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Important notice about reduced STEREO science operations

What's New

Follow this link for news highlights about the STEREO mission. Below, we list additional entries concerning the STEREO instruments and data.

July 11, 2014

The test of operating the STEREO Ahead spacecraft during the upcoming period of reduced operations has been successfully concluded. Recovery of the science instruments after being off for the last several days has begun.

June 26, 2014

Unexpectedly high temperatures in the high gain antenna feed horns on both STEREO spacecraft will require corrective action in the coming months that will severely limit science operations. The high temperatures are being caused by the small angle between Earth and the Sun as seen from each spacecraft. In other words, pointing the antenna at Earth is putting too much solar heat on the antenna feed horn. To bring down the feed horn temperature, and preserve the spacecraft for years to come, the antennas will be pointed off at an angle from both Earth and the Sun, so that less heat will fall on the feed horns. Communication will still be possible using one of the antenna side lobes, but the telemetry rate will be extremely low. What instrument operations can be supported while the antennas are off-pointed is still being studied.

A test of operating the STEREO Ahead spacecraft in this antenna off-pointed mode will be conducted during the week of July 6-12, 2014. All science instruments will be turned off during this time, and instrument recovery operations are expected to take several days.

More information about the upcoming period of reduced operations can be found on this page, which will be updated as more information becomes available.

May 30, 2014

A new version of the SECCHI/HI Level-2 product is available on the STEREO Science Center website. These data have have actually been partially available for a while now, but announcement was delayed until the ingestion of the files was mostly complete. At the time of this writing, some data from the first year of the mission is still being ingested, but the data should be complete from 2008 onwards.

The new data are available in three different units: detector data numbers per pixel per second (DN/Pixel/Sec), Mean Solar Brightness (MSB), and the astronomical diffuse magnitude scale known as S10. The MSB and S10 data have had the diffuse brightness correction applied. The file naming convention has been updated for these data.

January 6, 2014

The Inertial Measurement Unit (IMU) on STEREO Behind failed at 9:46 UT on Sunday, January 5, putting the spacecraft into coarse point mode. Recovery operations are currently being carried out. All the instruments continue to take data. However, the COR1 and COR2 doors are closed.

Update: Fine pointing mode has been restored on STEREO Behind. The COR1 and COR2 doors have been reopened.

August 13, 2013

A page describing possible roll maneuvers has been added to the discussion about the planned Comet ISON observations.

July 22, 2013

The STEREO Behind spacecraft has been completely recovered, and is operating nominally. The cause of last week's transponder anomaly is still under investigation.

July 19, 2013

The STEREO Behind spacecraft is currently in a low-rate telemetry mode. The mission operations team is diagnosing the problem. More information will be posted as it becomes available.

Update:The The transponder on the STEREO Behind spacecraft has been recovered back into 120 kbps mode. The remaining recovery activities, including activating the beacon rate between passes, will be completed on the next pass. The rest of the spacecraft has been operating normally the entire time, and the instruments have been collecting data.

February 14, 2013

A new web page has been put together describing the possible observations of Comet ISON by STEREO in October-December 2013.

December 4, 2012

The mode of operations for the COR1 telescope on STEREO Behind was changed back to the normal sequence of 0, 120, and 240 degrees.

November 29, 2012

Starting November 29, the mode of operations on the COR1 telescope on STEREO Behind was changed to take images at polarizer angles of 60, 180, and 300 degrees instead of the previous 0, 120, and 240 degrees. This was done in an attempt to correct occasional position errors that had developed in the 240 degree images. Changing the polarizer angles introduces subtle effects in the instrumental background. It will take some time for sufficient data to be collected to create new background files. In the meantime, provisional background files have been formed based on the older data. As a result, the COR1-B images will appear noisier than usual until new background files are available.

