NASA's Dawn spacecraft focused on Ceres as it nears end of mission

July 17 (UPI) -- Even as NASA's Dawn spacecraft approaches the end of its mission, the probe continues to collect valuable data.

According to NASA, Dawn's instruments continue to observe Ceres and its unique geological features in gamma ray, infrared and visible spectra. The spacecraft also continues to beam back gravity data to Earth.

Most of the probe's recent observations have focused on Ceres' Occator and Urvara craters. An improved understanding of the dwarf planet's geological features could help scientists more accurately model Ceres' formation and evolution.

"The new images of Occator Crater and the surrounding areas have exceeded expectations, revealing beautiful, alien landscapes," Carol Raymond, principal investigator of the Dawn mission and scientist at NASA's Jet Propulsion Laboratory, said in a news release. "Ceres' unique surface appears to be shaped by impacts into its volatile-rich crust, resulting in intriguing, complex geology, as we can see in the new high-resolution mosaics of Cerealia Facula and Vinalia Faculae."

Dawn first began observing the Occator and Urvara craters in June, and will continue to do so for several more weeks -- perhaps until it can no longer function properly. The NASA probe is running out of hydrazine, a fuel vital to Ceres' thrusters, which control the spacecraft's orientation. Hydrazine is also essential to the probe's ability to communicate with Earth.

Scientists are preparing to share their latest Occator and Urvara data, including information about the composition of Ceres' surface, at this week's Committee on SPAce Research, COSPAR, meeting in Pasadena, Calif.

Dawn will continue to operate even after it runs out of hydrazine, which will happen sometime between August and October, but it won't be able to travel. The probe will remain in orbit around Ceres, and it's communication with Earth will be spotty, limiting its ability to transfer scientific data.

Dawn is the only spacecraft to circle two deep-space targets, Ceres and Vesta, the largest bodies found between Mars and Jupiter.

The craters currently being surveyed by Dawn are home to the phenomena known as Ceres' bright spots. Dawn's observations have helped planetary scientists explain the dwarf planet's unique reflectivity.

"Observations, modeling and laboratory studies helped us conclude that the bright spots are either formed by impacts interacting with the crust, or that a reservoir of briny melt contributed to their formation," said JPL scientist Jennifer Scully.

During Dawn's final orbits, the spacecraft has moved ever closer to Ceres surface. The probe has collected high-definition images of Ceres' Occator and Urvara craters during dives to 22 miles above the dwarf planet's surface.

"Acquiring these spectacular pictures has been one of the greatest challenges in Dawn's extraordinary extraterrestrial expedition, and the results are better than we had ever hoped," Dawn's chief engineer and project manager, Marc Rayman, said earlier this month. "Dawn is like a master artist, adding rich details to the otherworldly beauty in its intimate portrait of Ceres."