In article ,
says...

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.

The first experiment related to this was done 50 years ago.

http://blogs.scientificamerican.com/...tch-the-first-
artificial-gravity-experiment/

It's not a pipe-dream, it's an engineering problem that is relatively
straight forward to solve. It requires zero tech beyond what was
available 50 years ago.

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.

You don't need a big spinning wheel, you just need a big old cable.
Those aren't hard to make. This is a problem solved by throwing mass at
it. Again, reduce launch costs, and problems like this are far easier
to solve.

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.

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.

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.

I'd expect operations in the first few days to be very Apollo-like, just
in case something important failed and they had to leave right away.
Look at how many EVAs were done by all of the Apollo landing missions
put together and note that their surface stays were measured in just a
few short days.

ISS is very
expensive, but at least now it's "fully assembled" from the US point of
view. Plus it gives a purpose for commercial cargo and commercial crew,
which are lowering the cost of access to space for US astronauts.

Yep, that's called tossing good money after bad.
Or building a 'bridge to nowhere' for the jobs
it would create.

I get your point, but without ISS, NASA would learn nothing about long
term missions because they have no existing hardware to get them beyond
LEO.


SLS/Orion is certainly not going to lower costs. If you want to
cancel
something at NASA that's expensive and completely useless, cancel
SLS/Orion.



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.

To solve your expensive chicken and egg problem, you would smash your
eggs along with killing the chickens?

I don't agree. Canceling manned spaceflight completely to wait for
costs to go down kills commercial cargo and commercial crew which *are*
making huge strides in lowering costs of both launch vehicles and
spacecraft.

Kill SLS/Orion. The data on projected costs and projected flight rates
dooms it to failure before it's first test flight. There is your
"bridge to nowhere".

Jeff
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