Flyby (spaceflight)

• 1. Defining Flyby Operations

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  A flyby is a spaceflight operation where a spacecraft passes in proximity to another body. This maneuver serves as the primary objective for many exploration missions. It also acts as a source of gravity assist, often called a swing-by. The swing-by impels the craft toward its next target without using extra fuel. Important parameters include the time and distance of closest approach. Spacecraft designed specifically for this purpose are known as flyby spacecraft. The term has also been used regarding asteroid flybys of Earth. These operations can be conducted with a planet or a natural satellite. They may also involve non-planetary objects such as small Solar System bodies.

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• 2. Planetary And Lunar Missions

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  Mariner IV flew by Mars in July 1965. It returned more accurate atmospheric data than previous attempts. The probe captured much closer views of the Martian surface. Mariner 6 and Mariner 7 followed with flybys of Mars in 1969. Their infrared radiometer results showed that the atmosphere was mostly carbon dioxide. They detected trace amounts of water on the surface. Rosetta swung by Mars at a distance of 250 kilometers. This marked the closest flyby of Mars ever recorded. Apollo 13 had an exploded oxygen tank during its journey. The crew had to fly by around the Moon instead of landing. Artemis 2 will include a lunar flyby in future plans. In 2018, twin Mars Cube One probes performed a relay flyby. They supported communication for the InSight lander during entry. Both MarCOs reached Mars successfully on the 26th of November 2018. Tianwen-1 Deployable Camera imaged its transit to Mars in September 2020. It made a flyby of Mars around the 10th of February 2021.

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• 3. Exploring The Kuiper Belt

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  New Horizons performed the most distant flyby to date on the 1st of January 2019. The target was the Kuiper belt object Arrokoth. The spacecraft previously flew by Pluto in July 2015. That first encounter occurred about 32.9 astronomical units from the Sun. The New Year's Day 2019 flyby happened at 43.6 AU. These distances place the mission far beyond the orbit of Neptune. The trajectory diagram shows the path taken during the Pluto flyby. This mission expanded human knowledge of the outer solar system. No other probe has traveled this far before. The data collected remains unique and invaluable for astronomers.

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• 4. Saturnian Moon Encounters

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  Cassini-Huygens launched in 1997 and orbited Saturn from 2004 until 2017. It performed flybys of many moons including Titan. The first flyby of Titan occurred in October 2004. Cassini achieved 126 flybys of Titan over its mission life. Its final close flyby took place on the 22nd of April 2017. This event marked the end of an era before retirement. An animation shows the trajectory around Saturn over ten years. The craft passed closely by many moons during that time. Each flyby provided new scientific observations. The extensive data collection helped scientists understand the Saturnian system better.

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• 5. Comet And Asteroid Proximity

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  International Cometary Explorer passed through the plasma tail of comet Giacobini-Zinner. This flyby happened at a distance of 3,000 kilometers from the nucleus. The encounter occurred on the 11th of September 1985. In 2010, Deep Impact conducted a flyby of comet Hartley 2. This was part of the EPOXI mission. P/2016 BA14 was radar imaged at a distance of 1.2 million kilometers from Earth in 2016. The imaging enabled calculation of the nucleus size to about 1 kilometer in diameter. On the 16th of December 2018, short period comet 46P/Wirtanen had its closest approach. It came within 11 million kilometers of Earth. These encounters allowed detailed study of cometary composition and structure.

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• 6. Natural Object Approaches

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  Flyby is sometimes used loosely when an asteroid approaches Earth. The object coasts past without human intervention. A comet did a flyby of Mars in 2014. P/2016 BA14 was radar imaged during its flyby in 2016. This event helped calculate the size of the nucleus. On the 16th of December 2018, comet 46P/Wirtanen made its closest approach. It came within one of its closest distances to Earth. These natural flybys occur regularly throughout the solar system. They provide opportunities for observation without spacecraft involvement. Radar imaging allows scientists to determine physical characteristics. Such events highlight the dynamic nature of our cosmic neighborhood.

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