Sorry, feeling a bit post happy today...FYI a 5 seg SRB weighs almost 1.6 million lbs ready to go. Unlike a liquid engine, you have to carry all that mass to the pad (liquids fill at the pad). They weigh almost an order of magnitude more than the empty tank / spacecraft. Thus, adding two more doubles your weight and is much to heavy for the crawler - so upgrade crawler, and for the crawler way - so rebuild path. It's just way too expensive when you could better design your spacecraft.
I am assuming the longer SRB's give you longer burn times rathar than just more (thrust), but I'm not sure. As I understand they burn from the inside out, top to bottom, so a reduced orafice will extend burn time?
That would be the same Lockheed-Martin that gave us the mass estimates for X-33 and Venture-Star?
Existing? Human rated Delta doesn't exist yet as far as I know.
Quote from: kraisee on 01/13/2009 04:25 amFifth is the fact that the SRB's were never designed to be utilized in this fashion with hundreds of tons of stage and payload on top. They just weren't designed for these loads.Why are these loads a big issue for the SRB, but not for Jupiter's ET-based core stage? Is it because the core (being mostly tanks holding the liquids) can be redesigned to handle the loads, but the SRB can't be modified similarly?Steve
Fifth is the fact that the SRB's were never designed to be utilized in this fashion with hundreds of tons of stage and payload on top. They just weren't designed for these loads.
I'm thinking of going with "I'm A Direct Fan Boy, and Proud Of It!"
Quote from: mrbliss on 01/13/2009 02:51 pmQuote from: kraisee on 01/13/2009 04:25 amFifth is the fact that the SRB's were never designed to be utilized in this fashion with hundreds of tons of stage and payload on top. They just weren't designed for these loads.Why are these loads a big issue for the SRB, but not for Jupiter's ET-based core stage? Is it because the core (being mostly tanks holding the liquids) can be redesigned to handle the loads, but the SRB can't be modified similarly?SteveRoss months ago I showed that the Ares I and Shuttle put the same loads on the SRB. Remember the SRB lift from the forward attachment
Quote from: clongton on 01/13/2009 03:55 pm1. Negative 11 nm x 100 nm is not an orbit - it's a crash and it's not useful for anything. It takes you 11 nautical miles beneath the surface of the earth. That "orbit" is a trajectory that safely disposes of the US just as Shuttle does with ET. If you bring with you the US to a stable orbit, then you need to deorbit your US (some solids and pyrotechnics involved... again impacting LOC/LOM). But now since the US is insulated in foam, you can't deorbit the popcorns...
1. Negative 11 nm x 100 nm is not an orbit - it's a crash and it's not useful for anything. It takes you 11 nautical miles beneath the surface of the earth.
-11x100nm is useful orbit for Orion.
It was just an analagy. But the my point is still converting an exsting vehicle to do something it was never intended to do, -can- be much more involved than one thinks it might be, and in the end, you can end up with basically a morphidite in a role it was never intended for and a purpose built-vehicle would have been a better option.The SST was never intended to carry nose payload, or have thrust directly under it, or go beyond LEO.This is part of the issues with those thinking about using the EELV's for man missions.