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Mars Colonization Discussion Thread

NSEP

By NSEP
in Science & Spaceflight

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What are your opinions about colonizing Mars?  

121 members have voted

  1. 1. Do you think Colonizing Mars is a good idea?

    • No, its not really usefull and will have negative consequences
      8
    • Yes/No its not that usefull but will have no negative or positive outcomes
      13
    • Yeah its a good idea! It will have positive outcome.
      58
    • Hell yeah lets colonize Mars it fun!
      34
    • Other
      8

  2. 2. Do you think we are going to colonize Mars one day

    • Yes, soon!
      46
    • Yes, but in the far future.
      51
    • No, but it could be possible
      12
    • No, never.
      5
    • Other
      7

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PB666

PB666

Posted
Posted

Im going to add some facts to this thread. I know many of you want to consider cost first.

Launches.
So my basic assumption is that using a variety of shuttle vehicles we can transports goods to an orbit of 150 km. The dV required is in the 10E4 dV range. At best currently 20% of launchpad mass can be placed in orbit. You could pack 100 humans in a sardine can with 30 minutes of oxygen and a CO2 scrubber and for the cost of Falcon-9 you could have them into space. Good luck finding a place to keep them alive. The weight of the human and its immediate needs are not the problem, therefore keeping them alive is.

Earth Elliptical space. From LEO-150km to SOI is 3300 dV, in this zone we can convert payload into fuel. So for instance if you have a ship that does not have enough dV. You can burn 3300 dV to get in a highly elliptical orbit, refuel that lost dV with a supply ship, and then tweek the supply ships orbit so that it reenters Earths atmosphere. Another option is that you have a ION drive and solar panels and slowly bring the ship back to an orbit where it can be used to resupply.

So lets consider the competition. For the Elliptical LEO-150-SOI limit how much dV is required.  These are best case transfers (to targets Pe if orbit is insides earth or Ap if orbit is outside earths) and all assume direct intercept, altitudes are assumed to be minimal and drag used whenever possible to break. The assumption is that shipping fuel to refuel a lander would be cheaper if one just attached fuel tanks to the transfer ship. All orbits assume that departure is at the semi-major axis for earth.

  Transfer Land (if possible) Total (m/s)
 Mercury  3438, 5851* (0.27 yr) 4254  16,543 dV
 Venus  493, 3422** (0.39 yr) ?**  3,915 dV.
 Mars  584, 1877*** (0.77 yr) 1104***  3,565 dV
 Ceres  2261, 4024 (1.4 yr) 392****  6,677 dV
 Jupiter  3156, 18465 (2.9 yr) *****  21,621 dV
 Saturn  4112, 11361 ( 6.6 yr) *****  11,361 dV
 Uranus  4753, 6777 (17.14 yr) *****  11,530 dV
 Neptune  4992, 7304 (31.3 yr) *****  12,296 dV
 Pluto  5237, 2226 (63 yr) 1197  8,660 dV
 Eris  5519, 1323 (179 yr) 1273  8115 dV
 Phobos  Not considered    
 Minos  Not considered    
MakeMake  Not considered    
 Haumea  Not considered.    

* Given that the priority is on transfer window very close to inclination node and the Mercuries short period and relatively low gravity, some additional dV would be needed to correctly intercept Mercury before the circularization burn close to Mercury.
** assumes that you are not using Eve's atmosphere for circularizing and that the ship does something other than land, although what is the question.
*** assumes that Mars atmosphere is not used for circularization, but that landing includes sometime of breaking (I used a tri-wing structure) and was able in KSP RSS (5 crew full science package) to have enough fuel to get back into orbit. The ship would then have enough dV to transfer back to Earth if it was refueled and provided with a supplemental tank. The lander used RL10-B and assumes an infinite life for engine (cheat).
**** Ceres landers could also be ION driven and ION drive could provide a means back to Earth provided a proper power supply can be devised. A major consideration with ceres would be the length of the transfer.
***** Other targets would require reformulating 2nd transfer dV number.

There are several judgements that one can make based on these numbers.
1. Mars is the best choice for 2 reasons . . . . . .a place to land, lowest dV, which includes the potential to return to orbit (4000 dV versus 8000 from Venusian cloud tops).
2. Eve and Ceres are the next two logical choices. Ceres becomes highly potent if a high power density nuclear reactor (such as a fusion reactor) is provided as a source of ION driven power).
3. While Mercury's transfer time is lower, the total dV is all but unobtainable for a chemical based engine, ION drives could be used to knock down the end transfer burn but this would require more orbits.
4. Transfer times to pluto place these out of range unless stasis is available. Ceres is still a better choice than pluto given the low landing requirement. 
5. Ceres gravity, at 0.029 g is the lowest on the list, the assumption is that the technology for microgravity survival exist for any medium duration interplanetary mission.

