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Radio_Flyer
2004-Jun-22, 04:15 AM
Question: How fast is Cassini going? I have researched and researched and I can not find a true speed of the Cassini spacecraft. I keep getting conflicting answers or no mention of the speed at all. They mostly explain the flybys in depth but leave out the most important after effect. How much speed are we getting as our bonus. I would like to know it's velocity on takeoff, the speed it picked up off of the Earth, Venus and Jupiter flybys. Maybe someone could send Frasier a table of dates and initial speeds and the after effect of the so called slingshot effect.

Thanks Guys!

Send it to me also if you could please. ramrom@foothills.net

John L
2004-Jun-22, 03:52 PM
Go here (http://saturn.jpl.nasa.gov/operations/present-position.cfm) for Casini position and speed. According to the Casini website, the craft is currently traveling at 22,864 km/h relative to Saturn and 17,465 km/h relative to the Sun. I don't know the other answers.

I once had a question like this about Voyager, so I e-mailed the contact at the Voyager website and actually got a reply. They're usually happy to give answers, and I'm sure someone there has a simple table of speeds before and after each.

antoniseb
2004-Jun-22, 05:01 PM
Originally posted by John L@Jun 22 2004, 03:52 PM
I once had a question like this about Voyager, so I e-mailed the contact at the Voyager website and actually got a reply. They're usually happy to give answers, and I'm sure someone there has a simple table of speeds before and after each.
I've had the same experience. They model the path of the spacecraft with a bunch of odd looking equations, and you can plot them out.

Specifically for Cassini's boost going by Jupiter, it seemed like it added about 2 km/sec to the velocity with respect to the sun. [Note, this is a dim recollection from when I plotted the motion a few years back]. I think the Jupiter boost for Cassini was not very big compared to the Voyagers because the angle of the boost wasn't all that favorable.

Duane
2004-Jun-22, 05:40 PM
I think too, you have to ask "the speed realtive to what?" to get a good answer. By this, I mean, are you asking its speed relative to the sun? To Earth? To Saturn? When I got a responce from the Voyager team, they had answers for each and they differed significantly.

John L
2004-Jun-22, 06:15 PM
Originally posted by John L@Jun 22 2004, 10:52 AM
...the craft is currently traveling at 22,864 km/h relative to Saturn and 17,465 km/h relative to the Sun.
Exactly, Duane. That's why I gave both available measurements above. And I look at the weekly mission status reports for Voyager, although the ones on the website are usually about two months behind. They post teh distance and speed relative to both the Sun and the Earth.