One of the most rewarding parts of a career in planetary science is involvement with NASA missions. Below are brief descriptions of the mission teams PI Sori has worked on and how we've used the resulting mission data.
HiRISE (High Resolution Imaging Science Experiment) is one of six scientific instruments aboard the Mars Reconnaissance Orbiter. It is a camera that takes images of the Martian surface with a resolution of ~30 cm/pixel. HiRISE stereo pair images can be converted into digital elevation models with vertical resolution of ~1m.
We have developed techniques to analyze the icy stratigraphy seen in HiRISE images at the Martian poles. Using this technique, we quantified the confidence with which an orbital signal can be detected in the stratigraphy. We have also used HiRISE to study viscous deformation of icy topography in the polar regions. We found viscous flow to be negligible for craters at the north pole, but important for steep cliffs (right) of ice that host avalanches.
3D reconstructions of cliffs at the edge of the north polar layered deposits made from HiRISE stereo images (top). These cliffs host avalanches of frost/dust (bottom, HiRISE image ESP_016228_2650)
Simulated west-facing view of Ahuna Mons on Ceres reconstructed from Dawn Framing Camera stereo images.
Dawn is a spacecraft that orbited two large bodies in the asteroids belt: Vesta in 2011 and 2012 and Ceres in 2015 through the present. It has three scientific instruments: a camera, a visible/infrared spectrometer, and a gamma ray/neutron detector, and additionally collects gravity data using radio science.
We have used Dawn data to study cryovolcanism on Ceres. Dawn observed Ahuna Mons (left), a prominent mountain thought to be a cryovolcanic dome. We showed that viscous relaxation is an important mechanism in modifying cryovolcanoes on Ceres. Interpreting Dawn data with numerical models, we constrained Ceres' cryovolcanic eruption rates and history.
GRAIL (Gravity Recovery and Interior Laboratory) was a mission launched in 2011(right) that measured the gravity field of the Moon extremely accurately. The mission consisted of two spacecraft, Ebb and Flow, orbiting the Moon in sequence. The measurement made is the distance between the two spacecraft, which can be translated into gravitational acceleration.
We used GRAIL data to quantify lunar volcanism on the Moon that is obscured from view by overlying bright material by searching for the gravitational signatures of such hidden deposits. We also used the gravity data to study how topography is supported on the Moon.
Artist depiction of the two GRAIL spacecraft in lunar orbit.
Rectangular cylindrical projection of LOLA topography centered on the Moon's farside.
LOLA (Lunar Orbiter Laser Altimeter) is one of six scientific instruments aboard the Lunar Reconnaissance Orbiter, which launched in 2009 and is still orbiting the Moon today. It has resulted in a detailed topographic map of the Moon (left) using laser altimetry.
We have used LOLA data to study craters on the Moon. The dataset is also used in conjunction with GRAIL gravity data to study the isostatic state of the lunar highlands, which we found to be compensated by variations in crustal thickness.