The supply chain is gone:
To avoid any gap in providing independent repair spacewalks as a safety contingency for the space station, Congress, NASA and the ISS partners should evaluate the option of postponing the launch of STS – 135 until more external fuel tanks and other parts can be built to support additional shuttle flights in 2012.
2012? What are they smoking?
It would be at least two years, probably three, before they could resurrect the tooling and manufacturing needed to do this, and it would cost billions of dollars that NASA does not have, and isn’t going to get. Meanwhile, we’d have thousands of workers sitting around, forgetting how to launch safely. This is just crazy, and disappointing, considering the sources. Do they really so completely lack imagination that they can’t conceive of ways to do EVA and ISS repair and maintenance with what is currently coming on line, and not relying on an unsafe hyperexpensive vehicle? This is the product of emotion, not thought.
[Update early afternoon]
I have a sort-of-related bleg. I’m working on an article about the false lessons learned from the Shuttle, and how they’re continuing to screw up space policy. Suggestions in comments are appreciated. The first and most obvious one is that it proved reusables don’t reduce cost.
Arizona CJ Says:
I’ve never understood the Air Force insistence on massive cross-range. The explanation I’ve seen is so that the Shuttle, launching out ov Vandenberg, could do an abort-once-around. Due to Earth rotation, the non-crossrange return point would be 600 miles or more west (earth rotates at 15 degrees per hour), in the ocean. So, wouldn’t it have been a lot cheaper and safer to build the polar orbit shuttle launch facilities on the gulf coast instead?
You wouldn’t do this for the same reason why they don’t launch polar or sun-synchronous missions out of the Cape – range safety constraints. The goal is to avoid overflying populated areas where falling rocket stages (or debris) could hit people. A launch essentially due south from the gulf coast would overfly Mexico or other parts of Central America while doing that from the Cape would overfly Cuba.
The most powerful aircraft engine made is the GE90-115B which, at full chat, can crank out 127,900 lbs. of thrust (lbt). This is a civil aviation engine so no afterburner has ever been designed or fitted, but this is quite doable.
One of the problems with using an ultra-high bypass jet engine is that the design is optimized for subsonic flight. An engine like the GE90 has very large frontal area and trying to shove that past transsonic speeds would be quite difficult even if you did manage to fit it with afterburners. There’s a reason why supersonic fighters use relatively low bypass turbofan engines instead of high bypass engines. Those engines are also quite expensive, costing many million dollars each. Unless you have a way to recover them without exposing the innards to salt water, the cost per flight would be substancial.
I still think some form of flyback booster design using existig jet engine technology could be practical but I’d need to see some serious analysis. If you limit it to subsonic speeds, you could use airliner engines like the GE90. If you want to go supersonic, then use either older designs like the F100 or F110 (should be readily available with the number of F-15s and F-16s being decommissioned) or newer designs like those used to power the F-22 and F-35. The F-35’s P&W F-135 engine reportedly produces up to 43,000 pounds of thrust in afterburner with a dry weight of 3,750 pounds.
Quite so, Larry. My little thought experiment was never intended to go supersonic. Sorry if I didn’t make that clear. The putative afterburner is for extra thrust/lift capacity, not supersonic speed. I suppose a supersonic-capable version could, indeed, be cobbled up out of F-135’s, but it would take a lot of them. Don’t know if it would be worthwhile and I haven’t run any numbers. My notional flying donut was supposed to fly back to point of departure under its own power using fuel reserves carried along for the purpose. It wouldn’t use parachutes or get anywhere near the water so seawater resistance isn’t really much of an issue.