Marooned Off Vesta

Marooned Off Vesta was written in 1938 by Isaac Asimov when he was 18 years old. It was one of the first science fiction stories that I read as a kid back in the ’50s. It deals with three astronauts shipwrecked in orbit around the asteroid and how they use their limited resources to save themselves.

This video put together from images taken by the Dawn spacecraft shows what it might be like to be marooned off Vesta.

Video Credit: NASA, DLR

Dusk is Coming for Dawn

The Dawn spacecraft is about to wrap up it’s11-year mission which has included visits to the asteroids Vesta and Ceres. It’s now in a low orbit around Ceres gathering images and other science data, but in few months, it will run out of fuel for it’s attitude control thrusters. It will no longer be able to keep it’s antenna pointed toward Earth and, contact will be lost. The spacecraft will remain in orbit around Ceres.

The Gentle Reader may remember those intriguing bright spots that mystified observers as Dawn approached Ceres. They turned out to be mineral deposits in a large crater named Occator. The images above are close ups of some of those deposits taken from an altitude of 35 km. The top picture is a mosaic of multiple images of the formation called Cerealia Facula in Occator Crater. The bottom is of Vinalia Faculae also in Occator.

Image Credits: NASA

Organic Compounds Found on Ceres

organics-on-ceresThis enhanced color image was made with data from the Dawn spacecraft. It shows the area around a crater on the dwarf planet Ceres named Ernutet. The areas which show up as bright red are associated with evidence of organic material. Organic molecules are interesting to scientists because they are necessary, though not sufficient, components of life on Earth. This discovery adds to the growing list of bodies in the solar system where organic molecules have been found.

Image Credit: NASA

Ceres and Ammonia

Ceres from 240 kmThe Dawn spacecraft has moved into its lowest planed orbit around the dwarf planet Ceres. This picture of a chain of craters called Gerber Catena was take from an altitude of 385 km.

In early December, the Dawn science team announced that the bright material found in such notable craters as Occator is consistent with salt and suggested that a type of magnesium sulfate called hexahydrite may be present. The Dawn team has also found that ammoniated clays are present on Ceres. Because ammonia is abundant in the outer solar system, this could mean that Ceres was formed in the vicinity of Neptune and migrated inward during the early life of the Solar System.

Curiouser and curiouser.

Image Credit: NASA

Those Bright Spots on Ceres

Ceres has more than 130 bright spots. Most of them are associated with impact craters. Researchers at the Max Planck Institute for Solar System Research in Göttingen, Germany, suggest that the bright material could be a type of magnesium sulfate called hexahydrite. Epsom salt is another form of magnesium sulfate. Their theory is that these salt-rich areas were left behind as water-ice sublimated. Impacts from asteroids could have uncovered the mixture of ice and salt from a subsurface layer containing briny water-ice.

The Dawn spacecraft is still in orbit around Ceres. Perhaps additional data will validate this theory.

Video Credit: NASA

Mapping Ceres

CR-7881This color-coded map was assembled using topographic data from the Dawn mission. It shows the highs and lows of the surface of dwarf planet Ceres. It is labeled with names of features that have been approved by the International Astronomical Union. Click on the map to embiggen it.

Image Credit: NASA

A Mountain on Ceres

MountainThe Dawn spacecraft has returned images of this tall, conical mountain on Ceres. The mountain is located in the southern hemisphere and is about 6 km high. Its perimeter is sharply defined, and there almost no accumulated debris at the base of the brightly streaked slope.

This image was taken from an altitude of 1470 km. Dawn will spend the next couple of months mapping the planet from that height. Next, it will move to within 375 km of the surface.

BTW, there’s still no word on those bright spots.

Image Credit: NASA

Closer Still to Ceres

Dawn20150504The mysterious bright spots on the dwarf planet Ceres show up nicely in this sequence of images taken by the Dawn spacecraft on 4 May, 2015. The images were taken from a distance of 13,600 km.

The brightest spots within a crater in the northern hemisphere are composed of many smaller spots. However, their exact nature remains unknown, but the best guess so far is reflections off of water ice.

Image Credit: NASA

Vesta Trek

The folks out a JPL have come up with a nifty interactive tour of the asteroid Vesta derived from data taken by the Dawn spacecraft. You can find it here.vesta trekIt allows you to view the asteroid in 2D from the equator or either pole and in 3D. You can move around and zoom in and out. Give it a try.