Re: The crash of NASA's culture
Greetings Wallace
Thank you for the detailed comparison.
Is there any NASA project, which is in progress or that has been shelved, that
could be finished in a short time frame (with sufficient funds) to serve as an
interim replacement to the shuttle?
Be Well
Damian
"Mc Clure, Wallace A" wrote:
> Matt Wronkiewicz wrote:
> > What do you hope to get out of reinstating the X-33 program?
> > Regardless of how much work remains to be done, the X-33 craft as
> > designed was a suborbital demonstrator, not a Shuttle replacement.
> > Burt Rutan beat the X-33 altitude and payload goals last year.
>
> I'm not a fan of how the X-33 program turned out, and I think Rutan has
> done something that is really cool and quite amazing -- but I couldn't
> let this statement go past. Just as a note, the X-33 goals were quite
> different than that of Rutan's SpaceShipOne. The X-33 was specifically
> designed to provide the basis for making a decision to invest in a
> reusable launch system, including both flight and ground test programs.
> The SS1 was designed specifically to win the X-Prize. Quite different
> goals. It was expected the X-33 would include
>
> - Flight test in excess of Mach 10, with a goal of Mach 13 or
> higher. (This was to demonstrate thermal protection systems suitable
> for orbital reentry). Rutan's SS1 reached a maximum velocity of Mach
> 3.5. Since thermal loads run with the kinetic energy of the vehicle,
> which goes as the square of the velocity, the X-33 was expected to have
> more than 10X the thermal loads as SS1, requiring quite a different
> design approach.
>
> - Flight test to XXX dynamic pressure at velocity. Rutan's
> vehicle was designed to essentially go straight up and straight back
> down -- and it did go over 300,000' The X-33 was designed go achieve a
> dynamic pressure on the vehicle structure of XXX at a certain velocity,
> in order to stress the light weight structure while getting the full
> reentry heating condition. While this may look like around the same
> velocity, it should be noted that SS1 reached 300,000' at essentially
> zero velocity (think of SS1 as a ball thrown upwards, pausing at the top
> of its trajectory before falling back to the earth), whereas the X-33
> was designed to power through the atmosphere at the same altitude at
> more than Mach 10, giving it a much higher dynamic and thermal
> requirement. If you had fired the X-33 straight up, it would have gone
> quite a bit higher than SS1 -- but that was not why it was going to be
> built.
>
> - X-33 had NO payload requirement, other than carrying test
> instrumentation. Rutan's SS1 had to carry a pilot and mass equivalent
> to a passenger, which also meant some type of passenger module.
>
> - X-33 had to demonstrate light weight structures and thermal
> protection. Rutan's design did not have light weight, or integrated
> thermal protection as a design goal. SS1 did have thermal protection,
> but it was a simple spray on ablator, which was possible due to its
> thermal loads 10x less than that of something like the X-33.
>
> - X-33 had no turnaround requirements per se, although the
> turnaround operations were going to be judged as what was required for
> turning around a reusable orbital vehicle. SS1 had to meet the X-prize
> turnaround goals. On paper, these were approximately the same.
>
> - X-33 was going to demonstrate a highly efficient, integrated,
> reusable propulsion system (the aerospike). This was needed as part of
> the X-33 goals to demonstrate the propulsion system suitable for a
> reusable orbital vehicle, potentially a SSTO. Rutan used a replaceable
> low-efficiency hybrid rocket system on the SS1.
>
> Burt Rutan did not beat the X-33 altitude or velocity goals. He did
> beat the X-33 payload goals, but then the X-33 was not designed to carry
> a payload, whereas the X-Prize requirement (to a lower altitude and
> lower velocity) did have a goal of carrying a passenger.
>
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