MMM Classics Year 10: MMM #s 91-100 - Moon Society

fashioned NASA eyes, you will come up with a billion dollar
project. If you look at it with the eyes of an engineer, you
immediately come to the conclusion that a human powered
vehicle is just the ticket.
Research backs this up. In a Scientific American issue
on Human Powered Vehicles a number of years ago, an article
on bicycles had an extra data point for the performance of a
vehicle on the Moon. A racing biker, with no air resistance and
1/6 g could break 1000 km/h in sprints. A normal, healthy
person could cruise at over 100 km/h all day, and could easily
pull a trailer load at the equivalent of typical Earth- bound auto
driving speeds.
The form of the vehicle is the recumbent bicycle like
that used by Stephen K Roberts (Computing Across America).
And in fact, he would probably be the best person to speak to
on the design of a lunar rover. He crossed the USA from end to
end several times on his recumbent, traveling up and down
through the Rockies, keeping up reasonable highway speeds -
and all the while with a trailer that included solar power
gathering and a satellite uplink so he could type on the
keyboard in front of him (while peddling) and submit articles
to magazines that funded his journeys. He also had navigation
and maps built into his console processor. I don't think there is
anything that a lunar rover built for days of unsupported
prospecting would need that he didn't do 5-6 years ago.
Now, that is not to say there aren't issues unique to the
Moon. There is the issue of traction and off road travel which
will drive the gearing ratios, axle loading, weight and balance,
and wheel design.
Braking will have to be dynamic, feeding the energy
back into a dynamo. Normal friction brakes are a bad idea for
two reasons - 1) The abrasiveness of the regolith. 2) Brake
cooling is purely by radiation to the background and
conduction through the frame. Radiators are a problem as has
been suggested before; and since I expect the frame to be
composites, conduction is not very good either.
Gears and chains and deraileurs will have to be very
robust and spares will be required. A design that can be field
welded would be a good idea. Better to trade off a bit of
elegance and performance for field maintainability. These parts
can be built very ruggedly (I'm not talking about racing bikes
here!!) and would need to be able to withstand the rigors of
large temperature swings and abrasive particles. One could seal
them, but then it is more difficult to field strip. And not to
mention which, without herculean efforts the lunar grit will get
in anyway. If anyone out there was in Desert Storm...
Another area of concern is space suit cooling. The
loads will not be excessive under normal cruising since the
peddling is only enough to replace frictional losses.
Use of a small motor like that in a mini bike could
solve a number of problems (if they don't add too much
complexity on their own). The motor could be the means by
which braking returns energy to storage. Energy can be
recovered on downhill stretches and used to ease uphill travel.
It also can reduce the heat loading on the space suit during
acceleration from a standing start, or indeed any acceleration
under load. The motor would, of course, need to be built such
that it can be disconnected from the system entirely if it fails.
The over all system would have to be able to get the lunan back
home regardless. So think of it only as a luxury item on the
bike.
The suit would be a live-in suit, so that puts some
extra design load on it. You might have to do better than a
diaper if you're going to be out for a week... But this is a
problem that needs to be solved anyway. The Stars Wars rovers
that some NASA scenarios show us are not going to be feasible
on any realistic budget, and in any case you'd only be able to
afford one of them for the same price as giving every lunan
their own personal lunabike.
It seems wholly superior to any rover concept I've yet
to see. Just about anyone out there could have run circles
around the Lunar Rover and been out 20 km and back before it
was barely out of sight of the LEM...
Ah, you say, bikes are good on highways, but off-road
you’re going to want a trike! The lunar surface has huge areas
that are much like beaches and dunes. Covered with
hardpacked fine regolith that follows the contours of the land in
a very smooth and gently rolling fashion. This is not to say that
crater rims and such are quite the same - but large tracts of the
Moon should be easily negotiable.
As to bike vs. trike, there is no inference above, of a
two wheel design - in fact I believe the recumbents are usually
trikes. At least the Robertson one that I saw in 1989 was... DA
Out-vac trike-uits are a challenge
by Peter Kokh
Sounds delightfully low-tech, doesn’t it? Tired and
stressed out after a long day’s work in your lunar office, mine,
or factory? Just don your out-vac trike suit and head for the
airlock and get some heal-all unwinding exercise! Reminds me
of an Arthur C. Clarke’s story where the hero does a kangaroolope
to safety 600 km across Mare Imbrium in just a spacesuit.
The question arises: without an open air heat sink,
where does all the body heat generated by such exertion go?
An out-vac triking suit needs not only to be self-contained (in
RV-camper-trailer talk that means “with toilet”), but able to
handle/ shed internally-generated heat and perspiration as well.
That also means being able to keep the wearer from getting a
chill soaked in his/her own sweat once the exertion is over.
Perhaps the suit’s insulation material could be an eutectic salt
in a quilt of pocket cells, melting to absorb internally-generated
heat, solidifying to release it - automatically, on demand. PK
Or Perhaps a “Buppet” Bike
by Phil Chapman
with permission, from a post on Artemis-list
[* Buppet: etym. from Body Puppet]
(on the analogy of Muppet from Mitten Puppet)
Note: “buppet” is the editor’s word, not the writers
See MMM # 89 OCT ‘95: “Dust Control” pp. 6-7 -
Republished in MMM Classics #9]
Having tried both [an EVA suit and a diver’s dry suit],
let me tell you that a pressurized conventional spacesuit is
much more restricting than a drysuit.
Moon Miners’ Manifesto Classics - Year 10 - Republished January 2006 - Page 8