Spacecraft are vehicles designed for travel in outer space. Their systems and instruments vary depending on their mission, from piloted to unpiloted designs.
To land on Mars, a lander must separate from its orbiter and descend slowly through its atmosphere, protected from its harsh environment by an aeroshell and heat shield.
Phoenix
Phoenix was named for a mythological bird because its resilient spirit made its landing possible through thrusters instead of air bags – making its journey through Mars’ atmosphere less dangerous and slower than using airbags alone. Once on Mars’ surface, Phoenix used robotic arms with 2.35-metre arms to probe climate and geology with its 2.35-metre arm; returning soil samples back for analysis at its self-contained lab. A suite of Canadian components from MDA in Brampton such as lidar sensors and mast-mounted thermometers helped the spacecraft track daily weather changes on Mars’ surface.
Before the mission took off, flight engineers used THEMIS to select an ideal landing site: one with few rocks higher than half a meter. From Earth, THEMIS followed an 11 month Hohmann minimum-energy trajectory to Mars with up to six trajectory correction maneuvers along its journey. Once at Mars, its 2-meter mast allowed stereo cameras with two “eyes” per camera to survey its landing area for scientists’ use while multispectral capability allowed identification of local minerals.
Spirit
Spirit was one of two rovers launched by NASA as part of their second wave of Mars exploration. Launched on June 10, 2003 and arriving at Gusev Crater on January 4, 2004, Spirit used an aeroshell deceleration method before its parachute deployed and careened back down towards Gusev Crater where it eventually stopped exactly where NASA intended.
The Mars Exploration Rover quickly discovered signs of violent past on Mars, including impact marks and indications of subsurface water. Furthermore, it successfully scaled Husband Hill – marking a first for any planet other than Earth – where its view revealed stunning topography as well as rock layers with apparent water-rich sediment deposits.
At the end of its mission, Spirit ran into trouble. One of its wheels got stuck in sand and prevented it from charging; engineers attempted to free it but were ultimately unsuccessful; by March 2010, communication between Earth and Spirit had stopped altogether and NASA concluded that Spirit likely wouldn’t survive through Martian winter.
Opportunity
NASA’s Opportunity rover explored Mars for 15 years until finally running out of power and shutting off. Here, planetary scientist Steve Squyres shares his impressions from this incredible journey.
The golf-cart-sized rover launched from Cape Canaveral, Florida on July 7, 2013 and arrived on Mars just over six months later. Specifically, Meridiani Planum’s Eagle Crater served as its landing site, similar to an impact crater; after bouncing 26 times it eventually settled in a gully filled with hematite-rich rocks.
The rover was equipped with various instruments that enabled it to investigate rocks and soil, including spectrometers for studying chemicals and minerals as well as rock abration tools equipped with brushes to sweep away dust off surfaces.
Curiosity
Curiosity, designed to explore past environments for life on Mars, has been driving across Gale Crater and Mount Sharp since September 2014 in an effort to determine whether Mars ever supported habitability. Like Spirit and Opportunity before it, Curiosity hopes to uncover evidence for habitable conditions on this distant world.
Curiosity stands out as a truly mobile science laboratory. Equipped with navigation cameras to guide its drive, and equipped with 17 cameras and tools to investigate rocks while searching for signs of life – including drills and scoopers that collect powdered rock samples – its 7-foot arm allows scientists to place these tools close to rocks they wish to study while its instruments search for water molecules as well as organic compounds – the chemical building blocks essential to life on our planet.
The Radiation Assessment Detector monitors radiation hazards on Mars while the Rover Environmental Monitoring System measures atmospheric pressure, air and ground temperatures, humidity, ultraviolet light intensity and wind speed and direction. The Rover uses an expected nuclear power source of at least 50 years for power supply.