The above list is prefaced by the fact that getting the 13,000 dV required to place materials in near escape orbits about earth and to routinely dock with and resupply vessels in that orbit prior transfer. The alternative is that the refueling occurs at N1 or N2. However there are certain advantages of taking the final burn at Pe of 150km in getting to difficult targets (like Mercury or Ceres). Thus the total dV values given are the 'must be carried' dV required.

 

 

 

 

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Diche Bach

Diche Bach

Posted
Posted (edited)

To be completely honest . . . I am deeply offended at even the mere suggestion of "sending humans on a journey to Mars" much less "colonizing Mars" when "we" the human species have yet to:

1. Build a functioning space habitation in orbit. By which I mean, one which affords its residents at least some semblance of artificial gravity as they go about their daily lives.

2. Build a somewhat self-sufficient outpost in orbit. By which I mean, a space station with sufficient solar power and arcological integrity that it can function (meaning sustain human life and its day-to-day functioning) for up to 2 years without any need for resupply from Earth.

3. Build an orbital ship construction facility and fuel depot

4. Fetch an appropriate asteroid that can provide a strategic range of raw materials for future projects at the orbital shipyard

5. Build a space craft at the orbital shipyard that derives at least 50% of its materials, fuel and propellant from off-Earth sources.

At that point, discussion of

7. Sending people back to the Moon, and to Mars will be prudent. Once at least 5 manned missions to Mars have been deemed an overall success, then discussion of

8. "Preliminary Steps Toward Long-term Habitats on Mars" will become prudent.

9. "Colonizing" Mars? Why? Why on Earth would we imagine it to be meritorious to project a future in which children are born in a hell hole like a rough underground concrete bunker on Mars? Oh yes, the "multi-planet species" thing, i.e., save us from extinction of Earth goes birds up . . . Okay fine. Long-term not a bad ethos and even reasonable and salutary, though there are lots of ethical questions about people giving birth to the first children off Earth which even the most broad-thinking authors of science fiction have yet to really address, much less entrepreneur web-site salesmen like Elon . . .

However, putting the Colonization cart (see Step "9" above) before the horse comprising steps 1 through 5 (*See Note below . . .) is such utter fatuity it defies comprehension how otherwise intelligent adults can fall for the sales pitch.

If all you manage to do is "get people to Mars" and maybe "get them home" then you STILL have to do steps 1 through 5 in order to have any prospect of a sustainable long-term "colonization" production and supply chain.

(*) Note: It is possible human beings could survive a 2 to 3 year journey in micro-gravity. But at this point we really don't know. More importantly, we really don't know what the long-term effects would be on their health. Given that the mechanics of generating centrifugal forces that can simulate gravity are not tremendously challenging, I consider manned-spacecraft which skip the "generate gravity" stage of things to be inherently unethical and believe that, in a very short number of years, such spacecraft will be made illegal for use as long-distance vehicles because of their health impact. Likewise, the mass of carrying along 2 to 3 years of provisions is probably not so much as to dramatically impact the engineering of the Mars craft; in sum, you don't HAVE TO HAVE a self-contained, self-sufficient arcology onboard the first Mars craft, i.e., one that recycles the atmospheric, nutritive and liquid wastes and resources and requires only infrequent "top ups" with expendables from Earth. But when the first Mars mission suffers a catastrophe and there are three or four survivors in the wreckage on Mars, who now face 2 to 3 years before they can be rescued and have only some 6 months of provisions left, and virtually no facilitate to setup a long-term habitation with replenish-able food, air and water, then the Elons of the world will be shown for what they are: con men else delusional.

Edited by Diche Bach
typo
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DAL59

DAL59

Posted
Posted (edited)
14 minutes ago, Diche Bach said:

2 to 3 year journey in micro-gravity.

4 months.  And it isn't hard to tether two ships together and spin them.

14 minutes ago, Diche Bach said:

then the Elons of the world will be shown for what they are: con men else delusional.

Not really.  He has made space costs 10 times cheaper, and is also trying to do the same with solar panels.  

14 minutes ago, Diche Bach said:

Build an orbital ship construction facility and fuel depot

An ITS doesn't need a construction facility.  It refuels in orbit, which is kind of a depot.

14 minutes ago, Diche Bach said:

Build a somewhat self-sufficient outpost in orbit.

Very different from a Mars colony.  On Mars, you have soil and mining materials and plenty of water to work with(100% humidity and underground glaciers).

