DSCOVR will monitor solar winds, the stream of charged particles from the sun, from a point 932,000 miles from Earth. It was more Earthly winds just 25,000 miles up that kept the Falcon 9 rocket on the launch pad Tuesday night at the Cape Canaveral Air Force Station. Balloon data showed upper level winds exceeding 115 mph, significantly stronger than allowed by launch commit criteria.
SpaceX and the Air Force set the next launch attempt for 6:05 p.m. Wednesday. The 45th Weather Squadron’s forecast couldn’t be much better with less than 10 percent probability of violating those weather constraints again. Forecasters continue to keep a close eye on winds.
The satellite will be positioned at Lagrange 1 point (L1) after launch. The five Lagrange points offer neutral gravity between the Earth and sun. More importantly, L1 is positioned directly between the Sun and Earth and offers 15-60 minute warning time before coronal mass ejections and other solar events reach us. Though there are a number of NASA satellites studying the sun currently orbiting L1 (such as Wind, SOHO and the aging ACE which will be replaced by DSCOVR), DSCOVR will be the first NOAA satellite positioned so far from home.
DSCOVR will help provide more timely and accurate warnings of harmful space weather including solar flares and storms. These could interfere with Earth’s electromagnetic field causing disruptions in power grids, telecommunications and GPS. Instruments will measure the speed and direction of solar wind particles, a spectrometer will monitor electrons and a magnetometer will measure magnetic fields.
Perhaps the most exciting instrument is NASA’s Earth Polychromatic Imaging Camera or EPIC. EPIC’s 2048x2048 pixel camera can view the entire sunlit Earth in a single image, from sunrise in the west to sunset in the east, something that has never been done from a satellite and hasn’t been done since the Apollo 17 astronauts did it in the early 70s. EPIC images in 10 very narrow wavelengths to measure ozone amounts, aerosol amounts, cloud height and phase, vegetation properties, and provide estimates of UV radiation at Earth's surface. This data will be useful to climate science, as well as hydrology, biogeochemistry as well as ecologists.
The mission was originally scheduled in 2003 to be placed in initial orbit by the ill-fated space shuttle Columbia mission STS-107. Then called Triana, the satellite was warehoused for a decade through several presidential administrations and congresses before it was removed from storage in 2008 for initial power on testing and then again in 2012 when it was completely disassembled and retested.
This launch is also another opportunity for SpaceX to attempt to land the first stage of the Falcon 9 rocket on its drone ship. The last attempt was not successful but produced spectacular video of the vehicle reaching the ship at an angle and bursting into flames.
Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on twitter @rtphokie.
