KENNEDY SPACE CENTER, FLA. -- At Astrotech Space Operations, technicians help lower the THEMIS spacecraft onto the Delta II upper stage booster. Once mated, the spacecraft will then be installed into its transportation canister and moved to Launch Complex 17 on Cape Canaveral Air Force Station for mating with the Delta II. THEMIS consists of five identical probes, the largest number of scientific satellites ever launched into orbit aboard a single rocket. This unique constellation of satellites will resolve the tantalizing mystery of what causes the spectacular sudden brightening of the aurora borealis and aurora australis - the fiery skies over the Earth's northern and southern polar regions. THEMIS is scheduled to launch Feb. 15 Pad 17-B.