When all the planets are explored in the solar system

In message , Sea Wasp
writes
Kleopatra44 wrote:

You can come home if thing's turn out bad on the moon. You can't do
that from Mars :-(

Um, why do you think that you could do the one and not the
other? Any expedition sent to either place would be designed for return
capability. If "something went wrong", which place would be better
depends on what the "something" is.

Don't think of the Moon as somehow being a hop,skip, and a jump.
It's still a hell of a long way away through a hell of a lot of vacuum.

It _is_ a hop compared to Mars.
If you had the means, you could at least rescue the crew if something
went wrong on the Moon that didn't totally destroy the ship.. "Mission
to Mars" notwithstanding, anyone on Mars is on their own.

Jonathan Silverlight wrote:
In message , Sea Wasp
writes

Kleopatra44 wrote:

You can come home if thing's turn out bad on the moon. You can't do
that from Mars :-(


Um, why do you think that you could do the one and not the
other? Any expedition sent to either place would be designed for
return capability. If "something went wrong", which place would be
better depends on what the "something" is.

Don't think of the Moon as somehow being a hop,skip, and a jump.
It's still a hell of a long way away through a hell of a lot of vacuum.

It _is_ a hop compared to Mars.
If you had the means, you could at least rescue the crew if something
went wrong on the Moon that didn't totally destroy the ship.. "Mission
to Mars" notwithstanding, anyone on Mars is on their own.

Not really. In both cases the only situation in which EITHER would
permit a "rescue" after "something" went wrong is if they had
sufficient material to survive long enough for a rescue mission. This
means sufficient reserve for them to survive being marooned for the
length of time it would take for a rescue mission to be mounted.

In BOTH cases, you clearly have the technology to reach the target.
In BOTH cases, you clearly know the planned duration of the mission.
In BOTH cases, you would have to have some reserve, X, available and
planned for.

In BOTH cases, the space mission would be planned using the same
physics limiting assumptions. If you assume the Moon mission brings a
survivable reserve, the Mars mission would too.

In BOTH cases, based on prior missions, there would NOT be such a
reserve, and there would NOT be anyone standing by to rescue you. See
"Apollo 13". They had to either solve the problems themselves, right
there, or die. You're not one of the people that thinks the Space
Shuttle could have gone to the Space Station and waited for rescue,
are you?

--
Sea Wasp
/^\
;;;
Live Journal: http://www.livejournal.com/users/seawasp/

John Schilling wrote:
In article , Sea Wasp says...

They had to either solve the problems themselves, right there, or die.
You're not one of the people that thinks the Space Shuttle could have
gone to the Space Station and waited for rescue, are you?


You're not one of the people that thinks the Space Shuttle represents
a sensible way to engage in space exploration, are you?

Your argument assumes an incompetent approach to the Mars mission --
as only an idiot would go to Mars WITHOUT that emergency reserve. Sent
on ahead, I would recommend.


--
Sea Wasp
/^\
;;;
Live Journal: http://www.livejournal.com/users/seawasp/

In article , Sea Wasp says...

John Schilling wrote:
In article , Sea Wasp says...

They had to either solve the problems themselves, right there, or die.
You're not one of the people that thinks the Space Shuttle could have
gone to the Space Station and waited for rescue, are you?

You're not one of the people that thinks the Space Shuttle represents
a sensible way to engage in space exploration, are you?

Your argument assumes an incompetent approach to the Mars mission --
as only an idiot would go to Mars WITHOUT that emergency reserve. Sent
on ahead, I would recommend.

You still haven't answered the first question I asked: By "reserve", do
you mean tanks of oxygen, water, etc sufficient to complete the trip and/or
await rescue from Earth, if things go wrong?

If so, you need to do the math, because any "competent" approach to the
Mars mission suddenly got a *lot* harder. Harder than going to the Moon,
by far, and hard enough that it's probably not going to happen in your
lifetime.


