Ground controllers will pull the plug on the solar probe Ulysses ending an epic mission that has lasted more than 18 years. Ulysses launched in October 1990 and swung past Jupiter in 1992, putting it into an orbit that crosses the sun's poles – the first and only spacecraft ever to do so. In mythology, Ulysses – the Latin name for the Greek king Odysseus made famous in Homer's epic poems The Iliad and The Odyssey – returned to his home in Ithaca, Greece, after a 20-year absence.
Although not officially confirmed SDO was bumped off it's Oct 14th ride in favor of Intelsat 14, a communications satellite. SDO will pick up the next Atlas V Booster and is scheduled for a December 5th Launch.
MDI has a technical problem with its Image Processor. Unfortunately, as we are currently in a "keyhole" (http://sohowww.nascom.nasa.gov/hotshots/2004_01_04/), our DSN contacts with the spacecraft are very limited. A lot of patches, tables, etc. need to be re-loaded and due to the keyhole that is expected to take days. I hope that MDI can be returned to science mode towards the end of the week.
Station keeping manuevers involve thrustser firings, and the LASCO optics must be protected against contamination by hydrazine.
Here is the response to my question about anomalous objects in LASCO images, such as the one below:
No, don't have a good estimate of the distance of the debris in the image of 20090720. I also think that it is rather close, though. I suspect it is a dust particle close to the spacecraft, possibly released during the various door openings earlier that day (CDS, UVCS, LASCO). The multi-layer insulation (MLI), which is wrapped around the spacecraft and most instruments has probably become a little "flaky" after over 13 years in orbit.
And the answer to my last question regarding the recent lack of MDI images recently:
MDI has a technical problem with its Image Processor. Unfortunately, as we are currently in a "keyhole" sohowww.nascom.nasa.gov/hotshots/2004_01_04/ , our DSN contacts with the spacecraft are very limited. A lot of patches, tables, etc. need to be re-loaded and due to the keyhole that is expected to take days. I hope that MDI can be returned to science mode towards the end of the week.
"We will have to make do with other image sources until SOHO MDI gets back online. I'd be in favor of voting for a couple more of these MDI imagers in space. MDI Ahead, Behind, Above & Below. One of the best instruments NASA has put up there. A real Solar Hubble."
You will be in awe from what comes out of SDO when it is launched in December. SDO will carry its own Magnetic Imager, HMI, that will blow the doors off MDI !
A couple of years ago I had a very interesting conversation with Dr Chris O st Cyr of NASA at the Fall AGU Conference. He told me that NASA expects Reliable High Resolution Far-Side Images of the sun from HMI. Where as MDI Farside images where spotty and erractic.
SOHO also is limited by it's Downlink Data Speed. Because of this SOHO stores it's data and compresses it before downloading. The act of compression causes some of the informational content to be lost. SDO will have a High Speed Downlink capability and will send it's data down directly without massaging it.
SDO will have Helio-Magnetic and Atmospheric Imagers of it's own that will furnish photo orders of magnitude beyong anything that came out of SOHO. SDO will also have an Ultraviolet instrument far more accurate than that of SOHO. Once SDO is up and calibrated most instruments on SOHO will be powered down. The two LASCO Instruments will be left on as SDO does not have an Occulting Mechanism. But for the most part it's time to give the Old Girl a break she's been going at it for nearly 15 years.
Post by brokenheadphonez on Aug 3, 2009 5:43:56 GMT
Just to play devil's advocate here for a minute,
If the spacecraft is built in a clean room, how does a dust particle manage to hang around the area like that? Wouldn't the movement of the doors propel it away from the door (zero g) and not on a downwards trajectory?
Anything that lasts that long in space is a winner design. SOHO has to manage several mission assignments. We have a Stereo Ahead & Behind, but we don't have Magnetogram or Continuum coverage of the Poles or the Backside. A lot of the farside stuff doesn't match up to what rotates into view, and we cannot see magnetic signature at the poles due to the limb effect. I'm likening SOHO's imagers to the Mars Rovers. Small but get the job done.
Anything that lasts that long in space is a winner design.
Design is partly responsible for the lonjevity of SOHO but its far from all of it. Actually the lion's share of SOHO's success goes to the crew that rescued it after a bad batch of data was uploaded and the satellite lost it's orientation. SOHO also lost all of it's Gyros and became the first satellite ever to operating without such stabilization. SOHO also lost the mechanism that points it's High Gain Antenna. That's is why it looses some of its functionality during Keyhole Periods. The old girl has had it !
We have a Stereo Ahead & Behind, but we don't have Magnetogram or Continuum coverage of the Poles or the Backside. A lot of the farside stuff doesn't match up to what rotates into view, and we cannot see magnetic signature at the poles due to the limb effect.
Again, Scientist at NASA are confident that HMI on SDO will deliver much higher clarity and accurate Far side Images. Yes we lost Ulysees but there are some very interesting missions in the pipe line. Both Solar Probe + and Solar Orbiter are set for Cycle 25. Solar Probe will orbit the sun in an Eccentric Polar Ellyptical Orbit. Solar Orbiter will be in an Inclined Equatorial Orbit whose Inclination Angle will increase with every orbit.
Yes we have lost some capability but we will gain a great deal more when SDO is launched and the future will hold more surpises.
And if we have lost SOHO or parts of it, how long of a gap will there be before SDO is on the job? The new does not sound encouraging at this point. I'm sure they will let us know before too long.
Robert, to answer your direct question, SDO was scheduled to launch in January 2008 and had it's launch date pushed back a number of times. It's construction was completed in June 2008 and testing completed in January of 2009. It was delivered to the Astrotech Servicing Facility lin Florida last month for final prelaunch preparation. It was schedule to launch Oct 15th when it was bumped off it's ride by Intelsat IV, a communications satellite.
The next Atlas V booster is to be delivered to Vandenberg AFB for use with a military payload. The next booster to be delivered to Cape Canaveral will be launched Dec 5th. That will be the ride for SDO if there are no more surprises.
I gave you this lengthy explanation to show you there really is no wiggle room to get SDO up sooner.
About 10 years ago a bad batch of data was uploaded to SOHO. This fopar caused SOHO to lose it orientation with the sun and the error looked to be uncorrectable. NASA in press releases told the public the satellite was lost while feverishly working behind the scenes to recover it. For 6 months they tried to recover it unsuccessfully and finally caught a lucky break. The situation then was far worse than what it is right now. NASA pulled a rabbit out of its hat to save SOHO then they are capable of doing it again