Satellites Will Study Aurora Phenomena

Blame it on the weather. The launch date for the five small, identical satellites that comprise NASA's Time History of Events and Macroscale Interactions during Substorms (THEMIS) project has been bumped 24 hours, due to concerns at Kennedy Space Center about an advancing cold front and the severe storms accompanying it. The satellites are now slated to take flight aboard a Delta II booster Friday night.

Once the satellites are in orbit, THEMIS -- named for the Greek goddess of justice, wisdom and good counsel, and the guardian of oaths -- will spend two years analyzing what causes auroras in the Earth's atmosphere to dramatically change from slowly shimmering waves of light, to wildly shifting streaks of color.

NASA says discovering what causes auroras to change will provide scientists with important details on how the planet's magnetosphere works, and shed light on the relationship between the Earth and the Sun.

Understanding and predicting space weather is important to describe the environment in which spacecraft and astronauts operate and ensure their safety, the space agency says. Just as hail and tornadoes accompany the most severe thunderstorms, substorms accompany the most intense space storms – those that disrupt communications, cause power line transmission failures, and produce the most penetrating radiation.

THEMIS will study substorms to gain insight into the most severe space storms.

Loading of hypergolic propellants aboard the second stage of the vehicle will commence Wednesday. Friday's launch window extends from 6:05 to 6:23 pm EST.

FMI: www.nasa.gov/mission_pages/themis/main/