Your argument might as well be that wintering over at the South Pole is
as easy a trip as a weekend in the local state park, for a Boy Scout
troop. Because, see, only incompetents would make the trip without
adequate training and equipment, therefore the Boy Scouts will have
right training and equipment whether they're going to the state park
or Antarctica, therefore it's just as safe and easy either way.

No, it isn't. Even if we handwave the transportation costs to be the
same, "training and equipment" or "adequate reserves" are so very much
harder in the one case than the other, that there's no comparison.


--
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*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
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* for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *

: Sea Wasp
: If you assume each one starts with IDENTICAL equipment -- and that
: the equipment in both cases is optimized for the Moon -- then hell
: yeah, the Mars group is screwed.
: If you assume they each start out with optimal equipment for the
: mission in question, they should be roughly equal.

Equally unscrewed, perhaps so. Equally bankrupt, I very much doubt.
There is some vigorous handwaving in the "and then they make air
and fuel from easily available martian household supplies", among
other issues that provoke my skepticism.

( I note, I'm still pending your recommendatin of Zubrin's "Case for Mars",
so my skepticism is conditional/tenative )


Wayne Throop http://sheol.org/throopw

Wayne Throop wrote:
: Sea Wasp
: If you assume each one starts with IDENTICAL equipment -- and that
: the equipment in both cases is optimized for the Moon -- then hell
: yeah, the Mars group is screwed.
: If you assume they each start out with optimal equipment for the
: mission in question, they should be roughly equal.

Equally unscrewed, perhaps so. Equally bankrupt, I very much doubt.
There is some vigorous handwaving in the "and then they make air
and fuel from easily available martian household supplies", among
other issues that provoke my skepticism.

( I note, I'm still pending your recommendatin of Zubrin's "Case for Mars",
so my skepticism is conditional/tenative )

Read that and get back to me on the skepticism. They did some demos
of the relevant processes using simulated martian atmosphere, and for
the most part these things aren't even using 21st century technology,
but late 19th -- early 20th.


--
Sea Wasp
/^\
;;;
Live Journal: http://www.livejournal.com/users/seawasp/

Let's assume that all the resources to get back to Earth can be made on
Mars. Big deal, that breaks the trip into one-way trips to Mars and from
Mars. Each of those is still over eighty times the distance of the Lunar
round trip.

"Sea Wasp" wrote in message
...

Not really. It does depend on the assumptions you make, true, but you
exaggerate a number of issues. Mars offers opportunities to support
your marooned astronauts, assuming they brought the right equipment,
which the Moon does not. There are reasonable ways for them to make
air and water from what's there, as opposed to the Moon, where you
really CAN'T do that unless you happen to be incredibly lucky about
what you bring and where you land. You can make fuel on Mars a lot
more easily than you can make it on the Moon.

If you assume each one starts with IDENTICAL equipment -- and that
the equipment in both cases is optimised for the Moon -- then hell
yeah, the Mars group is screwed.

If you assume they each start out with optimal equipment for the
mission in question, they should be roughly equal.

If you insist on analogies on Earth, it's the difference between
sending your Boy Scout troop to Antarctica from a ship anchored
several miles offshore (but not reachable in any way over the ice,
etc.) and sending the exact same Boy Scout troop there from New York,
and the Troop in question has to be self sufficient from the time they
leave until the time they return.

If you assume the Troops in both cases have only the supplies for the
short trip, then the long-trip one is screwed. If you assume the
long-trip ones expend planning and effort to make sure additional
supplies are there, they aren't screwed.

If you can get people there for colonization or research or whatever,
you can also send, ahead of them, an equivalent or greater mass of
supplies (especially since the supplies sent to mars can (A) use
aerobraking to assist in the slowing down and landing, which the Moon
ones can't, and (B) don't have to return, so the entire mass only has
to be able to land, not take off. Read Zubrin for the details on this
process.

