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General >> Discussion >> NASA's Stereo Mission
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Message started by Tony on 11/03/07 at 20:53:31

Title: NASA's Stereo Mission
Post by Tony on 11/03/07 at 20:53:31

On October 26, 2006, NASA launched a pair of spacecraft to observe the Sun in stereo.  On December 15, 2006, the pair of spacecraft swung by the Moon for a gravity assist.  Stereo A was ejected into solar orbit.  Stereo B remained in Earth orbit to receive another gravity boost from the Moon on January 21, 2007.


The simulation http://orbitsimulator.com/gravity/simulations/stereo10272006.gsim shows a trio of spacecraft: Stereo A, Stereo B, and their booster rocket, in Earth orbit following launch.  If you run this simulation, you'll notice that all three spacecraft crash to Earth at perigee.  While this was the fate of the booster rocket, Stereo A and Stereo B performed a burn while near apogee, raising their perigees above Earth's surface.
http://orbitsimulator.com/gravity/images/stereoABlaunch.GIF


The simulation http://orbitsimulator.com/gravity/simulations/stereo11022006.gsim shows these twin spacecraft as they continue to orbit the Earth in highly eccentric orbits that carry them from just above Earth's surface to slightly beyond the orbit of the Moon.
http://orbitsimulator.com/gravity/images/stereoABorbit.GIF


The simulation http://orbitsimulator.com/gravity/simulations/stereo12152006.gsim shows the spacecraft swing by the Moon for a gravity assist on December 15, 2006.  Watch as Stereo A is ejected from the Earth / Moon system, while Stereo B is boosted into a wider orbit around the Earth.
http://orbitsimulator.com/gravity/images/stereoAeject.GIF


On January 21, 2007, Stereo B returns to the Moon for another gravity boost that will eject it from the Earth / Moon system.  The simulation http://orbitsimulator.com/gravity/simulations/stereo01212007.gsim shows Stereo B just prior to the gravity boost.  Watch as it is ejected into solar orbit.
http://orbitsimulator.com/gravity/images/stereoBeject.GIF


Switch the Focus Object to the Sun and zoom out to watch the twin spacecraft in their solar orbits.
http://orbitsimulator.com/gravity/images/stereoSolar.GIF


The simulation http://orbitsimulator.com/gravity/simulations/stereoRF.gsim shows the spacecraft in a rotating frame with its period set to Earth's orbital period.  Year after year the spacecraft become more distant.  Soon stereo images will not be possible because the seperation between the two spacecraft will be too great.
http://orbitsimulator.com/gravity/images/stereoRF.GIF

Title: Re: NASA's Stereo Mission
Post by frankuitaalst on 11/04/07 at 02:11:14

The simulation http://orbitsimulator.com/gravity/simulations/stereoRF.gsim shows the spacecraft in a rotating frame with its period set to Earth's orbital period.  Year after year the spacecraft become more distant.  Soon stereo images will not be possible because the seperation between the two spacecraft will be too great.
Was is the intention to let the two spaccraft drift away ? Or don't they have any fuel or means to change their orbit anymore ? BTW : where does NASA provide the orbit data for this spacecrafts ?

Title: Re: NASA's Stereo Mission
Post by Tony on 11/04/07 at 11:34:01

The data is available on the Horizons system.  Their IDs are -234 and -235.

Wikipedia's article states that they drift about 21 degrees a year in opposite directions.  They probably don't have enough fuel to halt their drift.

Title: Re: NASA's Stereo Mission
Post by Tony on 08/22/16 at 21:08:36

Stereo B was lost for 2 years. Today they recovered it.
Here are some new browser sims of this remarkable pair of spacecraft.
http://www.orbitsimulator.com/gravit...es/stereo.html
http://orbitsimulator.com/gravitySim...s/stereo1.html
http://orbitsimulator.com/gravitySim...s/stereo2.html
http://orbitsimulator.com/gravitySim...s/stereo3.html
http://orbitsimulator.com/gravitySim.../stereo35.html
http://orbitsimulator.com/gravitySim...s/stereo4.html
http://orbitsimulator.com/gravitySim...s/stereo5.html
Descriptions can be found here: http://www.orbitsimulator.com/gravity/articles/stereo.html

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