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(CNN)
http://www.cnn.com/2004/TECH/space/0...eut/index.html

CAPE CANAVERAL, Florida (Reuters) -- Aerospace giants are already
prepared to compete for lucrative contracts in NASA's next big
step toward the moon and Mars but they aren't eager to start from
scratch on a new rocket to take it there.

Rather than a crash program to produce a new super-rocket, like
the Saturn 5 moon rocket in the 1960s, this new initiative --
which NASA is a year or more away from detailing -- is more
likely to use existing technology from space shuttles and
expendable rockets.

That was the word from industry representatives attending the
41st Space Congress this week in Cape Canaveral, Florida.

Boeing Co. and Lockheed Martin Corp. representatives say their
companies are both looking at new, or "clean sheet," rocket
designs but agree that the cost of building new systems from
scratch, including the manufacturing plants and launch facilities
that would be needed, might prove prohibitive.

"Clearly, one of the challenges is to make sure there's money
left for space exploration after you've built a launch vehicle,"
said Michael Gass, vice president for space transportation at
Lockheed Martin.

One of the main points of the proposal U.S. President George W.
Bush announced in January was that this initiative, unlike the
Apollo program, would move forward with only small, stable
increases in NASA's annual budget.

The early years will be the leanest. While the space shuttle is
still flying and the International Space Station is still under
construction, they will continue to eat up most of NASA's budget.

Both Boeing and Lockheed are looking at their new generations of
expendable rockets, Boeing's Delta 4 and Lockheed's Atlas 5, to
see if they can be modified for the job.

The problem is that both rockets were developed under U.S. Air
Force contracts for putting satellites into orbit. Launching
humans, or even heavy cargo, into interplanetary space would
require extensive modifications to both the rockets and their
launch facilities.
RECONFIGURING THE SHUTTLES

Both companies, along with ATK Thiokol, a unit of Alliant
Techsystems Inc., also have teams at work on how space shuttle
systems might be reconfigured for the job.

The advantage there is that the massive Vehicle Assembly Building
at Kennedy Space Center, one of the largest buildings ever
erected, and the shuttle's two launch pads are already in place
and would continue to be used, along with the engineers and
technicians who have worked on the shuttles for years.

"We have to take full advantage of what we have today. How do we
leverage what we already have, what we already know, what we can
already do?" said Mike Khan, an ATK Thiokol vice president.

The official report on the fatal crash of the shuttle Columbia
last year called for retiring the shuttle fleet as soon as
possible, but as Khan, Gass and others made clear, the aging
orbiters themselves would not be used. Instead, a cargo faring
would be bolted to the same place on the fuel tank.

For human launches, a new second stage would be built and mounted
on top of the fuel tank, with the crew capsule on top of that, so
the configuration would look much more like a traditional rocket.

Another advantage to modifying existing rockets or shuttles is
that they would fly much sooner than a new rocket. Industry
representatives all warned that prolonged development could cause
the public to lose interest.

"We think that might be the way to go. Get some early successes
without trying to hit the home run. A few good singles up the
middle to get the momentum going and get support behind the
program," said Dan Collins, Boeing's Delta program manager.

. . . .

Trying to economize is fine - BUT ...

Conventional propulsion will make even a trip to mars
a very, VERY long mission. Time is an enemy - more time
means more chances for systems to break down, more time
for radiation to kill the crew, more time for meteors
to strike, more time for the crew to go quietly nuts,
more food, more oxygen, more water, more time for Murphys
law to work ... more everything.

I agree, but with current technology there just isn't any other way. It will
take at least two more decades before a viable nuclear rocket is developed
that can make the journey in two weeks. That means a manned mission will not
occur before 2030 probably 2040. I'm not willing to wait that long, for one.
But more importantly: a long duration Mars mission would truly show that man
can live outside his own environment for long periods of time. I know, it's
extremely risky. Someone is bound to get sick or have an accident in the 3
year timespan of a 'Mars Direct' mission but still worth the risk.


The space shuttle is fine for a few weeks in orbit (even
if getting there and back are likely to kill you) but is
it a viable vessel for half a dozen people for a six
month flight to - and then six months back ? Not all
THAT much room inside ... and the cargo bay would have
to be stuffed full of provisions. Maybe if they orbited
one of the external fuel tanks and converted it to
crew quarters ... maybe.

Perhaps this 'economy' thing isn't such a good idea
after all ...

There have been some perfectly good designs for electric
and nuclear propulsion systems floating around for quite
some time. Either generate electric power with a reactor
and then accelerate ionized plasmas or run a hotter
reactor and dribble hydrogen or something into it to
produce exhaust gasses. Both of these can produce moderate
thrust for an extended period - a sum-total 'push' FAR
beyond anything conventional chemical rockets can offer.
Nothing about these designs are extraordinarily complex
or dangerous. Indeed they are in many ways simpler and
more reliable than conventional liquid-fuel rockets.
Six months can become two ...

As I said, nuclear propulsion will take quite some time to be viable for
manned missions.