November 27, 2012

Users may have noticed that there have recently been a significantly smaller number of SECCHI images from the Behind spacecraft, and large gaps in the IMPACT, PLASTIC, and SWAVES data from Behind. This is due to a shortage of telemetry coverage caused by Deep Space Network schedule conflicts with other missions. This situation started in mid-November 2012, and is expected to continue for the next several months. In upcoming weeks, the Ahead spacecraft will also start to be affected.

November 20, 2012

The Where is STEREO? page has been updated to include a link to a discussion of out-of-contact periods of 2015 when the two spacecraft pass behind the Sun.

July 11, 2012

The daily STEREO browse images pages now include daily synoptic maps generated from a combination of STEREO and SDO images, in all four EUVI wavelengths. These daily maps have been generated back through 2010, and earlier dates will be available soon.

March 26, 2012

A new searchable STEREO publication database is now available. This replaces the old database system which had to be taken offline. Authors of STEREO-related articles in the refereed literature are encouraged to submit them for inclusion in the database once they are accepted for publication. It would be particularly helpful to include the DOI, volume, and page number.

December 14, 2011

A new running difference browse product is now available for the SECCHI EUVI, COR1, and COR2 telescopes. These running difference images are available on the individual daily browse pages, and on the latest images page, and should be available soon via the image search tool. Currently, running difference images are available only for dates starting November 1, 2011, but earlier dates will be filled in over time.

July 22, 2011

The power outage earlier reported on the home page for July 22-23 has been canceled.

July 20, 2011

The software used to generate the SECCHI browse images has been changed to more closely reflect the actual data. In the previous version of the software, when the JPEG images being generated were larger than the original images, the data were interpolated to the larger size. The new version of the software resizes the images without interpolation. The result is a less-smooth, more "pixelated" image, but which is more representative of the actual data. Particularly affected are the beacon images. The smoother beacon images produced by the previous version sometimes confused people into thinking that they saw structures which were not supported by the actual data.

May 18, 2011

The SECCHI EUVI, COR1, and COR2 telescopes on STEREO Behind picked up an interference pattern on 9 May 2011 around 17:20 UT, thought to be due to a single event upset to the Camera Electronics Box (CEB). The CEB was restarted to fix the problem on 12 May 2011; however, in the meantime the background images for COR1 and COR2 had become corrupted, preventing the team from immediately realizing that the problem had been solved. New backgrounds are now being produced, and the browse images are being regenerated as corrected backgrounds become available.

April 5, 2011

A new "Downlink Performance" data product is now available as part of the Ancillary Data set.

January 13, 2011

The IMPACT/PLASTIC Data Processing Unit on Behind was autonomous switched off on 8 January 2011 due to unexpectedly high current. The IMPACT and PLASTIC instruments were switched back on, and all the instruments are now back into normal operating mode.

December 17, 2010

The SECCHI team is now making available movies made up from the last seven days of data. These movies are available from their Synoptic Movies page, under the sidebar heading "Current Weekly Movies". Note that each STEREO spacecraft is now within the field of view of the COR2 telescope on the other spacecraft.

December 16, 2010

The PLASTIC team has instituted a new data browse product called "Protons Projected to Earth" on their data plots page. These overplot the STEREO A, B and Wind proton data sets, with a simple time translation assumed for A and B. The purpose is to demonstrate how STEREO-B data can be used as an advance proxy for L1.

December 1, 2010

The remaining problems with connectivity between the STEREO Science Center and the Mission Operations Center after the move on November 29 have been resolved. All SSC services should now be functioning normally.

November 30, 2010

The STEREO Science Center has been successfully moved to its new location, and the website and beacon services are back up and running.

November 5, 2010

SECCHI/HI Level-2 data are now available.

September 8, 2010

The PLASTIC Level-2 data set for Iron now includes CDF files.

August 11, 2010

Plots of the PLASTIC Level-2 Iron data are now organized into two classifications: the previous plots of charge states and the new plots of monthly abundances.

July 8, 2010

We are now making available a prediction of the state of the Sun during the upcoming total solar eclipse on 11 July 2010, based on what STEREO Behind saw at the same heliographic longitude on 6 July 2010.

