Monday, February 15, 2010

SDO to Spike important Space Weather Data

Solar storms can wreak havoc on power grids, communications systems and delicate satellites. Currently, there's no way to predict severe space weather, but that could change with the heaps of information NASA's Solar Dynamics Observatory, or SDO, will send back to Earth after its 2010 launch.

"The biggest challenge of this mission was the data rate," said Liz Citrin, SDO project manager at NASA's Goddard Space Flight Center in Greenbelt, Md. "SDO will blast back 1.5 terabytes of information every day . . . that's equivalent to a half-million song downloads. It's unprecedented."

Citrin said there was no way to record that much data on board the spacecraft. Instead, the SDO team designed a mammoth 18-meter radio antenna, as well as a back-up, at White Sands Space Harbor in Las Cruces, N.M., to receive it all. Then, the data will be sent out to scientists at Stanford University in Palo Alto, Calif., the University of Colorado at Boulder, and Lockheed Martin's Solar Astrophysics Lab in Colorado.

The National Oceanic and Atmospheric Administration's Space Weather Prediction Center also is expecting to receive quick-look data the moment SDO is operational.

Another pretty cool technology developed by the SDO team to handle the data rate was the use of the Ka band, which recently was put to use for the Lunar Crater Observation and Sensing Satellite, or LCROSS, mission.

SDO has three major instruments on board that will send data back for at least five years, hopefully 10.

Both the Helioseismic and Magnetic Imager, or HMI, and the Atmospheric Imaging Assembly, or AIA, will allow scientists to see the entire disc of the sun in very high resolution -- 4,096 by 4,096 mm CCDs. In comparison, a standard digital camera uses a 7.176 by 5.329 mm CCD sensor.

AIA also will image the outer layer of the sun's atmosphere, while the Extreme ultraviolet Variability Experiment, or EVE, measures its ultraviolet spectrum every 10 seconds, 24 hours a day.

HMI will map the helioseismic and magnetic fields of the sun to understand its interior and magnetic activity.

"Space weather forecasting is in its infancy. . . just like hurricane forecasting was years ago. We built up experience in collecting data, designed models, tested those models, and now look what we can do," said Citrin. "SDO and all of NASA's Living with a Star Program missions will lead to better prediction of space weather."

SDO will travel to its geosynchronous transfer orbit aboard an Atlas V rocket, a trip that's been much anticipated. The mission was supposed to launch in August 2008, but the spacecraft team needed a few more months of test time.

"Atlas manifest challenges resulted in the current launch date in 2010. The mission team has been very patient and we're all happy to be launching now," said Rex Engelhardt, SDO mission manager.

NASA's Launch Services Program, or LSP, at NASA's Kennedy Space Center, began processing SDO for launch in July 2009.

Engelhardt said from the first day the team had to consider the spacecraft's high-contamination sensitivity.
Inside the Astrotech Space Operations facility in Titusville, Fla., technicians set up a laminar flow enclosure -- a four-wall clean enclose that blows air in one side and sucks it out the other -- keeping the spacecraft free of dust, particles, dirt and debris.

Another unique aspect of this mission is the rocket itself. Unlike other rockets assembled at the launch pad, Atlas rockets are put together in the Vertical Integration Facility on Launch Complex-41 at Cape Canaveral Air Force Station.

"Everything is protected until rollout, which right now is scheduled for Feb. 9," said Engelhardt. "If we needed to roll back, we perform a few disconnects and roll it back. The pad is just a slab of concrete, so after launch there's no tower to refurbish."

Things are looking good for Engelhardt and his LSP team members, who are ready to kick this year off from their home base. Last year they processed and launched eight missions, three from Vandenberg Air Force Base in California.

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