The KEY point about BOTH of them is that it is a nontrivial effort to
mount a rescue mission unless (in both cases) you have such a mission
STANDING BY. To just throw together something that would reach the
moon with sufficient capacity to go down, retrieve your astronauts,
and come back home safely is, likely, somewhat cheaper, and certainly
faster, than doing the same for Mars. However, in BOTH cases you have
already established the technology to actually accomplish the
objective, and if you were reasonably forward-thinking would make
allowances in supplies to deal with unforeseen events that somehow (by
great good fortune) left the astronauts in question alive.

The only *material* difference, as far as I see, is time; if you
assume they have only enough food for, say, a few weeks, yep, Mars is
screwed (fastest reasonable transit, given the right tech and right
orbital parameters, is about 3 months). Mars has water, and if they
brought the appropriate gadgets they can manage to keep up on the
water/air equation, but food isn't something you can make out of raw
materials yet.




--
Sea Wasp
/^\
;;;
Live Journal: http://www.livejournal.com/users/seawasp/

Sea Wasp wrote:
John Schilling wrote:

Your argument might as well be that wintering over at the South Pole is
as easy a trip as a weekend in the local state park, for a Boy Scout
troop. Because, see, only incompetents would make the trip without
adequate training and equipment, therefore the Boy Scouts will have
right training and equipment whether they're going to the state park
or Antarctica, therefore it's just as safe and easy either way.

Not really. It does depend on the assumptions you make, true, but
you exaggerate a number of issues. Mars offers opportunities to support
your marooned astronauts, assuming they brought the right equipment,

Which includes a fully robotic hospital to care for the invalid humans
whilst they re-adjust to Mars gravity after 300 days weightless. Sending
people to Mars with our present technology is pretty futile - humans are
too fragile for interplanetary travel in our crude chemical rockets. All
they will do is contaminate the place and die slowly on the surface (if
they manage to get there alive in the first place).

which the Moon does not. There are reasonable ways for them to make air
and water from what's there, as opposed to the Moon, where you really
CAN'T do that unless you happen to be incredibly lucky about what you
bring and where you land. You can make fuel on Mars a lot more easily
than you can make it on the Moon.

If you assume each one starts with IDENTICAL equipment -- and that
the equipment in both cases is optimized for the Moon -- then hell yeah,
the Mars group is screwed.

The time to reach Mars and mount any kind of rescue is so great that you
are sending them on a one way ticket to their deaths. The transfer
orbits are much slower between planets and the distances immense.

Going to the moon is a picnic by comparison and we haven't done that now
for more than three decades. AT the moment we can't even fly the shuttle

If you assume they each start out with optimal equipment for the
mission in question, they should be roughly equal.

Do you have any idea how much equipment and food that would be for Mars?
(even allowing for subsistence rations and make/find water on planet)

We do not have the lift capacity to send enough gear to Mars to allow
any reasonable chance of success of a manned human mission. It might
make gripping reality TV as they die slowly but that is hardly a good
reason for doing it.

The KEY point about BOTH of them is that it is a nontrivial effort
to mount a rescue mission unless (in both cases) you have such a mission
STANDING BY. To just throw together something that would reach the moon
with sufficient capacity to go down, retrieve your astronauts, and come
back home safely is, likely, somewhat cheaper, and certainly faster,

And faster is pretty important when you are mounting a *rescue* mission.
Not much use turning up so late that they are all dead.

The only *material* difference, as far as I see, is time; if you
assume they have only enough food for, say, a few weeks, yep, Mars is
screwed (fastest reasonable transit, given the right tech and right
orbital parameters, is about 3 months). Mars has water, and if they
brought the appropriate gadgets they can manage to keep up on the
water/air equation, but food isn't something you can make out of raw
materials yet.

Work out the weights of all the food and resources they would need to
subsist for the ~300 daya a Hohmann transfer orbit would take to reach
them. Or are you going to have some hypothetical gofaster rescue ship?