The problem with accessing recent AIA data for the STEREO synoptic maps has been resolved.

July 7, 2010

We are currently having problems accessing recent AIA data for the STEREO synoptic maps. The VSO and AIA teams are working on the problem, and we hope to have it resolved as soon as possible.

July 2, 2010

A new browse product displays the STEREO in-situ data as a function of Carrington rotation number.

June 24, 2010

SDO/AIA images are now being used to supply the "Earth-view" in the STEREO Latest Images and Daily Browse Images pages for dates after April 16, 2010. SOHO/EIT images are used for earlier dates, or if the SDO/AIA data are unavailable. Since AIA does not observe the Fe XV line at 284 Angstroms, the similar Fe XIV image at 211 Angstroms is used instead. Note that the SDO/AIA team has chosen to display their images in different color tables than were used for the SOHO and STEREO projects.

June 22, 2010

The STEREO heliographic maps on our Latest Images page now include SDO/AIA data for the Earthward-facing part of the Sun. Once the two STEREO spacecraft reach 180 degree separation on 6 February 2011, the combination of images from all three spacecraft will give us a complete view of the entire Sun.

June 17, 2010

Additional changes have been made to the PLASTIC archives. The Iron Level-2 subdirectory has been split into separate plots and text subdirectories. A new Level-3 tree has been created with suprathermal event lists and He+ relative fluxes.

April 20, 2010

The PLASTIC Level-2 archive has been reorganized. The former contents have been moved to a new subdirectory called Protons, and new subdirectories Alpha_RA, and Iron, have been added.

January 1, 2010

The pages on image artifacts due to beacon processing and cosmic rays have been updated to show how these two artefact sources interact.

November 18, 2009

A new webpage has been inaugurated showing side-by-side comparisons between the latest SECCHI beacon images, and the most recent GONG far-side maps. When candidate magnetic regions appear in the GONG maps, one can look for enhanced brightness in the corresponding area in the EUVI maps. There is still a region on the far side of Sun which is not yet observed by STEREO, but this region will shrink over time, and we should be able to observe the entire Sun by February 2011.

November 3, 2009

Beacon telemetry files are now available on the website for instrument teams who want to use the beacon telemetry to fill gaps in the level 0 telemetry

November 2, 2009

The IMPACT team has removed the following directories from their Level 1 data tree:

and the same for behind. MAG data are now to be found in the RTN and SC directories for data in RTN and spacecraft coordinates respectively.

October 15, 2009

We have been receiving a number of questions recently about planets visible in the STEREO telescopes. A new STEREO Planet Finder page shows the calculated positions of planets in the latest SECCHI beacon images. One can also use the STEREO Orbit Tool for older data. Select either the inner or outer solar system options to see which planets might be in the field of view of the STEREO telescopes.

August 26, 2009

The SECCHI instrument team has instituted new software for their HI2 beacon images. These images are now available on the latest images and daily browse pages. To save telemetry, only the sunward half of the images are sent down in the low rate beacon telemetry stream.

IMPACT/PLASTIC Level-3 event lists from UCLA are now archived within the SSC.

August 6, 2009

The IMPACT/SIT instrument has now been restored to full operation. Now all the STEREO instruments are recovered from the system reset on August 4.

August 5, 2009

The IMPACT/SWEA high voltage on Ahead is now at its nominal value. The only remaining detector still needing to be fully recovered is IMPACT/SIT.

August 5, 2009

PLASTIC on Ahead is back to operating mode. The high voltage supplies are still warming up, and are expected to take several hours to reach equilibrium temperatures. This may affect the data values during those hours.

August 4, 2009

The SECCHI telescope suite has been recovered, and is taking images again.

August 4, 2009

All the instruments have been powered back on successfully. Some beacon telemetry is now available from IMPACT and SWAVES. Instrument recovery will continue over the next few days.

August 4, 2009

Powering up of the instruments has begun.

