Happy 8th Birthday, SDO!

It was a cold day at Cape Kennedy as SDO rose slowly into the sky. Eight years later, SDO has sent over 260 million images of the Sun to the ground. Over 3000 scientific papers have described how the Sun's magnetic field is created and destroyed. We have a large number of citizen scientists who study our images, especially using HelioViewer.

SDO still produces high quality data of the Sun every day. Even Solar Cycle 24 fades from view, we are watching the polar region magnetic fields grow. Large coronal holes can often be seen in the AIA coronal images. Solar Cycle 25 will soon be visible. SDO is ready!

Telstar 401, A Ghost of Space Weather Past

Earlier the week we received our conjunction report that lists satellites that will pass close to SDO. Our inclined geosynchronous orbit means there aren't a lot of satellites near SDO, but every couple of months one will come within 20 km (12 mi) of our spacecraft. This week saw the return of Telstar 401 to our list (see the picture at left.) Telstar 401 is a large telecommunications satellite that failed January 11, 1997, and has since drifted around the geostationary belt of satellites. This is not a small satellite, the solar panels stretch about 60 ft across. It's good to know the other satellite is around, but it would be better if was moved to a graveyard orbit well outside of the geostationary belt.

It is possible that Telstar 401 failed because of the activity created by a coronal mass ejection that rose off the Sun on January 6, 1997. (The gray picture at left shows what the CME looked like at 1850 UTC on that date.) The CME is the white arc moving down from the occulting disk. It is called a halo CME because we see it as a ring around the Sun, which means it is heading straight towards Earth!

The impact of the CME was not very dramatic when it reached Earth a few days later. But the energies of the radiation belt protons and electrons were increased enough that they caused an electronic component to arc and fail. There were several attempts to revive Telstar 401, but it was eventually declared a loss.

According to the Union of Concerned Scientists, there are almost 500 satellites currently operating in geosynchronous orbits about the Earth. Most of them are in the geostationary belt that allows them to appear stationary in the sky. There are about 100 defunct satellites in graveyard orbits further away from the Sun. But it is the failed satellites and spent boosters that blunder along and show up on the SDO conjunction report every month or so.

Telstar 401, a true ghost of space weather!

German-American Day 2011 and the Discovery of the Solar Cycle

Today, October 6, 2011, is German-American Day, when we celebrate the arrival of German immigrants in Philadelphia in 1683. Germans have worked in physics for many years. Joseph Fraunhofer discovered the spectral lines in the Sun we call Fraunhofer lines. We measure the brightness, Doppler shift, and magnetic field effects of those spectral lines on SDO to study solar activity. At left we show the spectrum near the iron line at 6173 Å used by HMI to measure the velocity and magnetic field at the surface of the Sun. The slight motion to the left and right is what happens as the surface moves back and forth.


Another German, Heinrich Schwabe, wrote down the number of black specks he saw on the Sun for almost 20 years. When plotted we see the number of spots rising and falling with about a 10 year cycle. Schwabe had discovered the solar cycle. Here is a plot of Schwabe's data from his article Sonnen-Beobachtungen im Jahre 1843. The rise and fall can be seen in the crosses that show the number of spots in each year. I drew a sine curve with a 10 year period so you can see what Schwabe announced. Also called the 11-year sunspot cycle, we still measure the number of spots and produce the Sunspot Number. Along the way we have invented many more ways to measure spectra and active regions.

Happy German-American Day!

The Origins of the Patch

I received a request to tell the history of the SDO patch. The patch is derived from the sticker developed early in the mission. Initial designs of the sticker were produced by a graphics designer using an early version of the spacecraft. After a redesign, the spacecraft was replaced with the current version; the sticker was re-issued (see the version at the left) and the patch was designed and released.

We are a solar mission and the Sun is prominently featured in the patch. The Sun is shown coming out of eclipse, which happens periodically from our geosynchronous orbit. The abbreviations for the three instrument teams are placed in the lower border, the NASA acronym is at the lower edge of the central image, while the motto "Our Eye on the Sun" is placed in the upper border. The name of the observatory is the uppermost element in the lower part of the central image.

The motto was generated by members of the SDO Project team working with people from NASA headquarters. It emphasizes the almost 24/7 coverage of the Sun that SDO provides. It calls back to other sayings, such as "Don't Look at the Sun, That Our Job" that we had seen in other solar missions.

SDO is now in its operational orbit and producing the data that lives up to its motto.

SDO/EVE Calibration Rocket Delayed

White Sands Missile Range has notified the EVE team that their calibration rocket is now delayed. The team will safe the payload and return to Boulder to await a new launch date.

AIA Images are Delayed in Processing

As of 10:00 am ET this morning the AIA images are about 15 hours delayed. The problems with the ground processing software have been corrected and the AIA data is being transferred to the JSOC in a FIFO queue. This means the earlier data is being sent before today's data. All science data has been captured from the instrument. HMI and EVE data are current at this time.

Solar storms and space weather were a feature at this year's meeting of the AAAS in Washington, DC. Story (including an AIA image) is at Space.com.

SDO Calibration Rocket, February 23, 2011

The next launch of our EVE calibration payload is on NASA sounding rocket 36.275 planned for February 23, 2011 from the White Sands Missile Range (WSMR). This flight will provide the second underflight calibration for the SDO EUV Variability Experiment (EVE) instrument. The first calibration rocket flew on May 3, 2010 (NASA 36.258, the Black Brant rocket is shown "on the rail" at left).

