Update (7:00 p.m. Pacific time): Well, that'll teach me to go to dinner! A few minutes after the abort, the folks at SpaceX figured out what happened: sensors said the fuel was too cold. Well, that's enough to fix. They waited a little while! A phone call interrupted my dinner: a friend was telling me the launch was two minutes ago! Figures. Evidently, the second reached 300 km, which was the objective, but (for reasons I don't yet know) it re-entered the atmosphere. According to Space Pragmatism, Elon Musk (head of SpaceX) said that 90% of the goals were achieved, so this was an excellent day for the company.
My congrats to the whole team!
Update (5:07 p.m. Pacific time): NUTS. Aborted. I'll have more info later.
OK, SpaceX has reset the launch of the Falcon 1 rocket for 5:05 Pacific time today (Tuesday). I have heard they are loading the liquid oxygen into the tanks right now. The weather looks good, too. Let's hope they do it tonight!
Yesterday's launch abort was due to a software glitch; nothing serious (it was a minor difference between how simulations are run and how real hardware behaves; a reality in testing that can be totally innocuous or can lose you your ship). They decided to take a day to breathe and make sure the fix was correct, and they are ready to go now -- just an hour or so from when I write this.
Updates will be posted in this entry as I hear them.
Update 1 (4:29 p.m. Pacific time, T-37 minutes): NASASpaceFlight (not a NASA site) has a lot of info on this launch and the payload. Basically, the rocket is launching a package that provides information on how the rocket is performing. The second stage of the rocket will be placed into a low-Earth orbit, and they'll be getting telemetry on it.