In July of 2003, the Spirit and Opportunity Rovers were launched towards Mars. The purpose of Spirit and Opportunity being sent to Mars was to allow field study to be conducted, and to also make different observations of the atmosphere. The mission was planned to only last a few months, however, to this day the Opportunity is still making discoveries on Mars. The Spirit and Opportunity landed on opposite sides of Mars, each in very important locations. Some of the earliest findings of this mission included finding water on Mars, which lead to more research amongst the soil and rocks to find where this water is coming from. These findings proved that the environment of Mars used to be habitable. On this mission, the Spirit and Opportunity each carried high-tech scientific instruments that enabled photos of the soil and surface of Mars to be sent back to Earth. Additionally, the rovers were equipped with rock abrasion tools which allowed scientists to study the rocks and how they weathered. An alpha-particle x-ray spectrometer was also sent to Mars on the Spirit and Opportunity rovers. This tool allowed scientists to study the chemicals within the rocks. The two rovers contained many different tools along with those mentioned that allowed Mars to be studied more prominently. This mission brought new findings for us to explore; microbial life may have been present on Mars due to the similar characteristics Mars has to Earth. Despite the findings of water being present on Mars, there is still research to be done about the different soil times and conditions of Mars. The Spirit made final communication to Earth on March 22, 2010 and the Opportunity had final communication on February 13, 2019.
Prior to the Opportunity and Spirit being launched, there had been other orbital and surface missions to Mars, which provided scientists with some knowledge about the planet. Traveling to Mars in general is very difficult. The issues with travelling to Mars are it is many miles further than travelling to the Moon, meaning the need for fuel increases, which also leads to an increase in the weight of the rocket. Additionally, the orbits of Mars and Earth do not coincide, so the timing of when the rocket is launched both to and from Earth needs to be precise (Millis). There have been many attempts to conduct different missions to Mars, but the number of successful missions is very low. With previous missions being conducted, scientists were able to study both the surface of Mars and the global mineralogical information. The first mission before the Spirit and Opportunity rovers were launched was named “Sojourner” and allowed scientists to have the ability to study the rocks and composition of Mars through the Alpha X-Ray Spectrometer ? ?(Earth). With findings about the composition of Mars from previous missions such as the Sojourner mission, the Opportunity and Spirit rovers were sent to Mars to identify what the climate and conditions of the surface of Mars once truly were. The biggest concerns were whether or not Mars used to be habitable, and also if there was once microbial life on Mars. When the rovers were sent the locations at which they landed were important because each contained areas that looked as though water was once present. Both locations were selected because of both the flat surfaces, making landing easier, and because each location contained hints to different water sources. Opportunity landed on Meridiani Planum, and Spirit landed at the Gusev Crater (Staff). The rovers were equipped with panoramic cameras, microscopic cameras, miniature thermal emission spectrometer, alpha particle x-ray spectrometers, and rock abrasion tools to help determine whether water on Mars truly did once exist. With these tools, scientists were able to view the different mineral surfaces, composition of Mars, colors of rocks, chemicals, and soil constructions amongst Mars (Instruments). Scientists were able to find many different facts about the temperature, water conditions, and habitable conditions of Mars from the Spirit and Opportunity rovers. From the rovers, scientists found that, in fact, Mars once contained flowing water, a heated environment, hot springs, and salt water (Howell). After being launched in 2003, in May of 2011 Spirit made its final communication to Earth. Opportunity, on the other hand, lasted much longer than expected and just made final communication to Earth on February 7, 2019 (NASA). Scientists were able to conclude from the Spirit and Opportunity mission that Mars does contain characteristics that support water once being present on Mars, and also that at one point Mars may have been habitable.
