Writing about Mars-trips and how we can get there.

[pilot00]

Can you come up with other types of travel-options other than:

Getting in to orbit around earth and then use that momentum to get into orbit around an asteroid and use THAT momentum to swing the ship in the correct way towards Mars? Similar to a person swinging himself between bars.

Yeah and english is not my nativ language so sorry for that.

[VincentMcConnell]

I\'m pretty sure I\'ve never even read about a proposal like that until now...

Easy. Parking orbit around Earth, inject into Martian SOI with a TMI burn at the most efficient time.

[UmbralRaptor]

Maybe he\'s thinking of the mission plans that involve a Venus flyby? But yeah, Hohmann ellipses tend to be the most straightforward.

For another option, 'spiraling' out with VASIMIR or a more traditional ion engine? Unfortunately, information about long duration low thrust trajectories is somewhat hard to find (and apparently requires math skills well beyond what I currently have).

[Candre]

I smell a challenge... Do a Munar flyby into Minmus\' SOI? Haven\'t heard of it before...

[Lunniy Korabl]

For another option, 'spiraling' out with VASIMIR or a more traditional ion engine? Unfortunately, information about long duration low thrust trajectories is somewhat hard to find (and apparently requires math skills well beyond what I currently have).

It didn\'t stop at Mars, but there is this awesome chart of the thrust/coast spiral from the Dawn mission to Vesta and Ceres, which uses ion thrusters.

[Steve5451]

I smell a challenge... Do a Munar flyby into Minmus\' SOI? Haven\'t heard of it before...

I accidentally did that once. While trying to get to Minmus I accidentally got caught into the Mun\'s SOI and flung myself into Minmus.

Another time on a different flight, I was returning to Kearth from Minmus and got caught into the Mun\'s SOI and flung myself into Kearth.

[VincentMcConnell]

I accidentally did that once. While trying to get to Minmus I accidentally got caught into the Mun\'s SOI and flung myself into Minmus.

Another time on a different flight, I was returning to Kearth from Minmus and got caught into the Mun\'s SOI and flung myself into Kearth.

It\'s not Kearth, it\'s Kerbin... Why do people keep saying Kearth???

[Johno]

It\'s amazing how much more efficient complicated orbital transfers can be. It may be a longer trip (which has risks of its own), but gravity assists from multiple planets or bodies might well allow us to do the mission with much less propellant, which makes it easier to carry the prodigious amount of food, water and life-support that will be needed.

[Exoscientist]

Robert Zubrin has proposed lower cost missions using the new Falcon Heavy rocket:

MAY 16, 2011

Robert Zubrin\'s Proposes using three Space Falcon Heavy Launches to send two people to Mars by 2016.

http://nextbigfuture.com/2011/05/robert-zubrins-proposes-using-three.html

MAY 17, 2011

Zubrin provides more explanation of his Space Falcon Heavy Mars Plan.

http://nextbigfuture.com/2011/05/zubrin-provides-more-explanation-of-his.html

Bob Clark

[sneakeypete]

It\'s amazing how much more efficient complicated orbital transfers can be. It may be a longer trip (which has risks of its own), but gravity assists from multiple planets or bodies might well allow us to do the mission with much less propellant, which makes it easier to carry the prodigious amount of food, water and life-support that will be needed.

I don\'t think the extra momentum you could get from planetary flyby\'s would offset the extra food you\'d need to take. Not to mention other non tangible problems with a longer voyage, eg exposure to radiation, higher risk if crew sickness from natural causes etc.

[Johno]

Yes, up until now I\'d heard of using gravity assists to get robots to various destinations with a tiny booster. Generally speaking all plans that I am aware of for manned missions go direct.

[McLuv]

Read 'The Case for Mars: The Plan to Settle the Red Planet and Why We Must' By Bob Zubrin (Exoscientist also mentionned him, he\'s one of the biggest current proponents for a Mars Mission).

The real problem with a [manned] trip to Mars isn\'t getting there: it\'s getting back. Unlike the moon, the red planet has both an atmosphere and a sizeable force of gravity, so getting back out of it\'s gravity well and to the earth would require a return stage much larger than what the Apollo missions required.

The most common trip itinerary produced involves assembly of a large spacecraft in low earth orbit, which would fly both the astronauts their return ship and fuel to Mars. All of this is based on future technologies, too. Additionally, because of how staging works (requiring ever larger lower stages to accelerate the added mass of fuel from higher stages), the cost and magnitude of the project go up exponentially if this method were followed. Additionally, it wouldn\'t be a sustainable method of transportation, which would probably result in a planetary 'hit it and quit it'.

Zurbrin\'s suggestion, which I am completely in support of, involves using technology which is already available and low-weight, low cost methods of getting there and pack. An initial unmanned landing vehicle would arrive without any return fuel about a year before the manned launch, and during that waiting time it would synthesize new fuel through chemical processes powered by some small nuclear reactor it brings with it. Then, with the return capsule fully fuelled and ready, the astronauts blast off and reach the red planet, landing close to the return vehicle. They can then spend the time between then and their next launch window to conduct ground experiments, exploration and other scientific pursuits. When their launch window comes back, they ride their fully fuelled and stocked return vehicle back to the earth.

If you\'re simply looking at the orbital maneuvres however, I\'m afraid that a direct Hoffman transfer is really the only feasible solution that optimizes trip time for the crew and fuel required. Spiralling out using an ion engine of sorts is a possibility, but it also increases trip time and it\'s unproven technology, at least as far as manned missions are concerned. Ultimately that means that if we want to reach Mars in the near future it\'ll probably be on well proven chemical engines.

EDIT: Exoscientist, I took a look at both articles you posted, it seems I haven\'t seen his up to date plans...