Another little spacecraft that could: Dawn's photos reveal distant secrets

The robot interplanetary space explorers of NASA and the Jet Propulsion Laboratory have turned the remarkable into the routine again. Now come new photos from the Dawn spacecraft that’s been flying around out there for 11 (!!) years.

Cruising along at 25,000 miles an hour, it’s taken amazing pictures of a desolate asteroid named Vesta and for the past two years it’s been orbiting Ceres. That used to be thought of as another massive asteroid that just happens to be 590 miles across.

But Dawn’s discoveries have elevated Ceres to dwarf planet status with much more similarities to Earth and Mars than the Asteroid Belt’s other rocky remnants of the original big bang. Scientists speculate that “little” Ceres may contain more actual (frozen) water than Earth, which is 8,000 miles across and 71 percent covered  by water.

Dawn likely has only a few more months of useful life; its ion engines have been turned off for the last scheduled time. As a sort of grand finale, Dawn just flew over Ceres at a minuscule altitude of 21 miles, producing this photo here and hundreds of others still being downloaded by the dutiful little robot with the wide wings.

The mission’s chief engineer, Marc Rayman, talks like a proud papa: “Dawn is like a master artist, adding rich details to the other-worldly beauty in its intimate portrait of Ceres.”

The photo above is of just part of Occator, a massive crater about 57 miles wide and two miles deep. It shows landslide material clearly moving down the slope recently with some of it stuck partway.

Large bright deposits are sodium carbonate, the largest observed beyond Earth. But how did they get there? From shallow reservoirs of water laden with minerals or perhaps much deeper sources of brine seeping upward through cracks?

Water vapor has also been observed, suggesting to scientists’ surprise that Ceres is geologically active, making it a prime target for further study someday.

Here’s an intriguing short NASA/JPL video about Ceres and what Dawn has taught us so far. Prepare to be fascinated!