SECCHI - Solar Physics Branch - Naval Research Laboratory

What's New:

2007 Oct 3. SECCHI-A and SECCHI-B downlinks 1,000,000th image! See daily totals on the Database Search page.

2006 Oct 25. STEREO has successfully launched!! After a brief delay, the Delta II launch vehicle lifted off from Cape Canaveral, Florida, at 8:52pm EDT -- a full sixty seconds before the end of the launch window! About half an hour after launch, the spacecraft successfully separated from the launch vehicle, and from each other, and initial indications are that the spacecraft are in full health.

2006 Oct 24. STEREO has the go-ahead to launch! The Delta II second stage has been fueled and is almost ready to go. Launch countdown will begin tomorrow morning, with the launch window being 8:38pm to 8:53pm EDT.

2006 Oct 2. On Friday (Sept 28) the second stage of the rocket was reinstalled onto the first stage with the propellant tank that had been removed for testing.

2006 Sept 27. Yesterday the review board met to assess the situation with the propulsion tank on the Delta second stage. They cleared the tank for use on the STEREO rocket so that we are set for the currently scheduled launch date of Oct 25, 2006. Up to now, the STEREO spacecraft have been in the hazardous processing facility at the ASO complex in Florida, bagged and under purge. There hadn't been any SECCHI specific testing for several months (since early July) when we did the final inspections and prepared the instrument for flight. When the two spacecraft were stacked, the vent caps on the SCIP FPAs were removed for both spacecraft as there would be no access after they were stacked. The HI vent caps will be removed at the launch pad.

2006 June 30: The team remeasured the pointing of the COR1-B and reanalyzed the measurements. The COR1 team came up with a good model of the effect of chromatic aberration on the boresight measurement. The result of the additional testing and a reanalysis of the historical measurements has shown that the problem began prior to vibe and that there has been a drift in the pointing. Two results are evident: (1) there was not a sudden mispoint as the result of a single test and (2) the slope of the drift is low, so that the total amount of mispoint is within an acceptable range and we don't believe that there is a significant danger of the mispoint becoming unacceptable as a result of launch. This removes the impediment for launch!!!

2006 June 28. The SECCHI CPTs were successfully completed for both spacecraft. This is expected to be the final CPT before launch. The performance of the instrument as measured through these tests has not degraded since the instrument calibrations at NRL and CSL. The work on the COR1-B alignment issue is still ongoing.

2006 June 27: The Mission Readiness Review was held at NASA/GSFC. The committee approved the movement of the two STEREO spacecraft to the hazardous processing facility provided that two problems were resolved. The one problem is with the Spacecraft Power Supply Electronics (PSE) and the second problem is the misalignment of the SECCHI/COR1 telescope with the other SCIP telescopes. The PSE problem arose because of a failure of the same design on the Messenger mission. An investigation is underway. The SECCHI/COR1 problem is that the alignment between the COR1 boresight has shifted away from the pointing of the other three telescopes on the SCIP bench. This misalignment occurred during the last two measurements, part of the Comprehensive Performance Tests. The first was taken after TVAC and the second occurred after shipment to ASO. All of the measurements prior to these have indicated no problem. But the trend is now very alarming and an investigation is underway.

2006 June 23. With the successful launch of the Mitex mission on June 21, the battery issue could be resolved so that STEREO will use a heavier battery than had been anticipated. This increased weight (6-10 pounds) could be recovered by launching later in the launch period. Therefore the launch was moved to not earlier than (NET) July 30, 2006. This also gives the I&T team a few Sundays off.

2006 June 23. The launch simulation was successful. The instrument was put into the launch configuration including the appropriate CCD decontamination heaters. This simulation verifies our STOL procedure. Of course after the test, the configuration was returned to the I&T configuration, with the decontam heater relays turned off.

2006 Jun 9 The SECCHI COR1A objective lens assembly was reinstalled. It had been removed because an excessive amount of particles were found on the lens surface during an examination after thermal vacuum. Immediately after the replacement, the final Comprehensive Performance Test began. This test is the last test (other than aliveness tests) that the SECCHI instrument will undergo prior to launch. The testing is expected to last about 2 weeks.

2006 May 2 The two STEREO spacecraft arrive at Astrotech in Florida, after a day's journey of being trucked from GSFC. This major event culiminated the successful completion of the observatory level environmental testing. This testing began at the Applied Physics Lab of the Johns Hopkins University (JHU/APL) in June, 2005, with the integration of the SECCHI-A onto the Ahead spacecraft. The major environmental tests performed were vibration, acoustic, spin balance, thermal balance, thermal vacuum cycling and electromagnetic interference/compatibility.