Comments on: How I’d Go To Mars

By: Jay Manifold

Jay Manifold — Sun, 15 Feb 2004 01:41:17 +0000

I should have used a different metaphor; what I meant by “catnip-like effect,” etc, is that just about every engineer I know is irresistibly drawn to the space elevator project and wants to work on it! Skyhooks could definitely figure into the project, as well.

And I have no doubt that a permanent presence in space will be predicated on profitability. The commercial space industry is just beginning to branch out beyond remote sensing and telecommunications; I wish them all the best.

By: TM Lutas

TM Lutas — Sat, 07 Feb 2004 16:29:15 +0000

If you don’t want this to be another checklist space program (gone to the moon, we don’t need to be back) it needs to generate enough income to be profitable. You can get some government funds but it’s all impractical nonsense if you don’t find a way to make money reasonably soon.

By: Brett Bellmore

Brett Bellmore — Sat, 07 Feb 2004 16:14:52 +0000

Jay, suggest to your engineer friends that they actually look at the numbers. They might stop laughing. I expect that elevator to be in operation long before a manned mission to Mars could be launched. And the nice thing is, it not only gets you into orbit, it can launch you to many of the planets, as well.

Speaking of skyhooks, though, have you looked at the possibility of forgetting about landing craft at the Mars end of things? A geosynch skyhook is just barely feasible for earth, but Mars has a substantially shallower gravity well, and a natural satalite quite near Mars synchronous orbit. You don’t even need nanotubes, standard graphite composite, or one of the higher strength polymers would be sufficient. They could be manufactured on site.

While a skyhool lowered from Demos wouldn’t be perfectly stationary relative to Mars surface, it would be traveling slow enough to use very low performance craft to handle the last few miles of the trip.

By: Alan E Brain

Alan E Brain — Sun, 25 Jan 2004 10:05:14 +0000

Christmas Island is a likely spot.
See http://www.apsc2orbit.com/thespaceport/theSpaceport.html

The problem with Mass Drivers on Earth is that pesky atmosphere. Assuming an evacuated tube to accelerate in, you have the problems of frictional heating, and sheer g-force deceleration when you hit the atmosphere. Even Everest-level atomspheric density is problematic.

Now on the Moon, or even Mars, they become much more attractive. The Moon especially, lots of free soolar power…

By: Jay Manifold

Jay Manifold — Fri, 23 Jan 2004 19:49:48 +0000

David Rothman correctly suggests that an Earth-based mass-driver could work. Back in the '80s, I corresponded, met, and spoke with (but of course can't now remember the name of) a physicist who had worked out quite a few of the details, partly by sneaking into supposedly classified sessions of SDI-related conferences. It's my understanding that the only good location is Cayambe, and Ecuador is politically problematic. I remain irrationally fond of this idea, however. Michael Sargent also correctly notes that there are (my term) topological issues with security for an oceanic platform -- this is what, er, sank the Oceania project. I'd manage the risk by either locating it as far from land as possible or including defensive measures in the project -- perhaps both. A search at this nifty database finds, for example (warning: big *.jpg's), Ulu Seamount, which tops out at 1500 meters below the surface, and Winslow Reef, which reaches to -1650 m. Both are just east of the aforementioned Baker Island, about 2,500 km from Hawaii, and are nearly 4,000 km from large land masses (Australia, New Guinea, New Zealand). As Patrick notes, I'm a bit behind the curve in ignoring the space elevator. I've noticed that mention of it has a catnip-like effect on engineers of my acquaintance. Well, they don't actually roll around on the floor and make funny noises, but they certainly seem to find it ... stimulating. And as "ech" implies, few if any of my ideas are original. You want original thinking, start paying me to blog. ;)

By: ech

ech — Fri, 23 Jan 2004 18:57:37 +0000

Interestingly enough, much of what you have called for is already in the NASA plans, dispersed in various places. These include: propulsion, lunar base as testbed for Mars (a long-standing idea in the life support community), Comsat/GPS for Mars – a comsat is in the pipeline now and GPS is actively under study, ISRU is baselined in most Mars mission models (particularly for propellant production).

By: Patrick

Patrick — Fri, 23 Jan 2004 17:04:46 +0000

I’m surprised that in all the talk of sealaunch platforms and nanotech, nobody’s mentioned the platform-based space elevator, a possibly nearer-term “weak-nanotech” solution to high launch costs.

http://www.isr.us/SEHome.asp

Nanotube composite ribbon with the necessary strength is still in the realm of unobtanium, but the announcement of suitable stuff could come any day. As long as we’re talking multi-decade billion$ programs, makes sense to include it in the idea matrix.

By: Michael Sargent

Michael Sargent — Fri, 23 Jan 2004 15:50:29 +0000

Regarding the floating launch platform concept Jay, what PM strategies would you recommend to counter the risk of deliberate, malicious, and perhaps suicidal interference ranging from small boats or aircraft(or animals released) in the launch fan, to interdiction its supporting sea lanes and/or blockade its supporting seaports, to terrorist acts employing a wide variety of technologies, to seaborne or air attack by legitimately constituted national military forces? The difficulties NASA has had in the past with securing its launch envelopes, and the Navy’s debacle surrounding their practice range on Viaques island don’t bode well for a distant platform in international waters.

Perhaps the Boyz can lease NASA their fleet for a suitable charge?

By: covington

covington — Fri, 23 Jan 2004 14:56:26 +0000

Mars Express has found better evidence for water ice on Mars. That changes things a bit.

And Spirit has sent two streams of good data back – so today is a good day for space activists.

