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 in 2024, and one in 2026 which would not be returning to Earth. Although the announcement garnered much international publicity, the concept has been criticized by scientists, engineers, and those in the aerospace industry. Mars One is noted as being very short on funding, lacking critical concepts about hardware, life support, electrical power supply, and has been criticized as glossing over logistics, medical concerns, and protection against space radiation. The concept has been called a suicide mission both in academia, spaceflight, and international news. By February 2015, two conceptual studies were done by contractors. Despite the criticism and lack of