Epitaph for a fighter

The Little Rover That Could, which fell silent on a lonely plain on Mars on June 10th, 2018, has been declared lost after over a 1000 radio messages were transmitted to it in an effort to wake it up again. It has to be assumed at this point that the massive planetwide duststorm that silenced it also put it permanently out of commission, either by burying its solar panels in a thick layer of dust or by letting its electronics fall to too low a temperature.

The launch patch for
Mars Exploration Rover – B

Opportunity, officially “Mars Exploration Rover – B”, or MER-B, was launched on a Boeing Delta II rocket on July 7th, 2003. After a smooth, seven-month journey to Mars, it landed without mishap in the Meridiani Planum. Its twin, the Spirit rover, MER-A, came down on the opposite side of the planet. Each was designed for an operational life of 90 “sols” (a sol is a Martian day, a little longer than ours at 24 hours, 39 minutes and 35.244 seconds long). Although NASA privately expected the rovers to work for a bit more than that, nobody expected them to last as long as they did. Spirit, working on the far side of Mars, got stuck in the sand a bit over five Earth years after landing, 21.6 times the expected mission length. But Opportunity continued to wander around, perform tests, and take pictures for 55 times its planned lifetime, travelling 28.06 miles in the process. This is one of the most astonishing successes in NASA’s history, and beats the 24-mile record of the Soviet Lunokhod 2 on the Moon.

A timeline, found here, shows the incredible history of the two rovers.

From Wikipedia, here is an overview of Opportunity’s time on Mars:

From its initial landing, by chance, into an impact crater amidst an otherwise generally flat plain, Opportunity successfully investigated soil and rock samples and took panoramic photos of its landing site. Its sampling allowed NASA scientists to make hypotheses concerning the presence of hematite and past presence of water on the surface of Mars. Following this, it was directed to travel across the surface of Mars to investigate another crater site, Endurance crater, which it investigated from June to December 2004. Subsequently, Opportunity examined the impact site of its own heat shield and discovered an intact meteorite, now known as Heat Shield Rock, on the surface of Mars.

The Opportunity
rover on Mars

From late April to early June 2005, Opportunity was perilously lodged in a sand dune, with several wheels buried in the sand. Over a six-week period, Earth-based physical simulations were performed to decide how best to extract the rover from its position without risking its permanent immobilization. Successful maneuvering a few centimeters at a time eventually freed the rover, which resumed its travels.

Opportunity was directed to proceed in a southerly direction to Erebus crater, a large, shallow, partially buried crater and a stopover on the way south towards Victoria crater, between October 2005 and March 2006. It experienced some mechanical problems with its robotic arm.

In late September 2006, Opportunity reached Victoria crater and explored along the rim in a clockwise direction. In June 2007 it returned to Duck Bay, its original arrival point; in September 2007 it entered the crater to begin a detailed study. In August 2008, Opportunity left Victoria crater for Endeavour crater, which it reached on August 9, 2011

Here at the rim of the Endeavour crater, the rover moved around a geographic feature named Cape York. The Mars Reconnaissance Orbiter had detected phyllosilicates there, and the rover analyzed the rocks with its instruments to check this sighting on the ground. This structure was analyzed in depth until summer 2013. In May 2013 the rover was heading south to a hill named Solander Point.

During this time, the rover developed memory problems, probably due to age. It became unable to write anything reliably in its long-term memory (a human characteristic that may endear it to some). On May 23rd, 2015, NASA put the rover into RAM-only mode, where the retention of information relied upon precarious power levels, at the mercy of dust storms. Despite that handicap, Opportunity managed to keep moving and collecting valuable data until it encountered the giant dust storm in June of 2018.

Here is the very last full picture that Opportunity broadcast through its waning transmitter to those listening from Earth with giant radio antenna dishes (the left frame is infrared, and the right frame is monochrome visible light). It is looking back over its long journey across the sands and rock of Mars, as the shrunken sun sinks to the horizon and the gathering dust closes its eyes forever.

The sun sets on Opportunity
(Credit: NASA/JPL-Caltech/Cornell/ASU)

So long, little guy, we’re going to miss you.