[meteorite-list] Observe the Deep Impact Spacecraft Close In On Comet Tempel 1

[Ron Baalke]

http://neo.jpl.nasa.gov/orbits/deepimpact.html

Observe the Deep Impact Spacecraft Close In On Comet Tempel 1
Don Yeomans and Ron Baalke
NASA's Near Earth Object Program Office
February 3, 2005

An interactive 3D orbital plotter has been developed to 
show the trajectories of the Deep Impact spacecraft as it 
approaches and runs closely past comet Tempel 1.  The red 
orbital path of the Deep Impact spacecraft shows for dates 
beyond the launch on January 12, 2005 with the pink 
portion of the trajectory being above the Earth's orbital 
plane and the dark red portion being below this plane.  
To minimize the energy (i.e., fuel) needed to launch the 
spacecraft, the comet encounter takes place very near the 
point where the comet passes through the plane of the 
Earth's orbit (ecliptic plane); by launching from Earth, 
the spacecraft is already in the ecliptic plane so that 
no fuel need be used to push the spacecraft out of this plane.  

By running the orbital plotter forward in time, you will 
note that the comet overtakes the spacecraft on July 4, 2005 
with a relative velocity of 10.2 kilometers per second 
(23,000 mph) and it is at this time that the impactor 
spacecraft will collide with the comet.  After observing 
the impact itself, the flyby spacecraft will continue in 
its obit about the sun, pass within 0.033 AU (about 
4.9 million km or 3 million miles) of Mars on January 6, 2007, 
and return to the Earth's neighborhood in late January 2008 - 
some 3 years and two full orbits about the sun after launch.  
If the spacecraft is healthy and if NASA is able to grant 
the necessary permission and resources, the spacecraft 
could then be re-targeted for another cometary flyby by 
using the Earth encounter to re-shape the spacecraft's 
trajectory.