On July 2, another delayed mission launched to orbit. Virgin Orbit’s Straight Up mission was supposed to launch on June 30 as well but was delayed because of propellant temperature issues. That’s one of the downsides you get with a mobile launch system – it’s more difficult to condition liquid propellant after the plane takes off. Having propellant too warm or too cold can cause problems when entering the rocket engine, so the mission team made the best decision to take the time and make sure everything was right.

Straight Up, or STP-S28A as it was called by its customer the U.S. Space Force, was a collection of seven CubeSats for various government agencies but also one private company. These CubeSats had such fanciful backronyms as Gunsmoke-L, NACHOS 2, and Slingshot 1. Those satellites are for the U.S. Army, Los Alamos National Lab, and The Aerospace Corporation, respectively.

An hour before the drop, the Cosmic Girl 747 launch platform took off from the Mojave Air and Space Port in California and headed over the Pacific Ocean. Once in the drop zone, the team conducted one final poll and then dropped the rocket, which headed off into space. One burn of the upper stage took it into a parking orbit. An hour later, the second stage relit its Newton-3 engine and placed the seven satellites into their target orbit, which was a 500-kilometer circular orbit inclined 45 degrees to the equator. That particular orbit is not usually reachable from the west coast but can be with the air-launched system that Virgin Orbit uses.

More Information

PDF: Straight Up press kit (Virgin Orbit)

Virgin Orbit rocket launches 7 US defense satellites (AP News)