China and Robert Zubrin

In article ,
Hop David wrote:
I seem to recall some sci.space.policy regulars deriding the notion of
tethering the hab to a spent booster and spinning them like a bolo to
provide artificial gravity. Is this one of the technical problems Zubrin
dreams away? What's wrong with the bolo?

The general concept is not ridiculous, indeed it makes considerable sense.
He rather dreams away the problems of the dynamics of such a system; large
flexible structures with little damping are not necessarily very stable.
I'm sure it can be made to work, but it's not as simple as it looks.

And any other specific technical problems Zubrin doesn't address would
be of interest to me.

A big one is the problem of spacesuit design for Mars. The existing suit
technology is too heavy at 0.38G, except *perhaps* for very brief stays,
and its operating life is too short (and not very predictable -- JSC has
had surprise failures of flown suits retired to water-tank use). There
are possible alternatives, but they are poorly developed and there are
many engineering uncertainties.

Like Martha, I see positive things in Zubrin's
work and would like to know if I've been misled.

Oh, there certainly are positive things in it, no question of that. He is
definitely worth listening to; you just have to beware of taking it all at
face value.

In particular I very much like Zubrin's philosophy of using in-situ
resources to reduce mission requirements.

It's an eminently sensible idea, which Zubrin did not originate. Notably,
J.R. French at JPL was exploring it very seriously in the early 1980s.
What Zubrin did was to promote it well enough to make it at least semi-
respectable; French got very good technical results but had little success
in selling the idea within JPL.

I think this philosophy may
also be applicable to other missions than Martian.

Yes, although in most cases it's harder. Mars is a particularly nice case
because of its atmosphere, which is easily* available anywhere on the
surface. Exploiting surface or subsurface resources -- notably including
Martian permafrost -- is much more complicated and much harder.

(* "Easily" assuming that airborne dust is a manageable problem, a large
assumption whose accuracy is difficult to evaluate.)
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

In article ,
George William Herbert wrote:
intense focus on getting to Mars is a disastrous strategic mistake, all
too likely to lead to a repetition of the post-Apollo collapse.

Bob's counter to that is that done right, the Mars missions should
have more internal impetus for ongoing exploration than Apollo did.

He claims that, but I really don't see it in his proposals. Yes, at least
the early phases make a nice logical program, but there still isn't any
particular reason why somebody can't just call a halt after the first two
or three expeditions. Yeah, there's a fueled return vehicle sitting there
waiting for an expedition that's not going to come; so what?

At a more fundamental level, this is almost exactly the same as Apollo:
the argument against stopping is the investment already made, but that
investment is last year's money.

The only way I see to mount a Mars program which has built-in incentive
for continuation is to delete the return vehicles: all trips, including
the first, are one-way with no return capability. The permanent base
starts with the first expedition. *That* really does make it easier to
continue the program than to call a halt, given that as a matter of
practical politics, the latter would demand returning everyone to Earth.
But selling such a program would be difficult, even by the standards of
manned Mars programs.

And one of his original arguments is that Mars is the interesting
place in the solar system that is most accessable to and amenable
to human exploration and eventual colonization, and that a cautious
program to settle 'space' in general thus misses the low-hanging
fruit of a Mars program.

Mitch Burnside Clapp, a couple of years ago: "I picked fruit one summer,
and you pick the low-hanging fruit *last*, because you don't want to climb
the tree with a heavy bag."

And there's even an analogy the the heavy bag is "but you already did
what you said was the easiest and most important part". It's a question
of whether you want a piece or two of fruit to eat and never mind the
rest, or you want to harvest the whole tree. Doing the easy part first
isn't necessarily the right way to do the whole thing.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

Earl Colby Pottinger wrote:
(Martha H Adams) :


Would someone please outline for me, as a serious piece of information
that I might use seriously, what problems people are having with
Zubrin? I have read some of his work and I felt positive about what I
saw there. If I'm unrealistic, I'd like to know about it. Pointers
to publically accessible published material would be helpful.

