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.
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.
– read more
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.
3. Collaboration Drives Scientific Excellence
The Dawn at Vesta Participating Scientist Program, in which a set of international scientists were invited to contribute their distinct expertise to the mission in its time at Vesta, came to a close. It was a spectacular success.
4. Searching for Olivine
The discovery of where olivine is, and where it is not, is among Dawn’s most striking findings at Vesta. Olivine is a mineral (otherwise known as peridot) that crystalizes in magnesium-rich, silicon-poor magma and was expected in Vesta’s mantle.
Thus it was startling to find a complete lack of an olivine signature in the Rheasilvia basin, created by two massive impacts in Vesta’s southern hemisphere. Petrologic models for the structure of Vesta and modeling of large impacts suggest the Rheasilvia event *should* have punctured through the crust and into the mantle, exposing abundant olivine. That made the discovery of olivine as a near-surface material in the northern hemisphere of Vesta all the more fascinating, and suggests that the evolution of Vesta and its internal structure are not completely understood. Science makes its most rapid advances by uncovering the unexpected, not confirming expectations!
5. Vesta: Full of Surprises
Temperature maps of Vesta’s surface have been created by the VIR (visible and infrared spectrometer) team. The temperatures they find are different than we expected in some regions of the surface, indicating significant variations of the density. This showed that the surface is not all regolith, the dusty and rocky remains of impacts, but that there is some more solid material. Why this material exists is not known; we have just created a new interdisciplinary task group to explore it further. - read more
6. Mapping a New World
Only 15 months after Dawn left Vesta, a Mova_Globe * was developed using the Dawn altimetry data allowing the public to bring Vesta into their living rooms. That is just one measure of the remarkable mapping of this compelling world our science team is bringing us. Another is an atlas of high resolution composite maps, again contributed by the framing camera team.
Note: Thanks to team members Lucy Ann McFadden and David W. Mittlefehldt for their contributions.
*available in 2014