Wednesday Launch Scrubbed Due To High Levels Of Radiation In Space

Orbital Sciences has confirmed it will proceed with a launch attempt from NASA's Wallops Flight Facility in Wallops Island, Va. at 1307 EST Thursday, Jan. 9 of its cargo resupply mission to the International Space Station, pending closeout of all remaining prelaunch reviews and tests.

Wednesday's launch of Orbital's Cygnus cargo spacecraft on an Antares rocket was scrubbed because of high levels of space radiation that exceeded established rocket constraints. Orbital conducted a comprehensive review Wednesday of data related to the radiation environment in space, the rocket’s avionics systems, and weather forecast at Wallops. Following the review, Orbital’s engineering team, in consultation with NASA, determined the risk to launch success is within acceptable limits established at the outset of the Antares program.

A Thursday launch would result in the Cygnus spacecraft arriving at the space station early Sunday, Jan. 12.

Monitoring for space radiation – which refers to excessive high-energy protons in near-Earth space, often funneled in from space in association with an event on the sun such as the solar flares and associated coronal mass ejections that occurred on Jan. 7, 2014 – is a standard protocol for any launch attempt.  Excess radiation can affect the critical computer systems aboard the launch vehicle.

"The launch vehicle avionics do everything from guiding the rocket, to telling it when to start up, to moving it through the various stages, to communicating with the payload after it has been ejected," said Chris St. Cyr, a space weather scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "If there's too much radiation these crucial systems could be damaged."

There are two ways that the radiation can cause problems. First, a single well-aimed proton can interfere with the electronic systems, causing circuit damage or system shut downs. Second, a strong dose of radiation can cause degradation of microelectronics. Such radiation effects are also of concern to satellites that orbit high above Earth, and in the face of a strong proton storm spacecraft operators sometimes put their spacecraft into safe mode for added protection.

(NASA Image Antares rocket on Wallops launch pad)

FMI: www.nasa.gov/station