Thanks -- Martha Adams


I don't know him at all but an article he published in Analog magazine
probably shows the problem some people have with him and his logic. Basicly
in the article about life else in the universe he sets out a chain of logic
where each step has a high chance of probability (let's use 50% per step for
an easy example). By the end of the chain he has strung say eight steps each
that depend on the previous step to work in his favour. However, at the end
he does not act/treat his conculsions as the sum of probabilty 2^8 ie one
chance in 128, but rather acts and is it is still a 50% chance he is right.

So it it not that he is wrong in his conculsions that he rubs people wrong,
but because he assumes he is right before all the facts come in t know if he
is right or not.

Earl Colby Pottinger


I recall Zubrin arguing fossil life on Mars would be evidence that life
would arise anywhere where the conditions are right. This seems to
neglect the possibilities of panspermia.

For awhile I thought Mars, Europa etc. could be infected by meteorites
of earthly origin, but Henry Spencer recently told me he thought even
Chicxulub was inadequate to send earthly meteorites to other bodies in
the solar system. That bolstered Zubrin's argument a little in my eyes,
but I still regard it as suspect.

--
Hop David
http://clowder.net/hop/index.html

Earl Colby Pottinger wrote:


I don't know him personally at all, but an article he recently published in
Analog magazine probably shows the type of problems some people have with him
and his logic.


Googled "Analog Zubrin" and found a number of articles Zubrin has
published in that magazine but none that look like it's on the
possibility of intelligent life forming. Do you have the date of the
Analog magazine carrying that article?

--
Hop David
http://clowder.net/hop/index.html

Hop David wrote in message ...


Scott? Are you talking about Scott Lowther?

Yes, Scott Lowther. He worked for Zubrin at Pioneer Astronautics.

--Chris Vancil

Hop David wrote in message ...
CL Vancil wrote:

And an aside: on the concept of a single mission to Mars being Flags
and Footprints...I would say 1.5 to 2 years on the surface of another
planet is not F&F! It may leave no useful infrastructure, but it
seems not to matter here whether current infrastructure is retained.
So I see this all as a red herring for those who would advocate some
other mission (i.e. return to Luna, L-1, NEO or what have you)...

--Chris Vancil

I also hope and believe 1.5 to 2 years on another planet is not fantasy
and fiction. The chief arguments for 1.5 to 2 years on mars are
proximity and available in-situ resources.

If you are spending 1.5 to 2 years on Mars plus a 7 month trip out and a
7 month return trip that is three years off earth. Which I think is
possible. If asteroids have usable in situ resources, 3 years on a near
earth asteroid is also a possibility.

Yes, you could use the abilities and equipment built for manned Mars
missions on many other just as useful missions. The reverse isn't
true. And if you forced designs to be vastly over engineered folks
here would squeal like stuck pigs about it. I'm sure Congress would
also wonder at the costs. So the Moon is not a stepping stone to Mars
now anymore than it was during Apollo. All the testing etc can be
done on Earth or LEO or on Mars(ISRU) for a manned Mars mission.

--Chris Vancil

Henry Spencer wrote:
Hop David wrote:
I seem to recall some sci.space.policy regulars deriding the notion of
tethering the hab to a spent booster and spinning them like a bolo to
provide artificial gravity. Is this one of the technical problems Zubrin
dreams away? What's wrong with the bolo?

The general concept is not ridiculous, indeed it makes considerable sense.
He rather dreams away the problems of the dynamics of such a system; large
flexible structures with little damping are not necessarily very stable.
I'm sure it can be made to work, but it's not as simple as it looks.

I think he applies a somewhat simplifying "somebody else's problem"
field to it; he doesn't reject them completely, but he figures that
it's a detail that can be worked out later at small reasonable effort.

Most of the arguments are over how much that 'small reasonable effort'
really works out to be, when we get there...

And any other specific technical problems Zubrin doesn't address would
be of interest to me.

A big one is the problem of spacesuit design for Mars. The existing suit
technology is too heavy at 0.38G, except *perhaps* for very brief stays,
and its operating life is too short (and not very predictable -- JSC has
had surprise failures of flown suits retired to water-tank use). There
are possible alternatives, but they are poorly developed and there are
many engineering uncertainties.

