(190166) 2005 UP156

 is a stony asteroid and binary system, classified as near-Earth object of the Apollo group, approximately 1 kilometer in diameter. It was discovered on 31 October 2005, by astronomers of the Spacewatch survey at the Kitt Peak National Observatory in Arizona, United States. Its minor-planet moon with an orbital period of 40.25 hours was discovered in 2017.

Orbit and classification
is an Amor asteroid that approaches the orbit of Earth from beyond but does not cross it. It orbits the Sun at a distance of 1.1–3.1 AU once every 3 years and 1 month (1,124 days). Its orbit has an eccentricity of 0.47 and an inclination of 4° with respect to the ecliptic. The body's observation arc begins with a precovery image taken by NEAT at Palomar Observatory in November 2002, almost four years prior to its official discovery observation. Due to its high eccentricity, the asteroid is also a Mars-crosser, which means that it also crosses the orbit of Mars (at 1.666 AU).

Close approaches
This near-Earth object has an Earth minimum orbital intersection distance of 0.1316 AU which corresponds to 51.3 lunar distances. On 10 July 2017, it approached Earth to a distance of 0.133 AU and will make its next close approach at 0.128 AU in July 2057.

Physical characteristics
is an assumed S-type asteroid.

Rotation period
Since 2004, several rotational lightcurves of were obtained from photometric observations by French amateur astronomers David Romeuf, René Roy, as well as by American astronomer Brian Warner. Analysis of the best-rated lightcurve gave a rotation period of 40.542 hours with a brightness variation of 1.1 magnitude (U=2/3/3/2).

While not being a slow rotator, has a much longer rotation period than most asteroids, especially for it nearly sub-kilometer size. The lightcurve's high brightness amplitude also indicates that the body has a non-spheroidal shape.

Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, measures 1.045 kilometers in diameter and its surface has an albedo of 0.234, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.08 kilometers based on an absolute magnitude of 17.2. The asteroid has an estimated density of 1.8 g/cm3.

Binary system
In May 2017, photometric observations by Brian Warner and Alan Harris revealed that is a synchronous binary system with a secondary component orbiting around the system barycenter every 40.572 hours. The secondary has been confirmed by radar observations. Its provisional designation is.

Numbering and naming
This minor planet was numbered by the Minor Planet Center on 19 August 2008. As of 2018, it has not been named.