I didn't come up with all of these on my own (namely #1, #2) but here goes...
1.) Forget having an external fuel (ET) tank. The shuttle engines only produce 29% of the thrust for launch anyway. The SRB (Solid Rocket Boosters)
produce the other 71 percent. Add another one of those and the system weighs less (at least 300,000 pounds less from my calculations), produces a
little bit more power(1.5 times 71% or 106.5%), you don't have the foam problem because of different fuels that don't require insulation (not cold
liquid H2 and O2, but solid fuel) and every piece of the system is reusable ET was the only part not, SRB have parachutes and fall in ocean).
2.) Put foam insulation on the inside of ET so it is less likely to fall (less air resistance), less likely to be quickly accelerated because of
contact with outside air vs. relatively stationary inside air (less potential damage) and is not going to damage the shuttle, but only possible the
ET. Downsides are that the foam could then damage the ET and cause an explosion by damaging both the H2 and O2 tanks or it could hinder ET fuel to
shuttle causing either it crashing or not getting to its required orbit. A double skin (making system heavier) could address these problems. Also,
this idea could not even work at all if it doesn't prevent ice build up like the foam on the outside did.
3.)Redesign fuel tank so that at least 10 minutes before launch, you turbo pump O2 and H2 into tanks. The O2 and H2 tanks then are not cold for as
long and that prevents ice build up and no insulating foam is needed. There are tanks at the launch site that holds them. This is entirely possible,
as all the fuel is siphoned to the engines in 9 minutes in a regular launch as ET is separated at the point. Problems with this is that you might
crack the tanks by to rapidly and uneven change of temperature. If need be, extend filling to longer or pre cool or I guess you could pre-chill the O2
an H2 tanks.
4.) Go along as is. If you get dinged up by foam, don't return (wait on ISS) and get back on down by a different shuttle that is ready as a
precaution to a certain degree. Ways to detect problems have been improved (sensors). From my calculations, being on the shuttle on average at any
given moment is 3,000 times more dangerous than 'accidental' death at any given moment on Earth (car crashes, chain saw mistakes etc.). In other
words, the Deaths per man-hours on the shuttle is 3,000 times what 'accidental' deaths per man hours in the U.S. is. Given that the U.S. is probably
relatively safe, and given that this is space travel, is that a reasonable risk? Also, this is taking into account from the beginning up until now,
and the Shuttle is more safe now than it was on its average flight in the past IMO.
5.) Launch a emergency crew recovery vehicle (ECRV, not sure if I made that up) in various orbits that make one always accessible to the crew. It can
seat 7 people and is an Apollo style ablative shielded reentry vehicle. The shuttle docks if there is a problem, and the crew returns home leaving it
in space. Measures then can be taken to recover/repair it when it is safe, technical issues have been worked out, and the technology is available. You
can leave it up there and say "1 down, 3 more to go. Heck, now have two habitable space stations and also an ISS space ferry". You can also just
always keep one in the cargo bay or when you are heavy lifting to ISS, have one stationed there and use the room. This would be economical as it would
get the Shuttle back and also complete a needed program that had a spacecraft onboard ISS for transport.
6.) Replace foam with a skin (well, just cover it completely) of coils (like those in a toaster/light bulb) that is extremely close to the outside
wall and that heats it. Ice doesn't build up as you might be able to get it to above freezing and you don't need foam. Other variations on the theme
of heating the outside better is you could use ground based lasers or heaters (doesn't increase ET weight) or you could launch in a low humidity high
temperature area. That ladder could cause problems though. I think launch facilities for the Space shuttle are Vandenberg and Kennedy Space Center
(KSC) and that is it. You would probably have to build another site as you still want to be able to recover the SRB (nice if the land in an ocean) and
that might be best or only practical out of country (hotter climate, less populated areas to avoid for safety so you can also do polar and equatorial
launches from the same place unlike now). Out of country would increase assembly costs, but it would be in the name of safety. Maybe we could convert
a used up offshore oil platform. ship transport would be an efficient transport for the shuttle equipment.
Any other possible methods that I missed? Any critique on these methods that makes them unlikely to work? Which one is best in cost? safety? What are
the further technical details of implementation beyond if it could work? How much would each measure cost (one time vs. long term) and how long will
This post is dedicated lovingly to the Shuttle Program nay-sayers.
I see a new shuttle (upgraded) but very similar to the current one (to save
design costs) as a possible way to get to the Moon, but that is for some other time. So, I definitely believe the program is worth it as well as the
ISS. Reusable space vehicles and space stations are the future for space travel. So, we always have to be experimenting with this stuff if NASA/ESA is
to do anything. How much airplane versions were built to get as good at building and designing them as we are now? How much flights? How many
disasters and crashes? That is what space travel is going to take.