Dawn Is Almost There

The Dawn spacecraft:



After all the excitement with Rosetta getting into orbit and it's lander Philae's rather acrobatic landing onto comet 67P/Churyumov-Gerasimenko, I've been checking in on the status of NASA's Dawn space craft, which is headed to what was once called the largest asteroid in the solar system, Ceres.

Don't get the wrong idea, they didn't find something bigger than Ceres in the asteroid belt. It's still the largest object in the asteroid belt, but the IAU (International Astronomic Union) gave it a promotion from asteroid to dwarf planet.

Hubble image of Ceres:



When Dawn first arrived at Vesta, I was very excited then. Even on it's approach to Vesta, you could already make out quite a bit more detail than even the best Hubble images:



Then of course once it had arrived at Vesta, the images from Dawn were stunning:



With never before close-up detail of it's surface:



After Dawn completed it's very successful exploration of Vesta, it's been making it's way to Ceres on it's ion drive system. It's taken it a while, but it's finally drawing close to Ceres:

Dawn is about 1.3 million miles (2.1 million kilometers) from Ceres, closing in at less than 900 mph (0.4 kilometers per second). It is on course for arriving in orbit in early March 2015. A summary of the schedule for photographing Ceres during the approach phase in January.

Dawn Mission Status, November 28, 2014

That 1.3 million miles means it's less than 3 times the distance from the Earth to the Moon!

While I'm exited about it finally starting to take pictures in January, it's tempered by the fact that it will still be approaching Ceres, so the very first pictures will not the best. Still, it will be great to see it from closer than Hubble is able to do right now, and if they pictures we saw when it approached Vesta is a example, it will still be exciting.

So I'm thinking of it as a late Christmas present!

Here is my favorite artist concept of Ceres (based upon the Hubble images):



Artist image source

a reply to: eriktheawful

Hell yea it is, and there be water vapor plumes in them there hills....

Gizmag

Ceres has a rocky core about 750 km (465 mi) in diameter covered by a 100 km (62 mi) thick layer of ice. The lot are then covered by a thin layer of whatever debris has settled on Ceres' surface over the last four billion years. Ceres may have accumulated its horde of ice by originating further out from the Sun, and only later settling down into its present orbit by interacting with the giant planets once they were formed.

It is interesting to note that if this model is even close to reality, there is more water on Ceres than there is fresh water on Earth. A base on Ceres may be a must for the future of space exploration, colonization, and industry.

That pic of Vesta's surface looks like they colored over a quarter of it with MS Paint.......

originally posted by: eriktheawful
That 1.3 million miles means it's less than 3 times the distance from the Earth to the Moon!

Actually ~5 times the distance from the Earth to the Moon.

/nitpick

Vesta looks like our moon in that one picture. I hope we are allowed to see more of Ceres by NASA.

That photo almost makes it look like a planet with oceans on the surface. I can't wait to see what it really looks like up close, but something tells me I'll be disappointed. The blurry photo makes it look perfectly spherical and colorful, with lovely blue and white ice, but I'm imagining when the close ups finally come it'll look like warped, cratered, lumpy greyscale rock ala Vesta as opposed to a beautiful, perfectly round object that looks like a mini Europa or Enceladus.

Looks like a great candidate for Nibiru!

originally posted by: Saint Exupery

originally posted by: eriktheawful
That 1.3 million miles means it's less than 3 times the distance from the Earth to the Moon!

Actually ~5 times the distance from the Earth to the Moon.

/nitpick

Yah, that's what i get for doing the thread so late at night! I meant to say "3 times the moon's orbital diameter"

I almost forgot this mission. Yes, Ceres is interesting as its closest dwarf planet to us. It has whopping 32% of the total mass of the asteroid belt. There is slight change of life on this largest asteroid. There may also be liquid water on it.

And next year will be interesting in space exploration, not only Dawn taking pictures, but New Horizons arriving at Pluto. It has traveled 9 years and its finally at Pluto's doorstep, only 1,8 AU away (31,85 AU from Earth). Week from now, New Horizons finally awakens from its final hibernation, after that there is 5-week preparation and testing phase. In January 2015 it will start collecting data and in July 2015 its at closest point to Pluto, its first time we see more of Pluto than few pixels.

a reply to: eriktheawful

I thought Dawns primary mission was Pluto, and then on to Ceres years later?

Edit: oh sorry I mistook Dawn for new horizons, but I heard New horizons will also be heading out towards the far reaches after it goes by Pluto.

Great stuff, Erik

However, a side note to the whole Dawn mission is the Xenon ion engine that it has. Most people may not realize this, but it is a very unique thing for spacecraft that can go visit one target (the asteroid Vesta), and stay in orbit around it for an extended period AND THEN restart its thrusters to get to another target (Ceres) where it again will go into orbit and remain there for an extended period.

Most spacecraft are not like we see in sci-fi shows and films. They don't usually turn their thrusters on and off multiple times, whizzing all around different directions and going different places. Most spacecraft use 95% to 99% of their available fuel in the first 10 minutes after liftoff, reserving a scant bit for future course corrections. They are destined at launch to go to a certain place, and can't do much to change that once they are on their way. The space shuttle didn't "thrust" its way all the way up to the space station and zip around in space like in the movies. Rather, it used almost all of its fuel at launch to put itself in an orbit that would eventually raise up over time to eventually interest with the space station (for the most part -- some relatively minor engine burns help get it there).

Dawn is different; it has ion thrusters that uses small amounts of xenon gas to create ions that provide a small electrostatic thrust. The thrust is small, but it keeps thrusting for a very long time -- theoretically it could thrust for weeks or months. Over time, that very small thrust adds up. Another advantage of ion thrusters (and I touched on this earlier) is that they can easily be shut down and restarted several times, allowing a spacecraft the unique ability to wander around from place to place.

More reading:

NASA - Electric Propulsion

New Dawn for Electric Rockets [Opens directly to a pdf]

The Colorado State University Electric Propulsion & Plasma Engineering (CEPPE) Laboratory

originally posted by: NiZZiM
a reply to: eriktheawful

I thought Dawns primary mission was Pluto, and then on to Ceres years later?

Edit: oh sorry I mistook Dawn for new horizons, but I heard New horizons will also be heading out towards the far reaches after it goes by Pluto.

Yes it will. New Horizons will fly past Pluto in July, 2015 and after giving us our first close up images, it will be headed out to the Kuiper Belt and later have fly bys of other Dwarf Planets or Kuiper Belt objects.

Ceres is actually located in the inner asteroid belt between Mars and Jupiter.

a reply to: Soylent Green Is People

Yes, the ion engine of Dawn is unique, though I don't know if I would say that it's "whizzing around", hehe, considering how long it takes for it to build up thrust.

You know, they have a Ion Engine in the Kerbal Space Program. I've never messed with it. I need to build my own version of "Dawn" and go visit some of the asteroids in the game!