Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is currently carried out mainly by astronomers with telescopes, its physical exploration is conducted both by uncrewed robotic space probes and human spaceflight. Space exploration, like its classical form astronomy, is one of the main sources for space science.
A gravity assist, gravity assist maneuver, swing-by, or generally a gravitational slingshot in orbital mechanics, is a type of spaceflight flyby which makes use of the relative movement and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense.
A lander is a spacecraft that descends towards, then comes to rest on the surface of an astronomical body other than Earth. In contrast to an impact probe, which makes a hard landing that damages or destroys the probe upon reaching the surface, a lander makes a soft landing after which the probe remains functional.
The planet Mars has been explored remotely by spacecraft. Probes sent from Earth, beginning in the late 20th century, have yielded a large increase in knowledge about the Martian system, focused primarily on understanding its geology and habitability potential. Engineering interplanetary journeys is complicated and the exploration of Mars has experienced a high failure rate, especially the early attempts. Roughly sixty percent of all spacecraft destined for Mars failed before completing their missions, with some failing before their observations could begin. Some missions have been met with unexpected success, such as the twin Mars Exploration Rovers, Spirit and Opportunity, which operated for years beyond their specification.
The Discovery Program is a series of Solar System exploration missions funded by the U.S. National Aeronautics and Space Administration (NASA) through its Planetary Missions Program Office. The cost of each mission is capped at a lower level than missions from NASA's New Frontiers or Flagship Programs. As a result, Discovery missions tend to be more focused on a specific scientific goal rather than serving a general purpose.
Observations of the planet Venus include those in antiquity, telescopic observations, and from visiting spacecraft. Spacecraft have performed various flybys, orbits, and landings on Venus, including balloon probes that floated in the atmosphere of Venus. Study of the planet is aided by its relatively close proximity to the Earth, compared to other planets, but the surface of Venus is obscured by an atmosphere opaque to visible light.
The following outline is provided as an overview of and topical guide to space exploration.
Chang'e 2 is a Chinese uncrewed lunar probe that was launched on 1 October 2010. It was a follow-up to the Chang'e 1 lunar probe, which was launched in 2007. Chang'e 2 was part of the first phase of the Chinese Lunar Exploration Program, and conducted research from a 100-km-high lunar orbit in preparation for the December 2013 soft landing by the Chang'e 3 lander and rover. Chang'e 2 was similar in design to Chang'e 1, although it featured some technical improvements, including a more advanced onboard camera. Like its predecessor, the probe was named after Chang'e, an ancient Chinese moon goddess.
A flyby is a spaceflight operation in which a spacecraft passes in proximity to another body, usually a target of its space exploration mission and/or a source of a gravity assist to impel it towards another target. Spacecraft which are specifically designed for this purpose are known as flyby spacecraft, although the term has also been used in regard to asteroid flybys of Earth for example. Important parameters are the time and distance of closest approach.
The Planetary Missions Program Office is a division of NASA headquartered at the Marshall Space Flight Center, formed by the agency's Science Mission Directorate (SMD). Succeeding the Discovery and New Frontiers Program Office, it was established in 2014 to manage the Discovery and New Frontiers programs of low and medium-cost missions by third-party institutions, and the Solar System Exploration program of NASA-led missions that focus on prioritized planetary science objectives. The Discovery and New Frontiers programs were established in 1992 and 2001 respectively, and have launched fourteen primary missions together, along with two missions launched under the administration of the Planetary Missions Program Office. The Solar System Exploration Program was established alongside the office, with three missions planned for launch under the new program.
The Planetary Exploration of China, also known as Tianwen, is the robotic interplanetary spaceflight program conducted by the China National Space Administration (CNSA). The program aims to explore planets of the Solar System, starting from Mars, and will be expanded to Jupiter and more in the future.
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