Gusev Crater is an ancient impact crater of a diameter of 150 km located in the Aesis (tropical) region of Mars. It lies at the outlet of one of the longest valley systems on Mars, Ma'adim Valley, of 900 km and named after the Arabic name for the Red Planet. The maximum depth of the crater is about 1600 m.
It is situated at a latitude of 13° S and a longitude of 183° W. It is practically at 0 altitude.
Gusev crater formed at the mouth of a very wide and very long fluvial valley about 3.5 billion years ago and became the receptacle for its episodic floods. There is evidence of long-term sedimentation and, above all, the legacy of an ancient lake which could have been one of the martian oases for which planetary scientists are searching. The crater is markedly assymetric, not only because of the inclined terrain but also due to the distribution of the sediments in the valley bed.
This is one of the sites that exobiologists are more excited about. Although Gusev crater is not yet an official landing site for any of the planned missions, it is being considered as one of the sites with greater probabilities of being designated in the near future.