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An apsis (from Ancient Greek ἁψίς (hapsís) 'arch, vault'; pl. apsides /ˈæpsɪˌdiːz/ AP-sih-deez) is the farthest or nearest point in the orbit of a planetary...

The astronomical unit (symbol: au, or AU) is a unit of length defined to be exactly equal to 149,597,870,700 m. Historically, the astronomical unit was...

Mir (Russian: Мир, IPA: [ˈmʲir]; lit. 'peace' or 'world') was a space station that operated in low Earth orbit from 1986 to 2001, operated by the Soviet...

Space debris (also known as space junk, space pollution, space waste, space trash, space garbage, or cosmic debris) are defunct human-made objects in space –...

An eclipse is an astronomical event which occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another...

In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around...

A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol ′, is a unit of angular measurement equal to 1/60 of one degree....

The Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構, Kokuritsu-kenkyū-kaihatsu-hōjin Uchū Kōkū Kenkyū Kaihatsu Kikō, lit. 'National Research...

The Antikythera mechanism (/ˌæntɪˈkɪθɪərə/ AN-tih-KIH-ther-ə) is an Ancient Greek hand-powered orrery (model of the Solar System), described as the oldest...

This is a list of potentially habitable exoplanets. The list is mostly based on estimates of habitability by the Habitable Exoplanets Catalog (HEC), and...

This is a list of astronauts by year of selection: people selected to train for a human spaceflight program to command, pilot, or serve as a crew member...

SpaceX Starship flight tests include fourteen launches of prototype rockets during 2019–2024 for the SpaceX Starship launch vehicle development program...

Firefly Aerospace is an American private aerospace firm based in Cedar Park, Texas, that develops launch vehicles for commercial launches to orbit. The...

This article lists all active and upcoming orbital launch systems. For retired launch vehicles, see Comparison of retired orbital launch systems. This...

This is a list of Arabic star names. In Western astronomy, most of the accepted star names are Arabic, a few are Greek and some are of unknown origin....

Long March 5 (LM-5; Chinese: 长征五号; pinyin: Chángzhēng wǔ hào), or Changzheng 5 (CZ-5), and also by its nickname "Pang-Wu" (胖五, "Fat-Five"), is a Chinese...

In astronomy, Bok globules are isolated and relatively small dark nebulae containing dense cosmic dust and gas from which star formation may take place...

Stardust was a 385-kilogram robotic space probe launched by NASA on 7 February 1999. Its primary mission was to collect dust samples from the coma of comet...

Hygiea (minor-planet designation: 10 Hygiea) is a major asteroid located in the main asteroid belt. With a mean diameter of between 425 and 440 km and...

Space launch market competition is the manifestation of market forces in the launch service provider business. In particular it is the trend of competitive...