Space Forum / Shuttle / May 2004

That is one possibility.  There are two others.  Use of commercially
available vehicles (e.g. Delta IV and Atlas V) is one, and development
of a completely new launch vehicle is the other.

That's a topic for debate, as evidenced by recent threads in this
newsgroup.

Not without extensive modifications to the ET and the MLP's.  Big
changes like this are less shuttle derived and more new launch
vehicle.  Furthermore, if you're going to extensively modify the ET
and MLP's, why keep the solids at all?, The SRB's are an undesirable
part of the system, mostly due to safety concerns.

Actually the solids have been reliable, when compared to the
reliability of other launch vehicles.  The shuttle isn't really
statistically safer or more dangerous than many other launch systems.

The problem is that the failure modes of large solids tend to result
in complete loss of vehicle and crew.  They also can't be shut down if
there is a problem, further increasing the chances of catastrophic
failure.

This has been discussed in this newsgroup in the past.  The short
summary is that it's very difficult to do this with the current design
due to both manufacturing and transportation issues.  In other words,
they're too big to be convienently made monolithic.

This has been discussed in the past.  Google will turn up lots of info
on SRB pollution, including the release of clorine and such.  If
you're Google challenged, try searching for "nasa solid rocket booster
chlorine ozone".

Why do you ask questions that have obviously been answered in recent
threads?

The short answer is that NASA is looking at three options (in no
particular order):

  1.  Shuttle derived launch vehicle
  2.  Commercially purchased vehicle(s)
  3.  Newly designed luanch vehicle

You can find information on NASA "current eventS" on web sites such as
NASA Watch:

  http://www.nasawatch.com/

Jeff

It isn't an obviously terrible idea, as others have suggested, but it
all depends on the planned flightrate. Using Complex 39 will be
expensive, but there will be factors that mitigate those costs (i.e.,
abandoning toxic propellants, and shutting down the OPFs.)

A baseline SDLV should be no more expensive to develop than an EELV
upgrade to similar payload performance. Adding a fourth (and perhaps
fifth) core booster to the EELV will be a major expense, and I see no
way of approaching SDLV payload capabilities short of doing that.

Not without essentially starting from scratch.

Liquids tend to have better engine-out performance, but that's not
true of the EELV-Heavies. Lose and engine during Stage 1, and its
toast, just like an SRB failure.

That would greatly undercut the point of using existing components.

It depends on flight rate, but except for very high launch rates, no.

NASA should do that no matter what. Tell industry what it needs (x
pounds of payload to y orbit in z amount of time) and let industry
offer solutions. Unfortunately, it looks like NASA is heading down the
road of telling industry how to do it.

Brian

SD-HLLV ideas have been rattling around for at least 25 years. Remember the
Jarvis? It was a SD-HLLV design (named in memory of Greg Jarvis, a Hughes
Electronics employee/payload specialist, who perished on Challenger). It
consisted of a standard shuttle stack, except that the three SSMEs were
attached to the bottom of the ET and the 180,000-pound payload was stuck on
the top of the ET. NASA and Martin had worked out the ET structural mods
necessary to put the SSMEs on the ET bottom during the late 1970s as part of
the effort to get more payload lift from the shuttle for polar launches from
VAFB. And Boeing had done the mods to beef up the front end of the ET to
carry the payload.

Hughes and Boeing shopped the Jarvis design during 1986-87, but NASA was
involved in the Shuttle-C and ASRM projects and had no budget to spare. Like
dozens of other SD-HLLV ideas, the Jarvis is now just another historical
footnote.

Later
Ray Schmitt