Deep Impact Flyby SpaceCraft to enter Mars orbit Jan 1, 2007

[mpratt]

Strange as it may seem on Jan 1st, 2007 the Deep Impact Fly By vehicle will hit mars dead on, or perhaps go into orbit. <br /><br />If you don't believe me go to the Deep Impact website position indicator and move the time forward to Jan 1st, 2007.<br /><br />This has to be more then a coincidence, I mean what’s the chance that Deep Impact would enter Mars orbit (or even hit Mars)?<br /><br />NASA has no stated goal that the craft will go into Mars orbit. In fact it has no stated "extended mission". However, that being all said maybe there is an extended mission for it in Mars orbit, since it is going there anyway.<br /><br />My question to you all is how can we really know if there is a possibility that it might actually hit Mars, besides the java applet on the web site? Anyone know of any software packages that we could use to better model the flight path??<br /><br />It’s kind of weird, but it looks to be true. Anyone have any ideas on verifying this? I’m guess a correction maneuver might be planned to get the flyby craft (about the size of a ford ranger) into an elliptical Mars orbit. Any ideas on what its science package could do once there?<br /><br />Matthew Pratt<br />

 

[lycan359]

<br />Heh, it's possible I guess.

 

[henryhallam]

The planets (and especially comets!) in the solar system do not all orbit in exactly the same plane, although with the exception of Mercury and Pluto, the planets all orbit within 2 or 3 degrees of the same plane as Earth (known as the ecliptic).<br />The angle between the ecliptic and the plane that an object orbits in is known as that object's orbital inclination. Comets often have relatively high inclinations, and Tempel 1's inclination is 10.5 degrees. Deep Impact doesn't have to be in the same orbital plane as Tempel 1, because it only wants to fly past it rather than rendezvous and keep station with it. It is only necessary that the encounter happens when the two orbits, and the orbital planes, intersect. In fact going by a quick Google search, Deep Impact has an inclination of 0.6 degrees.<br />Mars on the other hand has an inclination of 1.9 degrees so Deep Impact cannot be orbiting in the same plane as Mars (this isn't the whole story: even if the two orbits did have the same inclination with respect to the ecliptic, they can still have some inclination with respect to each other).<br />What it boils down to is that Deep Impact will pass a long way "above" or "below" Mars. Changing orbital planes is very expensive in terms of propellant, so I doubt Deep Impact will have enough to be able to change planes in order to meet up with Mars. Even if it could, capturing into Mars orbit requires even more propellant (though a flyby could still have some scientific value, albeit not so much now that we have Mars Express, Mars Odyssey and Mars Global Surveyor there)