Nasa to keep Shuttles existing Rockets

I didnt realize how powerful the shuttle setup is. As for the technology being outdated, look at the B-52, how old is that thing and it is still a great plane. However, I think the orbiter can be made better and an unmanned heavy payload orbiter should be made too.

ok, got it...I think it was a while back when I read that "50% at launch"...guess I shouldn't believe everything I read.

If all three SSME's do not reach a mandatory thrust of 90% over the course of the next three seconds, a Main Engine Cutoff command is initiated automatically, followed by the cutoff of all three SSME's and a number of safety functions.

If all three SSME's are performing normally, the Space Shuttle can be launched. The SSME's achieve full power at launch, but are throttled back at about Launch Plus 26 seconds in order to protect the Space Shuttle from aerodynamic stress and excessive heating.

The SSME's are throttled back up to full power at about Launch Plus 60 seconds, and typically continue to produce full power until shortly before the Space Shuttle reaches orbit. During ascent, each SSME may be gimbaled plus or minus 10.5 degrees pitch and yaw to help steer the Space Shuttle.

The SSME's typically burn for about 8.5 minutes after launch. At about Launch Plus 7 minutes, 40 seconds the SSME's are throttled down so that the Space Shuttle will not experience gravitational force in excess of three g's. Gravitational forces in excess of three g's might adversely affect the Space Shuttle and its crew.

At about ten seconds before Main Engine Cutoff (MECO), a MECO sequence begins. About three seconds later, the SSME's are commanded to begin throttling back at intervals of 10% thrust per second until they reach a thrust of 65% of rated power, called minimum power. Minimum power is maintained for just under seven seconds, then the SSME's shut down.

For a different idea than the shuttle with all the same infrastructure, check out;

www.astronautix.com/lvs/ares.htm

Originally posted by Realist05
For a different idea than the shuttle with all the same infrastructure, check out;

www.astronautix.com/lvs/ares.htm

That site said a redesigned tank to hold loads above it. If the CEV will be on top instead of the side, would they need to redesign the tank to make it capable to hold the 20 ton CEV, or can it hold it? Whats the tank made of of? I'm assuming aluminum, but I hadn't thought about the fact if it can hold over 20 tons above it.

Also, the very first link in my first post said that they would only need 1 SRB for the CEV...that would be an odd looking stack.

I've seen the pictures of the single SRB booster concept, too. Gfiffen seems to be leaning that way.

NASA's CEV spec called for a 20 metric ton (44,000 lb) liftoff mass - which would include the escape system. This is roughly the mass of an earth-orbital Apollo CSM (Apollo 7, Skylab, ASTP), so that must have been NASA's starting point for CEV. Recently, Griffin has been talking about 30 metric tons (66,000 lbs), but that seems to be for lunar missions (and would
also be in-line with Apollo lunar mission CSM masses).

The ARES heavy lift concept is about 10 years old, the attraction being the little amount of VAB, crawler and hardware change to accomodate it. The problem is that it would still be expensive.

I suspect Griffen does not want NASA using the new Delta or Atlas, which are newer tech but not lower cost unless a higher launch rate could achieved. The problems with having to launch 3-4 or either to put together a lunar or mars mission in LEO are considerable.