Why the large differential in trips to Mars?

I read somewhere that a manned trip to Mars would take years. The
"Curiosity" probe, however, took only 8 months.

TIA,

-Ramon

On Mon, 13 Aug 2012 09:07:30 -0700 (PDT), "Ramon F. Herrera"
wrote:


I read somewhere that a manned trip to Mars would take years. The
"Curiosity" probe, however, took only 8 months.

The manned flight duration is for the round trip. Curiosity won't be
coming home!

The outbound flight will be about the same (using conventional
propulsion) whether it is manned or unmanned (eight to ten months,
depending on variations in the Earth/Mars distance with each close
approach... 2003 was particularly close.)

The return flight will take about twice as long, if they leave within
a month or so of landing on Mars. Beyond 30 days or so on Mars, Earth
is no longer in position to return quickly, and the crew has to wait
another two years before returning. Flying a course that swings by
Venus first will cut some of the return time, but we're still talking
about years total flight time.

Brian

On Aug 13, 12:55*pm, Brian Thorn wrote:

The outbound flight will be about the same (using
conventional propulsion) whether it is manned or unmanned

How far are we from any kind of non-conventional propulsion?? Have
there been any progress at all? Is it only in the whiteboard stage?

-Ramon

Hmm, maybe my post about the problems of manned missions to mars has not
got to this server for some reason...
Brian

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From the Sofa of Brian Gaff Reply address is active
"Ramon F. Herrera" wrote in message
...

I read somewhere that a manned trip to Mars would take years. The
"Curiosity" probe, however, took only 8 months.

TIA,

-Ramon

One issue is of course that to get anywhere fast means more speed, but when
you arrive at the place you wanna be, you need to slow down. Where you gonna
get all the fuels to do all that?
Brian

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From the Sofa of Brian Gaff Reply address is active
"Ramon F. Herrera" wrote in message
...
On Aug 13, 12:55 pm, Brian Thorn wrote:

The outbound flight will be about the same (using
conventional propulsion) whether it is manned or unmanned

How far are we from any kind of non-conventional propulsion?? Have
there been any progress at all? Is it only in the whiteboard stage?

-Ramon

On Mon, 13 Aug 2012 20:54:09 -0700 (PDT), "Ramon F. Herrera"
wrote:


The outbound flight will be about the same (using
conventional propulsion) whether it is manned or unmanned

How far are we from any kind of non-conventional propulsion?? Have
there been any progress at all? Is it only in the whiteboard stage?

Well, VASIMIR is still moving forward. But it would probably need a
nuclear reactor to power it for the kinds of mission we're talking
about, and a nuclear reactor launched atop a contemporary rocket is
almost certainly a political impossibilty in America, Japan, and
Europe.

Brian

Brian Thorn writes:

Well, VASIMIR is still moving forward. But it would probably need a
nuclear reactor to power it for the kinds of mission we're talking
about, and a nuclear reactor launched atop a contemporary rocket is
almost certainly a political impossibilty in America, Japan, and
Europe.

I think this would depend very much on the details. If the reactor is
inert at launch and the fuel is somehow sealed to withstand even a
launch failure...


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery

On Wed, 15 Aug 2012 16:19:36 +0200, Jochem Huhmann
wrote:

Well, VASIMIR is still moving forward. But it would probably need a
nuclear reactor to power it for the kinds of mission we're talking
about, and a nuclear reactor launched atop a contemporary rocket is
almost certainly a political impossibilty in America, Japan, and
Europe.

I think this would depend very much on the details. If the reactor is
inert at launch and the fuel is somehow sealed to withstand even a
launch failure..

That would probably be acceptable to me, too, but the problem is that
the general population shuts down its brain when the word "nuclear" is
mentioned.The protestors will scream bloody murder if anyone tries it,
guaranteed, and no politician will consider it worth the
confrontation. So I still think it is a political impossibily. Another
choice would be to let Russia or China (who don't seem to care much
about who is downrange of their rockets if they fail) launch the
reactor and attach it to the spacecraft in orbit. But after the
high-profile Proton failures of the last nine months, that would meet
protests too.

Brian

Brian Thorn writes:

That would probably be acceptable to me, too, but the problem is that
the general population shuts down its brain when the word "nuclear" is
mentioned.The protestors will scream bloody murder if anyone tries it,
guaranteed, and no politician will consider it worth the
confrontation. So I still think it is a political impossibily. Another
choice would be to let Russia or China (who don't seem to care much
about who is downrange of their rockets if they fail) launch the
reactor and attach it to the spacecraft in orbit. But after the
high-profile Proton failures of the last nine months, that would meet
protests too.

Still, Curiosity launched with 10.6 pounds of plutonium on board and
there wasn't much screaming at all.


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery

On 15/08/2012 20:18, Jochem Huhmann wrote:
Brian writes:

That would probably be acceptable to me, too, but the problem is that
the general population shuts down its brain when the word "nuclear" is
mentioned.The protestors will scream bloody murder if anyone tries it,
guaranteed, and no politician will consider it worth the
confrontation. So I still think it is a political impossibily. Another
choice would be to let Russia or China (who don't seem to care much
about who is downrange of their rockets if they fail) launch the
reactor and attach it to the spacecraft in orbit. But after the
high-profile Proton failures of the last nine months, that would meet
protests too.

Still, Curiosity launched with 10.6 pounds of plutonium on board and
there wasn't much screaming at all.


Jochem


Some plans I've seen for an initial human Mars settlement list a
heavy nuclear reactor as a mandatory requirement. Solar won't cut
it on Mars to supply power for us.

So, that's two problems. Launching a reactor that big and then landing
it safely on Mars. Something much more capable than a sky crane will
be needed for that task I would guess.

--
T