Shuttle Derived Launchers - Safe, Simple, Soon

Jorge R. Frank wrote:

Well, except for the ET. The current ET is designed to absorb loads along
the side through the intertank (orbiter and SRB forward attach points) and
the aft ring (orbiter and SRB aft attach points). The SDLV ET will have to
take thrust loads through the bottom of the tank, and to take the weight of
the payload from the top (which will also necessitate redesigning the LOX
tank ogive). The ET is such a lightweight, optimized structure that you're
pretty much going to have to redesign it.


I'm surprised they aren't using a lot of the ET's structure to build the
side-mounted cargo pod.

Pat

wrote:

This is going to need a fair bit of re-engineering anyway, it sounds like...

Why not go all the way and put the oxygen tank on the *bottom*?



That would change the balance point and might make the vehicle
unstable- though it might be better from a structural weight point of
view the further forward the center of mass is the more stable the
rocket becomes.

Pat

"Rusty" wrote in message
...
Website from Alliant Techsystems showing proposed
shuttle derived launchers, titled, "Safe, Simple, Soon":

http://www.safesimplesoon.com/media-images.htm

http://www.safesimplesoon.com/default.htm

Rusty

Interesting. In the "Future ELS" design - with the mention of J2S and SSME
I again see small parallels of the Boeing EELV entry (the current Delta 4
was the McD EELV entry). You could probably consider the "retrievable
engine pod" concept -- which Boeing did test (air drop) in the Gulf of
Mexico.

You have a "running" production line for the ET (with over 100 produced over
almost a 30 year period) -- so if you desire to minimize cost and capture
efficiency -- it a logical component to seriously consider for usage.

gb

On Sun, 26 Jun 2005 13:33:12 -0500, in a place far, far away, "Jorge
R. Frank" made the phosphor on my monitor glow
in such a way as to indicate that:

Well, these pretty pictures are all definitely for public relations
and politics, not engineering. But you can easily make the same claim
about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak.
At least for the SDLV, all the essential elements have either been
tested or are in service, even the 5-segment SRB.

Well, except for the ET. The current ET is designed to absorb loads along
the side through the intertank (orbiter and SRB forward attach points) and
the aft ring (orbiter and SRB aft attach points). The SDLV ET will have to
take thrust loads through the bottom of the tank, and to take the weight of
the payload from the top (which will also necessitate redesigning the LOX
tank ogive). The ET is such a lightweight, optimized structure that you're
pretty much going to have to redesign it.

Yes, I suspect that the only thing that they can really use from the
existing ET program is the barrel sections. Otherwise, it's really a
new tank.

On Sun, 26 Jun 2005 13:33:12 -0500, "Jorge R. Frank"
wrote:


Well, except for the ET. The current ET is designed to absorb loads along
the side through the intertank (orbiter and SRB forward attach points) and
the aft ring (orbiter and SRB aft attach points). The SDLV ET will have to
take thrust loads through the bottom of the tank, and to take the weight of
the payload from the top (which will also necessitate redesigning the LOX
tank ogive).

True, the in-line will need a new ET, but the 5-segment SRB /
side-carrier doesn't, and that chart shows it with 200,000 lbs. to LEO
capacity. Why the heck do we need the in-line, especially if the crew
is going up on a separate launcher (the Stick)?

200,000 lbs. is plenty. The huge expense of a new MLP and redesigned
ET for an extra 40,000 lbs payload isn't worth it.

Brian

"Reed Snellenberger" wrote in message
...
Rand Simberg wrote:

Yes, I suspect that the only thing that they can really use from the
existing ET program is the barrel sections. Otherwise, it's really a
new tank.

BUT, they have made at least 2 major ET upgrades .. in the same facility and
personnel ... I woudl think this would be easier .. AND maintain the
knowledge abse that has been built over 30 years of production.


They just need enough structure to transmit the thrust to the intertank
area, which is designed to handle the combined thrust loads from the
orbiter and both solids. The LH2 tank essentially "hangs" from the
intertank during launch -- the rear orbiter and SRM supports don't see any
significant thrust loads. It may be as simple as a change in the milling
that's done on the ET skin sections (removing less) to add (or strengthen)
the existing truss-like structure in the LH2 skin.

Another, "Goldbergian" solution could be to add a lattice structure that
extends from the thrust "module" and extends the length of the LOX tank to
the intertank. Since you can also reduce the SOFI thickness (you no
longer care so much about ice, but just boil-off), the weights may trade
off.

Propellant lines can remain essentially the same -- just re-direct them to
an interface on the (likely) thrust assembly below the ET that holds the
SSMEs. The lines are obviously large enough for a 3 SSME booster --
since you've eliminated the pressure drop caused by the current sharp
right-angle turn into the orbiter, the lines may actually be adequate for
a 4 SSME booster.


I think the Boeing used 2 SSME for EELV payload requirements, and using a 3
SSME design -- at least leverages "how NOT to do it" knowledge from the
Shuttle -- hopefully correcting the pipe nightmare of that "pre-AutoCAD
design" -- with changes for ease of service of "changeout" -- if required.
Hopefully some of the LM lessons for the Russian NPO Energomash RD 180
engine's adaptation to the Atlas 2 core would be useful.


