$5M Moon Rock Stolen From Malta Museum

In article ,
Vincent Cate wrote:
If you use an ion-drive to get to lunar orbit and back and a tether to
collect samples, you don't need to be so mass-limited in your design
and you could bring back much more lunar mass. The difficulty of having
the end of the tether pickup some samples seems much less than having
a couple more rocket stages...

However, the tether deployment, spin-up, and control are basically research
projects, whereas rocket stages are fairly well understood. You're right,
the results probably would be better, but it's a longer-term project with
higher risk.

And ion from LEO to lunar orbit has bad problems with the Van Allen belts.
Rad-hard electronics and solar arrays are very hard on the budget (and on
the schedule, because of availability problems).

An easy mass margin design should be much easier on R&D money.

Only if it doesn't incur major new R&D problems of its own. Much the best
way to provide generous mass margins is just to buy a bigger launch. (One
possible way of doing that without moving out of the Molniya class -- it's
a big step up to Zenit 3SL or Proton -- would be to launch Molniya from
Kourou. I don't know if the Soyuz pad there will be fitted for this, but
it might well be.)
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

In sci.space.policy Henry Spencer wrote:

However, the tether deployment, spin-up, and control are basically research
projects, whereas rocket stages are fairly well understood. You're right,
the results probably would be better, but it's a longer-term project with
higher risk.

And ion from LEO to lunar orbit has bad problems with the Van Allen belts.
Rad-hard electronics and solar arrays are very hard on the budget (and on
the schedule, because of availability problems).

compared to what? The availability of tethers is rather worse so far and
unlike almost anything else, ramping up rad hard electronics production
is not that hard. Its much easier than say ramping up production of rockets.


An easy mass margin design should be much easier on R&D money.

Only if it doesn't incur major new R&D problems of its own. Much the best
way to provide generous mass margins is just to buy a bigger launch. (One
possible way of doing that without moving out of the Molniya class -- it's
a big step up to Zenit 3SL or Proton -- would be to launch Molniya from
Kourou. I don't know if the Soyuz pad there will be fitted for this, but
it might well be.)

The pad is still in construction, no? What it will do, potentialy after upgrades
is thus open. I would be very suprised if its specs hadn't already changed from
what the original was.

--
Sander

+++ Out of cheese error +++

If we could get a block of launchers as previously suggested, say ten or so,
why not set a couple of landers containing robotics (dirt movers). One
would be backup in case of bad landing and both would carry homing beacons
to guide sample modules to the same spot. This would carry the advantage of
being able to decrease the return modules payload down to 5 kilos or so and
spread the return payload over the next 8 flights so the failure of one
flight would not kill the profit for the whole thing. A profit could
possibly be made if we had a 50% success rate, anything over that would be
gravy.

Questions:

1. Could a guidance beacon or possible a laser reflector provide enough
guidance for the landing modules to land close enough for this to work?
(Precision guided munitions seem to be able to do this within a few meters).

2. Could the orbital GPS system possibly help with guidance? Would it have
the range?

3. As a comparison what would be the relative worth of moon rocks compared
to diamonds gram for gram? ( I would love a tie pin set with a 10 or 20
carat moon stone)

Terry



"Sander Vesik" wrote in message
...
In sci.space.policy Henry Spencer wrote:

However, the tether deployment, spin-up, and control are basically
research
projects, whereas rocket stages are fairly well understood. You're
right,
the results probably would be better, but it's a longer-term project
with
higher risk.

And ion from LEO to lunar orbit has bad problems with the Van Allen
belts.
Rad-hard electronics and solar arrays are very hard on the budget (and
on
the schedule, because of availability problems).

compared to what? The availability of tethers is rather worse so far and
unlike almost anything else, ramping up rad hard electronics production
is not that hard. Its much easier than say ramping up production of
rockets.


An easy mass margin design should be much easier on R&D money.

Only if it doesn't incur major new R&D problems of its own. Much the
best
way to provide generous mass margins is just to buy a bigger launch.
(One
possible way of doing that without moving out of the Molniya class --
it's
a big step up to Zenit 3SL or Proton -- would be to launch Molniya from
Kourou. I don't know if the Soyuz pad there will be fitted for this,
but
it might well be.)

The pad is still in construction, no? What it will do, potentialy after
upgrades
is thus open. I would be very suprised if its specs hadn't already changed
from
what the original was.

