Jonathan wrote:

On 9/5/2016 9:30 AM, Jeff Findley wrote:

In article ,
says...

$3 to $5 billion per year to keep two (2) American
astronauts in space all year long is just too
expensive. What the ISS has primarily returned
is evidence bone loss for long duration space flight
shows the whole colonizing Mars dream isn't practical.

Bull****. This is an engineering problem, not a medical problem. Why
NASA continues to treat it as a medical problem baffles me.

Not until we can build spacecraft large enough to
supply artificial gravity and that means a sea-change
in cost to orbit.

Not that hard. All you need to do is attach your transfer stage to your
habitat module by a long cable and spin it up. Again, this is an
engineering problem that is not very difficult to solve.


Not that difficult? Don't be ridiculous, your cable
solution is another pipe-dream.


Physics, Jonathan. Get some.


A spacecraft large
enough to supply artificial gravity AND go to Mars
AND carry enough gear to support more than a few
days stay would make the $150 billion dollar
/several decade long/ ISS project look like
...chump-change.


That's why you don't use A spacecraft. You use a bunch of them. Like
most problems, things are much easier if you break it down into
bite-sized chunks.


ISS started in 1985. If we started now that
space craft to Mars might be done by 2050.


Hogwash. Musk is talking a private manned mission launching in 2024
that would have an 18 month stay time. I expect that will slide by 18
months or so (which would be the next launch opportunity).


Rovers could have mapped half the planet
of Mars by then.


Beyond hogwash. How many rovers are you going to send? In 4 years
Curiosity has gone about 6 miles.


You could double NASA's budget, spend every dime
of it on the manned Mars mission and it would still
take twenty or thirty years and only give astronauts
...HOURS on the surface.

A useless mission scientifically speaking.


Which is why that's never been the plan. Have you even bothered to
look at ANY of the NASA Reference Missions? How many hours in 18
months, Jonathan?



The next space station, manned space flight
in general, should wait until that day
arrives. We're not even close yet.

Waiting for "artificial gravity" stupid since it's something we could do
today given the motivation. NASA isn't doing anything meaningful
towards sending people to Mars. Just look at where the money is being
spent. There are no Mars landers being designed and built. There is no
habitat being built big enough for a Mars trip. There are no in-situ
propellant production experiments being run on Mars (could be used to
fuel an unmanned sample return mission). SLS/Orion is the only big
thing NASA is spending money on and neither, by themselves, will take
people to Mars. Orion doesn't even have a good enough heat shield for a
direct reentry of a returning Mars mission.

The biggest problem with going to Mars, or anywhere beyond LEO, is the
high cost to launch anything into LEO.


Thanks for agreeing with me.


He didn't. No thanks for acting like a moron. Are you going to stalk
out of here in high dudgeon after throwing a hissy fit AGAIN when
people point out you're just talking ignorant ****e?


LEO is "half way to anywhere" in
terms of delta-V. Low launch costs will open up spaceflight like we've
never seen before.

Until then we should spend our space budget
on more ambitious unmanned missions to Mars
not this pipe-dream of sending people there.

Toasters are fine, but can't do 1/100th what a person in an EVA suit
plus a pressurized laboratory module can do.

I'm sorry to but to think a few days, or week or two
on the surface of Mars is going to return useful
science is absurd. They'd be spending most of their
time on the habitat and surviving just like
with the ISS. Where some science is shoe-horned
in when they can.


18 months...


To discover life on Mars drilling below the
surface is required, that's where life will be.
A rover can do that and do nothing /but/ science
for months and years at a time.


But it can only do pretty simple science, which is always the problem.
That's why sending people is still about 3 orders of magnitude more
productive.


It's manned space flight that drives costs
so high, unmanned can shave costs by orders
of magnitude, and more importantly shave
time by decades. In the couple decades it
would take to launch a scientifically useful
mission to Mars, more ambitious rovers could
have scoured Mars for the data we want for
pennies on the dollar, and MORE importantly
in a few years, not a few...decades.


Remember, Curiosity has traveled around 6 miles in FOUR YEARS. A
manned mission would do that in an hour. There are 8,760 hours in a
year...


Add a rover to that and
people can do amazing things in a very short time.

At best we'd put a couple people on Mars
for a couple weeks, a symbolic event not
scientific, but at enormous costs and
more importantly enormous time, that
starves the budget for all else.

Cost is high because launch costs are high. Again, solve the launch
cost problem and everything else becomes easier and cheaper.

Let Musk have his 'fifteen minutes' on
Mars, the US space program should make
sense, and the ISS, current or future
versions, doesn't make sense.

ISS makes sense in that NASA is learning how to build and maintain a
large-ish habitat that needs to operate for years at a time.

To go to Mars, asteroids are make-work, not a
credible science goal.


I agree. But then who here said anything about asteroids?


We need to cancel...manned space flight except for military
uses until launch costs come way down. There's very little
humans can do in space that can't /now/ be done by
unmanned missions.


Then we CERTAINLY need to defund planetary science and shut all that
down, since if people aren't going there's no point to it.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw