Observatory's Mirror Inspected, Prepares for Deployment
The Stratospheric Observatory for Infrared Astronomy, or SOFIA, has completed an avionics upgrade and is currently undergoing inspection and maintenance of its telescope assembly. Should the observatory’s mirror be cleared for flight and preflight operations proceed with no anomalies this week, SOFIA will depart for the German Aerospace Center’s annual open house to be held Sept. 18, in Cologne, Germany.
On August 25, during a routine inspection of temperature and pressure sensors mounted on the non-optical side of SOFIA’s 2.5-meter (100-inch) primary mirror, technicians noticed that about one dozen of the more than 110 aluminum sensor wire tie-down tabs had detached. When the sensor tabs separated from the back surface, the adhesive used to attach the sensors took some of the mirror material with it. Each blemish was smaller than a postage stamp.
NASA managers immediately stood-down science operations to investigate the issue and determine whether any risks could be associated with continued operations. To help assess this risk, experts were brought in from industry and academia to supplement the SOFIA staff. The process to evaluate the mirror and assess the risk going forward took approximately 10 days.
"This week we have been working our way through the analysis and repair of the tabs on the SOFIA mirror," said NASA SOFIA Program Manager Bob Meyer. "The program met Sept. 9 and we received approval of our plan going forward from NASA Headquarters. In reviewing our plan, it was determined that we could not make the originally planned Sept. 15 departure for the German deployment, but could depart one day later on Sept. 16. Our goal is to obtain science data on the legs to and from Germany, and while some of the outreach goals in Germany will be compromised, the deployment is still very worthwhile and most of the original goals can be met. SOFIA staff will assess the progress daily and determine at close of business each day if we are still on track for the Sept. 16 departure."
During the time needed to inspect and repair SOFIA’s mirror, two previously planned science flights were postponed. They will be rescheduled for later this month or in early October.
SOFIA is a joint program of NASA and the German Aerospace Center, DLR, and is based and managed at NASA’s Dryden Aircraft Operations Facility in Palmdale, Calif. NASA’s Ames Research Center in Moffett Field, Calif., manages the SOFIA science and mission operations in cooperation with the Universities Space Research Association headquartered in Columbia, Md., and the German SOFIA Institute, DSI, at the University of Stuttgart.