1998 KY26  KY26 orbits the Sun at a distance of 1.0–1.5 AU once every 16 months (500 days). Its orbit has an eccentricity of 0.20 and an inclination of 1° with respect to the ecliptic. It has an Earth minimum orbital intersection distance of , which translates into 0.93 lunar distances. As a result, KY26 is one of the most easily accessible objects in the Solar System, and its orbit frequently brings it on a path very similar to the optimum Earth–Mars transfer orbit. This, coupled with the fact that it is water-rich, makes it an attractive target for further study and a potential source of water for future missions to Mars. The physical properties of KY26 were measured by an international team of astronomers led by Dr. Steven J. Ostro of the Jet Propulsion Laboratory using a radar telescope in California and optical telescopes in the Czech Republic, Hawaii, Arizona and California. KY26's rotation period of only 10.7 minutes means that it has one of the shortest sidereal days of any known object in the Solar System; most asteroids with established rotational rates have periods measured in hours. As a result, it cannot possibly be a rubble pile, as many asteroids are thought to be, and must instead be a monolithic object. KY26 was the first such object to be discovered, but since 1998, several other small asteroids have been found to also have short rotation periods, some even faster than .