Expendable launches with shuttle installs

Ok, probably a stupid question, but why can't some of the heavy
and sturdy Space Station components, like struts, be boosted to
the vicinity of the station, then grappled and installed by the
shuttle crew, leaving the shuttle either lighter, or with other SS
components or even with ... science. (could include the Hubble
repair in the question, I guess)

wrote:
Ok, probably a stupid question, but why can't some of the heavy
and sturdy Space Station components, like struts,

Because there aren't any such simple components. Even the trusses
contain considerable delicate support equipment.

be boosted to the vicinity of the station, then grappled and
installed by the shuttle crew, leaving the shuttle either
lighter, or with other SS components or even with ... science.
(could include the Hubble repair in the question, I guess)

The Station components for designed for Shuttle delivery are designed
to 'hang' (from their sides) inside the Orbiter's cargo bay - not to
'sit' on their tails on a more conventional booster. It would take
considerable money to redesign them, or to design a container in which
they could ride. They also rely on the Shuttle to provide power,
monitoring, enviromental control etc... etc...

Furthermore, the guidance and control systems to support such a
concept simply don't exist.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

"Derek Lyons" wrote in message
...
wrote:
Ok, probably a stupid question, but why can't some of the heavy
and sturdy Space Station components, like struts,

Because there aren't any such simple components. Even the trusses
contain considerable delicate support equipment.

be boosted to the vicinity of the station, then grappled and
installed by the shuttle crew, leaving the shuttle either
lighter, or with other SS components or even with ... science.
(could include the Hubble repair in the question, I guess)

The Station components for designed for Shuttle delivery are designed
to 'hang' (from their sides) inside the Orbiter's cargo bay - not to
'sit' on their tails on a more conventional booster. It would take
considerable money to redesign them, or to design a container in which
they could ride. They also rely on the Shuttle to provide power,
monitoring, enviromental control etc... etc...

Furthermore, the guidance and control systems to support such a
concept simply don't exist.

Why do so many people believe their questions are stupid? Heck, I'm just
happy to know other people are interested in this stuff besides me!

skrev i en meddelelse
ups.com...

Ok, probably a stupid question, but why can't some of the heavy
and sturdy Space Station components, like struts, be boosted to
the vicinity of the station, then grappled and installed by the
shuttle crew, leaving the shuttle either lighter, or with other SS
components or even with ... science. (could include the Hubble
repair in the question, I guess)


The cost of developing a system that is precise enough AND safe enough
(think a multi-tonne cargo out of control close to the space station) plus
the operational cost of actually flying the hardware can't compare to the
price of a few shuttle launches.

And without hard data, I'll take a guess, and say there aren't any 'heavy'
components. After all, they won't need to withstand great force. The
greatest force acting on the station is the occasional re-boost. And that is
a long soft push. No need to kick it anywhere - it is already in orbit. And
the Canadarm moves with the speed and grace of a gletcher.

Just my view on things.

Allan F

Allan F wrote:
skrev i en meddelelse
ups.com...

Ok, probably a stupid question, but why can't some of the heavy
and sturdy Space Station components, like struts, be boosted to
the vicinity of the station, then grappled and installed by the
shuttle crew, leaving the shuttle either lighter, or with other SS
components or even with ... science. (could include the Hubble
repair in the question, I guess)


The cost of developing a system that is precise enough AND safe enough
(think a multi-tonne cargo out of control close to the space station) plus
the operational cost of actually flying the hardware can't compare to the
price of a few shuttle launches.

And without hard data, I'll take a guess, and say there aren't any 'heavy'
components. After all, they won't need to withstand great force. The
greatest force acting on the station is the occasional re-boost. And that is
a long soft push. No need to kick it anywhere - it is already in orbit. And
the Canadarm moves with the speed and grace of a gletcher.

Just my view on things.

Allan F

Well, the Russians seem to do a fair job with Progress, using Cold War
era technology. Seems like the problem shouldn't be That hard with
what we have available these days. :-)

wrote in message
oups.com...

Allan F wrote:
skrev i en meddelelse
ups.com...

Ok, probably a stupid question, but why can't some of the heavy
and sturdy Space Station components, like struts, be boosted to
the vicinity of the station, then grappled and installed by the
shuttle crew, leaving the shuttle either lighter, or with other SS
components or even with ... science. (could include the Hubble
repair in the question, I guess)


The cost of developing a system that is precise enough AND safe enough
(think a multi-tonne cargo out of control close to the space station)
plus
the operational cost of actually flying the hardware can't compare to the
price of a few shuttle launches.

And without hard data, I'll take a guess, and say there aren't any
'heavy'
components. After all, they won't need to withstand great force. The
greatest force acting on the station is the occasional re-boost. And that
is
a long soft push. No need to kick it anywhere - it is already in orbit.
And
the Canadarm moves with the speed and grace of a gletcher.

Just my view on things.

Allan F

Well, the Russians seem to do a fair job with Progress, using Cold War
era technology. Seems like the problem shouldn't be That hard with
what we have available these days. :-)


Well, let's see ... (and the old hands 'round here can correct me if I'm
wrong about anything) ...

The ISS payloads (notably the truss segments, but also the various modules,
such as the nodes and the science laboratories Columbus and Kibo) are
designed to be lofted by the space shuttle. As such, they are suspended in
the payload bay from their sides, not from their ends. You'd have to rig a
suspension system with three "legs" to support a truss segment or a lab, and
mate that to some sort of propulsion bus, and wrap it with a payload
fairing.

Next, you have to supply the payload with electrical power, and in some
cases, cooling (I'm guessing). You would also want to monitor it as it flew
for any problems, which would involve telemetry and radio communications.

Then, you have to figure out a way to get it to within easy reach of either
the space shuttle robotic arm or the Canadarm 2 and GUARANTEE that it won't
hit the space station. That means some form of autopilot (which the US
doesn't have) or some form of remote piloting capability (which we don't
have, either).

On top of that, you need to have a vehicle capable of putting that much mass
into LEO. Since a truss segment can weigh in the neighborhood of 31,000
pounds (See
http://www.nasa.gov/mission_pages/st...ments/its.html for
details) (and this is without the alledged transport bus that doesn't
exist), you don't have that many options for lifting it to orbit. At
minimum, you're looking at an Atlas V 551
(http://www.astronautix.com/lvs/atlasv.htm) (or equivalent), given the
weight of the segment or module you're lifting, the weight of the transport
bus, and the inclination of the ISS.

Given the limited role of the shuttle in the few years left to it, the
shuttle's ready-made capability to loft the modules, the cost of developing
a reliable way to have a module deliver itself to the vicinity of the ISS
(and the cost of manufacturing more than a dozen of them!), and the expense
of buying the expendable rockets to launch them, I doubt very seriously that
anyone would pursue an expendable vehicle alternative to launching ISS
components.

I probably missed something ... correct me, please, if I have.

Godspeed Discovery.

James