By: David

David — Fri, 23 Jan 2004 14:08:02 +0000

Have you thought about the praccticality of using either an electric rail gun or “super gun” technology for boosting cargo to low earth orbit? Both systems are relatively low tech and essentially provide a first stage where all the hardware remains on the ground. Solid rocket engines would provide the remainder of boost to orbit. Because of extreme acceleration (1000s of g), these systems are useless for manned flight or transport of fragile components, but might be ideal for low cost shipping of fuel, building materials, water, food and other bulky low-tech stuff to low earth orbit.

To be practical, either system would probably have to be built at high altitude (moutain or alto-plano) to reduce air resistance for the projectile leaving the gun. For equatorial launch that means the Andes. Within CONUS, the closest mountain sites to the equator would be in south New Mexico.

By: Errol

Errol — Fri, 23 Jan 2004 01:49:21 +0000

re: Nauru – you’re thinking of Niue that recently got munted by a cyclone. Comments at http://headheeb.blogmosis.com/archives/020226.html

re: launch sites – Cape York peninsula, Australia has been suggested in the past. Scores fairly well on location, very well on stability, friendliness to US.

By: Jay Manifold

Jay Manifold — Thu, 22 Jan 2004 22:59:04 +0000

Wanting to be somewhere else when everyone on Earth has easy access to nanotech isn't tinfoil-hat at all. We can all think of people we'd just as soon not be living within thousands of miles of if they could grow missiles like so many cornstalks. I know I'll sure want to be able to scram if the occasion arises. The Moon probably isn't a great place to find uranium and thorium (though there are areas of higher concentration, including Mare Fecunditatis (40 kB *.pdf) -- the same source suggests that "deposits of uranium cover most of the nearside of the Moon"). A colorful map in this paper (2.2 MB *.pdf) indicates that thorium concentrations vary on a logarithmic scale by about 0.15, that is, around 40%, with the highest beingin Mare Insularum, southeast of Copernicus crater. Presumably, type M asteroids are elevated in all heavy metals, including uranium and thorium, and at least two near-Earth metallic asteroids (3554 Amun and 6178 [1986 DA]) are known. Paul Davies, writing in the NYTimes, suggested a one-way Mars mission. It's my understanding that the minimum viable population size to avoid inbreeding problems is ~10,000, but with genetic engineering techniques, I would expect this limitation to be more or less removed.

By: covington

covington — Thu, 22 Jan 2004 21:02:34 +0000

Wow, you’re talking about a hell of a lot of people if you want to get through the genetic bottleneck without inbreeding problems. Believe me, I know – I live in Kentucky.

By: Ken

Ken — Thu, 22 Jan 2004 20:22:59 +0000

“A nuclear-thermal booster launched from Earth’s surface”: my word, the Greens would scream themselves sick over that one.
(Giggle)
Go for it!”

Is there any extraterrestrial source of nuclear fuel nearby? Does the moon have a supply we can take advantage of for interplanetary travel. I’m not expecting any significant amount of nuclear fuel to leave Earth in the foreseeable future…

“Going to Phobos/Demios has an added advantage not really mentioned. Assume for a moment that the Mars missions are Mars Semi-Direct (that is the return vehicle is not sent ahead and only a hab and fuel creation is sent ahead and the return vehicle stays in orbit) and the return vehicle lands on Phobos where it the regolith provides radiation protection while the Mars teams do their duty on the planet bellow. ”

Better yet, no return vehicle. Plan on the human population being there to stay. Make sure half of them are female. If we abandon Mars the way we did the moon, they’re effectively independent, and after they’ve built up their infrastructure for a while, they can start running ships to Earth and back. If they think it’s worth the trouble…

By: covington

covington — Thu, 22 Jan 2004 19:41:33 +0000

Obviously I mistyped – I meant nanotech. We’ve got too much non-tech influence on the debate already.

By: covington

covington — Thu, 22 Jan 2004 19:40:55 +0000

Waiting for strong nanotech and real AI would be like continually waiting until NEXT year to buy that new computer… whenever we start getting serious about it will certainly be more expensive than the next year (unless we’re talking about 1972.)

Plus, as tinfoil-hat as it sounds, it wouldn’t be a bad idea to have self-sufficient outposts before we spread serious nontech capability around this turbulent globe.

By: Jay Manifold

Jay Manifold — Thu, 22 Jan 2004 18:09:03 +0000

Nauru's screwed up, all right, and broke enough to take money from Australia to hold boat people. But this page notes that "[a] plan ... to resettle the Nauruans on Curtis Island, off the north coast of Queensland, Australia, was abandoned in 1964 when the islanders decided to stay put." Of course, the phosphate mines were still producing lots of income then ...

By: Raoul Ortega

Raoul Ortega — Thu, 22 Jan 2004 15:25:42 +0000

re: Nauru– wasn’t it just recently hit hard by a hurricane ? So hard that rebuilding will be so costly that the government is considering disbanding and returning to being a dependency on New Zealand again? If so, somebody rich might be able to buy it cheap, and turn it into a spaceport.

By: ruprecht

ruprecht — Thu, 22 Jan 2004 15:14:51 +0000

Going to Phobos/Demios has an added advantage not really mentioned. Assume for a moment that the Mars missions are Mars Semi-Direct (that is the return vehicle is not sent ahead and only a hab and fuel creation is sent ahead and the return vehicle stays in orbit) and the return vehicle lands on Phobos where it the regolith provides radiation protection while the Mars teams do their duty on the planet bellow.

Followup trips would end up leaving a lot of gear on Phobos that could be used and bring the price down. You create a beachhead that has got to be valuable. Leaving infrastructure behind means we’re less likely to abandon Mars for thirty years as we did the moon.

By: J.Scott Barnard

J.Scott Barnard — Thu, 22 Jan 2004 13:46:19 +0000

I won’t be satisfied until I’m surfing the methane oceans of titan. Hang ten…million miles!