Polar Missions - Using Martian Poles

Crossman · 2002-09-30 15:56:56

Hi Folks,
Is anyone familiar with the work of Geoffrey A. Landis ? In articles in Analog Magazine (June 1999), as well as published in the proccedings from the first Mars Society convention (1998), he suggested sending the first Mars missions to the Martian poles. There are two great advantages to this:

1. Constant sunlight during the summer and spring (~383days, north pole; ~305days, south pole)
This allows simple energy collection w/ solar panels, no power storage requiered.

2. Easy access to an assured supply of water right on the surface, for fuel and life support.

This eliminates the need for nuclear power and bringing hydrogen. This makes the mission potentially much lighter.

There are disadvantages due to mission phasing. ie. summer does not arrive at the same time a vehicle approching from earth on a minimum energy transfer does, so not all mission opportunities can be used, and in all cases crews must loiter in orbit, sometimes for months.

There is also the objection that polar orbits are harder to achieve than equitorial orbits prior to landing. Does anyone know what the delta-vee penalty is ?
Also I am uncertain what the tempuratures at the poles are during summer Landis states that they are around -125 C, but in planetary society reports I have read tempuratures can rise to about 0C as demonstated by mists that are observed at the poles.

In his recent book Mars Crossing, Landis suggests a two man mission with the entire mission HAB and ERV combined, sent by the same launch to the poles, eliminating the need to send the ERV prior to the crew and the HAB.

I have estimated that with the advantages of the poles, plus a smaller crew we can take as little as 14 tonnes payload to Mars lanched by a 50T to LEO booster. The payload would also be boosted to near escape by a Solar dynamic stage mass 30 tonnes. (This adds 3-4 mounths to the six for the normal Mars Direct flight, with the aid of a chemical burn and a possible lunar gravity assist)

This would be a very long , hard, and higher risk mission architecture to adapt, but cheap, possiblely cheap enough to be done privatly.

Comments, anyone ?
Crossman

RobS · 2002-09-30 18:36:51

This is a fascinating idea. I'd like to know the delta-vee penalty as well. I suppose the big problem is that one has to stay more than 350 days in order to return to Earth, which means your solar panels get plunged into total darkness at some point before the launch window opens. Also, you can't set up anything permanent at the poles, because of the cold, windy, dark half-year nights.

-- RobS

Phobos · 2002-09-30 19:58:33

2. Easy access to an assured supply of water right on the surface, for fuel and life support.

I'm not sure about this part. I know there's water ice at the poles, but does it exist in such an amount that the crew could provide for all of their water and fuel needs by just harvesting the ice next to the hab? They might have to go far and wide in order to collect enough water since much of the cap is CO2 ice. Then again I have to admit I haven't really read up on the ice caps much so I could be completely wrong.

Crossman · 2002-09-30 22:45:31

Hi again,

The crew engaging in a polar mission would have to loiter in mars orbit both before and/or after their surface stay. In his June 1999 article Geoffrey Landis gives the example of the 2018 launch opportunity:

mars arrival: 1-17-2019
loiter in orbit till: 3-23-2019,vernal equinox
equal to 75 days.
leave surface on 5-10-2020, autumnal equinox
loiter in orbit 27 days,
leave Mars orbit: 6-6-2020

This example is for the north pole. The crew waits for spring when constant sunlight begins at the pole and leaves before the fall when pepetual night ensues, giving the crew 385 days on the surface out of the year and a half they spend in the Martian vicinity. I suspect that the poles are,( at least given our current inexperience with conditions that will freeze CO2, and with tempuratures that must plunge well below -125C, that must prevail for the (Earth) year long fall and winter on Mars), quite uninhabitable during the winter or in the fall.

Perpetual sunlight is key at least if you want to utilize the abundant solar energy available without the need for heavy power storage systems that would be requiered at lower latitudes due to day/night cycles.

It is true RobS that nothing that can be used year round can be set up at the pole, but the point is a cheap dirty mission that lets us get a toehold on Mars. The poles could be used on subsequent missions to fuel expeditions south (or north) where a base could be emplaced.

To my knowledge Phobeus the water ice at the pole is kilometers thick and especially at the north pole the CO2 ice sublimates with the coming of spring (this pole due the excentricity of Mars' orbit gets a longer summer and is warmer than the CO2 covered south polar ice cap). How fast this sublimation of dry ice happens each spring I do not know, any suggestions as to where I might find out would be greatly appreciated.

