Asteroid 2002 AA29 (also written 2002 AA29) is a near-Earth asteroid discovered in January 2002 by the LINEAR asteroid survey. The asteroid spends most of its time following a "horseshoe orbit" that makes it come near the Earth every 95 years as it follows Earth's orbit around the Sun. Every 600 years or so it switches to a quasi-satellite orbit. During this time it appears to orbit the Earth. It measures about 60 metres across.
On January 8, 2003, the asteroid came within approximately 5.9 Gm (3.7 million miles) of Earth, its closest approach for almost a century.
J. Richard Gott and Edward Belbruno from Princeton University have speculated that 2002 AA29 might have formed together with Earth and Theia, the postulated planet that, according to the Giant Impact hypothesis collided with Earth in its early history.
The orbit of the asteroid is such that it would be relatively easy for a spacecraft to retrieve rock samples from it and bring them to Earth for analysis.