STEREO
The STEREO (Solar TErrestrial RElations Observatory) project of the U.S. space agency NASA consists of two nearly identical space probes that observe the sun and the interaction of their Teilchenausbrüche and fields with the magnetosphere of the Earth for the first time three-dimensional ( stereo effect). The launch took place after a long series of displacements on October 26, 2006 at 0:52 UTC clock with a Delta II 7925 -10L from Cape Canaveral in Florida from.
The mission is led by the Applied Physics Laboratory (APL ) of the Johns Hopkins University. The cost of the mission, including all development and construction costs (including international), the launcher, the primary mission (two years) and data analysis (three years ) are about 550 million U.S. dollars.
Scientific Objectives
- Understanding of the causes and mechanisms of coronal mass ejections (English coronal mass ejections, CME)
- Description of the propagation of coronal mass ejections in the heliosphere
- Discovery of the mechanisms and sites of the acceleration of the particles in the lower corona and in interplanetary space.
- Determine the exact structure of the solar wind
- Due to the high stability with the cameras are the data collected for other astronomical purposes of benefits, so over a hundred double stars were rediscovered.
Evaluation
When evaluating the data also numerous volunteers use their time, classify the photographs of the sun through the website Solar Stormwatch.
Mission History
The two probes STEREO A and STEREO B were successively mounted housed in a Delta II launcher. These transported the spacecraft into a highly elliptical orbit with an apogee of about 400,000 km height. The apogee was in the plane of the lunar orbit and was a little farther away from Earth than the moon's orbit.
During several Erdumläufe the spacecraft apart. On 15 December 2006 resulted STEREO A (Ahead ) and B ( behind) a swing-by on the moon, where the moon happened STEREO A at a distance of 7322 km and STEREO B in 11,750 km. STEREO A passed by the escape velocity of the Earth- Moon system and flies the earth in its orbit around the sun ahead. STEREO A stepped it into a solar orbit that is slightly inside Earth's orbit and its orbital period is 346 days. STEREO A orbits by the sun faster than the earth and runs every year towards the Earth by 22 ° further in its orbit to the front.
STEREO B was brought to a much larger orbit through the swing-by. Then she passed on 21 January 2007 highlighted the moon, but this time on the opposite side of the earth. In this second swing-by at 8800 km altitude STEREO B was accelerated to escape velocity and flew against the direction of rotation of the earth around the sun it. Stereo B joined by a solar orbit with an orbital period 388 days. STEREO B encircled by the sun more slowly than the earth and remains at 22 ° back in its orbit relative to the earth per year. Therefore, the two STEREO probes are expected to be in 2015 on the opposite side of the earth to the sun.
On February 6, 2011, the probe passed through their mutual opposition; June 1, 2011 recordings were first made , which make up a complete picture of erdabgewandten sunny side had put together.
Structure of the probes
The two probes are largely identical and were built by APL, which also monitors the mission. The space probes are each 1.10 m high, 2.01 m long and 1.19 m wide ( with extended solar panels 6.49 m). The probes are three-axis stabilized and have a full tank has a mass of 618.7 kg each. The energy consumption of each probe is 596 watts. The data transmission to Earth at a speed of 720 Kbps; simultaneously has each of the spacecraft over 1 GB of internal storage.
Instruments
The two STEREO probes each have the same four instruments or instrument packages on board.
Sun Earth Connection Coronal and Heliospheric Investigation ( SECCHI )
STEREO / WAVES ( SWAVES )
In - situ Measurements of Particles and CME Transients ( IMPACT)