Mars and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System. The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan. There are ongoing investigations
Mars One before arrival at Mars) and a lander (see "Human Lander" below). In 2012, Mars One speculated that the Transit Living Module could potentially be designed and built by Thales Alenia Space. A concept study was produced by Lockheed Martin for a demonstration lander based on the 2008 "Phoenix" lander. In December 2013 Mars One awarded a contract to Surrey Satellite Technology for a study of the satellite technology required to provide 24/7 communication between Earth and the Mars base. Mars One proposed at least two satellites, one in areostationary orbit above Mars and a second at the Earth – Sun