Today at 10:10am ET (15:10 UTC) SpaceX will be launching an unmanned Dragon capsule, perched atop a Falcon9 rocket, to the International Space Station. The capsule is filled with about 1,200 pounds of supplies for the ISS crew, and it is scheduled to arrive early Saturday morning. The return trip, on March 25, will bring over 2,000 pounds of cargo back to Earth when Dragon re-enters the atmosphere and falls into the Pacific Ocean. Both NASA and SpaceX are covering the launch live. For text and pictures, you can watch on SpaceX Launch Central or NASA's launch blog. For streaming video, check out NASA TV. Spaceflight Now has both, and their live updates provide a bit more detail. SpaceX's press kit for the mission (PDF) explains how the launch will proceed: "At 1 minute, 10 seconds after liftoff, Falcon 9 reaches supersonic speed. The vehicle will pass through the area of maximum aerodynamic pressure—max Q—15 seconds later. This is the point when mechanical stress on the rocket peaks due to a combination of the rocket’s velocity and resistance created by the Earth’s atmosphere. Around 170 seconds into the flight, two of the first-stage engines will shut down to reduce the rocket’s acceleration. (Its mass, of course, has been continually dropping as its propellants are being used up.) The remaining engines will cut off around 3 minutes into the flight—an event known as main-engine cutoff, or MECO. At this point, Falcon 9 is 80 kilometers (50 miles) high, traveling at 10 times the speed of sound. Five seconds after MECO, the first and second stages will separate. Seven seconds later, the second stage’s single Merlin vacuum engine ignites to begin a 6-minute burn that brings Falcon 9 and Dragon into low-Earth orbit."