Crossman

C.COMMARMOND (FR) · 2002-10-01 09:33:05

Hi Crossman,

From my readings about pole delta vee penalty is about 35/45%, that mean that with the same amount of fuel, you get 35/45% less cargo to polar orbit and the same when you go back to go from polar to equatorial orbit...

About pole missions, I think the main problem on Mars is that the ground could be really dangerous, with 'cracks' (I miss the word, I hope you'll understand) on the floor, and, as you say, very thick CO2 ice that will blow up while your rockets fire to land your vehicle, and the problem that any thing you use which heat will be dangerous in this place...

And all the other problems you talked about...

It is maybe better to land at the limit of the ice, reducing risks, and to extend pipes to the ice to use it. It is easy to get gazeous CO2 by covering floor with a black plastic sheet and pump the gaz from under the plastic....

For the time the crew have to stay in space, they can work on Phobos to set up a plant at the beginning of the mission and take products at the end. But since Phobos can produce the same products (fuel) that you'll get on the Mars poles, a Mars pole mission is maybe not usefull at short term.

All this said, I think it's better to land on equator and use a small nuclear reactor to get a continuous power.

Maybe others will think different, but the question will be to find volunteers to go there... I'm not.

CC

Crossman · 2002-10-01 23:12:42

Hi again,

I was able to find a paper by C.S.Cockell in From Imagination to Reality:Part II, Ed. Zubrin, AAS Vol.92. The paper titled The Polar exploration of Mars, gives facts about conditions at the poles. Apperently the North cap is 5km. thick with the south being one fifth that. Both caps are water ice, with a C02 layer that is less than 1M thick. Come spring this layer sublimates away completly in the north and partially in the south.

Due to this I am confident that water will be accesable all spring and summer at both poles, since a thin CO2 layer is easily drilled or 'melted' through.

Since northern summer occurs during apehelion it is longer and cooler than southern summer which occurs at perihelion. Conversely northern winters are shorter and milder, soutern winters longer and colder. The summer temperatures for the poles in summer are given as -70C for the north, and -110C for the south, this seems to contradict the previous statement, but I'm just quoting here.

Never the less these seem to me to be acceptable parameters for a mission to endure.

If C.Commarmond is correct about a 35%-45% penalty for going to the poles over the equator, this can be accomidated by a second 50T to LEO launch, and an orbital rendevous. Could you tell me how you were able to estimate the penalty ?

As for the terrain the most recent hi-resolution images do not show any cracks or fissures common to the terestrial polar ice caps but there are pits estmated to be ~2m deep over much of the north cap. If l anding on ice is such a concern there are spiraling valleys clear of summer ice that could be used. These valleys probably have ice buried beneath them. These valleys are easily navagated by rover and some of them spiral in from the Vastas Borealis to quite near the pole itself.

As for nuclear power, in this scenario I am assuming that only the absolutly cheapest systems are used, (as well as those that will stir up the least political controversy),you could call this scenario the poor mans mission to Mars. Two people, minimal equipment, less than optimal (for basing anyway) landing site etc., in other words a mission that one does if you can not get support for a more traditional Mars Direct type mission.

In determinig the masses of cargo needed for this mission I escentialy halved the masses that are used in Mars direct, lowered the daily consumption of wash water to ~40% and combined the Hab and ERV, as I mentioned earlier. Quarters here will be cramped but acceptable for the small crew. Also the astronauts must depend on insitu propelant production, which is all done while the crew is on the surface, with no back up if it fails: again dangerous but economical ???

C.COMMARMOND (FR) · 2002-10-02 07:52:35

Hi,

About polar orbit penalty, go to this site:
http://www.spaceandtech.com/spacedata/e … pecs.shtml where you'll find a comparaison of payload from a 11? orbit (12000) to a 90? orbit (polar) for a launcher (9200). So, it is 25%, I added some loss for the 0? to 11? if we suppose we arrive on an equatorial orbit. This is for Earth, I don't now about Mars, but we can suppose that it could be about the same ratios.

The important thing is that there is a big loss and that because you need fuel to correct the orbit around Mars, you need more fuel from Earth... Have to recalculate all the weights of the mission.

About the poor's mission, I think that the most expensive thing in Mars mission is design of vehicles and processes. When the design is done, build the rockets, vehicles, chemical plants is not expensive. In Zubrin's plans, I think that 50% is for design, 25% for the build and 25% for the launches from Earth, and the design cost is the same if you have 2, 4 or 24 people in your mission and it is the same if you land on equator or on poles. The difference from your plans with his plans is that you go, walk and forget, so you use less vehicles and launchers. This is why I don't think your plan is so good as a poor's mission. But it is good as a part of a colonization because it will be easier and more efficient to get water and CO2 and solar energy from the poles. And to take it back to the main base on equator or in fuel tanks on orbit.

