Eighteen months of successful operation on-orbit is a crucial milestone for SORCE, because this is the criterion point NASA considers to determine the mission a success. In NASA’s eyes, SORCE has been on-orbit long enough to have obtained scientific success by collecting continuous TSI and SSI measurements. SORCE was launched on Jan. 25, 2003 from Kennedy Space Center in Florida. The spacecraft, instruments, and ground systems are all functioning flawlessly.

Plans are in the works to acknowledge this special NASA accomplishment, and details will be forthcoming. Of course, everyone anticipates many more SORCE milestones in the years to come on this 5-year mission.

Special Experiments Run for SORCE’s July 6 Solstice – 
The SORCE planning team has been extremely busy lately with all of the recent opportunities. Just a month after the Venus Transit, SORCE had another opportunity to show-off its capabilities with the July 6th solstice. Unlike Earth, the longest day of sunlight for SORCE’s orbit occurred on this day.

SIM measured the spectrum of atmospheric absorption on July 5th. Test-run experiments were performed prior to the solstice to ensure correct performance of the template. Data from the test were used to produce a wavelength scale, which was necessary for converting the real data to an atmospheric absorption spectrum.

Rather than conduct normal eclipse operations, i.e. point at stars, the spacecraft continued to track the Sun as it was occulted by the Earth. SOLSTICE performed two mini-scan experiments for these observations – one centered at Lyman-alpha, and the other near 225 nm to observe nitric oxide.

To read more, see the July 2004 newsletter.