Again, I think he applied a SEP field. He has noted that it's an
area requiring focus and work. He has encouraged suit stuff becoming
a minor Mars Society focus area and encouraged the work that is
now being funded on Mars suits from NASA. But it's not something
he personally seems to feel very attached to solving.

Like Martha, I see positive things in Zubrin's
work and would like to know if I've been misled.

Oh, there certainly are positive things in it, no question of that. He is
definitely worth listening to; you just have to beware of taking it all at
face value.

In particular I very much like Zubrin's philosophy of using in-situ
resources to reduce mission requirements.

It's an eminently sensible idea, which Zubrin did not originate. Notably,
J.R. French at JPL was exploring it very seriously in the early 1980s.
What Zubrin did was to promote it well enough to make it at least semi-
respectable; French got very good technical results but had little success
in selling the idea within JPL.

It is important to note that Mars Direct seems to have been really
*the* first well done coherent overall ISRU architecture, from the
ISRU cycle and chemistry chosen to the mission architecture / vehicle
breakdowns. The concept of ISRU was certainly not something he came
up with first, but the papers pre-MD were for architectures that are
clearly inferior in a post-MD analysis or just looking at the
chemical cycles without integrating them into a mission.

He was clearly standing on a bunch of pre-existing thought and
research work in formulating Mars Direct, but it was a major
step forwards and stood clearly ahead of its contemporaries.
And despite a lot of arguing back and forth, the architecture
still seems viable today and may well still be the best choice
were we to start a mission today. Warts / 'engineering details'
and all... the NASA Reference Mission is another good choice
with some slightly different high level philosophy / requirements.
But Mars Direct hasn't faded from view, and it's not just because
Bob's out there pushing the PR angle all day.


-george william herbert

Henry Spencer wrote:


(snip some informative stuff)
In particular I very much like Zubrin's philosophy of using in-situ
resources to reduce mission requirements.


It's an eminently sensible idea, which Zubrin did not originate. Notably,
J.R. French at JPL was exploring it very seriously in the early 1980s.
What Zubrin did was to promote it well enough to make it at least semi-
respectable; French got very good technical results but had little success
in selling the idea within JPL.

Good to know - I'll try to remember J.R. French.



I think this philosophy may
also be applicable to other missions than Martian.


Yes, although in most cases it's harder. Mars is a particularly nice case
because of its atmosphere, which is easily* available anywhere on the
surface.

About the only low-tech, unmanned scheme for asteroid ISRU I've seen are
Kuck Mosquitoes. These would only be good for asteroids with icey
interiors but I hope and believe such near earth asteroids exist.

http://clowder.net/hop/railroad/KuckMosq.html

Exploiting surface or subsurface resources -- notably including
Martian permafrost -- is much more complicated and much harder.

Isn't there a Martian crater basin that has some warm spots? perhaps
geothermal (maybe "geo" is the wrong prefix) activity might make liquid
water reservoirs within well drilling distance.


Hop David
http://clowder.net/hop/index.html

Hop David wrote:
George William Herbert wrote:
Henry Spencer wrote:
First, he tends to fall in love with his ideas to the point that he
ignores, or casually dismisses, alternatives and practical snags. Always
check with somebody else about the detailed engineering. Donna Shirley
(who headed the engineering team for the Sojourner rover) on Zubrin: "He
dreams away the technical issues."

. . . I ran into some stuff in the
book The Case for Mars which seemed wrong, bothered Bob about it,
and finally wrote the paper to lay out the case in more detail
and more formally. I then went on to a bunch of other points
I had been fiddling with, but that's how it started.

George, could you go into more specifics? Shirley's statement "He dreams
away the technical issues" is very vague. And your "I ran into some
stuff . . . which seemed wrong" also leaves me wondering.

The specific stuff was regarding... I think it was the fuel cell
versus IC engine, and rover range calculations methods he used
in _The Case for Mars_ (the book). I don't know what happened to
the notes I was taking when I started to go "that's not right..."
and I am loath to spend the rest of the day searching my five or
more year old old-account email archives for the email I exchanged
with him that prompted the paper specifically, but I think that
was the specific topic.

