1566 Icarus (/ˈɪkərəs/ IK-ə-rəs; provisional designation: 1949 MA) is a large near-Earth object of the Apollo group and the lowest numbered potentially hazardous asteroid.

This stony asteroid and relatively fast rotator with a period of 2.27 hours was discovered on 27 June 1949, by German astronomer Walter Baade at the Palomar Observatory in California.

[4] This near-Earth object and potentially hazardous asteroid makes close approaches to Earth in June at intervals of 9, 19, or 28 years.

[23] During this approach, Icarus became the first minor planet to be observed using radar, with measurements obtained at the Haystack Observatory[24] and the Goldstone Tracking Station.

[10][13][14] During the asteroid's close approach in June 2017, observations of the fast-moving object were taken by Italian astronomers Virginio Oldani and Federico Manzini, Brian Warner at the Palmer Divide Station (U82) in California, and by Australian astronomers at the Darling Range and Blue Mountains Observatories (Q68).

[6] The Collaborative Asteroid Lightcurve Link adopts an albedo of 0.14 based on the radar-derived equivalent diameter of 1.44 kilometers and absolute magnitude of 16.96.

This project was an assignment by Paul Sandorff for his group of MIT systems engineering graduate students to devise a plan to use rockets to deflect or destroy Icarus in the case that it was found to be on a collision course with planet Earth.

[29][30][31] Time magazine ran an article on the endeavor in June 1967[30] and the following year the student report was published as a book.

During the course of their study, the students visited the Kennedy Space Center, Florida, where they were so impressed with the Vehicle Assembly Building that they wrote of "the awesome reality" that had "completely erased" their doubts over using the technology associated with the Apollo program and Saturn rockets.

The final plan hypothesized that six Saturn V rockets (appropriated from the then-current Apollo program) would be used, each launched at variable intervals from months to hours away from impact.