Description of Mission
After landing in 2004, the Spirit and Opportunity rovers have uncovered many facts about Mars, leading to new research being able to be conducted by scientists. The names of the two rovers were established by a 9-year-old girl named Sofi Collis, who won the NASA naming competition with her submission of her personal story about living in an orphanage and always looking up into the sky during the night and finding “spirit and opportunity” ? ?(Howell). The Spirit Rover was launched on June 10, 2003 and the Opportunity rover was launched on July 7, 2003 ( ?Greicius) ?. When conducting any sort of mission to Mars, intense planning occurs. Since the orbits of Earth and Mars are not the same, the exact date of launch has to be planned many months in advance. The orbits of Earth and Mars take 26 months to become at a distance that is most efficient time to travel. With that being said, when going to or from Mars, one needs to wait 26 months between each launch. Once launched, it takes approximately 8 or 9 months to actually reach Mars (Seeker). If scientists were trying to plan a mission that would need to return to earth (a mission carrying humans), that means that the total travel time to and from Mars would be over three years, not including any time exploring the surface of Mars. As pictured by Universe Today in Figure 1, one can see the difference of orbits between the Earth and Mars, including each specific time it takes for one orbit around the sun (Williams).
The Spirit and Opportunity rovers were each successfully launched towards Mars despite the difficulty with the orbital planning. After Spirit landed on Mars on January 3, 2004 and Opportunity on January 24, 2004, the two rovers began communicating new findings to earth. From landing on Mars, Opportunity provided one of the most memorable missions to exist, outlasting its expected 90 day lifespan by numerous years. Each rover had specific jobs to search the red planet for facts about what type of life may have once been present. Additionally, each rover was equipped with special equipment to help uncover the hidden facts of Mars. Included in these tools were a panoramic camera, miniature thermal emission spectrometer, mössbauer spectrometer, alpha particle x-ray spectrometer, magnets, a microscopic imager, and a rock abrasion tool (Overview). Panoramic cameras were used to take panoramic images in color of the surrounding area which help determine the conditions of the planet (Howell). Miniature thermal emission spectrometers examine the rocks and soils and provide detail on the construction of the rocks and soils. Mössbauer spectrometers allow investigation on iron-bearing rocks and soils to be done. The alpha particle x-ray spectrometer worked to uncover the up-close view of what makes the soil and rocks. Magnets separated the magnetic particles from the non-magnetic particles. A microscopic imager took high resolution, up close pictures of the rocks and soils, providing scientists with a different view than a standard photograph. Finally, the rock abrasion tool removed weathered surface from rocks to allow a clearer view for the instruments to observe ( ?Greicius) ?. As seen in figure 2, a diagram by NASA, each rover was constructed to include many different instruments in order to communicate information to earth as best as possible (Mars).
For construction and launch of these rovers came a price of nearly $1 billion (Brown). Each rover explored different areas of the planet. Landing on opposite sides provided a good idea of the differences of surface materials amongst the planets. The location chosen for each rover to land was important because each marked a specific crater where water may have once existed (In Depth). The goal of each rover was to examine which types of potential life on Mars may have existed. With previous hints to water on Mars existing, the two rovers targeted different locations and wanted to study further into this idea. After communicating back and forth with earth for far longer than expected, each mission was labeled successful. Both rovers were able to communicate important facts back to earth, supporting the idea that water once was present on Mars (Exploritarium).
At 1:48pm EDT on June 10, 2003, the first of the twin rovers was launched from ?Cape Canaveral Air Force Station Space Launch Complex 17 in Florida. Nearly a month later on July 7, 2003 the Opportunity rover was launched at 11:18pm EDT from the same location as the Spirit rover. Each rover was launched from the Delta II vehicle (Spirit). As stated previously, reaching Mars is not easy due to the difference of orbits. The Delta II is a very popular launch design, taking part in 155 missions since 1989 (Heritage). The Deltas are expendable launch vehicles. This means for each Delta design, they can only be used once. For the Spirit and Opportunity launches, the launch vehicles used differed slightly. The Delta II 7925 and Delta II 7925H were used (Launch). The difference between the two as described by NASA are pictured below in figure 3, and the main purpose for creating a design that was slightly different was the different orbit positions at the time of launch (Launch Differences).
