The United Launch Alliance Delta II rocket is moved inside the mobile service tower.

On Launch Pad 17-B at Cape Canaveral Air Force Station in Florida, the United Launch Alliance Delta II rocket is moved inside the mobile service tower where nine solid rocket boosters will be attached in sets of three. The rocket is the launch vehicle for the THEMIS spacecraft, consisting 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 aboard the Delta II at 6:07 p.m. EST on Feb. 15. Photo credit: NASA/George Shelton