New Mars Forums

Yes - nice storm - classic Phoenix summer storm.  My dog and cat were scared out of their minds

- yet another Arizonan

More on the PSB :

In fact, don't just cut the ribbons when creating the equatorial elevators.  Double them up first, so when you let the new equatorial elevators go, you keep a PSB in place.  Reel the ribbons in a bit so they begin to revolve fairly quickly. 

Now you can slide cars out without any power, and they'll quickly get moving fast enough to get humans through the van Allen belts with minimal danger.  In fact, they'll go so fast that you wouldn't want to use wheels in contact with the ribbon (they'd fly apart).  The main limit on speed would be that you'd want to spread the acceleration out over time for the benefit of the human occupants as well as to keep from distorting the ribbon too much.

You'd probably want to use a sealed ribbon, and create a thin gas bearing on each side to slide on.  A few cubic meters of liquid nitrogen ought to be enough to supply one trip.  A gas bearing also has the advantage that most frictional heating is discarded with the gas.

Since sealing the whole ribbon would add too much weight, create two large loops of sealed ribbon material - one for each side of the ribbon.  Use a gas bearing plate to push these loops against the ribbon from each side, holding the car on the ribbon.  As you get going, the loops would spin out into circles - effectively very large, light and strong wheels.

(This would also be a decent way to let things slide down a normal space elevator, BTW.)

If you toss in "forever", everything eventually fails.  But if it went a century without a collision, that's plenty of time to get good value from it and build several more elevators.  The ribbon is more likely to be cut by a meteor than it is to collide with a big, obvious and avoidable obstacle like Phobos.

And WRT your second point - yes, all free-falling satellites must cross the equator - but as I was trying to say, the space elevator ribbon need not be attached to Mars at the equator.  It can be attached at a higher latitude so that the ribbon does not cross the equatorial plane inside the orbit of Phobos.   It just puts a bit more strain on the ribbon.  This was discussed at some length in that forum I mentioned.

Here's a link explaining the idea:

http://www.mit.edu/people/gassend/space … quatorial/

Ok - why?  With a combination of swinging the elevator at the half of phobos' orbital period, and making small computer controlled adjustments over time to keep it synchronized, what do you see as being the big problem? 

You could simply attach the space elevator maybe 300km off the equator (which requires a slightly stronger elevator - easy since Mars has less gravity and it is only about half a degree tilted).  According to my rough calculations, phobos should never come near it.

If you assume the technology to get to Mars and build a space elevator there - no mean feat in itself - is arranging to not hit an ~3x/day orbiting moonlet 13km wide really so tough?

Instead of trying to raise the station in place, maybe just build the bottom in an inverted wedge shape.   When it gets buried a bit, slide it to one side using a winch and anchor system, up the ramp of snow that will have built up under it, and shove snow in behind it to hold it in its new position.

Follow the "local resources" approach - build what you can out of ice/snow.  The main thing might be windbreaks.  With those in place, a multi-walled tent might be sufficient for the walls of the structure.  The need to support snow accumulation probably means the structural supports and roof must be solid.  Note that on the south side you could probably just put up a tent-like wall, and let snow accumulate behind it due to the wind - a giant snow drift build using the local wind-energy resource.  Move the wall to the top of the drift (and back a bit from the edge) to build the drift higher.

Since the winds are mostly from the southeast, and the sun will be mostly to the north, maybe use a high windbreak on the south side that can reflect in extra light during the darker (non-night) months.  More to save on lighting than anything else.

OK, this is a bit 'out there', but...
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"Hi! and welcome to Dream Lottery - the Lottery where YOUR Dreams CAN come true!!  Here's tonights slate of Possible Dreams...