The best way is that when the design is done, take a mission to each pole and work continuously with automated systems, and send a crew at spring to restart the plant and at fall to stop it...

I think we should explore:
- meteo at poles: if a 6 months dust storm stop the plant production because solar panels are 90% less efficient in the storm, what to do...
- automated systems to get and process CO2 and water
- transportation of final products to orbit gas station or another base.
...

From these, we could now if it is possible, usefull and economically efficient.

CC

Crossman · 2002-10-02 22:36:17

Back again,

Thank you Commarmond for your source. I believe actually that your comparison may not quite apply in this instance.

The 25% penalty, for most bosters I've seen it quoted closer to 10%, is the penalty for launching from a planet's surface. And has to do with the free boost one gets near the equator due to the planets rotational speed.

The penalty I'm looking for is due to the tiny plane change one must make during interplanetary flight, to go into a polar orbit about Mars instead of an equitrorial one. For instance the deta V to reach Earth escape velocity from a polar LEO is about 100m/s greater than doing the same thing from an equitorial LEO, that's about 3% more. From a fuel consumption standpoint this is a very minor concern. Essentially you are changing the point you are aiming at from 100 million Km away by < a couple thosand Km. For these reasons the Delta V penalties are surely <3%.

The launch penalty you pointed out certainly will apply when it comes time to launch for Earth (or Mars orbit), from the surface, something which I had forgotten to consider, but ultimately it only means you need slightly larger fuel tanks and more time to produce more propellant.

I think historically it has been shown that to develop a new aerospace system it cost about $11000 US/Kg of equipment regardless of the type of system being developed. For this reason I believe size and complexity DO matter. A case in point Canada is developing an astonomical research satalite called MOST, it will cost about $4M US to deploy. US scientists proposed a satalite to do EXACTLY the same job, it was slated to cost $170M US! :0 Why the descrepency; culture, Canada can't afford what US researchers would consider a rather low sum for such a probe. $170M is adout the price for one of thier BETTER, CHEAPER, FASTER projects, Canadian researhers just invented systems at various universities that simply did the job avoiding the much more entrenced ways things must be done in the US, with out sacraficing mission quality, or reliability, I might add.

Applying the same logic to manned missions will take more daring and inventiveness but there is no fundimental reason why it can not be done.

This is really the point I am trying to explore with G.Landis' polar mission proposal. Find things that will make aspects of the mission fundamentally easier (like avoiding nuclear power, or bringing chemical feedstocks from Earth), and use them to simpify the types of equipment you have to develop in the first place.

Shaun Barrett · 2002-10-03 00:34:38

Hi Crossman!

That cost comparison between similar Canadian and U.S. missions is astounding! Are you for real? Can such enormous discrepancies be due simply to differences in 'culture' and cost expectations?!

Imagine such economies being applied to crewed Mars missions. The ultimate expression of the K.I.S.S. principle ('Keep It Simple, Stupid' ... for those who don't know )!!

At this rate, we might be able to get humans to Mars for more like $3 billion than $30 billion !!

RobS · 2002-10-03 13:50:48

There is some research being done about the problem of drilling into Mars. Some scientists hope they can drill 100 meters or so with an automated probe. This is good news, it seems to me, because if one lands near the poles or on polar terrain one can pretty much guarantee landing on ground with lots of ice in it. So it should eventually be possible to land an automated vehicle with a small reactor or big RTG that could drill into the regolith, vaporize the water, and make fuel. But the drills would want to go diagonally into the ground; otherwise they'll melt a cavity under the spacecraft!

-- RobS

Crossman · 2002-10-03 21:56:55

Hi folks,

Well Shaun that is EXACTLY the point I am trying to make.
You could go to the Canadian Space Agency's website to learn more about MOST. As for the cost comparison I heard that on CBC's science program Quirks and Quarks some time ago. Another example was written about in an article in the Space Studies Institute's newsletter Update. Here the founder of Vancouver's CanDive corporation compared how his company had designed financed and built a new manned submersable, the complexity of which, as well as the extreams of environment it had to operate in, made it comperable to a NASA proposal for a one man space vehicle. The cost difference; $4M for the operational submersable and $400M for the proposed one man space vehicle. That was back in the eighties. I call this the 1% rule: anything NASA does could probably be done for between one tenth and one one hundreth the cost in the 'real' world.

