Archive for January, 2014


 

31 Jan
2014
Marc Rayman
Marc Rayman
Chief Engineer/ Mission Director, JPL

Dawn Journal | January 31, 2014

by Marc Rayman
 

Dear Rendawnvous,

Dawn is continuing its trek through the main asteroid belt between Mars and Jupiter. Leaving behind a blue-green wake of xenon from its ion propulsion system, its sights are set on dwarf planet Ceres ahead. The journey has been long, but the veteran space traveler (and its support team on distant Earth) is making good progress for its rendezvous early next year.

The final part of Dawn's approach trajectory to Ceres

The final part of Dawn’s approach trajectory to Ceres, including when the dwarf planet captures the spacecraft. Dawn continues ion thrusting to its first observational orbit at an altitude of 8,400 miles (13,500 kilometers). Credit: JPL/NASA

Last month, we had a preview of many of the activities the probe will execute during the three months that culminate in settling into the first observational orbit at Ceres in April 2015. At that orbit, about 8,400 miles (13,500 kilometers) above the alien landscapes of rock and ice, Dawn will begin its intensive investigations. Nevertheless, even during the “approach phase,” it will often observe Ceres with its camera and one of its spectrometers to gain a better fix on its trajectory and to perform some preliminary characterizations of the mysterious world prior to initiating its in-depth studies. The discussion in December did not cover the principal activity, however, which is one very familiar not only to the spacecraft but also to readers of these logs. The majority of the time in the approach phase will be devoted to continuing the ion-powered flight. We described this before Vesta, but for those few readers who don’t have perfect recall (we know who you are), let’s take another look at how this remarkable technology is used to deliver the adventurer to the desired orbit around Ceres.

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12 Jan
2014
Marc Rayman
Marc Rayman
Chief Engineer/ Mission Director, JPL

Another Top Five: Dawn 2013

by Marc Rayman
 

From Our Chief Engineer

I was delighted to be asked to name my top five accomplishments for the Dawn mission in 2013. This is a very ambitious and exciting interplanetary adventure, exploring some of the last uncharted worlds in the inner solar system. Thanks to its advanced ion propulsion system, this is the only spacecraft ever targeted to orbit two extraterrestrial destinations, and it leaves behind a blue-green wisp of xenon ions as it blazes a unique trail in humankind’s efforts to know the cosmos.

2013 was an extremely successful year, and it is not easy to select only five accomplishments (especially for someone as enthusiastic and wordy as I am), but it also was gratifying to review the year. The specific activities in 2013 may not be as obviously spectacular as in some other years, in which the spacecraft left its home planet behind, swooped past Mars on its way to more distant places, maneuvered into orbit around a giant protoplanet, spiraled down to a daringly low altitude for astonishing views, or climbed away from a world it unveiled, breaking free of its gravity to journey elsewhere in the solar system. But the many accomplishments of 2013 are valuable and impressive, and it will be interesting to see what different members of the team choose for their top five. Here are mine:

Artist’s concept of NASA’s Dawn spacecraft at the giant asteroid Vesta and the dwarf planet Ceres.

Artist’s concept of Dawn thrusting with its ion engine over a view of the actual rugged surface of the giant protoplanet Vesta. Image credit: NASA/JPL-Caltech

1)     Delivery of large volumes of richly detailed observations of Vesta with the science camera, the gamma-ray and neutron spectrometer, and the visible and infrared mapping spectrometer to the repository used by the scientific community (the Planetary Data System, or PDS). We went to Vesta to collect these data, and now they are available for use by scientists (and the public) around the world for generations to come, ensuring there will continue to be many wonderful discoveries about this fascinating, complex protoplanet. (The gravity measurements will be available at the PDS in 2014.) For a summary of some of Dawn’s findings at Vesta, which is more closely related to Earth and the other terrestrial planets than to typical asteroids, see the January 2013 Dawn Journal.

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1 Jan
2014

Six of Dawn’s Top 2013

by Chris Russell
 

From our Principal Investigator, Chris Russell

As 2013 drew to a close, we asked the Dawn team to choose their top stories or news from the Dawn mission in 2013 and received some compelling responses. Over the next several weeks, more top choices will be coming your way. We are beginning with principal investigator Chris Russell’s perspective.

It is often hard to ascribe dates to projects that extend across year boundaries, but here are six great contributions from Dawn in 2013.

colorized image of Aelia crater

Assigning colors to different wavelengths of light revealed not only geological structures invisible to the naked eye, but landscapes of incomparable beauty. Image: NASA/JPL-Caltech/UCLAMPS/DLR/IDA

1. Dawn Objectives at Ceres
Plans were developed allowing Dawn to achieve all its level 1 objectives within its technical resources at Ceres and NASA agreed with these plans.
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2. Color Illuminates Vesta
Another important achievement in 2013 was the improvement in the color images from Dawn. The framing camera team assigned colors to different wavelengths of light and, in the process, revealed in unprecedented detail not only geological structures that are invisible to the naked eye, but also landscapes of incomparable beauty. Researchers at Max Planck led by Andreas Nathues can now see structures such as melts from impacts, craters buried by quakes and foreign material brought by space rocks.

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