| Minorplanet: | yes |
| 100000 Astronautica | |
| Background: |
|
| Discovered: | 28 September 1982 |
| Mpc Name: | (100000) Astronautica |
| Named After: | |
| Epoch: | 27 April 2019 (JD 2458600.5) |
| Uncertainty: | 0 |
| Observation Arc: | 35.59 yr (12,999 d) |
| Perihelion: | 1.7388 AU |
| Semimajor: | 1.9048 AU |
| Eccentricity: | 0.0871 |
| Period: | 2.63 yr (960 d) |
| Mean Motion: | / day |
| Inclination: | 21.185° |
| Asc Node: | 186.56° |
| Arg Peri: | 199.64° |
| Moid: | 0.7440 AU (290 LD) |
| Abs Magnitude: | 16.9 |
100000 Astronautica (provisional designation ) is a sub-kilometer asteroid and member of the Hungaria family from the innermost region of the asteroid belt, approximately 940m (3,080feet) in diameter. It was discovered on 28 September 1982, by American astronomer James Gibson at Palomar Observatory, California, United States. The likely bright E-type asteroid was named Astronautica, the Latin word for "star sailor", on the 50th anniversary of the Space Age.
Astronautica is a core member of the Hungaria family, an asteroid family and dynamical group, which forms the innermost dense concentration of asteroids in the Solar System. It orbits the Sun in the inner asteroid belt at a distance of 1.7–2.1 AU once every 2 years and 8 months (960 days; semi-major axis of 1.9 AU). Its orbit has an eccentricity of 0.09 and an inclination of 21° with respect to the ecliptic. The body's observation arc begins with its discovery observation at Palomar Observatory in September 1982.
This minor planet marked the milestone of the 100,000th numbered minor planet in October 2005. It was named by the International Astronomical Union's Committee on Small Body Nomenclature to recognize the 50th anniversary of the start of the Space Age, as marked by the launch of the Soviet Sputnik spacecraft into orbit on 4 October 1957. The official was published by the Minor Planet Center on 26 September 2007 . The number 100,000 is significant because it marks the altitude in meters where outer space begins, as delineated by the Kármán line established by the Fédération Aéronautique Internationale. The name "Astronautica" is Latin for "star sailor".
Most members of the Hungaria family are E-type asteroids, which means they have extremely bright enstatite surfaces and albedos typically around 0.35. Based on the body's estimated albedo and its absolute magnitude of 16.9, Astronautica measures approximately 940m (3,080feet) in diameter. As of 2018, no rotational lightcurve of Astronautica has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.