Volume: 05, Issue: 09 02/14/2007 
Technicians place the five THEMIS satellites inside the nose fairing of their Delta II rocket. Image credit: NASA/George Shelton.
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Image above: Technicians in Florida prepare one of the five THEMIS satellites for a solar panel test. Image credit: NASA/Jack Pfaller.
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A Delta II launched NASA's Deep Impact spacecraft from Florida. Image credit: NASA/KSC.
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Other Articles in This Issue:
The Colorful Demise of a Sun-Like Star
Spacewalks Continue at the International Space Station
Student Contests- Your Students Could Win a Trip To Space or Space Camp
History of Spaceflight and the Future of Human Space Exploration
 

Launch Week Arrives for THEMIS

On February 3, 2007, THEMIS was transported from Astrotech payload processing facility near Kennedy Space Center to Pad 17-B. The five satellites and their rocket were then subjected to a combined systems check to ensure everything is ready for the flight into space on launch day. Following the test, technicians installed the Delta II rocketís protective payload nose fairing around THEMIS.

For launch week, loading of the Delta II rocketís second stage with hypergolic propellants took place on February 14, 2007 along with a countdown dress rehearsal. Launch Day begins with the retraction of the launch padís mobile service tower at 9 a.m. EDT on February 16, 2007. Next, crews will begin filling the first stage with RP-1 kerosene fuel at 3:30 p.m. The pumping of liquid oxygen aboard the first stage will follow at 4:15 p.m. Once the propellants are aboard the rocket, the countdown will continue to a liftoff between 6:08 and 6:26 p.m. EDT.

THEMIS is a 2-year mission consisting of 5 identical probes that will study the violent colorful eruptions of Auroras. Understanding and predicting space weather is important to describe the environment in which spacecraft and astronauts operate and ensure their safety. Just as hail and tornadoes accompany the most severe thunderstorms, substorms accompany the most intense space storms Ė 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.

Substorms occur when the magnetosphere suddenly releases vast amounts of stored solar wind energy. Substorms start from a small region in space, but within minutes cover an immense region of the magnetosphere. Different possible triggers have different locations, so the key to solving this mystery is placing spacecraft in various locations in Earth's magnetic field to help find the elusive substorm point of origin.

For the first time NASA will launch a constellation of five satellites to study substorms. The THEMIS probes will line up over North America once every four days. Over the missionís two-year lifetime, the probes should be able to observe some 30 substorms.

THEMIS is the fifth medium-class mission under NASA's Explorer Program, which was conceived to provide frequent flight opportunities for world-class scientific investigations from space within the Heliophysics and Astrophysics science areas. The Explorers Program Office at Goddard Space Flight Center, Greenbelt, Md., manages this NASA-funded mission. The University of California, Berkeley's Space Sciences Laboratory and Swales Aerospace, Beltsville, Md., built the THEMIS probes.

For more information, please visit the followings websites:
http://www.nasa.gov/mission_pages/themis/main/index.html
http://www.nasa.gov/mission_pages/themis/news/Themis_intro.html.

    
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