Yep, the Soyuz has abort modes throughout the whole launch. The shuttle doesn't have any between SRB ignition and SRB burnout, about two and a half minutes later. Even if NASA had detected the burnthrough at the instant the Challenger launched in 86, for instance, there would have been nothing they could have done.
Raider, I was on the feed and they said they scrubbed it because one of the four low fuel sensors in the hydrogen part of the ET was falsely triggered. It's important for them to have that because if they ran the tank dry, it would eat up the SSMEs (which are really highly strung, high performance rocket engines that don't react well to suddenly running dry).
The Soyuz design is really top notch, wish we had something equivalent in our inventory. The weight/performance advantages over the Apollo command module are pretty amazing. The Soyuz has two pressurized compartments, one in back where they sit during launch and re-entry, and one up front that has the docking module, toilet, living room, etc. When they re-enter, they get rid of the propulsion/power module behind them and the living room section in front so it's a tiny compartment that does the re-entry. Less need for heat shield, reduction in weight that's launched, etc. There are some remarkable similarities between the Soyuz and the GE Apollo reference design of the 1960s...
but that's fodder for spy buffs.
One final thing about the Soyuz, it launches on a Soyuz booster which is a direct evolutionary descendant of the R-7 booster that put the original Sputnik in orbit (first satellite). Look at the two boosters side by side, and it's immediately obvious that the Soyuz booster is the same R-7 structure (with performance and technology improvements, of course) with an extra upper stage. The great thing about this is that it's an evolutionary design. The US space program has, until now, started almost from scratch for each new manned vehicle. According to some memos, the new manned launcher (similar in size to a Soyuz) will launch atop a single SRB descended from the Shuttle design. Crikey.