The launch window is from 11:20-11:50 MST. This is near local noon to minimize the atmospheric absorption of the solar EUV radiation observed during the rocket flight. Unlike the TIMED rockets, where SEE had to also be turned on, EVE is taking data all the time.

More information is at the LASP Rocket webpage.

Due to security regulations, we cannot provide realtime coverage of the launch.

SDO Launched One Year Ago!

At 10:23 am ET February 11, 2010, SDO launched from SLC 41. 108 minutes later SDO became a spaceship!

Happy Birthday SDO!

Today's Delta-H Maneuver

At 1940 UT (2:40 pm ET) on February 9, 2011 SDO will execute a Delta-H maneuver. This is a planned activity. Science data will be interrupted for about 30 minutes. The actual duration will be determined by the onboard software as it changes the reaction wheel speeds and fires the thrusters of the spacecraft to complete the maneuver. The goal is to adjust the reaction wheel speeds so we can maintain the pointing of the spacecraft over the next few months.

Here is a picture of a test thruster being fired on the ground in 2006 (we cannot see the actual thrusters on the spacecraft.) The thrusters should fire for up to 4 seconds.

UPDATE: The maneuver was completed using 66.6 gr of propellant with the thrusters firing for 4.05 sec. The satellite was pointing away from the Sun for about 15 min.

SDO Images are Available

The JSOC is repaired, the pipeline is running, and the images are again flowing to our near-realtime partners. Just in time for the region with the large prominence that erupted at the beginning of December to come across the disk.

Happy New Year, but better, Happy Perihelion at 1900 UT (2 pm ET) today!

SDO app for Android Phones

Check out the new SDO app at the Android marketplace! You can view SDO images on your Android phone anywhere you have a network connection.

We will feature other apps that show SDO data this week.

Guide Telescope Adjustments

Today (December 9) the AIA Science Team is adjusting the guide telescopes on AIA. One of these small telescopes is mounted above each science telescope, allowing the pointing to be precisely controlled. Every so often we need to tune the control tables. Today was one of those times. Small motions of the images will be seen in the data on the SDO website.

SDO Weekly Report for November 19, 2010

Based on discussions with the science teams, it was decided to use the new offset procedure for future Lunar Transit operations to minimize instrument off-pointing during the transitions from Science to Inertial mode and back.

Obtained agreement from the HPA vendor to replace all DC fans with AC fans to improve reliability. The repairs will be done on a rotating cycle to continue operations while units are being repaired.

SDO Weekly Report for November 11, 2010

The second HGA handover season ended on November 1. Operations went smoothly throughout this handover season and another Lunar Transit on 11/6. The data capture completeness for October was 99.94% for all three Instruments. Only rain on DOY 278, a spacecraft station-keeping maneuver on DOY 279, and the HMI Roll calibration on DOY 285 kept us from 100%.

The Inertial/Science mode pointing test was run on Wednesday, 11/10 between 1800 to 1830 UTC. This tested the STOL procedure that redefines the target attitude to minimize the attitude shift between Science and Inertial modes is minimized. This will benefit future Lunar Transit operations.

The "Sun as an Andy Warhol Poster," made from an AIA image, can be seen in the background of an episode of The Big Bang Theory on CBS, with a short clip on Youtube.

The Moon Gets in the Way (again)

Here comes the Moon! Right on schedule the Moon passes between SDO and the Sun, seen here in the AIA 171 bandpass. We use these transits to understand the pointing of the spacecraft. One of these transits will someday block out an active region so that we can study the energy in that region with EVE. Today's transit covered part of the southern hemisphere, which is pretty quiet, and blocked the quietest part of that.

Next lunar transit is December 6 at 0310 UTC.

Images are Flowing Again

Images are flowing from the JSOC to the SDO website again.

SDO Weekly Report for November 4, 2010

The EVE cruciform was delayed for one day and performed on Thursday. Some of the images in Thursday's movies were taken when SDO was pointed away from the Sun so they are missing or have the stripes we saw last week.

The Instrument calibration activities were shifted this week to accommodate the 40-hour continuous observation campaign of the Hinode satellite observation. This was to study the emergence and disappearance of magnetic flux at the Sun’s disk center. EVE reported that there was some improvement in the MEGS-B performance after the previous CCD bakeout but they will return to a 24 hour bakeout during the next eclipse period. The FOT updated the jitter wheel speed limits to 850 rpm from the 380 rpm limit set prior to launch.

Spectacular Prominence Eruptions

Check out the latest 48 hour movies to see some spectacular prominence eruptions on both sides of the Sun! AIA 304 48 hour movie.

Kepler "asteroseismology" and SDO HMI "helioseismology"

The HMI instrument onboard SDO uses Helioseismology to look at "sunquakes" to determine some of the physical properties and motions inside our Sun. There is a great news release about the Kepler mission using a similar technique, Asteroseismology, to look at "starquakes" to determine similar characteristics of other stars. Both sets of observations will lead to significant advances about the evolution of stars, including our own, to better determine the activity cycles over short (years) and longer (hundreds and millions of years) time scales. Make sure to check out more about HMI at:

http://hmi.stanford.edu/

and also see the article at Space.com about Kepler at:

http://www.space.com/scienceastronomy/starquakes-kepler-star-evolution-101026.html

A lively active region

With a large active region currently in the northern hemisphere of the Sun, there has been a flurry of small solar flares over the past day. This larger active region may actually be comprised of four different active regions that are very close to each other forming one large, interconnected active region with multiple magnetic poles. This magnetically complex region has lead to 12 B-class and 1 C-class solar flare over the last 24 hours. Make sure to check out the daily and past 48-hour movies to see this rapidly evolving active region!