--
Sander

+++ Out of cheese error +++

In article , Doug...
wrote:

Remember, our one and only attempt to deploy a long tether in LEO met
with failure and near-disaster. I'm aware that the conditions in lunar
orbit are different than in LEO, but still, it seems to me that until we
demonstrate something as simple as deploying a 20km tether in LEO, we're
talking out of our asses when speaking of 100km tethers pulling up lunar
materials from orbit.

It depends on whether you do it with an elaborate international project
requiring a separate Shuttle launch or two, or as a cheap afterthought
piggybacked on somebody else's launch.
http://www.islandone.org/APC/Tethers/02.html

--
David M. Palmer (formerly @clark.net, @ematic.com)

In article ,
Sander Vesik wrote:
Rad-hard electronics and solar arrays are very hard on the budget (and on
the schedule, because of availability problems).

compared to what? The availability of tethers is rather worse so far and
unlike almost anything else, ramping up rad hard electronics production
is not that hard...

Yeah, but they're not going to *do* that for you unless you're spending
millions, maybe tens of millions, on parts alone. I'm talking about
practice, not theory.

The practical reality is that it's hard to do anything low-cost with parts
that cost several orders of magnitude more than commercial ones (and no,
I'm not kidding about the "several" part), and have acquisition lead times
of many months rather than one UPS package travel time.

...would be to launch Molniya from
Kourou. I don't know if the Soyuz pad there will be fitted for this, but
it might well be.)

The pad is still in construction, no? What it will do, potentialy after
upgrades is thus open. I would be very suprised if its specs hadn't
already changed from what the original was.

Indeed so. Certainly there's a lot more interest in manned operations
there, now, than was heard a year or two ago.

On reflection, I'd expect that Molniya operations *were* part of even the
original plan, given that one reason for wanting to operate from Kourou is
to go to GTO, which basic Soyuz can't do at all. But I could be wrong.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

In article ,
Terry Goodrich wrote:
why not set a couple of landers containing robotics (dirt movers). One
would be backup in case of bad landing and both would carry homing beacons
to guide sample modules to the same spot. This would carry the advantage of
being able to decrease the return modules payload down to 5 kilos or so...

I'm not sure where the advantage would lie. There's no need for precision
landing capability at all, if what you're selling is simply rocks. The
guidance requirement for landing is driven by the need for soft landing,
not precision landing.

spread the return payload over the next 8 flights so the failure of one
flight would not kill the profit for the whole thing...

A failure is, if anything, more likely to be in descent than in ascent.
Ascent is a lot simpler.

1. Could a guidance beacon or possible a laser reflector provide enough
guidance for the landing modules to land close enough for this to work?
(Precision guided munitions seem to be able to do this within a few meters).

It's not *quite* that simple, alas, not without adding quite a bit of
hardware to each lander. But there are ways it could be done, if there
was a use for it.

2. Could the orbital GPS system possibly help with guidance? Would it have
the range?

GPS is pretty nearly useless beyond LEO. The GPS satellites do not
broadcast in all directions; they beam their signals at Earth. So you get
continuous coverage only if you are on or very near Earth. (There are
things you can do with the limited and intermittent coverage at higher
altitude, which comes from spillover past Earth, but it's not very useful
for real-time guidance.)

3. As a comparison what would be the relative worth of moon rocks compared
to diamonds gram for gram? ( I would love a tie pin set with a 10 or 20
carat moon stone)

Really, nobody knows for sure. It depends very heavily on the size of the
market, which is almost unknown.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

Henry Spencer wrote:

Yep. Too much of a single-point design for my taste, especially given
modern electronics. Full guidance and a capability for small midcourse
corrections just isn't that big a deal any more.


I always thought it was a great example of the Soviet Union's KISS*
philosophy in regards to spacecraft; no midcourse correction needed
means no failure of midcourse correction equipment; gravity (one can
hope) won't break down.
Of course you end up having your choice of landing sites severely
curtailed; but if it's a propaganda victory as opposed to useful lunar
science you are after, then it's a pretty clever way of keeping down
both the weight and complexity of your return spacecraft. It would be
interesting to know how they handled the possibility of the lander
coming down on uneven or sloped ground, so as to keep the ascent stage
aimed straight upwards.

*- "Keep It Simple, Stupid!"

Pat

(Henry Spencer) wrote in message ...
In article ,
Vincent Cate wrote:
If you use an ion-drive to get to lunar orbit and back and a tether to
collect samples, you don't need to be so mass-limited in your design
and you could bring back much more lunar mass. The difficulty of having
the end of the tether pickup some samples seems much less than having
a couple more rocket stages...

