Solar Dynamics Observatory – Launch

The Sun
Image Credit: NASA
The Sun – Target for the Solar Dynamics Observatory
SDO on Altas V 401
Image Credit: NASA TV
SDO aboard Atlas V 401 – One Hour to Launch


At 7:30 AM Phoenix time (9:30 AM EST) the Solar Dynamics Observatory (SDO) is at T-minus 45 minutes in the countdown and 54 minutes from launch at 8:26 AM (10:26 AM EST). The entire rocket and payload is 191 feet tall, weighs 750,000 pounds at launch and will take off with 860,000 pounds of thrust .

SDO is a 5-year mission that will determine how the sun’s magnetic field is generated, structured, and converted into violent solar events like turbulent solar wind, solar flares, and Coronal Mass Ejections (CMEs).

Currently, the winds are above 20 knots with gusts at 28 knots. Winds would like to be in the low 20’s for a maximum.

Liquid Oxygen (LOX) loading has been completed and Liquid Hydrogen (LH2) for the Centaur upper stage has stated.

The Sun
Image Credit: NASA TV
T-Minus 30 Minutes

At 7:50 AM Phoenix time, LH2 loading is at 50%. There are no technical issues at this time.

SDO will observe the sun, from its deep interior to the outermost layers of solar atmosphere, at the highest ever time cadence. SDO will snap a full disk image in 8 wavelengths every 10 seconds… SDO will send down about 1.5 terabytes of data per day, equivalent to downloading half a million songs each day. SDO’s spatial resolution gives it a tremendous advantage over earlier missions. All solar images will be 4096 pixels x 4096 pixels—almost IMAX quality.

At 7:58 AM Phoenix time, LH2 loading is complete. There are 12,000 gallons of LH2 and 4,000 gallons of LOX in the Centaur stage.

SDO Payload at T-Minus Four Minutes
Image Credit: NASA TV
T-Minus Four Minutes

We are now in the built in hold at t-minus 4 minutes. There are no technical issues. The wind conditions are above requirements and the hold will likely be extended all the way through to the end of the launch window at 9:26 AM Phoenix time (11:26 AM EST). The wind conditions are expected to improve towards the end of the launch window.

At 8:30 AM Phoenix time, launch is expected no earlier than 8:56 AM (10:56 AM EST).

The Atlantic Range has confirmed the launch area is clear (no planes, no boats) for launch. We are waiting on the winds. Comment from the Forum at NASASpaceFlight: “If these winds are the same ones that passed over the Gulf Coast yesterday, don’t look for any relief. They just got worse and the temperature just dropped all day long. Today is much calmer but frigid.”

The Launch Director has polled all systems, and they are go. The winds are not cooperating, and the launch will be delayed until 9:26 AM Phoenix time. The count would resume at 9:22 AM (11:22 EST). SDO has been put back on external power, and will be put back on internal power a few minutes prior to resuming the count.

The launch has been scrubbed due to wind, and rescheduled for tomorrow.

Image Credit: NASA
Solar Dynamics Observatory Toward the Sun
Image Credit: NASA
Observatory End of SDO


There are three instruments on board the Solar Dynamics Observatory:

  • Helioseismic and Magnetic Imager The Helioseismic and Magnetic Imager (HMI) will measure sound waves reverberating inside the sun to build up a picture of the interior.
  • Atmospheric Imaging Assembly The Atmospheric Imaging Assembly (AIA) will take highresolution pictures of different layers in the sun’s atmosphere to further understand how changing solar magnetic fields release the energy that heats the solar corona and creates flares.
  • Extreme Ultraviolet Variability Experiment The Extreme Ultraviolet Variability Experiment (EVE) will measure the sun’s ultraviolet brightness. The sun’s extreme ultraviolet output constantly changes. Slow variations in ultraviolet flux affect Earth’s atmosphere and climate.

3 thoughts on “Solar Dynamics Observatory – Launch

  1. Pingback: Solar Dynamics Observatory – Launch – Day 2 « The National Space Society of Phoenix

  2. Pingback: February 2010 « NSS Phoenix Space News

  3. Pingback: April 2010 « NSS Phoenix Space News

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