The delta design had three different stages, a payload fairing, and solid rocket motors (Launch). As stated before, the orbits of Mars Earth are different, thus successfully reaching Mars is very difficult. Prior to the Spirit and Opportunity rovers being launched and successfully landing, many missions had failed due to the timing of the orbits being incorrect. To this day there have only been eight successful Mars missions (Mars Exploration Fast). The path that is planned to Mars for each spacecraft to take is unique, and as pointed out prior, every 26 months is the best time to launch a spacecraft to Mars. From launch, it will take approximately a year for the spacecraft to reach Mars (Seeker). Since the launch pad did not allow Spirit and Opportunity to be launched at the same time, the amount of power required to launch the two differed due to the differences in orbit at each specific launch time. The Spirit rover required less energy than the Opportunity rover. During the trip to Mars, the Spirit and Opportunity each have to undergo “trajectory correction maneuvers” which ensure that the rover is in orbit and in line for the correct landing location. The Spirit was able to skip its last two since it was so on-point with its location. The Opportunity only required three total maneuvers. A star and sun scanner enabled the location to be identified in regards to distance from the sun and other stars. The navigational system used was a method called “delta differential one-way range measurement.” With all of these tools, the Spirit and Opportunity rovers were able to late relatively close to their intended destinations. The Spirit rover landed within 10 km and Opportunity was within 24 km (Propulsion). The landing site for the Spirit was the Gusev Crater, and the landing site for the Opportunity was ?Meridiani Planum (Staff). As stated before, the reason for landing at these two locations were that they had been specific places where water had potentially been present.
Made With the tools listed above, the Spirit and Opportunity rovers were able to provide evidence behind the idea of water one being present on Mars. The Spirit rover began communicating images back to earth nearly right after landing on Mars. During the mission, the Spirit ended up losing one of its six wheels, however that did not stop it from making different observations about the possible past wet life of Mars. One specific observation made by the Spirit rover was uncovered by the thermal emission spectrometer. In 2007, findings showed that the Mars content contained a high level of silica. The idea of having a large level of silica supports the idea of water one being present because silica is often found with a volcanic activity and water combination, or even simply found near hot springs. This was not the first time that the Spirit rover had found evidence supporting the idea that water was once present on Mars. Prior to finding the silica rich content, the Spirit rover uncovered things such as sulfur-rich soil and evidence of explosive volcanoes, both supporting the idea that water was once present on Mars (?Dunbar) ?. The Opportunity rover also made its own discoveries. One of the very first discoveries Opportunity made was finding blueberries on Mars. Of course these were not real blueberries, however the rock-like objects supported the idea of water once being present on Mars as pictured in figure 4 ( ?Zolfagharifard).
Additionally, the Opportunity rover discovered a meteorite in 2006. This was the first meteorite ever discovered on a different planet ( ?Weitering).
Over the many years that the twin rovers were roaming Mars, many facts were uncovered, allowing scientists to have better knowledge of the planet.
After a very successful mission, the Spirit rover died on March 22, 2010 outlasting its expected 90-day lifespan. The Spirit rover ended communication with scientists after getting stuck in a sand-trap. The Opportunity rover was just as successful as the Spirit. Lasting nearly 15 years, Opportunity was able to communicate many different photographs and facts about Mars back to earth way longer than expected. Additionally, the Opportunity rover now also holds the longest distance travelled by a rover, travelling around 25 miles (NASA long). The Opportunity rover just recently died on February 13, 2019 (Wall). Each rover outlasted their 90-day expected lives, enabling scientists to discover more about the climate of Mars and the idea of water once being present on Mars.
