contributes nothing to that.

And as others have noted, if you have a "buddy system" rule of doing
moonwalks in teams of two, there's a big difference between three guys on
the surface and four. Note that the spacewalk-intensive shuttle missions,
like the Hubble repair flights, have four spacewalkers, precisely so two
teams can take turns. Each team spends one day at hard labor out in the
suits, and a second day indoors, recovering and providing support for the
other team.
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In article ,
Ami Silberman wrote:
...The CMP was responsible for performing
orbital science (primarily photography), and the final phase of docking was
performed by the CSM.

Note that the main reason for the CSM doing the docking was some awkward
design details of the spacecraft -- problems that could be avoided in a
new design, now we know about them.

For one thing, the LM's docking window was *overhead*, which was more than
slightly awkward. (This was fallout from the decision to specialize the
LM forward hatch for surface work, so it couldn't be used for docking --
the original plan used that hatch for post-ascent docking, so the LM guys
could look through the forward windows during docking.) But particularly
in a larger vehicle, it should be easy enough to put the docking controls
beside the docking hatch.

For another, the late change to a foil outer surface for the CM turned its
surface into a conical mirror, which made for a very confusing target for
eyeball tracking. Something as simple as pre-wrinkling the foil would
fix that.
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In article ,
John Whisenhunt wrote:
...Can the the already mentioned advantage of having a piloted
capability for either vehicle to be the active rendezvous platform basically
trump any other lunar surface advantages?

Not likely, since there's nothing that hard about doing *rendezvous* by
remote control. Docking is the part that really needs local
intelligence... but there is successful experience with doing docking by
remote control from the other spacecraft. It's not that difficult a
problem to provide most any desired level of confidence in this.
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spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

Henry Spencer wrote:
(Yes, an old thread, but I'm behind...)

(But very welcome...it perks up the group having you back!)

[...]
Even in 1969, there wasn't
really any compelling need to leave one guy in orbit

And with six-month stays, 1 guy in orbit becomes a big logistical
burden as well as a harder task to fit astronauts to (any fur trappers
around who are computer literate? ;-} )

/dps

Henry Spencer wrote:

...The CMP was responsible for performing
orbital science (primarily photography), and the final phase of docking was
performed by the CSM.



Note that the main reason for the CSM doing the docking was some awkward
design details of the spacecraft -- problems that could be avoided in a
new design, now we know about them.

For one thing, the LM's docking window was *overhead*, which was more than
slightly awkward. (This was fallout from the decision to specialize the
LM forward hatch for surface work, so it couldn't be used for docking --
the original plan used that hatch for post-ascent docking, so the LM guys
could look through the forward windows during docking.) But particularly
in a larger vehicle, it should be easy enough to put the docking controls
beside the docking hatch.


I suspect that docking will be entirely automated, with a manual backup
system... by making the spacecraft capable of flying and docking
unmanned, you can derive a Progress type cargo craft from it with
minimal modifications. Simple cargo shipment to a space station could
up the payload by leaving the crew and associated equipment behind,
while saving yet more weight by not having an escape tower attached.

For another, the late change to a foil outer surface for the CM turned its
surface into a conical mirror, which made for a very confusing target for
eyeball tracking. Something as simple as pre-wrinkling the foil would
fix that.



I'll bet laser ranging will play a big part in the docking procedure.

Pat

Gene Cash wrote:

Pat Flannery writes:



I suspect that docking will be entirely automated, with a manual backup
system...



And NASA has demonstrated automated docking *WHEN* ??


DART...okay, it may have been unintentional, but.... ;-)
This would be a very good time to start... I always thought that part of
the reason that nothing like that was developed was that it was
perceived as a threat to manned spaceflight with astronauts manually
flying things together, the way God and Robert A. Heinlein intended.
But if they go that route they are going to make assembling any space
structures a lot more difficult for themselves, they lose the ability to
do it unmanned the way Mir was assembled, as well as developing unmanned
cargo delivery systems, which are a pretty economical way of getting
things from point "A" to point "B" (and which used to figure heavily in
1950s and 60's science fiction...remember all those robot cargo rockets
that would bring the supplies up to the Moon Base?).
On a side note, doesn't their unmanned Mars sample return concept rely
on orbital transfer of the sample to the Earth return vehicle? They'll
have to develop the technology at that time anyway.

I'm not so convinced running into the target (and not even knowing you
did that!) actually counts as "docking" - that's pretty goddamn sad,
actually.

Even with "boy, that Progress docked a whole lotta times with
MIR... once in the solar panel, once on the side of the lab
module... and even once in the docking port!" NASA is pretty damn far
behind.

I'm embarrassed to admit I paid taxes for this space program. "Nope, not
mine! I'm, er, Canadian, eh?"



The point is to get the crew to their destination - Earth orbit or the
Lunar surface- in the most simple, low cost, and reliable way possible.
Not to do it in a really neat and exciting way.
An advantage of an automated approach is that it can be set up to take a
fair amount of time, and conserve as much RCS propellant as possible by
doing very precise maneuvers and velocity changes to arrive at the
docking. Saving propellant saves weight, and saving weight saves money.
Once the crew is where they are supposed to be, that's when the work of
the mission starts.



I'll bet laser ranging will play a big part in the docking procedure.



I'll bet Russian hardware will play a big part in the docking procedure.



We should be able to come up with something a lot lighter and more
effective than their clunky stuff.

Pat

Gene Cash wrote:

The DART team is on line 1 for you, Henry...




Hey, it worked better than that docking with the comet... ;-)

Pat

Even in 1969, there wasn't really any compelling need to leave one guy in orbit, were it not that the hardware and procedures were already built around it.

Not long after that NASA routinely left Skylab unattended and docked
the Apollo CSM's to it for the next mission. Of course these crews
could always return to Earth if it didn't work out, but I am not aware
of any mission (even the Gemini-Agena docking missions) which failed
because the target spacecraft couldn't maintain attitude.

Gene Cash wrote:

We should be able to come up with something a lot lighter and more
effective than their clunky stuff.



What's that... "keep going until you hear a thud"? :-)



"He raped me! He raped me!"
Soyuz 5 crew after the Soyuz 4 performed a fairly rough docking with
their spacecraft.
They were reprimanded for this remark.

Pat

In message , Gene Cash
writes
Pat Flannery writes:

The point is to get the crew to their destination - Earth orbit or the
Lunar surface- in the most simple, low cost, and reliable way

Hm, I'm confused, I thought you were talking about NASA? That's
definately not NASA!

Have you been reading Joe Haldeman's "Forever Free"? :-)

(Among other things, his all-powerful aliens set up NASA to slow down
human spaceflight)
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