2002 AT4

2002 AT₄ is a near-Earth object and potentially hazardous asteroid of the Amor group, approximately 350 meters (1,100 feet) in diameter. It has an eccentric orbit that brings it sometimes close to Earth's orbit, and sometimes halfway between Mars and Jupiter. It is a dark D-type asteroid^[3] which means that it may be reddish in color.

2002 AT₄

Discovery[1]
Discovered by	LINEAR
Discovery site	Lincoln Lab's ETS
Discovery date	8 January 2002 (first observed only)
Designations
MPC designation	2002 AT4
Minor planet category	NEO · Amor · PHA[1][2]
Orbital characteristics[2]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 0
Observation arc	4.94 yr (1,805 d)
Aphelion	2.7000 AU
Perihelion	1.0339 AU
Semi-major axis	1.8670 AU
Eccentricity	0.4462
Orbital period (sidereal)	2.55 yr (932 d)
Mean anomaly	260.39°
Mean motion	0° 23m 11.04s / day
Inclination	1.4997°
Longitude of ascending node	323.48°
Argument of perihelion	203.06°
Earth MOID	0.043 AU (16.8 LD)
Physical characteristics
Mean diameter	350 m (est. at 0.047)
Spectral type	SMASS = D[2]
Absolute magnitude (H)	21.2[2]

Due to its relatively low transfer cost of ~5.5 km/s,^[4] 2002 AT₄ was under consideration by the European Space Agency as a candidate target for the Don Quijote mission to study the effects of impacting a spacecraft into an asteroid; however, it is no longer under consideration.^[5]

2002 AT₄ orbits the Sun at a distance of 1.0–2.7 AU once every 2 years and 7 months (932 days; semi-major axis of 1.87 AU). Its orbit has an eccentricity of 0.45 and an inclination of 1° with respect to the ecliptic.^[2]

T. M. Ribeiro et al. proposed a conceptual sample return mission named CARINA to 2002 AT₄ [^[6]]. The goal of CARINA would be to return for the first time a sample from a D-type asteroid for an in-depth characterisation in Earth-based laboratories. Among other things, CARINA aims to: (i) explore the relationship between dark asteroids and comets; (ii) investigate the role of dark asteroids in the origin of life; (iii) improve our understanding of early Solar System evolution.