NASA's Deep Impact Moved Into Cruise Phase

karvind writes "NASA is reporting that the Deep Impact spacecraft has completed the commissioning phase of the mission and has moved into the cruise phase. Deep Impact mission planners have separated the spacecraft's flight operations into five mission phases. Cruise phase will continue until about 60 days before the encounter with comet Tempel 1 on July 4, 2005. Deep Impact has been covered on slashdot before"

Comments

Re:Fastest non-atomic collision ever?

[mike5904]

Not the fastest, as Sandia National Laboratories have used one of their railguns to propel a .1 gram object at 16,000 m/s (nearly 36000 miles per hour). A spacecraft is certainly larger than that though, so perhaps the greatest kinetic energy of any such collision?

Re:Halfassed NASA Eggheads?

[Anonymous Coward]

uhhh, the reason for the wide range in their estimates is because the composition of the comet is largly unknown. They won't know what its made of until they smash into it and attempt to get some readings from the core of the comet. So it nearly impossible for them to attempt to calculate a reasonable size for this impact since the size of the impact will be determined by the comets composition. Thats the whole point of the mission; to find out what the comet is made of. Since the comet was made during the begining of the our solar system's creation it will give us a good insight into how our solar system was created and what type of materials are most abundant.

Re:Kinetic Energy.

[khallow]

Incidentally, this is on the order of the kinetic energy of a fully loaded (with oil) supertanker travelling at speed. Apparently, the top speed is roughly 8.3 m/s (30 km/hr) and the mass of a fully loaded tanker can exceed 400,000 tons. So

KE=0.5*4*10^8 kg*(8.3 m/s)^2 = 1.3 * 10^10 J.

This is on the order of the above calculation.

I got a slightly higher value for the velocity, but it's basically 1.035+/-bunch *10^4 m/s. KE is around 2.0*10^10 J. So you have a little more than the energy of the largest supertankers hitting a comet. Should be spectacular.

Re:I'm Not Sure...

[MillionthMonkey]

wouldn't it be easier to just drill a core sample from the comet?

No.

In the solar system frame, the comet is approaching very fast. Its aphelion is just inside Jupiter's orbit. Our probe is poking along at an Earthlike velocity in a roughly Earthlike orbit- it's the comet that's going to crash into the probe, really, not the other way around.

To get your Black & Decker to it in one piece, you'd have to accelerate to 0 mph relative to the comet. That alone requires gravity assists off other planets. Then you need to design robotics to move around on an object with almost no gravity and a surface that can't be surveyed very well from Earth (thanks to the bright coma). You'd have to drill a hole into a material of unknown composition, in a process lasting minutes to hours rather than microseconds. That means you'll have to make decisions at certain points during the operation, requiring bug-prone programming or impractical communication links to ground-based controllers.

Simply allowing the comet to crash into something and taking pictures of the explosion from a distance is much cheaper and more likely to work.

Book your tickets to Hawaii now!

[Shag]

They're trying to time the collision so it will be visible from Hawaii, where Karen Meech will be coordinating observation from all these telescopes (in their respective favorite wavelengths) that night. (Technically, I think it'll still be July 3, local time.)

This will hopefully bring to fruition the hard work of Jana and Audrey and all those other Honolulu-based astrobiology folks for whom I sometimes point this scope at comets.

Now I just have to remember to ask way far ahead of time to be running the scope around then. Or... maybe not. Maybe I should just drive up to the visitor station and kick back with their 16-inch Meade and some popcorn.