
Elon Musk's space ship Dragon 'can land on Mars' - sasvari
http://www.theregister.co.uk/2011/04/21/musk_mars_dragon_claim/print.html
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sbierwagen
Note that a crew escape system, what the article treats as an absolute minimum
for a manned vehicle, doesn't exist on the space shuttle for budgetary
reasons. The space shuttle has many, many abort modes[1], but absolutely
nothing can be done while the solid boosters are firing, since you can't shut
them off or detach them from the stack.

Maciej Cegłowski (pinboard.in) complains at length about this in an essay[2]
about the space shuttle.

[1]: <http://en.wikipedia.org/wiki/Space_Shuttle_abort_modes>

[2]: <http://www.idlewords.com/2005/08/a_rocket_to_nowhere.htm>

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bfe
This is excellent.

Many human Mars mission architectures use an Earth return vehicle that is
separate from the outbound vessel. The requirements are very different, and
there's an overwhelming advantage to placing an Earth return vehicle on the
surface ahead of time to produce the methane fuel for its return flight in
situ ahead of time, so a vessel that can get astronauts out to Mars without
being able to return them is still an important contribution.

On a poignant side note, the article notes that the only feature Dragon now
lacks to become qualified for carrying humans is a launch abort system; the
original Space Shuttle was designed without a launch abort system.

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hugh3
It's nice that it has this capability, but it's still not an ideal Mars
lander, and I think the economics work out that it's cheaper to design a new
ship than to send a non-ideal ship all the way to Mars.

For instance, the Dragon's heat shield is (I assume) far heavier than it needs
to be for a Mars entry. A purpose-built Mars lander could be made
significantly lighter than a purpose-built Earth lander, and sending
unneccessary weight to Mars winds up expensive.

Besides, there's going to be a lot of custom hardware needed for a manned Mars
mission anyway. At a minimum you'll need a large "Command Module" for the
astronauts to travel in (sitting in a Dragon ain't gonna cut it for a one-year
voyage) and a custom-built Mars takeoff craft.

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jerf
I went and carefully read the statement. It says the capsule can carry crew,
and that the capsule can land on Mars. It did not say that the capsule can
_carry crew to Mars_ , which is a wildly different thing. I think the Register
added that accidentally.

I don't think that's possible, because solving the equations to carry enough
supplies to get the crew to Mars alive while still being able to stop when you
get there almost certainly has no solution with any capsule primarily designed
to get to Earth orbit. On the other hand, merely getting hardware to Mars if
you don't care how long it takes can be relatively low energy [1], which would
also be an orbit not requiring a lot of propellant to enter Mars orbit.

[1]: <http://en.wikipedia.org/wiki/Hohmann_transfer_orbit>

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Radix
The discussion of not yet having a return vehicle for a trip to Mars reminds
me of a Reddit AMA with a Russian engineer through his grandson. There he
claims his Grandfather worked on a plan to send an astronaut to Mars orbit
then return, but there was a second and favored plan with which the astronaut
would land on the surface, walk around, then die.

[http://www.reddit.com/r/IAmA/comments/etu2s/i_was_born_in_sh...](http://www.reddit.com/r/IAmA/comments/etu2s/i_was_born_in_shchigry_ru_in_1932_i_worked_as_a/c1ax3x1)

I wonder how it would be received if the goal was to create a permanent
settlement on Mars rather than returning.

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roc
The other benefit to a settlement plan, is that you could send the habitat and
tools ahead of time, to be assembled by robots. Which implies multiple
missions, which lowers per-mission weight requirements, and allows for habitat
tests prior to having human life (and larger, more temperamental resources) on
the line and for fixes to be bundled in subsequent missions.

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Vivtek
SpaceX stories always read like they were written by Ben Bova.

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bhewes
Why do people assume that the people we send to Mars need to come back? Could
we not send large supply stores first and then send people on a one way trip?
I would guess people would sign up even knowing that the trip to Mars is one
way.

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mey
As always, landing is the easy part. Escaping the gravity well is not. (Looks
like they plan to make it a one way trip, setup a colony, then mfg fuel before
the return trip.)

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patrickgzill
I suggest you read "The Moon is a Harsh Mistress" and think about why any
Earth-bound government would hate the idea of allowing space based travel or
settlement by any agency not under their direct control.

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api
I'm sure it will be done by governments and/or big business, and will be under
their control...

at first...

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benl
Does anyone know any details of the thrust and delta-v capabilities of the
proposed combined launch abort / retro landing system?

Is it going to be just a bunch more Draco thrusters, or something else?

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ars
Landing is the relatively easy part. Surviving the journey is harder. The
necessary shielding is too heavy to launch, so we need some new ideas there.

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wtn
I hate how the British use single quotes. It's sometimes ambiguous and
relatively hard to parse.

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hugh3
The convention is that double quotes are for actual quotes, while single
quotes are for paraphrasing things that others have said.

