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Dawn probe reaches Ceres orbit!

Or as I like to call it, a Ceres circuit. Ba-dum-bum!

But Ceres-ly, folks…

This morning, at about 1239 GMT (or 7:39 AM where I am), the Dawn space probe successfully entered orbit around the dwarf planet Ceres. The NASA press release is here:

Nasa Spacecraft Becomes First to Orbit a Dwarf Planet

Unfortunately, Dawn is currently on the dark side of Ceres, and is orbiting slowly enough that it won’t come around to the light side until mid-April. So the best we get for a photo at the moment is this one from March 1:

Ceres March 1 2015

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

 

This is historic as the first orbit of a dwarf planet (the New Horizons probe later this year will only fly by Pluto, I believe) and the first time a probe has orbited two different bodies. And it’s significant to me since it means Dawn has now visited both of the Main Belt protoplanets featured in Only Superhuman, first Vesta back in 2011 and now Ceres. With Vesta, the timing was right to let me incorporate a bit of what Dawn discovered into the novel during the revision process — but with Ceres I just have to hope nothing contradicts what I wrote. My main description of Ceres in the book was as follows:

The sunlit side of the dwarf planet was a dusty gray, except for the bright glints where craters or mining operations had exposed fresh ice beneath.

So far, so good, I’d say, given the other photo we got recently:

Ceres bright spots

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Scientists are speculating that those bright spots might be exposed ice, or maybe salt. Although you know what they kinda look like to me?

The on switch.

More news as it develops…

Dawn probe reaches Vesta orbit!

Yesterday, July 16, 2011, NASA’s Dawn space probe entered orbit around the asteroid (or more properly, protoplanet) Vesta, the second-most massive object in the Main Asteroid Belt.  This is a mission I’ve following with interest, and I made a previous post about it back in April.  But now I can reveal why I’m particularly interested in this mission — because my upcoming novel Only Superhuman is set in the Asteroid Belt, and much of its action takes place on habitats around Vesta (or around Ceres, which Dawn will visit in 2015).  The novel mentions little enough about Vesta itself that I hope I won’t have to do any rewrites as a result of Dawn‘s findings, but I’m going to keep my eye on this just in case, and who knows — maybe I’ll get to write more about Vesta in a sequel.

Here’s the NASA press release:

http://dawn.jpl.nasa.gov/feature_stories/spacecraft_enters_orbit.asp

And here’s the clearest photo of Vesta to date, taken on July 9:

 Dawn photograph of Vesta

So… we now have direct experience of Vesta.  I guess that means we aren’t Vestal virgins anymore! 😀

Science orbit!

Today I was catching up on the status of the Dawn space probe, which is mere months away from a rendezvous with Vesta, one of the largest asteroids in the Main Asteroid Belt, so much so that the Dawn mission scientists prefer to call it a protoplanet.  Dawn is a really cool mission, an ion-powered spacecraft maneuverable enough to rendezvous with Vesta, spend a year in orbit of it, then thrust its way to a rendezvous with Ceres, the full-on dwarf planet member of the Main Belt, in 2015.  We’ll finally get detailed images and surveys of these sub-planetary bodies, which are very different from each other: Vesta is dry and rocky and differentiated like a planet, Ceres carbonaceous and probably covered in a thick layer of ice that contains more fresh water than exists on Earth.  These are of particular interest to me because of the spec novel I’ve written that’s set in the asteroid belt, and which I’ve alluded to before on this blog.

Anyway, another article I looked at today was this one from the JPL Dawn journal page, and I noted the following paragraph in it:

In December, we saw that by sensing the irregularities in the gravity field, Dawn will reveal the nature of Vesta’s internal structure. Until those detailed measurements have been made and accounted for in the design of the flight plan, however, the subtle effects of the gravity field will cause deviations from the planned trajectory. Therefore, as the spacecraft travels from one science orbit to another, it will thrust for a few days and then stop to allow navigators to get a new fix on its position. As it points its main antenna to Earth, the Doppler shift of its radio signal will reveal its speed, and the time for radio signals (traveling, as all readers know so well, at the universal limit of the speed of light) to make the round trip will yield its distance. Combining those results with other data, mission controllers will update the plan for where to point the thruster at each instant during the next phase of the spiral travel, check it, double check it, and transmit it to the distant explorer which will put it into action. This intensive process will be repeated every few days as Dawn maneuvers between science orbits.

I think that “science orbit” is the most awesome phrase I’ve seen all week.  Everything is made cooler by putting “science” in front of it.  Can’t you just hear it?  “Helmsman!  Prepare to enter… science orbit!

Dawn will enter science orbit! of Vesta in the science month of Science July, and will surely do much science to it.

Categories: My Fiction, Science Tags: , ,
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