August 4, 2009

The STEREO Ahead spacecraft was successfully reset today (Aug 4) to load new guidance and control software. The spacecraft is back on the high gain antenna, and recovery is proceeding as scheduled. Powering up of the instruments is expected to begin soon.

August 3, 2009

The STEREO Ahead spacecraft will be reset on August 4. Complete recovery is expected to take several days. This page, and our status page will be updated as more information becomes available. The expected sequence of events is as follows:

  1. The instrument start preparations for shutdown at 5:45 UT. High voltages will be ramped down.
  2. Instruments will be powered down at 9:40 UT.
  3. The spacecraft will be commanded to reset around 10:30 UT.
  4. Powering up of the instruments is expected to commence around 15:50 UT.
  5. Pass ends at 17:40 UT.
Instrument recovery will continue over the next couple of days.

July 28, 2009

PLASTIC Level-2 data are now available in ASCII format.

July 23, 2009

The PLASTIC Level-2 directories have been reorganized. Under the directories for each spacecraft now appear directories labeled "10min", "1hr", and "1min" for different time resolutions. The previous data appear in the "1min" directory tree.

July 15, 2009

The STEREO website has been restored. There are still a few features which are disabled, but most things should work. In particular, the popular image search utility is working again, as is the orbit tool. We are endeavoring to restore the remaining features as quickly as possible.

July 14, 2009

The STEREO/VSO interface, which went offline along with the webserver on June 22, is back online. STEREO data can now once again be retrieved either through the web interface, or through the IDL interface (recommended), such as through the routine secchi_vso_ingest.pro.

July 13, 2009

Time-elongation plots of SECCHI beacon data are now available. These plots are designed to show the propagation of CMEs through the telescope fields of view.

July 2, 2009

The data and browse directories have been restored to the website, but scripts are still not functional.

June 29, 2009

The STEREO Science Center website went offline on June 22, 2009. Currently, we're running a minimal website with some, but not all, of the functionality of the original website. Please excuse us while we try to address the problem.

May 18, 2009

We have been informed that all instruments have now been completely recovered from the planned spacecraft reset on May 12, 2009, including ramping up high voltages.

May 14, 2009

The STEREO Behind spacecraft was successfully rebooted on May 12, 2009 to use the new Guidance and Control software. Recovery of the spacecraft has been completed, and all instruments have been powered up and are operating. High voltages on some of the instruments may still require adjustment.

May 12, 2009

Starting around 23:00 UT on May 12, 2009, the STEREO Behind spacecraft will be reset to load a new Guidance and Control software version. Full recovery of all the instruments is expected to take several days. Please check the status page for updated information as it becomes available.

May 11, 2009

Initial processing of COR1 images was changed in an attempt to bring out more of the solar features before the preliminary time-dependent background subtraction has settled down to its permanent value. Later processing of the COR1 images, at 15 and 35 days after the observation date, uses the original method.

This new procedure turned out to be unsuccessful, and was removed.

May 4, 2009

The PLASTIC team now provides solar wind proton data as "condegrams", showing five Carrington rotations at a time in a spiral format. This brings out recurrent features (such as CIRs), and shows changes in magnitude from one Carrington rotation to the next. These plots are available from our instrument data page.

April 8, 2009

The SSC is now providing heliographic maps formed from the latest SECCHI Ahead and Behind EUVI images to provide a more integrated view of the current state of the Sun. The synoptic map, updated hourly, can be found on our latest images page. Note just how much of the Sun we can see now.

April 6, 2009

A new IMPACT/SEPT data browser has come online at the University of Kiel, Germany.

March 27, 2009

The IMPACT SEPT files have been reprocessed to remove the timestamp bug. The corrected files are version V06 and above. SEPT files below version V06 should not be used.

February 25, 2009

Updated Warning: A software bug has been discovered causing times in the IMPACT SEPT Level 1 data to be too early by about 33 seconds. The IMPACT team is in the process of correcting the files and appreciates your patience. They have verified that the problem exists only for the IMPACT SEPT level 1 data. No other IMPACT data products, including products for MAG, SWEA, STE, LET, SIT and Beacon, are affected.