45% - Cure Cancer   
22% - Mars Colony
15% - Cure Heart disease
8%   - Cure Alzheimers
5%   - Feed the Hungry
3%   - Life Extension
2%   - World Peace

"First, Carla, if you'll activate the Dream Picker?  And the winner of the big $100M donation is...."
"...Mars Mission!   Congratulations all you Mars dreamers!  As specified in the terms of the lottery, tonights winnings are being donated to the Mars Society to advance research and development towards the eventual establishment of a Mars colony. 
"And now, Carla, if you'll randomize the Lucky Dreamer Machine to see which of our Mars Dreamers will be taking home a share of the $10M dream jackpot?"
"Thanks Carla - and our numbers tonight are 4 2 17 8 11."
"Congratulations you Lucky Mars Dreamers! "

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The more tickets are bought for a goal, the higher the chance of that Dream winning.  The tallies would be posted continuously - and it'd quickly become a horse race between the top two or three dreams - because only those who "invest" in the winning dream have a chance to win the jackpot.  Naturally most will buy tickets for the popular Dreams.

Now, here's the scam... and if you don't tell people this is how it works, I think we can get away with it...  :;):

Every lottery is 100% fair and honest.  But every lottery will have a different mix of Dreams.  (And, BTW, in the long run your odds of winning any given amount of money are the same whether you pick a popular dream or less popular one - since if a less popular dream wins, there'll be fewer people splitting the jackpot.  That part is 100% honest too.)

The first and biggest trick is that "Mars" is included at all - i.e. we get to pick the Dreams (taking suggestions from the public, of course), and we make sure OUR Dream is often included.

The second trick is a bit sneakier.  Popular Dreams can be diluted - e.g. above, the common Dream of curing a major disease is diluted by listing several diseases.  This doesn't help us in any one lottery - but over time, the diluted choices are considered by naive players somewhat less "lucky", since they win less often, while the un-diluted Mars Dream is considered somewhat MORE lucky.

The last trick is rather subtle.  The mix of dreams will change for every lottery.  We'll freely admit that it's a mix of random and deliberate choices - "to keep it interesting, for example, after a Dream wins we leave it out for several lotteries, so the other Dreams have a fair chance".  People will develop favorite Dreams that have been "lucky" for them in the past.  So we'll include "Mars" a bit more often against less popular choices, increasing it's chances of being chosen, so that over time more and more people come to view "Mars" as a lucky choice and a popular Dream.  Because the more popular a dream is, the bigger chance it has of winning.

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"For me and Carla - Thank you and... Keeeeep Dreaming!" 

Uh - Mars Direct estimates $7B for each mission subsequent to the first.  My estimate is that a re-supply mission every 2 years would probably take about $200M - so $100M even if the colonists can't become mostly self-sufficient.  And that's for 10 colonists, so it's about $10M per colonist.

My more optimistic projection is that we'd end up sending another group of colonists along instead of just a re-supply mission.  If we do that every 2 years for $8B each time, that'd be $100M/person_yr for the second mission, $67M/person_yr for the 3rd, $50M/person_yr for the 4th, etc.

If we then stopped sending colonists at 40, and just sent $200M supply missions every 2 years, it's only $2.5M/person_yr.   Quite a bit below your $15B estimate!

Absolutely - just insist that they make that decision before they go.   

Seriously though - the astronauts will actually be at greater risk trying to return, than staying!  Consider the hazards of returning  (estimated as 1% or 5% - obviously very rough guesses) :

- The lander has to be designed to lift off again, rather than just landing.  ANY time you add capabilities to a system, you end up with compromises.  In this case, you'd compromise the safest possible landing, in return for the capability of lifting off again.  (Added Risk of Death [ARoD]: 5%)
- Rocket launches are always hazardous - and they'll have no ground support crew on Mars. (ARoD: 5%)
- They'll be leaving behind most of the supplies (especially the Hab) that made life on Mars tolerable and safe, to squeeze into a rocket for a 6 month trip home. (ARoD: 1%)
- They'll absorb another radiation dose equal to the one they took on the trip to Mars  (ARoD: 1%)
- Landing back on Earth may be even more hazardous than landing on Mars, due to the higher gravity and thick atmosphere.  (ARoD: 5%)
- They'll have to adjust to full gravity again - more strain on their bodies. (ARoD: 1%)

