"J. Clarke" wrote in message
in.local...
In article e204c1ab-9ece-48df-a2bc-2f1b4598d283
@h4g2000yqo.googlegroups.com, says...

Major cool factor....

TMT

NASA funds research into self-building spaceships
Technology News Blog

Considering the difficulties of getting even relatively small
spacecraft like the SpaceX Dragon into orbit, the idea of launching
larger interplanetary craft from Earth's surface seems especially
daunting. To address this, NASA thinks that future spacefaring
vehicles could actually construct themselves after they've launched
using onboard 3D printers, eventually transforming into ships much
larger and more complex than anything that could ever be built on the
planet.

While I'm all for advances in technology, this makes it clear that NASA
simply DOES NOT UNDERSTAND THE PROBLEM.

If spacecraft are to be "constructed" using 3d printers, you still have
to get the mass needed into orbit.

The problem is that it still costs vastly too much to get a pound of
mass into orbit. As long as we are throwing away a multimillion dollar
booster on each launch, that will continue to be the case. The fuel
cost for an Apollo launch, at today's prices, would be about 5 million
dollars. To put that in perspective, a Falcon 9 launch costs 54 million
dollars to put up less than 1/10 the payload.

The Space Shuttle was a blunder that should never have been built. NASA
should have followed the Air Force model and gone by small steps. Get
the thermal protection system working right. Get the engines working
right. Get each individual piece working right, then put them together
in a slightly scaled up package and get that working right. Then scale
it again. But instead NASA in their arrogance assumed that their
untried engines and their untried thermal protection system and their
untried solid rocket boosters and the rest would all work just as
predicted, and when they didn't it was a disaster.

The space agency recently awarded $100,000 to a project called
SpiderFab that aims to study this concept and ultimately produce
designs for such a craft. In theory, a small vehicle could launch in a
rocket carrying the raw materials needed by an onboard 3D printer.
Unlike fully-assembled craft, it wouldn't need to be designed to fold
up or built to withstand the extreme forces involved in liftoff and
ascent into space.

NASA thinks the concept could also be expanded to create a spaceship
that would find its own raw materials once in space, such as metal
from asteroids or even spare parts from defunct satellites. In
addition to building vehicles, the technology could be used to
construct massive radio telescopes and other hardware of a scale and
complexity that could never be launched from Earth.

Just imagine a space station that could "print" itself, without the
need for astronauts or multiple, expensive trips to bring loads of
components into orbit. Or maybe just a giant space baby like the one
seen in "2001: A Space Odyssey."

This article was written by Randy Nelson and originally appeared on
Tecca

How about we just shoot NASA and give their budget to DARPA, that
actually seems to do useful things with it?



I do not disagree with your assesment of the shuttle (although hindsight is
usually more accurate than foresight), But I would not hold up DARPA as a
paradigm of wise spending. They fund way more wacky, useless stuff than
NASA. Most large corporations that fund their own research are no better;
their bad decisions are just hidden from public view (and usually covered up
inside the company as well).

Regarding the 3D printer project. It is not necessarily as silly as the
above article makes it sound. Here is a better summary:
http://www.nasa.gov/offices/oct/earl...spiderfab.html

The point is to make kilometer scale objects that could never be launched,
such as large interferometer baselines or long baseline radio telescope
arrays. The 3D printing can also be used to reduce weight by making more
complex truss patterns the same way they make lighter 3D printed bicycles.

$100,000 is not a lot of money for an engineering project, so it may be just
an early proof of concept study.