A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of solar radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently bright, a comet may be seen from Earth without the aid of a telescope and may subtend an arc of 30° across the sky. Comets have been observed and recorded since ancient times by many cultures and religions.
The Mariner program was conducted by the American space agency NASA to explore other planets. Between 1962 and late 1973, NASA’s Jet Propulsion Laboratory (JPL) designed and built 10 robotic interplanetary probes named Mariner to explore the inner Solar System - visiting the planets Venus, Mars and Mercury for the first time, and returning to Venus and Mars for additional close observations.
The Cassini–Huygens space-research mission, commonly called Cassini, involved a collaboration among NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a space probe to study the planet Saturn and its system, including its rings and natural satellites. The Flagship-class robotic spacecraft comprised both NASA's Cassini space probe and ESA's Huygens lander, which landed on Saturn's largest moon, Titan. Cassini was the fourth space probe to visit Saturn and the first to enter its orbit. The two craft took their names from the astronomers Giovanni Cassini and Christiaan Huygens.
Giotto was a European robotic spacecraft mission from the European Space Agency. The spacecraft flew by and studied Halley's Comet and in doing so became the first spacecraft to make close up observations of a comet. On 13 March 1986, the spacecraft succeeded in approaching Halley's nucleus at a distance of 596 kilometers. It was named after the Early Italian Renaissance painter Giotto di Bondone. He had observed Halley's Comet in 1301 and was inspired to depict it as the star of Bethlehem in his painting Adoration of the Magi in the Scrovegni Chapel.
The COmet Nucleus TOUR (CONTOUR) was a NASA Discovery-class space probe that failed shortly after its July 2002 launch. It had as its primary objective close flybys of two comet nuclei with the possibility of a flyby of a third known comet or an as-yet-undiscovered comet.
Rosetta was a space probe built by the European Space Agency launched on 2 March 2004. Along with Philae, its lander module, Rosetta performed a detailed study of comet 67P/Churyumov–Gerasimenko (67P). During its journey to the comet, the spacecraft performed flybys of Earth, Mars, and the asteroids 21 Lutetia and 2867 Šteins. It was launched as the third cornerstone mission of the ESA's Horizon 2000 programme, after SOHO / Cluster and XMM-Newton.
Uncrewed spacecraft or unmanned spacecraft are spacecraft without people on board, used for robotic spaceflight. Uncrewed spacecraft may have varying levels of autonomy from human input; they may be remote controlled, remote guided or even autonomous, meaning they have a pre-programmed list of operations, which they will execute unless otherwise instructed.
Vega 2 was a Soviet space probe part of the Vega program to explore Halley's comet and Venus. The spacecraft was a development of the earlier Venera craft. The name VeGa (ВеГа) combines the first two letters Russian words for Venus and Halley They were designed by Babakin Space Centre and constructed as 5VK by Lavochkin at Khimki. The craft was powered by large twin solar panels. Instruments included an antenna dish, cameras, spectrometer, infrared sounder, magnetometers (MISCHA) and plasma probes. The 10,850 pounds (4,920 kg) craft was launched on top of a Proton 8K82K rocket from Baikonur Cosmodrome, Tyuratam, Kazakh SSR. Both Vega 1 and 2 were three-axis stabilized spacecraft. The spacecraft were equipped with a dual bumper shield for dust protection from Halley's Comet.
Stardust was a 390-kilogram robotic space probe launched by NASA on 7 February 1999. Its primary mission was to collect dust samples from the coma of comet Wild 2, as well as samples of cosmic dust, and return these to Earth for analysis. It was the first sample return mission of its kind. En route to comet Wild 2, the craft also flew by and studied the asteroid 5535 Annefrank. The primary mission was successfully completed on 15 January 2006, when the sample return capsule returned to Earth.
The Discovery Program is a series of solar system exploration missions funded by the US 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.
Deep Impact was a NASA space probe launched from Cape Canaveral Air Force Station on January 12, 2005. It was designed to study the interior composition of the comet Tempel 1 (9P/Tempel), by releasing an impactor into the comet. At 05:52 UTC on July 4, 2005, the Impactor successfully collided with the comet's nucleus. The impact excavated debris from the interior of the nucleus, forming an impact crater. Photographs taken by the spacecraft showed the comet to be more dusty and less icy than had been expected. The impact generated an unexpectedly large and bright dust cloud, obscuring the view of the impact crater.
Mariner Mark II was NASA's planned family of unmanned spacecraft for the exploration of the outer Solar System that were to be developed and operated by JPL between 1980 through the year 2010.
The nucleus is the solid, central part of a comet, once termed a dirty snowball or an icy dirtball. A cometary nucleus is composed of rock, dust, and frozen gases. When heated by the Sun, the gases sublimate and produce an atmosphere surrounding the nucleus known as the coma. The force exerted on the coma by the Sun's radiation pressure and solar wind cause an enormous tail to form, which points away from the Sun. A typical comet nucleus has an albedo of 0.04. This is blacker than coal, and may be caused by a covering of dust.
The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of furthering the understanding of the Solar System. The program selects medium-class missions which can provide high science returns.
A space probe, or simply probe, is a robotic spacecraft that doesn't orbit the Earth, but instead explores farther into outer space. A space probe may approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or enter interstellar space.
Discovery and exploration of the Solar System is observation, visitation, and increase in knowledge and understanding of Earth's "cosmic neighborhood". This includes the Sun, Earth and the Moon, the major planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, their satellites, as well as smaller bodies including comets, asteroids, and dust.
The Solar System — our Sun's system of planets, moons, and smaller debris — is humankind's cosmic backyard. Small by factors of millions compared to interstellar distances, the spaces between the planets are daunting, but technologically surmountable.
C/2013 A1 is an Oort cloud comet discovered on 3 January 2013 by Robert H. McNaught at Siding Spring Observatory using the 0.5-meter (20 in) Uppsala Southern Schmidt Telescope.
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.
Chimera is a NASA mission concept to orbit and explore 29P/Schwassmann-Wachmann 1 (SW1), an active, outbursting small icy body in the outer solar system. The concept was developed in response to the 2019 NASA call for potential missions in the Discovery-class, and it would have been the first spacecraft encounter with a Centaur and the first orbital exploration of a small body in the outer solar system. The Chimera proposal was ranked in the first tier of submissions, but was not selected for further development for the programmatic reason of maintaining scientific balance.