February 24, 2009

Warning: A software bug has been discovered causing times in the IMPACT CDF files to be too early by about 33 seconds. The IMPACT team is in the process of correcting the files and appreciates your patience. They have verified the problem exists for the IMPACT SEPT and Beacon data files and may also be present for several other IMPACT Level 1 data products. The times are known to be correct for the LET Level 1 data product.

September 11, 2008

Although some technical problems may still need to be worked out, data ingestion from NRL has resumed. The most recent data has been ingested, but some backlogged data is still being copied over.

September 5, 2008

Because of server problems at NRL, the processing and ingestion of SECCHI FITS data is temporarily suspended.

August 22, 2008

A new IMPACT/PLASTIC Level 1 data product including data from the 200h housekeeping packets is now available on the SSC server for both ahead and behind.

August 15, 2008

Ingest of SECCHI data into the Stereo Science Center was resumed on Tuesday, August 12. The backlog of data has now all been ingested and processed into images.

August 8, 2008

Ingest of SECCHI data into the Stereo Science Center has been temporarily suspended until additional disk space can be installed. Data ingestion is expected to resume on Tuesday, August 12th, 2008. All other data products continue to be ingested.

July 31, 2008

The first announcement for the combined STEREO-3/SOHO-22 Workshop, "Three eyes on the Sun - Multi-spacecraft studies of the corona and impacts on the heliosphere", is now available.

July 22, 2008

Information about STEREO plans for the solar eclipse of August 1, 2008 is now available.

June 5, 2008

IMPACT/PLASTIC Level-3 event lists are now available from UCLA. This and other event lists are available from our new events page, as well as our instrument data pages list.

April 14, 2008

Automated detection of CMEs from STEREO/SECCHI data is now available as part of the SEEDS: Solar Eruptive Event Detection System from the George Mason University Space Weather Lab.

April 10, 2008

The STEREO proposal to the 2008 Senior Review is now available from our publications page.

April 8, 2008

The PLASTIC level-1 data archived at the SSC have been moved down into a new level1 subdirectory to make way for new level-2 data which are now available.

March 20, 2008

Daily browse movies are now available from the CDAW Data Center. This website allows one to examine side-by-side images from STEREO Ahead and Behind, or from two SECCHI telescopes on the same spacecraft.

December 27, 2007

Normal operations have resumed on Behind, one day earlier than originally expected. Both spacecraft are now operating as expected.

December 26, 2007

The Behind star tracker has continued to perform nominally since December 23. Should no further problems develop, Mission Operations plans to resume normal operations on Friday's track (Dec 28).

December 23, 2007

The Mission Operations team was able today to command the star tracker on Behind back into operational mode. The star tracker continued to operate throughout the track. As a precaution, use of the star tracker was suspended at the end of the track, and the spacecraft was switched from the high gain to low gain antenna. Mission Operations will continue to staff tracks, and proceed with caution regarding ST usage. Contingency planning will continue as will discussion with the star tracker supplier.

December 22, 2007

Problems persist with the star tracker on Behind. The high gain antenna continues to point to Earth, and the Mission Operations team was able to use it to download science telemetry. All other spacecraft systems continue to operate normally.

December 21, 2007

The star tracker on STEREO Behind had an anomaly at 10:10 GMT this morning. This resulted in the spacecraft autonomously switching to the low gain antenna. All other spacecraft systems are healthy. Diagnostic telemetry is being collected, and corrective action is under consideration.

Science data is still being collected, but at the current low telemetry rate it is not possible to send it to the ground. Some science data may be lost when the onboard recorders reach their maximum capacity.

December 19, 2007

Running difference images and movies from the SECCHI Heliospheric Imager HI-2 telescope are now available on the SSC browse and image search pages. So far, only a few days are available, mostly in December 2007, but more days will be populated in the near future.