14 minutes ago, Diche Bach said:

Build a space craft at the orbital shipyard that derives at least 50% of its materials, fuel and propellant from off-Earth sources

What exactly does this have to do for Mars?  The sabatier reaction is old and well  understood.  

Edited by DAL59
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tater

tater

Posted
Posted

4-6 months Transfers are typical. Some as few as 3 months.

1 minute ago, DAL59 said:

You do not need a self sufficient closed loop habitat for a Mars colony, since there is a planets worth of materials to use, plus plenty of ice.  

True on entirely closed loop, but you instead need self-sufficiency in repair parts, as you are 2+ years from possible resupply.

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Diche Bach

Diche Bach

Posted
Posted
3 minutes ago, tater said:

https://trajbrowser.arc.nasa.gov

 

Very cool tool. . . https://trajbrowser.arc.nasa.gov/traj_browser.php?NEAs=on&NECs=on&chk_maxMag=on&maxMag=25&chk_maxOCC=on&maxOCC=4&chk_target_list=on&target_list=Mars&mission_class=roundtrip&mission_type=rendezvous&LD1=2017&LD2=2040&maxDT=120&DTunit=days&maxDV=20&min=DV&wdw_width=365&submit=Search

20 km/s 2017 to 2040, 120 days (re the "4 months" Dal referred to) : 

Query took 1.49s, returned 0 trajectories. Try relaxing constraints on ΔV or duration and opening the launch window.

3 minutes ago, DAL59 said:

You do not need a self sufficient closed loop habitat for a Mars colony, since there is a planets worth of materials to use, plus plenty of ice.  

That site is so useful.  

Right, so why haven't people colonized Antarctica? There are even MORE resources there, plus penguins, air, and inherent radiation shielding (in the sky)?

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DAL59

DAL59

Posted
Posted
1 minute ago, Diche Bach said:

Very cool tool. . . https://trajbrowser.arc.nasa.gov/traj_browser.php?NEAs=on&NECs=on&chk_maxMag=on&maxMag=25&chk_maxOCC=on&maxOCC=4&chk_target_list=on&target_list=Mars&mission_class=roundtrip&mission_type=rendezvous&LD1=2017&LD2=2040&maxDT=120&DTunit=days&maxDV=20&min=DV&wdw_width=365&submit=Search

20 km/s 2017 to 2040, 120 days (re the "4 months" Dal referred to) : 

Query took 1.49s, returned 0 trajectories. Try relaxing constraints on ΔV or duration and opening the launch window.

You are not using it correctly.  You are calculating for a round trip rendezvous, that does not include landing.  Not only will the ITS use aerobraking, but  

it will refuel at Mars.  

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DAL59

DAL59

Posted
Posted

Yes, since it refuels and aerobrakes.  Set it to one way flyby.  

It also stays on Mars for 500 days.  

Add another km/s to the delta vee though, for supersonic retropropulsion.  

6 minutes ago, Diche Bach said:

so why haven't people colonized Antarctica?

Same reason for the moon- weeks of darkness on end, so no growing plants.  Mars has soil.  

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Diche Bach

Diche Bach

Posted
Posted
4 minutes ago, DAL59 said:

Yes, since it refuels and aerobrakes.  Set it to one way flyby.  

It also stays on Mars for 500 days.  

Add another km/s to the delta vee though, for supersonic retropropulsion.  

Same reason for the moon- weeks of darkness on end, so no growing plants.  Mars has soil.  

I would say there is another reason people have not colonized Antarctica:

The Return on Investment does not exceed the risk to reward ratio (by which I mean all the "risks" including the sheer discomfort and long-term life history impacts, even if you don't die).

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Diche Bach

Diche Bach

Posted
Posted
1 minute ago, DAL59 said:

Orbital refueling

https://en.wikipedia.org/wiki/Arnold_J._Toynbee#Challenge_and_response

Look, I'm not saying that colonizing Mars is impossible. It is clearly POSSIBLE.

I'm saying: there is a smart way to promote that eventuality and a stupid way. Taking shortcuts is the stupid way.

I don't see the value added by taking short cuts to get people to Mars which increase risk and do not provide long-term sustainable solutions.

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tater

tater

Posted
Posted

BFR/BFS is 6-9+ km/s depending on cargo mass to Mars.

Any use of the trajectory browser should likely not use flyby velocities above ~7.5 km/s (which is what Musk said a Mars entry could look like). You can sort by that, and ignore them.

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DAL59

DAL59

Posted
Posted
Just now, Diche Bach said:

taking short cuts to get people to Mars which increase risk and do not provide long-term sustainable solutions.

The ITS is sustainable.  Plenty of money from satellites and point to point transport.  

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