UPDATE at 9:00 p.m. Saturday: The shuttle Discovery launched on time tonight, apparently without a hitch. That clears the way for the launch of TacSat2 Monday morning from the Mid-Atlantic Regional Spaceport, at NASA's Wallops Flight Facility in Virginia. The weather there looks good for liftoff at 7 a.m. Earlier post follows.

I don't think I've ever had to tell readers about TWO rocket launches that might be visible from Maryland. But that's what we're looking at here over the next few days.

The launch of space shuttle Discovery, with Baltimore-born astronaut Robert Curbeam aboard, is now scheduled for 8:47 p.m. Saturday night, after its planned Thursday night launch was postponed.

Whenever it lifts off the pad, we can expect to see it crossing our sky - very low on the eastern horizon - about six minutes later. You can follow launch developments on NASA TV, which is available on some cable systems, and on the Web. There's also a Launch Blog here.

Assuming the Discovery launch goes off on schedule, we can expect the launch of a four-stage Minotaur rocket from the NASA Wallops Flight Facility sometime after 7 a.m. Monday morning. Watch for a story in The Sun Sunday morning. The Minotaur, carrying two government satellites into orbit, should be visible for hundreds of miles in all directions. Joe Rao, a columnist with Space.com, estimates that people as far as 800 miles from Wallops Island may be able to see it, weather permitting. Download rao.minotaur.txt .

Baltimore is 115 miles northwest of Wallops. Rao thinks people from Maine to Florida, and as far west as Kentucky might get a look. We'll see.

Here again, you'll need a clear view of the southeastern horizon. Check Wallops' website for news of flight delays.

Any delay in the Discovery launch Saturday would probably force delays in the Minotaur launch Monday, to allow Wallops personnel to shift gears and help NASA track the shuttle up the coast. Here's the forecast for Cape Canaveral, and for Wallops.