Solar Dynamics Observatory Spacecraft

The Solar Dynamics Observatory is a new spacecraft that NASA is launching to study solar activity and space weather. The new spacecraft is designed to take measurements of the Sun’s interior, its magnetic field, the solar corona, and the sun’s irradiance. To do this, the SDO has three main instruments.

The third of these instruments is the Atmospheric Imaging Assembly (AIA). The AIA is a collection of four telescopes which will photograph the Sun’s surface and atmosphere. The AIA uses a 4096×4096 thinned back illuminated CCD to capture the images of the Sun. The AIA will take these images across 8 different wavelengths (out of the 10 available wavelengths) every 10 seconds. This will cover nine ultraviolet or extreme ultraviolet bands, and one visible light band. It is anticipated that that scientists will discover how storms start on the Sun, and propagate through the Sun’s atmosphere. Read more after the break, including a the official video on SDO.

The CCD used in the Atmospheric Imaging Assembly.

Think about that for a moment. That is eight 16.78 million pixels images every 10 seconds. To handle that much data, the scientists will use both lossless RICE type compression and a lossy compression scheme based on Square Root binning. It is expected that SDO will beam back 150 million bits per second, or about 1.6 terabytes of data per day. That much data equates to over one-half of a petabyte of data per year. If that does not boggle your mind, then lets put it into context. That much data is like downloading 500,000 iTunes songs per day. That much data could be stored on 32 Blu-Ray disks per day.

From the SDO Guide:

SDO is going to send us images ten times better than high definition television,” says Pesnell, the project scientist for the new mission. A typical HDTV screen has 1280 x 720 pixels; SDO’s images will have almost four times that number in the horizontal direction and five times in the vertical. “The pixel count is comparable to an IMAX® movie—an IMAX® filled with the raging Sun, 24 hours a day.

The second of these instruments is the Extreme Ultraviolet Variability Experiment (EVE). EVE will measure the fluctuations in the Sun’s ultraviolet output. This radiation can effect the Earth’s upper atmosphere by heating it up. The heated atmosphere expands outward which can cause drag on satellites in orbit.

The third of these instruments is the Helioseismic and Magnetic Imager (HMI). The HMI will measure the magnetic field at the surface of the Sun to study the motions of materials inside the Sun. In particular, they want to understand better the origins of the solar magnetic field.

At solar maximum, the Sun is about 0.1% brighter than it is at solar minimum. … “Add it all up and you get a lot of energy,” says Judith Lean of the Naval Research Lab. “How this might affect weather and climate is a matter of—at times passionate—debate.”

The Solar Dynamics Observatory was supposed to launch today, but high wind gusts above the 20-knot limit prevented liftoff throughout the launch window. The next attempt will be on Thursday, when the winds are expected to be weaker.

via : No go for SDO today; next shot is Thursday
via : SDO Guide