Austin Stanley · 2002-10-13 01:10:15

While I would certianly be cautious about landing on the Poles due to the difficulties of terrian there. From my experince here on Earth, Glaciers (or for that matter larger bodies of ice anywere on earth), would make terrible landing sights due to large crevasis, hidden caves, and generaly unstable terrian (not to mention it's inherint slipperyness). The yearly sublimination of CO2 ice from the poles doesn't make me any more comfortable either. However, Mars is a diffrent planet than Earth and so the glacial landforms may be very diffrent.

Also on such a mission you douldn't cout on just hanging around on the surface until another assent/return vehicle could be sent to you if yours malfunctioned. Winter and night would come and you would be up the proverbiale creek. It might be wise to send two such vehicles at the start.

I also tend to think that the potential for scientific investigation might not be as great on the poles as it would be elsewhere. The terrain might limit your travel options. However, such a mission would certianly have unique scientific oportunities as well.

It cannot be forgoten that it is well, colder on the poles, then it is elsewhere on the planet. Which may cause some additional hardships. As well as the fact that all that ice will make footing more dangerous for the explorers (even with crampons and the like).

What about weather on the poles? on Earth the weather on the poles is generaly much more sevear (in many ways) than elsewhere on the planet. Even with Mar's less-dense atmosphere this should be considered. Maybe wind-power would be more attractive on the poles?

Finaly a perminate facility while difficult is not necessarily impossible. While the weather and CO2 situation makes putting something on the surface next to impossible. The situation may not be the same beneath the surface! Like in Kim Stanley Robertsons Green Mars, book a habitat under the ice might be possible. Construction would be relativily simple, and insulation would be great. Shifting of the ice might be a problem though (don't know if that is a factor on the Martian poles).

Shaun Barrett · 2002-10-13 04:13:00

Hi Austin!
Your mention of the KSR-type ice habitat as a possibility for polar expeditions on Mars might be workable.
I read somewhere lately that layering in the polar ice indicated an age in the hundreds of thousands of years at the north pole (if memory serves), and maybe up to five million years at the south pole!
Don't quote me on the actual figures here, in case I'm off base a little.
Anyway, the point is that man-made ice caves would probably be stable over long periods. And, as you said, would be relatively easy to create and would provide their own very effective insulation.

I have reservations, though, about the necessity or desirability of landing at the poles, for the reasons you mentioned. Considering it now looks as though water will be easier to find at various places all over the planet than we once thought, do we really need the aggravation of high winds and searing cold?
Mind you, the suggestions made so far about the MGS camera having possibly snapped shots of 'things' growing on Mars' surface, are at least predominantly (if not exclusively) related to polar regions. But then, I have trouble with these suggestions for exactly the same reasons again: Why would vegetation on a freezing planet deliberately choose the coldest areas to live in?!!

Isidis Planitia's southern extremes recently featured on a list of places where it has been found to be theoretically possible for liquid water to persist at the surface. Nobody said there was actually any water there, but that liquid water is possible for certain portions of the Martian year because of the ambient pressures and temperatures.
That would be one place I'd be interested in exploring. Especially since it quite probably formed an inlet of the Oceanus Borealis in Mars' balmier youth, and former shorelines, and maybe even fossils, might be found.
Besides, it's almost at the equator and I could wear short pants and a T-shirt under my pressure suit!!

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#1 2002-09-30 15:56:56

Re: Polar Missions - Using Martian Poles

#2 2002-09-30 18:36:51

Re: Polar Missions - Using Martian Poles

#3 2002-09-30 19:58:33

Re: Polar Missions - Using Martian Poles

#4 2002-09-30 22:45:31

Re: Polar Missions - Using Martian Poles

#5 2002-10-01 09:33:05

Re: Polar Missions - Using Martian Poles

#6 2002-10-01 23:12:42

Re: Polar Missions - Using Martian Poles

#7 2002-10-02 07:52:35

Re: Polar Missions - Using Martian Poles

#8 2002-10-02 22:36:17

Re: Polar Missions - Using Martian Poles

#9 2002-10-03 00:34:38

Re: Polar Missions - Using Martian Poles

#10 2002-10-03 13:50:48

Re: Polar Missions - Using Martian Poles

#11 2002-10-03 21:56:55

Re: Polar Missions - Using Martian Poles

#12 2002-10-13 01:10:15

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#13 2002-10-13 04:13:00

Re: Polar Missions - Using Martian Poles

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