Spirit and Opportunity were launched on separate Delta 2 rockets from Cape Canaveral in 2003. The Spirit and Opportunity rovers share the same mission and design.
Spirit and Opportunity were twin craft sent on the Mars Exploration Rover Mission. Spirit was called Mars Exploration Rover A. Opportunity was called Mars Exploration Rover B. The rovers were initially expected to last 90 Martian days. However, their photovoltaic cells received more power than expected, allowing them to last longer than expected. The Mars Exploration rovers were controlled by the Jet Propulsion Laboratory in Pasadena, California.
Each rover has a panoramic camera and a microscopic imager. They carry thermal emission spectrometers, devices which can measure the temperature of the air or rocks. Each carries a Mössbauer Spectrometer used for studying iron bearing rocks. They also have X-ray spectrometers for studying all types of rocks. Both rovers have rock abrasion tools to dig through the surface of a rock to analyze the material underneath. They also have magnets to collect magnetic iron particles for analysis. A microscopic imager is used to take pictures of mineral samples.
Each rover had heaters to keep their temperatures between -40°C and 40°C.
The rovers are powered by triple layer solar panels. Each rover must spend the winter on a sun facing slope in order to remain fully powered until spring brings longer days. The solar panels capture sufficient sunlight to charge the batteries about four hours a day.
The craft were 1.5 meters tall, 2.3 meters across and 1.6 meters long. They have six wheels each. Their top speed is two inches per second, roughly 0.2 kilometers per hour. Each craft weighed roughly 400 pounds or 180 kilograms.
The Spirit Rover was launched June 10, 2003. Spirit landed on Mars on January 4, 2004. Spirit landed in Gusev crater. Spirit was sent there because Gusev is suspected of holding a lake in the center of the crater at one time. In March, 2004, Spirit arrived in Bonneville crater. It was then sent to Missoula crater and the Columbia Hills.
In 2005, Spirit sent back video of a dust devil on Mars. The dust devil did not harm the rover. In fact, it removed much of the dust that had collected on the solar panels. Spirit was sent to Husband Hill and then Home Plate. The Spirit rover was sent to McCool Hill for the Martian winter but ended up at Low Ridge Haven because the soil was too loose for it to travel on. In 2007, the Spirit rover had a wheel become stuck in the dirt. When the rover came free, it left a significant gouge in the ground. This gouge was essentially an excavation of the soil on Mars. The soil under the iron-rich top layer was primarily silica. The silica could have been created by an ancient geyser or acidic steam rising through the ground. Both of these possible scenarios mean that there was warmth and flowing water in the area in Mars’ past.
Spirit travelled almost 5 miles or 8 kilometers across Mars until it became stuck in 2009. It was left with only four operational wheels. Due to the coming Martian winter and poor location of the rover, Spirit would not have been able to operate until May, 2010. In January 2010, Spirit started missing communications with Earth. In March, 2010, it stopped communicating with Earth. NASA spent another year attempting to contact the rover before declaring it dead. It is thought that the rover’s batteries got too weak due to a lack of sunlight on the dark side of Mars. The equipment either shut down due to a lack of power for its heaters to keep it from failing due to the cold, or it failed to restart when enough sunlight started to reach its panels again because it forgot its mission parameters.
The Opportunity Rover was launched on July 7, 2003. Opportunity landed on Mars about three weeks after Spirit, landing in Meridiani Planum on January 25, 2004.
Opportunity first examined the outcrop area of the crater where it landed. It moved on to El Capitan. Opportunity dug the first deliberate trench on Mars there. Opportunity travelled to Endurance crater and stayed there for 180 Martian days. Opportunity then travelled to Heat Shield Rock, a rock later determined to be meteor found near Opportunity’s own heat shield.
Opportunity travelled to Argo Crater and Erebus crater.
Opportunity explored Victoria Crater for two years. In 2010, Opportunity reached Concepcion crater. In 2011, the Opportunity rover reached Santa Maria crater.
In 2012, the Opportunity rover did a “walkabout” of Matijevic Hill, located on the edge of Endeavour Crater. Here, it has found what is suspected to be clay. On July 2, 2012, Opportunity celebrated 3,000 sols or Martian days of operation.
Opportunity is now the longest running craft on Mars. It lasted longer than the previous record holder, Viking 1. It has also lasted more than thirty times its planned operational life.
The Spirit and Opportunity craft discovered objects called “blueberries” upon landing on Mars. These “blueberries” are relatively round iron rich spheres that dot their landing sites. These features are thought to have formed in mineral rich water.
Opportunity discovered the first meteorite found on another planet, excluding meteorites found on Earth’s moon. Opportunity caught the first dust devil documented via video in history, though images of them had been captured by orbiting craft before.
Opportunity found a vein of gypsum. This is important because gypsum is a sign of running water existing on Mars at one time in its history.
The Mars Odyssey is in orbit above Mars. The Opportunity rover periodically communicates with Odyssey. According to NASA, Opportunity can communicate with Earth when orbital relays are not available.
In 2007, both rovers had their flight software updated from Earth. This software change gave the rovers more decision making ability. They could decide whether or not to send images to Earth, instead of storing, compressing and sending back all images to Earth. The rovers gained the ability to decide whether or not to extend their arms, reducing the time it took for the rover to start exploring an interesting feature.
There is a Twitter account for Spirit and Opportunity called Spirit and Oppy (@MarsRovers). The Curiosity rover is on Mars right now, and its findings are also announced via this Twitter account. The Mars Rover twitter account is maintained by NASA.
In 2011, the Spirit and Opportunity rovers were awarded the Popular Mechanics Lifetime Achievement Award.