2016 marks the 25th anniversary of the creation of what has become one of the primary venues for the publication of research in planetary science: the Journal of Geophysical Research: Planets. This occasion is a good opportunity to look back at what we have learned in this era of expanded exploration and to try to take a peek at the future.
There is one less robot exploring the solar system today. MESSENGER, which has orbited Mercury for four years, finally ran out of fuel and crashed into the planet at 17:26 UT on Thursday, April 30, 2015.
At last week's Lunar and Planetary Science Conference, the MESSENGER team held a press briefing to share results from the recent few months of incredibly low-altitude flight over Mercury's surface. The mission will last only about five weeks more.
The two spacecraft currently orbiting the two innermost planets are both flying low in their orbits in the final phases of their missions. MESSENGER just performed a rocket burn to raise its orbit slightly, while Venus Express did the opposite.