Add a lengthened cylinder above the intertank that rises above the LOX
tank, and you're done -- assuming that you add a "droppable" interstage
like the S-II's to compensate for the length of the upper stage's engines
& the exhaust bells.

For the "in-line" design ---
Where is the equivalent Instrumentation Unit (Saturn V reference) going to
be located? Granted with today's electronics this can be significantly
smaller -- and much more powerful -- BUT the Apollo 12 launch proved the
advantage of a separate or redundant system for the launch vehicle from the
payload computing system.

Since the booster's SSME's no longer have to fit in the re-entry shadow of
the shuttle, do you change the nozzle and/or bell geometry? Do we need to
air-start the SSMEs (a la Titan III & IV), or just light everything off on
the ground the way we do now?
Reed

On Sun, 26 Jun 2005 18:16:39 GMT, wrote:


From: Brian Thorn

Well, these pretty pictures are all definitely for public relations
and politics, not engineering. But you can easily make the same claim
about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak.
At least for the SDLV, all the essential elements have either been
tested or are in service, even the 5-segment SRB. The Atlas 5 Super
Heavy seems to require new tooling for a wider core stage and a new
pad to launch it from.

For the SDLV, you're going to need new tooling: the "core" will be
substantially different, as it takes loads through different directions and
different attachment points;

Only the high-end, in-line SDLV. I'd stop at the biggest side-mount
design. 200,000 lbs. to LEO should be fine.

AFAIK, the 5-segment SRB isn't in service,

No, but it's been test-fired.

and
finally, I believe it will need a new pad to launch from (as the engines are
in a different place on the vehicle, among other things).

Well, for the in-line a new MLP at least. A stretched tower, too, but
the VAB and pad infrastructure should all be usable with relatively
little modification. You'd need a lot more than that for the Atlas
5-Mega Heavy at, say the old Pad 40 site. The VAB was built for Saturn
V-class rockets (with growth potential out to Nova) but the
Titan-heritage infrastructure at 40/41 is far too small for Atlas
5-Mega.

Since we're talking about NASA, Atlas 5-Mega would almost certainly
end up launching from Complex 39. Might as well choose the vehicle
that will need fewer mods... that would be SDLV.

Brian

gb wrote:


For the "in-line" design ---
Where is the equivalent Instrumentation Unit (Saturn V reference) going to
be located? Granted with today's electronics this can be significantly
smaller -- and much more powerful -- BUT the Apollo 12 launch proved the
advantage of a separate or redundant system for the launch vehicle from the
payload computing system.


There's quite a bit of space in the intertank area, together with
electronics and cabling for the tanks and solid rockets, so another few
boxes ought to fit in there pretty easily. The guidance computers,
gyros, etc will certainly take up a lot less space than the S-V
instrument unit...


--
I was punching a text message into my | Reed Snellenberger
phone yesterday and thought, "they need | GPG KeyID: 5A978843
to make a phone that you can just talk | rsnellenberger
into." Major Thomb | -at-houston.rr.com

On Sun, 26 Jun 2005 19:17:11 GMT, in a place far, far away,
made the phosphor on my monitor glow in such a
way as to indicate that:


From: h (Rand Simberg)

Yes, I suspect that the only thing that they can really use from the
existing ET program is the barrel sections. Otherwise, it's really a
new tank.

You don't think they'll need more wall thickness in that area?

I'm guessing not. Considering that you're already carrying well over
a million pounds of LOX at the top of the structure, adding another
quarter of a million pounds probably won't make that difference.

Hi!

Brian Thorn writes:
True, the in-line will need a new ET, but the 5-segment SRB /
side-carrier doesn't, and that chart shows it with 200,000 lbs. to LEO
capacity. Why the heck do we need the in-line, especially if the crew
is going up on a separate launcher (the Stick)?

Possible benefits:
If it is intended to be used for a very long time it would be kind of
strange to limit the payload to roughly shuttle dimensions. An inline
design gives a lager payload diameter.
A simpler layout that should be slightly cheaper to produce.
The larger diameter might make it easier to use cheaper RS-68 engines.
It could give a margin to downgrade the "ET" to a cheaper aluminium
alloy but that would probbaly not make economical sense.
Trading some of the mass margin for robustness in the design could
make the development work easier.

Btw, a side by side stick might make more sense. That might make it
possible to use exactly the same solid booster for both the heavy
booster and the "stick". But it would give a long and thin second
stage not suitable as a second/third stage for the heavy launcher.
2/3 Arianne V? :-)

An intresting possiblity with that idea is that identical solid
boosters makes it easier to in the future replace the solid boosters
with a reusable liquid fueled booster.

Best regards,
--
Min politiska hemsida http://www.lysator.liu.se/~redin
uppdaterades senast 2004-04-19.
Magnus Redin, Klockaregården 6, 586 44 LINKöPING, SWEDEN
Phone: Sweden (0)13 34 00 676 or (0)705 16 00 46