Unlike the other SECCHI telescopes, the HI-2 images are only processed from the full resolution level-0 science data. Thus, there is a delay of several days before any HI-2 images are available.

December 6, 2007

Data from the IMPACT STE detectors are now available on the SSC archive.

November 29, 2007

Realtime SWAVES radio beacon plots are now available on the In-Situ & Radio Space Weather Beacon Data page.

The STEREO Journal Publication Database is now online. Users are encouraged to submit published journal articles involving the STEREO mission for inclusion in the database.

August 10, 2007

Realtime SECCHI HI1 telescope images are now available on the Latest SECCHI beacon images page.

Daily MPEG summary movies are now available from the Daily Browse page.

August 10, 2007

Images from the SECCHI HI1 telescope are now available on the Daily Browse and Image Search Tool pages. Because the HI1 images are derived from the level-0 science data, they take a few days to appear on the website.

August 7, 2007

IMPACT Level-1 data files are now available.

August 6, 2007

Images from the SECCHI COR2 telescope are now available on the Latest SECCHI Beacon Images page. As they become available, these images will also appear on our Daily Browse and Image Search Tool pages.

July 10, 2007

Images from the SECCHI COR1 telescope are now available on the Latest SECCHI Beacon Images page. We hope to add images from the other SECCHI telescopes soon. As they become available, these images will also appear on our Daily Browse and Image Search Tool pages.

June 27, 2007

Several improvements have been made to the in-situ beacon pages at http://stereo-ssc.nascom.nasa.gov/beacon/beacon_insitu.shtml. The IMPACT magnetometer data is now in the standard Radial-Tangential-Normal (RTN) coordinates, and total magnetic field strength has been added to the plots. New pages have been added for solar energetic particle data.

March 22, 2007

The daily data browse pages are now available at http://stereo-ssc.nascom.nasa.gov/browse/. So far, only a few days worth of data are available, but earlier data will be steadily added. We're also working on adding more in-situ data, as well as the daily summary plots from SWAVES.

March 21, 2007

Realtime beacon in-situ plots are now available at http://stereo-ssc.nascom.nasa.gov/beacon/beacon_insitu.shmtl.

February 14, 2007

SWAVES data is now archived within the STEREO Science Center at http://stereo-ssc.nascom.nasa.gov/data/ins_data/swaves.

February 14, 2007

Real-time space weather beacon images from SECCHI are now on-line at http://stereo-ssc.nascom.nasa.gov/beacon/beacon_secchi.shtml.

SECCHI and PLASTIC science data are now available through the Virtual Solar Observatory.

New web page for auxiliary data, which is data produced by other observatories either in conjunction with the STEREO project, or which is useful for analyzing STEREO data.

January 23, 2007

The Behind spacecraft flew by the Moon for the second and last time on January 21. Both spacecraft are now in heading away from Earth into their orbits around the Sun. The official science mission started January 22.

The baffle cover on the SECCHI Heliospheric Imager on Behind was opened on January 11. The scientists were thrilled to find that Comet McNaught was in the HI-1B field of view. The IMPACT SIT and SEPT covers were opened on Behind on January 16. All instrument covers are now open.

December 22, 2006:

The A spacecraft performed its lunar flyby last Friday and is now in heliocentric orbit.  The drift rate of the spacecraft is +21.66 degrees/year (relative to the earth), this is well within its specification of 22+/- 2 deg/year. The B spacecraft also performed a lunar flyby, but its trajectory has another flyby scheduled for 21 January 2007.  The B spacecraft successfully completed its final trajectory adjustment maneuver on this Thursday.

December 14, 2006:

All the subsystems on both spacecraft continue to perform very well.  On Monday, Dec. 11, the Ops team performed a peak power test on the A-spacecraft.  The arrays are producing slightly more power than expected  (720W vs 690W).  The G&C team has started to tweak the control algorithms with the result that mechanical oscillation of the SWAVES antennae has completely disappeared on both spacecraft.  They will continue to fine tune the system and are planning a test which would run all the wheels through all speeds to investigate the effect of wheel speed on jitter.

