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Subject: 4 year mars mission: a thought expiriment rss

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Rakaydos Vashini
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Mars is the most time consuming destination in the normal game, and has the greatest penalty from a nasy solar radiation card. The "normal" responce is to use an Adran capsule and hope for the best... but I've become rather taken by the rule on page 26: you can remove an hourglass from a maneuver by doubling it's difficulty. Moreover, the earth orbit to Inner Planet Trnsfer isnt actually a radiation maneuver.

So by combining these two, it is possible to send crew to mars, facing only a single hourglass of radiation each way. Even at Radiation level 2, it seems a reasonable gamble- the radiation on the way back hardly even counts as there are plenty of doctors back on earth.

The maneuver chain, then, is:
Earth
(3)Suborbital
()Orbit
(3)Inner planet transfer
(8)Mars orbit
(0)(landing)
(3)(Launch)
(8)Inner planet transfer
(3)Earth orbit
(0)earth reentry

Those two 8s are painful, masswise, but there are games we can play to manage them.
The largest mass for the first 8 that we can ignore is actually the return booster. Rockets dont care about radiation, so we can push out the return booster ahead of time. All you need to push for the mars orbit burn is the crew capsule and a single supply. (though it needed a second supply when it left earth orbit) Prepositioning a vostok with the return rocket means the crew only needs an eagle, so 2 mass over difficulty 8 means 2 soyeuz or a single Saturn(if you use the saturn, you may as well use the vostok)

The return burn is trickier, as Inner planets transfer has an automatic maneuver to "Lost". However, it does NOT have a restriction of docking/separating. If a resupply craft leaves earth orbit the same time the crew leaves mars orbit, they will reach inner planet transfer the same year, and can dock, allowing the resupply to bring the astronaut home. this means the return booster can be the same 2 soyeuz or a saturn.

So we've broken the mission down into 3 launches.
-The mars presupply, which includes the return Saturn, an atlas for surface return, and at least 2 supply (assuming there's a mars base mission at stake), making for a 20+4+2 (with possibly a juno for phobos sample return thrown in as well)mass, which is sent to mars by Saturn+soyeuz (20+9 mass) for a total of 55-56 mass in orbit.
-The mission, which includes a Vostok (with astronaut) and 2 supply, a Saturn for the mars insertion burn, and again posibly a juno for phobos sample return (20+2+2+1) needing a pair of soyeuz to reach inner transfer, for a total of 43-44 mass in orbit.
-And finally the rescue mission, which needs to pick up 3-4 mass in inner transfer and bring it back to earth orbit, requiring an atlas, and bring a supply to feed the astronaut for the trip, for a total of 5 mass. another atlas can throw the pair of them out there, for a total of 9 mass in earth orbit.

The entire mission requires 107 mass in earth orbit (10 Saturns and 2 soyeuz)and 5-6 turns from first launch to astronaut return. There is a 1/5 chance the mission fails due to radiation on Rad level 2.

Total mission cost is 12 saturns, 5 soyeuz, 3 Atlas, 1 vostok, 5 supplies. (15x12, 8x5, 5x3, 2x1, 1v5= 180+40+15+2+5) 242 million- 10 turns money

Additional cost to include a phobos sample return is 2 additional mass of orbital lift (can be dregs from other missions), 2 Junos (in orbit)

Required technoligy is Rendevous, Atlas, Soyeuz, Saturn, Reentry, Landing, Life support-70, or 3 turns money.

2 test launches of each rocket and buying off a single failure from each tech costs 30+16+10+2+20+15=93. By sending a pilot, we can leave Landing untested and introduce a single additional 1/6 chance of failure. Lifesupport and rendevous have no testing overhead- they are incidental to a delay in reentry testing. Reentry testing requires 1 saturn launch and 2 vostoks- saturn launch can be combined with saturn testing, though a major failure requires an additional 2 vostok purchace.

Total estimated cost including R&D:97+70+242= 409 million.
Turns to generate: 17
To complete mission before turn 20, Recovery ship must be launched by turn 18, Mission ship must be launched by turn 15, Presupply must be launched by turn 14.

Mission may be viable in multiplayer, or if corners are cut in testing/minor failures are recoverable. Phobos sample return additinal mission unlikely to be viable in single player.
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Very interesting, but why not just put 5 doctors on the Aldrin and use ion thrusters everywhere except liftoff? That should significantly cut down the cost of the mission and still probably leave a 90% chance of survival against radiation.
 
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Rakaydos Vashini
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Simply because that's not the expiriment I'm performing.

A better optimization of this approach is a 5 year mission, not caring how sick the astronaut gets on the way home, but exposing him to only a single year of radiation on the way out.
Prepositioning enough lift to get 7 mass (2 for capsule, 3 for supply, plus phobos and mars samples) back to earth orbit takes a soyeuz, IIRC, which reduces my earth lift significantly and removes the resupply mission entirely. the mission launch itself should be the same. will recalculate later.
 
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Ahh, I see. You can still do it much cheaper by using ion thrusters:

Mars pre-supply mission needs 1 Saturn, 1 Atlas, and 2 supply (26 mass) in Mars Orbit. So, following Earth Orbit - Mars Orbit maneuver in t years, you would need N = 26/(t - 1) ions, rounded up. For example, 4 ion thrusters get you there in 6 years. 7 thrusters get you there in 3 years (the minimum). You can then get those thrusters back to Earth orbit for reuse in 2 years. (Doubling the MO -> EO maneuver.) Let's assume we go with 7 thrusters to save 3 years of time. (Total 6 years.)

The manned mission is the following:
Launch Saturn, vostok, astronaut, 4 supplies (mass 26), and the 7 ion thrusters that came back from the pre-supply mission.
Fire ion thrusters to maneuver to IPT in 3 years.
Now undock ions and follow your prescription to Mars and back doubling the MO-IPT maneuver (2 time total, 3 if base on Mars). While that's happening, the ions go back to EO to pick up supplies for the rescue mission (1 time to go back).

The rescue mission is done entirely with ions:
7 ions pick up 1 supply in Earth Orbit and go back to IPT (1 time).
Rendezvous with Vostok and astronaut.
Go back to Earth Orbit (1 time).

Total mass that needs to be launched to EO for all missions:
60

Total cost, including R&D and launches to EO: $239M
Total time mission takes starting from pre-supply mission launch: 12/13 (6 for pre-supply, 6/7 for actual mission, depending on whether astronaut is left for a year on Mars).

Alternatively, if you buy and launch 7 new ions rather than reusing pre-supply ones, you can save 6 years by running pre-supply and manned missions in parallel:
Total cost: $339
Total time: 6/7 years

I am sure this is not the optimal solution, you can probably reduce the cost and/or time more by tweaking what ions you use where and when. The point is that for complicated missions, using ions results in major savings.

By the way, I do not believe that you can afford for the astronaut to become incapacitated on the return radiation hazard, because incapacitated astronauts die at the end of the year. So, chances of astronaut survival on this mission for the case of rad level = 2 are 9/16 = 56%.

With the Aldrin capsule and 5 doctors, you can have a purely ion-based mission (except for non-timed maneuvers) that is much cheaper than either option above, has a >90% chance of survival, and takes about the same mission time. Of course, you can increase the chances of survival on the above missions by bringing more astronauts (e.g. using the Apollo capsule instead of Vostok), but I am pretty sure that it is always more cost-effective to use ions, Aldrin, and not double maneuvers, than to use rockets, not use Aldrin, and double maneuvers. The doubling of maneuvers can of course become important if you are racing somebody and you have all the components already, or need to rescue somebody at any cost.

Fun thought experiment!
 
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