New Mars Forums

Hi people,

  I find this discussion interesting, however since NASA is not developing anything in this area perhaps we should consider changes in the shuttle-C/Ares baseline.
  1. Switch to methane as the primary fuel (7X as dense as hydrogen), meaning smaller lighter, easier to manufacture  tankage.
  2. Use hybride solid/liquid rockets in place of SRB's.(safer to use and to fuel, can be sut-down and throttled, simpler than liquid fueled engine like those of the Zenit)
  Yes I know the prevalent philosophy is to use so called off the shelf, equipment, but is it really all that much cheaper this stuff IS AFTER ALL MADE FOR NASA hardly cheap.  Private companies have developed engines etc.

Just some thoughts,
                           Crossman

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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.

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

Hi Everybody,
I would like to elaborate on a thought I had earlier about creating a constituency for those of us who, want to see a continuos and expanding human presence on Mars.
We all would agree that the status quo is NOT working for us.  It has become clear to me that as long as the pro Mars community does not command the monetary or political  clout to move the rest of our societies we are not going to see sustainable progress.
Years ago I read two books that gave me some ideas, Ben Bova's Welcome to Moonbase, and Marshall Savage's, The Millennial Progect.  The plans potrayed by either book are not in my opinion practical, but there are useful elements to both.
Savage envisions constructing a floating city of 100000 in the Indian ocean, and using the industries created there to finance expansion into space.  Unfortunatly, the concept gets bogged bown in his visions of a new society : alot of New Age foolishness.  Savage himself is reported in Wired magazine to have quit his own organization over squabbles about just how this new society would function.  However the idea of free floating sea habbitats is hardly new Savages contributions in this area include:
-Ocean Thermal Energuy Converters (OTECs)
  providing electricity
  producing hydrogen fuel and fresh water
  bringing nitrates to the surface for use in algae and seafood   production.
-Accretion of structures using the calcium carbonate and magnesium.
The practicalities of these systems have been tested to various degrees at various institutions over the last thirty years but never combined as  Savage suggested.
Creating a habitat for 100000 people was said to require 7 100MW OTECs six years to accrete the nescesary material.  With an initial cost of $1.1B US to puchace the first OTEC, a ship and support equipment.
Details aside, I would like to suggest a corporation be formed to build something similar to Aquarius (Savages name for his city).
The corporation could build a smaller version of say 50000 people.  Savage calculated that Aquarius would prduce enough products to bring in $8B, and due to the efficiancy of such habitats, have $4B-$5B in funds available for future projects each year. $2B would be enough for a robust industry lead humans to Mars program.
If 50000 people could be encoraged to invest $10,000, or some equivalent we would have half a billion dollars in seed capital.
Have to  go, will elaborate later.