Re: Instant Shuttle turnaround ?


"John Doe" <jdoe@xxxxxxx> wrote in message
news:e5182$493eb857$cef8887a$18681@xxxxxxxxxxxxxxx
Jeff Findley wrote:

But how close? Why bring back a whole experiment rack when all you
really
*need* is the *results* of the experiment?

One of the major lessons learned from the NASA participation in Mir was
the need to be able to bring back equipment that is no longer necessary,
otherwise the station gets cluttered to a point where you can no longer
bring up equipment and hinders day to day operations.

The larger CBM hatches and the MPLM which uses those large hatches was
done in part to allow large objects to be brought in and OUT.

With demise of shuttle and MPLMs, all that will be left at the tiny
Progress hatches (until HTV materialises) and the USA segment was not
designed to have all its parts fit through them.

The MPLM concept enabled types of experiments that would have required
the rack be brought back down for analysis. (can't think of any such
applications off hand). With demise of MPLM, only experiments where
results are analysed on station will be possible, and tyey will now have
to be designed to be field-disassembled to fit through progress hatches
for disposal. (unless HTV proves to be real, and with high eough frency
to be relied upon).

HTV ought to be real and will allow disposal of entire racks.

http://iss.jaxa.jp/en/htv/spec/

From above:

The Pressurized Logistics Carrier (PLC) will carry cargo such as
International Standard Payload Racks (ISPRs)

Also, ATV is real enough. ATV is actually pretty huge. I wonder if ESA has
thought of building one with a CBM instead of SP&D. But then you'd lose the
ability to refuel the Russian side of the station. You might also lose the
ability to do reboosts of ISS using ATV's engines, unless there is an open
CBM/ISS configuration which would allow this.

http://en.wikipedia.org/wiki/Automated_Transfer_Vehicle

From above:

The CARV (Cargo Ascent and Return Vehicle) study investigated
a larger lifting capsule, capable of bringing back a few tonnes
of payload, which could have been installed in place of the ATV
pressurized cargo hold. In addition, a goal was to allow CARV
to dock at the US side of the station. Given the larger docking
ports there, it would be possible to transfer complete
International Standard Payload Racks (ISPRs) from the ATV to
the station, which is not possible now. Such vehicles could
have been available by 2010. However, the financial situation
of ESA led to a priority given to PARES over the CARV. In the
end, PARES was not proposed by ESA for approval at the latest
Ministerial conference of ESA.

So it's been thought about. But the question is, is it really worth the
cost? Also proposed for ATV is a smaller return capsule, similar to ones
used previously by the Russians with Progress capsules. I'm guessing that
this would be cheaper and quicker to develop since it's just an add on to
the existing ATV where the CARV replaces the pressurized section with a
capsule.

The PARES (PAyload REtrieval System) would have included a
small ballistic capsule similar to VBK-Raduga embedded into
the ATV docking interface, which would have brought back a
few tens of kilograms of payload. PARES could have featured
a deployable heat shield system. The European Space Agency
was also proposing the system for use with the Progress
spacecraft and the H-II Transfer Vehicle (HTV).

Jeff
--
"Many things that were acceptable in 1958 are no longer acceptable today.
My own standards have changed too." -- Freeman Dyson


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