The rescue trip would have to fly with 50% more food resources than the
original mission to cater for the crowded return trip.

Regards,
Martin Brown

"Wayne Throop" wrote in message
...
: Sea Wasp
: If you assume each one starts with IDENTICAL equipment -- and that
: the equipment in both cases is optimized for the Moon -- then hell
: yeah, the Mars group is screwed.
: If you assume they each start out with optimal equipment for the
: mission in question, they should be roughly equal.

Equally unscrewed, perhaps so. Equally bankrupt, I very much doubt.
There is some vigorous handwaving in the "and then they make air
and fuel from easily available martian household supplies", among
other issues that provoke my skepticism.

Some healthy skepticism is a good idea since it hasn't been done on the
scale that Zubrin claims can be done. (at least not in a pure Martian
environment.)

But even w/o that, other things change... cooling mechanisms for your lander
and space suits for one thing. What works on Mars won't work on the Moon
and what works on the Moon won't work as well on Mars for example.

Dealing with day/night issues are also different.

Yes, some stuff will transfer between the two places but a lot won't.



( I note, I'm still pending your recommendatin of Zubrin's "Case for
Mars",
so my skepticism is conditional/tenative )


Wayne Throop http://sheol.org/throopw

Martin Brown wrote:
Sea Wasp wrote:

John Schilling wrote:


Your argument might as well be that wintering over at the South Pole is
as easy a trip as a weekend in the local state park, for a Boy Scout
troop. Because, see, only incompetents would make the trip without
adequate training and equipment, therefore the Boy Scouts will have
right training and equipment whether they're going to the state park
or Antarctica, therefore it's just as safe and easy either way.


Not really. It does depend on the assumptions you make, true, but
you exaggerate a number of issues. Mars offers opportunities to
support your marooned astronauts, assuming they brought the right
equipment,


Which includes a fully robotic hospital to care for the invalid humans
whilst they re-adjust to Mars gravity after 300 days weightless.

No, actually. They spend most of the trip in Mars gravity. Read The
Case For Mars.



Going to the moon is a picnic by comparison and we haven't done that now
for more than three decades. AT the moment we can't even fly the shuttle

Which is irrelevant as the scenarios assume that we have, in fact,
created the appropriate tech. If we can't get there, there wouldn't be
any concern about how you'd do a rescue mission, would there?



If you assume they each start out with optimal equipment for the
mission in question, they should be roughly equal.


Do you have any idea how much equipment and food that would be for Mars?
(even allowing for subsistence rations and make/find water on planet)

Yes, I do. And so does Zubrin, who among other things worked on these
sorts of things at NASA.



The KEY point about BOTH of them is that it is a nontrivial effort
to mount a rescue mission unless (in both cases) you have such a
mission STANDING BY. To just throw together something that would reach
the moon with sufficient capacity to go down, retrieve your
astronauts, and come back home safely is, likely, somewhat cheaper,
and certainly faster,


And faster is pretty important when you are mounting a *rescue* mission.
Not much use turning up so late that they are all dead.

Depends on what you're rescuing them FROM. If you sent them somewhere
that they have limited X (food, water, etc.) and they cannot get more,
then yes, time is the issue, and what time they have will be dictated
by X. Which is why a prudent mission would start off with the proper
survival stockpile.


Again, read Zubrin. I'm not going to try to type in ~300 pages of his
text, where he covers each and every objection, ranging from the
radiation issues to the food/transport issues to the gravity issues
and on and on and on. If you've READ it and you have cogent arguments
to take apart his reasoning, that's fine, I'm interested to hear them
(it won't make any difference in the Boundary universe since the
book's already published, but it makes a difference in this one) but
so far the most I've seen someone do is say "well, some of his
assumptions may be optimistic" which is about as weak an objection as
one can get.

--
Sea Wasp
/^\
;;;
Live Journal: http://www.livejournal.com/users/seawasp/