NASA solar observatory to probe Sun

NASA used a United Launch Alliance Atlas rocket to blast its 6,800lb Solar Dynamics Observatory into an orbit 22,300 miles above Earth.

The $808 million spacecraft will ultimately study the Sun and send back what NASA called a prodigious rush of pictures about sunspots, solar flares and a variety of other never-before-seen solar events. The idea is to get a better idea of how the Sun works and let scientists better forecast the space weather to offer earlier warnings to protect astronauts and satellites, NASA said.

The Solar Dynamics Observatory will deliver high resolution images of the Sun ten times better than the average High-Definition television to help scientists understand more about the Sun and its disruptive influence on services like communications systems on Earth. Specifically, NASA says the SDO will beam back 150 million bits of data per second, 24 hours a day, seven days a week. That’s almost 50 times more science data than any other mission in NASA history. It's like downloading 500,000 iTunes a day, NASA stated.

Key to the satellite’s operation will be three high-tech telescopes:

• The Helioseismic and Magnetic Imager (HMI) will look into the sun and map the plasma flows that generate magnetic fields. HMI will also map the surface of the magnetic field, NASA said.
• The Atmospheric Imaging Assembly (AIA) will image the solar atmosphere in multiple wavelengths that cannot be seen from the ground. The idea is that HMI and AIA will link changes on the solar surface to the sun’s interior, NASA said. AIA filters cover 10 different wavelength bands, or colors, selected to reveal key aspects of solar activity. The bulk of SDO's data stream will come from these telescopes, NASA said.
• The Extreme Ultraviolet Variability Experiment (EVE) will measure how much radiant energy the sun emits at extreme ultraviolet wavelengths—light that is so completely absorbed by our atmosphere it can only be measured from space, NASA said.

The satellite will also be placed in what NASA called a unique orbit. Unlike a geostationary orbit, which would keep the spacecraft above the same area of Earth all the time, the satellite will trace a figure-eight path above Earth, NASA said.

The orbit will let SDO watch the sun almost 24 hours a day, seven days a week, for at least five years with only brief interruptions as Earth passes between SDO and the sun, NASA said. To gather data from SDO’s instruments, NASA has set up a pair of dedicated radio antennas near Las Cruces, New Mexico.

The orbit will also let high resolution images be recorded every three quarters of a second, producing enough data to fill a single CD every 36 seconds, NASA said. The SDO will providing in-depth information about the Sun’s magnetic fields and space weather generated by solar flares and violent eruptions from the Sun’s atmosphere known as Coronal Mass Ejections.

Such powerful ejections are of particular interest because they can carry a billion tons of solar material into space at over a million kilometers per hour. Such events can expose astronauts to deadly particle doses, can disable satellites, cause power grid failures on Earth and disrupt communications.