The risks of having to stay on Mars?  I see:
- The Unknown - something totally un-anticipated that they can't deal with.  The probability seems small, given the broad capabilities they should have and their support by earth's best minds.  (ARoD: 1%)
- Disaster - something big goes wrong - not big enough to kill them all outright (or prevent them from returning if they had the means), yet big enough that they can't use their many resources to recover.  An O2 fire in the Hab early on that destroys most of their equipment and food while some of them are outside.   (ARoD: 1%)
- Very Long term progressive debilitation (muscle, bone, organs) due to lower gravity.  Frankly, I expect they'll experience some of this - but as long as they stay on Mars they will probably live nearly as long as they would have on Earth.  (ARoD: 1%)
- Psychological issues due to isolation.  Mostly avoided by testing in advance and by having a larger crew, and ideally by having more colonists join them a few years later.  (ARoD: 1%)

In short - given the hazards of staying on Mars for a year or two in the first place, the added risks from staying on Mars for the rest of your life and skipping the ride home seem small.

Well, your demand for a business plan in a discussion forum is amusing, to say the least.  Sure, if I were proposing this to NASA or a group of billionaire philanthropists, I'd need a detailed plan.  Are you either of those?   

However some responses:

Much of the stuff on your lists is already in Mars Direct - and you left out several big pieces that are in Mars Direct without mentioning the savings.

In Mars Direct and my proposal - fuel factory, Air factory, lots of spares, staff, robots.  Also a nuclear power plant and HAB.

In Mars Direct, not in my proposal - spare HAB, spare nuclear power plant, two landers able to re-fuel and lift off.  BIG savings in R&D as well as manufacture and launch - probably around $5B.   Repeat missions at $7B (or more) a pop are dropped.

Not in Mars Direct, added by my proposal - several large inflatable modules (to be buried) for added living, work and greenhouse space; more variety of larger machine tools; fish and turtle eggs and plant seeds.  More people - mainly adds more life support mass for the trip and first few years - they're volunteers, not employees, and training costs are relatively small if you pick highly skilled people to begin with.  Probably about an extra $500M to launch the extra mass of life support and supplies.  Use an inflatable compartment to add more living space for the long transit, at modest added cost - call it $1B total added cost.

I also need a lander whose only purpose is to get the colonists safely down - I'm thinking that a very large dirigible or a blimp might be just the thing - lots of drag to slow the small mass of the landing capsule quickly down from orbital velocity and let it fall with a moderate terminal velocity until it hits "thicker" Mars atmosphere.  Yeah, it'll need to be BIG, but it won't need that much gas to inflate it in the near vacuum Mars conditions, and the material would be a valuable resource as well.  It can be tested, lowering the first HAB to Mars.  I'd guess maybe $2B to develop it and produce one to drop the HAB and one to drop the crew lander - and only that much because we'll want to focus on safety.

Since only the crew landing craft needs to enter orbit, the rest of the Mars Transit craft would continue on, in a cycling orbit that brings it back near Earth - allowing another group of colonists to rendezvous if desired, for maybe $2B a pop.

Resupply missions could be sent every two years, if needed.  Raw materials like refined metals can just crash land a few hundred KM away.   More senstive stuff can chute/bounce down like the rovers or blimp down like the lander.  I'd guess these missions will each cost under $200M.  The interest saved on the $7B of one Mars Direct "second mission" would pay for these, indefinitely.

Dropped from my original thinking - food animals other than fish and turtles, at least initially.  Drop orbital animal test labs too - eventually we'd send other animals there, and just see how they do - chickens probably.  Starch (food) factory to be made by colonists only if needed to supplement greenhouse production.

The colonists would make just about every other major component of their colony.

Ok - by my count, I'm coming in around $2B cheaper on the first mission, and $6.8B more every couple years after that as we don't need to send additional missions - or just $5B more if we decide to send another 10 colonists on the cycler.

And of course, this plan leaves more and more colonists on Mars, creating more and more infrastructure to make life on Mars safer and more comfortable and self-sustaining, as well as doing lots of good exploration/science.

And that's enough of a "business plan" for a discussion formum