Brown, E. (2012, July 30). Is exploring Mars worth the investment? Retrieved from http://articles.latimes.com/2012/jul/30/science/la-sci-mars-science-cost-20120730 Dunbar, B. (n.d.). Mars Rover Spirit Unearths Surprise Evidence of Wetter Past. Retrieved February 28, 2019, from https://www.nasa.gov/mission_pages/mer/mer-20070521.html Earth as a Tool for Astrobiology – A European Perspective. (n.d.). Retrieved February 18, 2019, from https://www.researchgate.net/publication/317889242_Earth_as_a_Tool_for_Astrobiology _-_A_European_Perspective ?https://www.thoughtco.com/why-getting-to-mars-so-difficult -3073187 Exploratorium. (n.d.). Spirit and Opportunity | Return to Mars | Exploratorium. Retrieved February 27, 2019, from http://www.exploratorium.edu/mars/spiritopp.php Greicius, T. (2015, February 18). Mars Exploration Rovers – Spirit and Opportunity. Retrieved from https://www.nasa.gov/mission_pages/mer/index.html Heritage of Success. (n.d.). Retrieved from https://www.ulalaunch.com/rockets/delta-ii Howell, E. (2018, September 12). Opportunity: Longest-Running Mars Rover. Retrieved February 25, 2019, from https://www.space.com/18289-opportunity-rover.html In Depth: Spirit – Solar System Exploration: NASA Science. (2018, January 26). Retrieved March 2, 2019, from https://solarsystem.nasa.gov/missions/spirit/in-depth/ Instruments. (n.d.). Retrieved February 17, 2019, from https://mars.nasa.gov/mer/mission/instruments/ Launch Differences. (n.d.). Retrieved from https://mars.jpl.nasa.gov/mer/mission/launch-vehicle/differences/ Launch Vehicle. (n.d.). Retrieved from https://mars.jpl.nasa.gov/mer/mission/launch-vehicle/ Mars Exploration Fast Facts. (2019, February 14). Retrieved from https://www.cnn.com/2013/10/21/world/mars-exploration-fast-facts/index.html Mars Exploration Rover Instrument Diagrams – NASA’s Mars Exploration Program. (n.d.). Retrieved from https://mars.nasa.gov/resources/8896/mars-exploration-rover-instrument-diagrams/ Millis, J. P. (2018, August 27). The Barriers to Human Exploration of Mars. Retrieved February 25, 2019, from https://www.thoughtco.com/why-getting-to-mars-so-difficult-3073187 NASA. (2019, February 13). What Opportunity, NASA’s Mars rover, achieved for humankind. Retrieved February 25, 2019, from https://www.nationalgeographic.com/science/2019/02/nasa-mars-rover-opportunity-dead- what-it-gave-humankind/ NASA Long-Lived Mars Opportunity Rover Sets Off-World Driving Record. (2014, July 28). Retrieved February 27, 2019, from https://www.jpl.nasa.gov/news/news.php?feature=4232 Overview. (n.d.). Retrieved from https://mars.jpl.nasa.gov/mer/mission/overview/ Propulsion. (n.d.). Retrieved March 4, 2019, from https://mars.nasa.gov/mer/mission/technology/propulsion/ Seeker. (2018, August 26). How Long Does It Take to Get to Mars? Retrieved from https://www.seeker.com/videos/space/how-long-does-it-take-to-get-to-mars Spirit and Opportunity. (n.d.). Retrieved March 1, 2019, from https://marsmobile.jpl.nasa.gov/programmissions/missions/past/2003/ Staff, S. (2014, January 24). Top 10 Discoveries by Mars Rovers Spirit & Opportunity: A Scientist’s View. Retrieved February 23, 2019, from https://www.space.com/24397-mars-rovers-spirit-opportunity-best-discoveries-ray-arvids on.html Wall, M. (2019, February 13). Mars Rover Opportunity Is Dead After Record-Breaking 15 Years on Red Planet. Retrieved March 5, 2019, from https://www.space.com/mars-rover-opportunity-declared-dead.html Weitering, H. (2019, February 13). The Weirdest Mars Discoveries by Opportunity and Spirit Rovers. Retrieved from https://www.space.com/weirdest-mars-discoveries-opportunity-spirit-rovers.html Williams, M. (2018, July 31). When Will Mars Be Close to Earth? Retrieved from https://www.universetoday.com/14820/when-will-mars-be-close-to-earth-1/ Zolfagharifard, E. (2014, January 08). ‘Blueberries’ on Mars! Stunning images of the red planet taken by Spirit and Opportunity rovers are revealed in a new exhibition. Retrieved March 5, 2019, from https://www.dailymail.co.uk/sciencetech/article-2535708/Blueberries-Mars-Stunning-ima ges-red-planet-taken-Spirit-Opportunity-rovers-revealed-new-exhibition.html