The SECCHI SCIP-B telescope doors (EUVI, COR1 and COR2) were successfully opened Dec. 13 at 6:30am. First light images were taken and reviewed by a bunch of very happy scientists on the east and west coasts.  Performance was as expected and comparable to the SCIP-A telescope images taken last week. In addition, there was a successful opening of the first HI telescope door on S/C-A. The HI images appear to be exceptional. This means that of the 10 SECCHI telescopes, 8 have successfully opened their doors and taken good images. The HI-B door, which covers the last 2 telescopes, will open at the end of December or early January, depending on when we verify that there will be no more B Observatory maneuvers.

The IMPACT SEPT-NS, SEPT-E and SIT doors were deployed Dec. 14 on Ahead. In anticipation of this exciting event, the Sun decided to become active making it easy to confirm the door openings in the science telemetry. There were 5 door actuations - one for SIT and two for each set of doors on SEPT-E and SEPT-NS. The door deployments for SIT, SEPT-NS and SEPT-E on Spacecraft B will be in mid January.

December 4, 2006:

The SECCHI team opened the doors to the SECCHI SCIP-A instruments and took a few first-light images. Everything went absolutely smoothly. The three doors opened without incident. The first images look great even though they were sent down highly compressed to keep the downlink time reasonable.

The EUVI was opened first and an image from each of the four quadrants looked fine - no major tears or pinholes in the front filters. The sun is close to being in the center of the CCD, and the resolution is beautiful.

Then we opened COR2 and took an image--also beautiful, although there is a slight offpoint (which we expected). The exposure time is just about where we expected, about 3-4 seconds. We then took a pB sequence of 3 images with the result that streamers could be seen all the way to the edge of the field.

Then COR1 was opened and it was also as expected. A pB sequence shows the inner corona nicely out to about 2.5 R, which is what we expected.

November 29, 2006:

Both the Ahead and Behind spacecraft performance continue to perform very well with all subsystems nominal. The instruments on both observatories continue to perform well. The SECCHI instrument team is planning to open the doors on the STEREO-A coronagraphs next week and is completing internal tests.

The definitive orbit solutions from FDF indicate that the STEREO A Observatory will achieve its required drift rate without further maneuvers. The STEREO B Observatory will require a 0.2m/s maneuver currently scheduled approximately December 8th. Both spacecraft will swingby the moon on December 15th, with a second lunar swingby for STEREO B on January 21st.

The guide telescope has been enabled on both spacecraft. G&C is assessing the performance of the attitude control algorithms and will upload new parameters in December.

November 22, 2006:

The SWAVES team is now producing daily summary plots through their website at http://swaves.gsfc.nasa.gov. Follow the links to "data" and then "data plots".

Both the Ahead and Behind spacecraft performance continue to perform very well. So far, all the planned maneuvers have been completed successfully. The Mission Operations team is studying the current orbit of the Ahead spacecraft to see if any more orbital maneuvers are necessary. At least one more delta-V maneuver is planned for the Behind observatory.

The instruments on both observatories continue to perform well. They were powered down prior to the P2 maneuvers and then powered back on successfully. The SEP Central, HET, LET, SIT, SEPT-E, SEPT-NS detectors on IMPACT have been successfully been powered on and checked out on both observatories. The Caltech team was able to correlate the first 100 minutes of data from the STEREO LET instrument on IMPACT with ACE data and the spectra were found to be consistent.

A spacecraft roll to calibrate the IMPACT Magnetometer was performed on each observatory. Initial results show that the test was highly successful.

PLASTIC continues to ramp up their high voltage levels on their MCPs. At the current HV levels they are starting to see counts from penetrating particles or photons on their position detectors. The SSDs are also seeing penetrating particles and photons.

The SECCHI team has completed their decontamination heating of the CCDs on the COR1 and COR2 telescopes and are preparing to do the same with the EUVI and HI telescopes.

