I think the most feasible idea for a mars trip or mars colonization or
trade etc. would be to find an asteroid that frequently crossed paths with
Earth's orbit and mars's orbit and dig into it. Such a habitat would not be
a very good one, but it would be very satisfactory for making the long trip
and carying cargo. It would also be the most safe. Anyway, I think I once
heard this kind of object called something special, does anyone know what
that name was?
I think the most feasible idea for a mars trip or mars colonization or
trade etc. would be to find an asteroid that frequently crossed paths with
Earth's orbit and mars's orbit and dig into it. Such a habitat would not be
a very good one, but it would be very satisfactory for making the long trip
and carying cargo. It would also be the most safe. Anyway, I think I once
heard this kind of object called something special, does anyone know what
that name was? You're probablythinking of Aldrin's proposal for Mars ships following such paths which he called Cyclers. Cyclers would save a lot of fuel over accelerating and decelerating the entire ship again and again, but he was still assuming certain course adjustments at each end of the trip. It would be hard to repeatedly adjust the course of an asteroid like this, at least if it was of any significant size. There would really be no advantage to traveling on the asteroid unless you had a continuous ongoing need for very large amounts of new raw materials. I think closed life support systems would be a pretty good bet for a continuously cycling Mars ship. There's really no need todig into an asteroid for protection from meteoroids either; the actual threat is more modest than many realize. If seeking protection from cosmic rays, 6 feet of shielding is all you would need to safely spend an entire lifetime on the ship; anythingmore than this would be overkill.
Mike Combs
(903)-868-6314
In reference to "... an asteroid that frequently crossed paths with
Earth's orbit and Mars's orbit ...", John Lewis in Mining the Sky,
Addison-Wesley, 1996, discuss using such cyclers to have a sort-of scheduled
bus services to Mars and the asteroid belt. But to get on, one would need
to match their velocity, or else there would be a collision, and if one has
the same velocity as the cycler, then you would already be in the same
orbit. So apart from the shielding and maybe an opportunity working the raw
materials while in route, I don't see the advantage. Orbital periods to the
main belt are 3 to 5 years, so a round trip would be at least that, making
the 3 day travel time to the Moon seem rather attractive.
Sincerely,
Jay S. Huebner at jhuebn@...
>>>>In reference to "... an asteroid that frequently crossed paths with
Earth's orbit and Mars's orbit ...", John Lewis in Mining the Sky,
Addison-Wesley, 1996, discuss using such cyclers to have a sort-of
scheduled
bus services to Mars and the asteroid belt. But to get on, one would need
to match their velocity, or else there would be a collision, and if one has
the same velocity as the cycler, then you would already be in the same
orbit. So apart from the shielding and maybe an opportunity working the
raw
materials while in route, I don't see the advantage. Orbital periods to
the
main belt are 3 to 5 years, so a round trip would be at least that, making
the 3 day travel time to the Moon seem rather attractive.
Sincerely,
Jay S. Huebner at jhuebn@...
carbon, nitrogen and hydrogen, then one obvious advantage would be, that
you don't have to take along all of the consumables that you need.
Providing transportation for colonists wanting to go to Mars, could be a
potential source of revenue for an L5 industry. Large mass driver propelled
ships, capable of carrying several thousand people per trip, could easily
be constructed at L5. O'Neill described such large, Mass driver propelled
vessels in his book, "the High Frontier". With large amounts of asteroidal
material available at L5, we could easily manufacture all of the
consumables needed to support such a population, for a year long trip to
Mars. The food could be grown as surplass in L5 habitat rings. The
propellant for the mass driver would most likely be frozen oxygen, produced
as 'waste' from the L5 industries.
Tony
Maybe I am slow, but I don't get it. " If we are talking about a
carbonaceous chondrite, with large supplies of carbon, nitrogen and
hydrogen, then one obvious advantage would be, that you don't have to take
along all of the consumables that you need." I don't see how carbon,
nitrogen and hydrogen from an asteroid would be useful consumables for folks
traveling on the inside of an asteroid bound for Mars. They would need to
breath, drink and eat, and of course no matter how they travel, their wastes
would be available for recycling. Are you saying they could also use
asteroid materials in a garden or factory to make consumables? Or are you
considering the usefulness of those materials when one gets to Mars?
Jay S. Huebner at jhuebn@...
>>>>Are you saying they could also use
asteroid materials in a garden or factory to make consumables? Or are you
considering the usefulness of those materials when one gets to Mars?>>>>
asteroid. Rather you would use the large supply of material that is already
located on the correct orbit, in order to construct it. It is quite true
that wastes would need to be recycled, but if you start out with large
amounts of Water, Carbon and Nitrogen already on the correct orbit, then
shipping them to the cycler in the first place, becomes unnecessary.
Towards the end of the 21st century, 100's of thousands of colonists could
be emigrating to Mars, every year. Under these conditions it would be
convenient to construct an island-2 colony on a cycler orbit, to house the
waves of immigrants.
Tony
Thank you for the prompt reply, " 100's of thousands of colonists could be
emigrating to Mars, every year. Under these conditions it would be
convenient to construct an island-2 colony on a cycler orbit, to house the
waves of immigrants." But if you get on an island-2 colony, why get off at
Mars? This assumes life on Mars will be better than on the island-2
colonies. I admit that is possible, but I think unlikely, and there are so
many asteroids and only one Mars. Lewis (Mining the Sky) claims that our
future can include millions times billions of people all living in colonies
made from the asteroids.
Sincerely
Jay S. Huebner at jhuebn@...
