The Virginia-based company Orbital Sciences Corp. is expected to test-fire the first stage engines of its new Antares rocket at the Mid-Atlantic Regional Spaceport on Wallops Island, Va., between 6 p.m. and 9 p.m. EST (2300 and 0200 GMT). NASA's Wallops Flight Facility, also based on the island, is supporting the so-called static fire engine test, in which the Antares rocket will fire its engines without leaving the launch pad.

"The test is a key milestone leading up to the first flight of the Antares rocket, which is preliminarily scheduled for about four to six weeks following the completion of the engine test," NASA Wallops officials said in a statement.