November 14, 2006:

All the spacecraft subsystems are performing very well. The Guide Telescope was enabled on the A spacecraft Sunday and acquired the sun. The GT on the B spacecraft was enabled Monday. In both cases the GT data looks good and the spacecraft algorithms are correctly using the data. The spacecraft pointing improved markedly with the GT enabled. There are more planned tests of the GT and spacecraft control algorithms in December and more tweaking of the control algorithms.

A complete functional test of the both SECCHI suites was completed at the end of last week and both suites are working well.

The SEP instruments on the B spacecraft were turned on for the first time this afternoon. Initial indications are very good.

November 6, 2006:

Both spacecraft went through a 25 minute eclipse as they went through perigee this morning. The spacecraft behaved nominally throughout eclipse and are now on their way out to moon radius. The Ahead spacecraft was intentionally sent to Earth Acquisition mode in order to test the EA system. The operation of the spacecraft was completely nominal in EA and recovery from EA to Standby was nominal. The instruments on the A spacecraft were turned off as part of the EA test. The instruments were turned back on and are continuing with commissioning activities.

The PLASTIC SSD high voltage has been turned on both spacecraft. The MCP high voltages have been turn on at low voltage on both spacecraft. The MCP voltages will be ramped up to operational voltages over the next month.

November 3, 2006 UPDATE:

This is STEREO's second week in Earth orbit(s). It is still in it's first of four phasing orbits--prior to the first lunar swingby. So far the planned commissioning activities have occurred without any serious anomalies. The major deployments of solar arrays, spacecraft separation, and high gain antennas occurred almost immediately after launch. Since then, the SWAVES antennas on each observatory have been deployed -- and SWAVES started producing significant science data.

This week, the significant commission events were the execution of the apogee propulsive maneuvers on both spacecraft that raised their perigees to altitudes that are comfortably above the atmosphere. These 'burns' were accurate to within 0.5% -- that is considered very good considering that the observatories have not yet been fully characterized. The other significant event was the deployment of the four meter rigid IMPACT boom on each observatory. The MOPS and Engineering teams performed other important activities: 1) the High Gain Antennae were successfully exercised over their full range of motion on both spacecraft. 2) The software team completed its assessment of observed SEU bit flips on the C&DH and G&C computers and uplinked a patch (after a change control board review) to correct an issue in the memory scrub software.

Currently, both observatories are operating nominally. All subsystems and instruments on both observatories have a GREEN health status. Some IMPACT detectors are currently saturated, possibly due to the proximity to Earth. This effect is still being investigated. MAG is seeing higher than expected offsets, which is correctable in software. SWAVES-Behind observes two interference signals (100 kHz and 16 kHz) associated with the boom deployment. With the booms deployed the spacecraft pointing has become very stable with the pointing much less than 7 arc-seconds. We have ended our 24/7 coverage from DSN and have gone to our nominal 3 hour tracks per day per spacecraft.

November 3, 2006:

Engineering burns were performed on the C thruster set of both spacecraft. Both burns were completely nominal so all the thrusters have been checked out and are working. All the spacecraft subsystems are performing nominally.

November 1, 2006:

Previous item should have reported that PLASTIC was also partially powered up successfully on both observatories.

The A1 maneuver was successfully completed on both spacecraft.

The two IMPACT booms have been deployed.

The High Gain Antennae were exercised through their full ranges of motion.

October 30, 2006:

Spacecraft subsystems are performing normally. The SECCHI instrument suites were turned on on both observatories and all telescope subsystems passed their functional tests. The SWAVES instruments were turned on, and both sets of antennae were successfully deployed. Parts of the IMPACT instruments have been powered on.

October 25, 2006:

The twin STEREO observatories were launched at 8:52 p.m. EDT. [Press release]

Follow this link for prelaunch news.

Last Revised: Friday, 11-Jul-2014 10:56:09 EDT
Responsible NASA Official: [email address: Joseph.B.Gurman<at>nasa<dot>gov]
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