However, the tether deployment, spin-up, and control are basically research
projects, whereas rocket stages are fairly well understood.

On the other hand there is not so much room for improvement in rockets.

Just because NASA has a hard time deploying a tether does not
mean a private venture would. If you start spinning a bit before
you start deployment you could have a steady tension, and things
might work out well.

You're right, the results probably would be better, but it's a
longer-term project with higher risk.

From a venture capital standpoint, a system that had a bit more risk
in the R&D but then lower operating costs and produced 100 times as
much product seems better. If a company like spacex or spacedev
were developing a tether system, I don't think it would really take
too long. You could test scoop systems on Earth and tether deployment
in LEO.

And ion from LEO to lunar orbit has bad problems with the Van Allen belts.
Rad-hard electronics and solar arrays are very hard on the budget (and on
the schedule, because of availability problems).

Ouch. I can't buy an off-the-shelf rad-hard module that does
my computation, guidance, and communications? Do ion drives
tolerate radiation ok?

An easy mass margin design should be much easier on R&D money.

Only if it doesn't incur major new R&D problems of its own. Much the best
way to provide generous mass margins is just to buy a bigger launch.

The difference in initial launch mass between an all-chemical-rocket mission
and a tether/ion/regolith-thruster mission, for a given payload returned,
seems to be something like a factor of 100 to 1000. As long as launch
costs are high, this seems like an overwhelming advantage. Both testing
and operations have something like 1/100th the launch cost for the
same payload size.

-- Vince

In article ,
says...
(Henry Spencer) wrote in message ...
In article ,
Vincent Cate wrote:
If you use an ion-drive to get to lunar orbit and back and a tether to
collect samples, you don't need to be so mass-limited in your design
and you could bring back much more lunar mass. The difficulty of having
the end of the tether pickup some samples seems much less than having
a couple more rocket stages...

However, the tether deployment, spin-up, and control are basically research
projects, whereas rocket stages are fairly well understood.

On the other hand there is not so much room for improvement in rockets.

Just because NASA has a hard time deploying a tether does not
mean a private venture would. If you start spinning a bit before
you start deployment you could have a steady tension, and things
might work out well.

Oh, yeah -- I'm going to invest many millions of dollars because a
technique someone thought of and posted on Usenet "might" work out well?

I want to point out that tether dynamics are NOT that well understood.
Just try and get any company to pony up large amounts of capital for
something that requires the amount of R&D that's yet to be done before
*any* tether system can be understood well enough to be deployed.

You're right, the results probably would be better, but it's a
longer-term project with higher risk.

From a venture capital standpoint, a system that had a bit more risk
in the R&D but then lower operating costs and produced 100 times as
much product seems better. If a company like spacex or spacedev
were developing a tether system, I don't think it would really take
too long. You could test scoop systems on Earth and tether deployment
in LEO.

And ion from LEO to lunar orbit has bad problems with the Van Allen belts.
Rad-hard electronics and solar arrays are very hard on the budget (and on
the schedule, because of availability problems).

Ouch. I can't buy an off-the-shelf rad-hard module that does
my computation, guidance, and communications? Do ion drives
tolerate radiation ok?

Nope, you can't. It doesn't exist.

An easy mass margin design should be much easier on R&D money.

Only if it doesn't incur major new R&D problems of its own. Much the best
way to provide generous mass margins is just to buy a bigger launch.

The difference in initial launch mass between an all-chemical-rocket mission
and a tether/ion/regolith-thruster mission, for a given payload returned,
seems to be something like a factor of 100 to 1000. As long as launch
costs are high, this seems like an overwhelming advantage. Both testing
and operations have something like 1/100th the launch cost for the
same payload size.

Where are you getting your cost estimates? Off the top of your head?
You have no real idea what the costs would be on either side. Good luck
getting capital based on your gut feelings as to what the costs ought to
be...

Doug

In article ,
Doug... wrote:

Where are you getting your cost estimates? Off the top of your head?
You have no real idea what the costs would be on either side. Good luck
getting capital based on your gut feelings as to what the costs ought to
be...

To be fair, Vincent Cate has more to go on that gut feelings. He has
fairly detailed simulations, and cost-estimate spreadsheets, all of
which are open and available to critics. He also seems to have a small
group of helpers who presumably might point out any blatant mistakes in
the simulation or estimates.

Of course he could still be blatantly wrong for some reason, but it's
not fair to say that he's just making stuff up. He's put a fair amount
of time into getting reasonable numbers.

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