>>>>But if you get on an island-2 colony, why get off at
Mars? This assumes life on Mars will be better than on the island-2
colonies. I admit that is possible, but I think unlikely, and there are so
many asteroids and only one Mars.>>>>
How much is known about the asteroid Ceres? It is the largest known
asteroid and contains about half of the material in the belt, but I can
find little or no information on it. Are there any telescopic maps of its
surface? Has the signature for water ever been detected in its emission
spectra? Given its large size, we would expect to find a planetary
arangement of a mantle, core and crust. Asteroid Vesta, showed large,
ancient lava flows on its surface. I have heard reports that Ceres is of
carbonaceous nature. If this is true, then early internal heating could
have resulted in pockets of liquid water existing in the interior of the
asteroid. This body could have some interesting geology.
In 'The High Frontier', O'Neill gave details of a mass driver driven ship
(Beagle-2) that would be sent on voyages of exploration to interesting
asteroids. Ceres is a bit further away than most of the NEO asteroids that
he had in mind, but it would make an interesting target.
Tony
[...Ceres...]
> spectra? Given its large size, we would expect to find a planetary
> arangement of a mantle, core and crust.
cycles of differentiation and fragmentation that (in certain cases)
give access to (differentiated) core material without having to dig
for it. This is the essence of what makes PGM mining in NEAs
potentially very attractive (if you can find the right NEA). Going
to a planetessimal that's small enough to have lousy gravity (making
surface operations difficult) but big enough to be differentiated
seems to me like one of the worst possible options. For water and
extinct comet seems like the best bet. For other materials, asteroids
representing a shattered larger body (so you get core or mantle material
without having to dig through crust) seems like the way to go. The
only advantage of an intact differentiated body in the Ceres size range
seems to me to be that you have everything in one place. Since digging
is going to be more expensive in energy than transport from a nearby
smaller asteroid, I don't see the benefit.
as always, YMMV,
......Andrew
Andrew Case
acase@...
Institute for Plasma Research
University of Maryland, College Park |
I suspect that when we eventually get interested in mining lots of metal
from asteroids, we will seek out a stony-iron asteroid that has a
significant regolith blanket. The metal particles could be beneficiated
out of the mix by magnetic separation --- a much easier process than trying
to cut a chunk of stainless steel with a carborundum saw. It is thought
that even undifferentiated asteroids like Eros still have significant
amounts of free metal particles in their regoliths.
http://www.space.com/businesstechnology/technology/m2p2_winglee_010621.html)?
Ron Menich
Andrew Case
ssi_list@...
06/22/01
10:21 AM
Please
respond to
ssi_list
[...Ceres...]
> spectra? Given its large size, we would expect to find a planetary
> arangement of a mantle, core and crust.
The nice thing about asteroids, IMHO, is that they have undergone
cycles of differentiation and fragmentation that (in certain cases)
give access to (differentiated) core material without having to dig
for it. This is the essence of what makes PGM mining in NEAs
potentially very attractive (if you can find the right NEA). Going
to a planetessimal that's small enough to have lousy gravity (making
surface operations difficult) but big enough to be differentiated
seems to me like one of the worst possible options. For water and
extinct comet seems like the best bet. For other materials, asteroids
representing a shattered larger body (so you get core or mantle material
without having to dig through crust) seems like the way to go. The
only advantage of an intact differentiated body in the Ceres size range
seems to me to be that you have everything in one place. Since digging
is going to be more expensive in energy than transport from a nearby
smaller asteroid, I don't see the benefit.
as always, YMMV,
......Andrew
Andrew Case
acase@...
Institute for Plasma Research
University of Maryland, College Park |
I think the attractive asteroids will be the smaller ones, not the larger
ones like Ceres.
asteroid rather than on its surface due to the constant availability of
energy in orbit. This implies lots of trips between the facility and the
asteroid surface. To do that on Ceres would entail several hundreds of
kilometers per hour of delta-V each way. To do that on Eros would entail
only 20 kmph each way. To do that on a 1-km asteroid would be trivial ---
one could simply toss bags of regolith from the asteroid to the facility
using springs, with no usage of propellant whatsoever.
Not that several hundreds of kilomters per hour is insurmountable --- it's
a lot less delta-V than required to get off the Moon, and of course less
than is required to get off Mars. But why do that when you could reduce
that delta-V requirement by 2 orders of magnitude simply by choosing a
smaller asteroid?
Ron Menich
hollroa@...
Please respond to
ssi_list
>>>>But if you get on an island-2 colony, why get off at
Mars? This assumes life on Mars will be better than on the island-2
colonies. I admit that is possible, but I think unlikely, and there are so
many asteroids and only one Mars.>>>>
I can't think of one good reason.
How much is known about the asteroid Ceres? It is the largest known
asteroid and contains about half of the material in the belt, but I can
find little or no information on it. Are there any telescopic maps of its
surface? Has the signature for water ever been detected in its emission
spectra? Given its large size, we would expect to find a planetary
arangement of a mantle, core and crust. Asteroid Vesta, showed large,
ancient lava flows on its surface. I have heard reports that Ceres is of
carbonaceous nature. If this is true, then early internal heating could
have resulted in pockets of liquid water existing in the interior of the
asteroid. This body could have some interesting geology.
In 'The High Frontier', O'Neill gave details of a mass driver driven ship
(Beagle-2) that would be sent on voyages of exploration to interesting
asteroids. Ceres is a bit further away than most of the NEO asteroids that
he had in mind, but it would make an interesting target.
Tony
> " 100's of thousands of colonists could be
> emigrating to Mars, every year. Under these conditions it would be
> convenient to construct an island-2 colony on a cycler orbit, to house the
> waves of immigrants." But if you get on an island-2 colony, why get
> off at
> Mars? This assumes life on Mars will be better than on the island-2
> colonies.
would prefer to live on a planet
than in a space station, and vice versa, no matter what the conditions
are for each of them.
B