Strange that I can't remember the topic for sure. I remember
where I was fairly clearly. I was at a hotel south of Vancouver BC,
where my wife was at a dance and music festival, and I was resting
and working on some tradeoff studies on the mass and cost inefficiency
of orbital assembly of small launch payloads for space habitats and
for Mars lander missions specifically. I had _The Case for Mars_ with
me and was re-reading sections to take breaks from the small payloads
integration work when something in the Rovers section bothered me.
I think it was the fuel cell / IC power and range stuff that got
me going, but lacking the notes and emails I'm not sure.

I seem to recall some sci.space.policy regulars deriding the notion of
tethering the hab to a spent booster and spinning them like a bolo to
provide artificial gravity. Is this one of the technical problems Zubrin
dreams away? What's wrong with the bolo?

As Henry replied, not a lot, but it needs to be tested and the
dynamics may not be trivial to debug.

And any other specific technical problems Zubrin doesn't address would
be of interest to me. Like Martha, I see positive things in Zubrin's
work and would like to know if I've been misled.

ISRU details; suits; the equipment loadout for the mission;
operational details; etc etc etc.

Bob's fundamental work is not bad. Mars Direct is a very good
mission architecture. It is not completely debugged yet.
Some of the bugs are in areas Bob is not good in and has not
spent a lot of effort to address, and he tends to think are
minor implimentation details. He may be correct, in the total
project scope they may not be worth worrying about much
(who cares if it takes 5 years and $500 million to make
the tether work properly and test it if the total project
costs $50 billion and takes 15 years?). But he may be
underestimating serious issues. In a lot of cases,
we really don't know how serious the problem is, because
the work to quantify how bad it is hasn't been done.
The Mars Dust problem is currently in that category,
as is the space suits problem, and the tethers problem,
and the fractional-G biological effects problem.

The latter, Bob was getting the Mars Society to work
on Translife, which Elon Musk then took off and ran
with for a while. But Musk is now doing Space-X
as his primary focus. So I don't know where the
current situation lies.

Does anyone who's inside Space-X (I have been told a couple
of you are reading) know what's up on Translife?
Anyone? Buehler?

In particular I very much like Zubrin's philosophy of using in-situ
resources to reduce mission requirements. I think this philosophy may
also be applicable to other missions than Martian.

There is nothing wrong with ISRU other than some implimentation
issues as Henry points out.

Some of those may end up being very serious implimentation issues,
but they aren't known to be catastrophic.


-george william herbert

"CL Vancil" wrote in message
m...
Hop David wrote in message
...
CL Vancil wrote:

And an aside: on the concept of a single mission to Mars being Flags
and Footprints...I would say 1.5 to 2 years on the surface of another
planet is not F&F! It may leave no useful infrastructure, but it
seems not to matter here whether current infrastructure is retained.
So I see this all as a red herring for those who would advocate some
other mission (i.e. return to Luna, L-1, NEO or what have you)...

--Chris Vancil

I also hope and believe 1.5 to 2 years on another planet is not fantasy
and fiction. The chief arguments for 1.5 to 2 years on mars are
proximity and available in-situ resources.

If you are spending 1.5 to 2 years on Mars plus a 7 month trip out and a
7 month return trip that is three years off earth. Which I think is
possible. If asteroids have usable in situ resources, 3 years on a near
earth asteroid is also a possibility.

Yes, you could use the abilities and equipment built for manned Mars
missions on many other just as useful missions. The reverse isn't
true. And if you forced designs to be vastly over engineered folks
here would squeal like stuck pigs about it. I'm sure Congress would
also wonder at the costs. So the Moon is not a stepping stone to Mars
now anymore than it was during Apollo. All the testing etc can be
done on Earth or LEO or on Mars(ISRU) for a manned Mars mission.

Not all the testing. We still haven't made anything out of in situ
resources in space. The moon seems like a good place to start. The moon
offers much better radiation shielding than ISS. ISS is boring and I don't
know how much longer funding will last for it. If ISS is cancelled, there
might not be any funding for testing in LEO.