Antares Go For Launch

[UPDATE (Apr. 17, 21:00 UTC): The launch was aborted due to an umbilical coming loose from the second stage shortly before the launch window opened. It's unclear what happened at this time, but there will be no launch today, and it may be a day or two before they can try again. I'll have more information when I get it.]

[UPDATE 2 (Apr. 17, 23:15 UTC): Orbital has confirmed the earliest next possible launch attempt is Friday, Apr. 19, at 17:00 Eastern time (21:00 UTC).]

[UPDATE 3 (Apr. 18, 22:00 UTC): Orbital has announced the earliest launch attempt will be on Saturday, Apr. 20, at 17:00 Eastern time (21:00 UTC).]

[UPDATE 4 (Apr. 21, 21:15 UTC): At 17:00 Eastern time, the Antares rocket successfully roared into orbit, a pitch-perfect launch. Congratulations to Orbital Sciences Corporation and NASA!]

If you live in or around Virginia, you may get a treat tonight: a rocket launch. And this oneâs special: The company launching it, Orbital Science Corporation (OSC), will become only the second entirely private commercial business to launch a rocket into orbit.^*

The rocket is called Antaresânamed after a bright red supergiant star in the heart of Scorpius. Itâs a two-stage rocket that is designed to lift about 6100 kilograms (6.7 tons) into low-Earth orbit. It will be the workhorse of OSC, taking supplies to and from the International Space Station (ISS), as well as carrying independent satellites into orbit. This is all part of NASAâs commercial space initiative, of which I am an ardent supporter.

The launch tonight doesnât have a specific time, but the window for launch opens at 17:00 Eastern time (21:00 UTC) and lasts for three hours. UniverseToday has a great guide on how to view it if you live in the area. It should be visible as far south as South Carolina and as far north as Maine, but the closer you are to Virginia the better.

The rocket is launching from the NASA Wallops Flight Facility, not far from the Chincoteague Wildlife Refuge on the eastern shore of Virginia. I worked at Goddard Space Flight Center near DC for years, and never made it down for a Wallops launch. I wish I had, and Iâm very jealous of folks in that area who will see it (especially you, Kim Boekbinder).

This flight is a test to see if the rocket can get to orbit and deploy satellites, including one dummy module that has the same mass as the OSC Cygnus cargo delivery spacecraft, and a handful of smaller satellites. The planned orbit is an ellipse about 250 x 300 km (155 x 186 miles) above the Earthâs surface, and inclined at an angle of 51.6° to the Equatorâthe same tilt as the ISS orbit.

The launch will be streamed live on NASA TV. Coverage starts at 4:00 p.m. Eastern (20:00 UTC). I plan on watchingâIâm pretty excited about this, and any rocket launch is fun. Iâll live tweet it as well if I can.

^* Correction (Apr. 17, 15:20 UTC): I originally wrote that this would be the first launch of a rocket from Wallops that would go into orbit (as opposed to sub-orbital rockets); however, the first orbital launch from Wallops was Explorer 9 in 1961. My thanks to brx0 on Twitter for pointing this out.