Reusable Successor To EELV Moving Ahead

On Apr 25, 6:17*am, Jeff Findley wrote:
In article , bthorn64
@suddenlink.net says...



On Tue, 24 Apr 2012 17:38:06 -0400, Jeff Findley
wrote:

Good thing that SpaceX and the USAF are taking a sane approach to
resuability of the first stage. *NASA certainly isn't. *I wonder if
today's flavor of SLS will include "reusable" SRB's... *:-P

Nope. Reusability was dropped.

That's what I thought. *Hopefully they'll still try to recover at least
some of them for inspection. *Otherwise, a Challenger like failure can't
be predicted.

snip

Yet the Challenger disaster happened, even though the Shuttle SRBs
were recoverable.

"Jeff Findley" wrote in message
...

I'm not too happy about the runway landing, but since they're staging at
a relatively high Mach number (and presumably some distance downrange
from the launch site), the vehicle will need wings to return to the
launch site. Once you stick wings on a vehicle, it's going to be
awfully hard to convince the USAF to not land it on a runway.


True. (And if it was the Army, they'd want rotary wing ;-)

Also being unmanned, makes things easier.

The alternative is to stage earlier, at a lower Mach number, and/or use
for an initial trajectory that's more vertical. This makes return to
the launch site and vertical landing easier. The trade is a less
"efficient" trajectory for the first stage and puts more of a burden on
the upper stage to be more efficient. As an engineer, I'd make this
trade in order to replace wings and (horizontal) landing gear with
vertical landing gear.

I would tend to agree. But still harder to incrementally test.



Jeff

--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

"Jeff Findley" wrote in message
...

In article , bthorn64
says...

On Tue, 24 Apr 2012 17:38:06 -0400, Jeff Findley
wrote:


Good thing that SpaceX and the USAF are taking a sane approach to
resuability of the first stage. NASA certainly isn't. I wonder if
today's flavor of SLS will include "reusable" SRB's... :-P

Nope. Reusability was dropped.

That's what I thought. Hopefully they'll still try to recover at least
some of them for inspection. Otherwise, a Challenger like failure can't
be predicted.


Ayup. That alone made the SRB recovery worth it in my mind. Now if only
NASA had acted upon the burn-thru issue before Challenger.


Just because a rocket stage works several times in a row, doesn't mean
it isn't close to failure. Reusability means that inspections are done
after each flight. Dropping expendable stages in the ocean generally
means inspections are rarely, if ever, done.


It also means you can further optimize future production runs, even on
expendables. If you find certain components were over-rated, you can start
to modify them for future craft.


Jeff

--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

wrote in message
...

On Apr 25, 6:17 am, Jeff Findley wrote:
In article , bthorn64
@suddenlink.net says...



On Tue, 24 Apr 2012 17:38:06 -0400, Jeff Findley
wrote:

Good thing that SpaceX and the USAF are taking a sane approach to
resuability of the first stage. NASA certainly isn't. I wonder if
today's flavor of SLS will include "reusable" SRB's... :-P

Nope. Reusability was dropped.

That's what I thought. Hopefully they'll still try to recover at least
some of them for inspection. Otherwise, a Challenger like failure can't
be predicted.

snip

Yet the Challenger disaster happened, even though the Shuttle SRBs
were recoverable.


Yes, and that was almost certainly a managerial issue, not an engineering
one. NASA knew there was a problem. They deluded themselves into thinking
it wasn't as bad as it was. The fact that there was burn-thru at all should
have been taken more seriously than it was.




--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

On Apr 25, 12:34*pm, "Greg \(Strider\) Moore"
wrote:
"Jeff Findley" *wrote in message

...



I'm not too happy about the runway landing, but since they're staging at
a relatively high Mach number (and presumably some distance downrange
from the launch site), the vehicle will need wings to return to the
launch site. *Once you stick wings on a vehicle, it's going to be
awfully hard to convince the USAF to not land it on a runway.

True. (And if it was the Army, they'd want rotary wing ;-)


Yeah! Then Roton could make a comeback:

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

http://www.youtube.com/watch?v=X--EDUqP9wI

Yes, USAF foresees RBS as a horizontal lander. There are very long
runways at CCAFS and VAFB.

In article 5eb83c61-563d-49e3-9e56-c4064efbd649
@z17g2000yqf.googlegroups.com, says...

On Apr 25, 6:17*am, Jeff Findley wrote:
In article , bthorn64
@suddenlink.net says...



On Tue, 24 Apr 2012 17:38:06 -0400, Jeff Findley
wrote:

Good thing that SpaceX and the USAF are taking a sane approach to
resuability of the first stage. *NASA certainly isn't. *I wonder if
today's flavor of SLS will include "reusable" SRB's... *:-P

Nope. Reusability was dropped.

That's what I thought. *Hopefully they'll still try to recover at least
some of them for inspection. *Otherwise, a Challenger like failure can't
be predicted.

snip

Yet the Challenger disaster happened, even though the Shuttle SRBs
were recoverable.

The low level engineers who knew the data from those recovered SRB's
recommended that Challenger *not* launch. They were essentially
overruled.

For the long gory details, the CAIB report is a good read. But the
engineers *did* have the data in hand to recommend not launching.
Letting the SRB's sink to the bottom of the Atlantic gives the engineers
zero data from inspections.

Jeff
--
" Ares 1 is a prime example of the fact that NASA just can't get it
up anymore... and when they can, it doesn't stay up long. "
- tinker