Launch of GRAIL twins slips to Saturday

NASA's GRAIL twin spacecraft await launch atop a United Launch Alliance Delta II rocket at Cape Canaveral Air Force Station [NASA].

The launch of a Delta II vehicle carrying NASA’s Gravity Recovery and Interior Laboratory (GRAIL) was scrubbed once again to Saturday morning, to provide "additional time to review propulsion data from Thursday's detanking operation." The Delta II and GRAIL remains safe and secure, and the launch has now been tentatively rescheduled for September 10, from Space Launch Complex-17B at Cape Canaveral Air Force Station. There are two instantaneous launch opportunities at 12:29:45 and 13:08:52 UT.

Emily Lakdawalla of The Planetary Society quotes professional launch photographer Ben Cooper, "This is the final Delta mission from Complex 17 after nearly six decades of launches from this, the oldest active pad still in use at Cape Canaveral. Complex 17 saw its first launch in January 1957, from Pad B, and its first space launch in 1960 when Echo 1, the world's first communications satellite, failed to make orbit on what was the first Delta vehicle by name, having been transitioned from the Thor IRBM."

NASA's Jet Propulsion Laboratory, Pasadena manages the GRAIL mission, and the Massachusetts Institute of Technology, Cambridge, is home to the mission's principal investigator, Maria Zuber. Using a precision formation-flying technique, the twin GRAIL spacecraft will map the moon's uneven mass. The result should be the most accurate gravity map of the moon ever made. The mission also will answer longstanding questions about Earth's moon, including the size and nature of mass concentrations, "voids" of low desity materal and the Moon's possibly liquid inner core.

SpaceflightNow.com is sponsoring live streaming video of the launch. More information about GRAIL is online at: http://www.nasa.gov/grail and http://grail.nasa.gov .