page_title: Flyby (spaceflight)
section_title: Natural flyby
hierarchical_section_title: Flyby (spaceflight) / Natural flyby
caption_attribution_description: English: This movie of asteroid 2014 JO25 was generated using radar data collected by NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California on April 19, 2017. When the observations began 2014 JO25 was 1.53 million miles (2.47 million kilometers) from Earth. By the time the observations concluded, the asteroid was 1.61 million miles (2.59 million kilometers) away. The asteroid has a contact binary structure -- two lobes connected by a neck-like region. The largest of the asteroid's two lobes is estimated to be 2,000 feet (610 meters) across. Asteroid 2014 JO25 approached to within 1.1 million miles (1.8 million kilometers) of Earth on April 19. There are no future flybys by 2014 JO25 as close as this one for more than 400 years. The resolution of the radar images is about 25 feet (7.5 meters) per pixel. 154 images were used to create the movie shown. More information regarding asteroid 2014 JO25 can be found at https://cneos.jpl.nasa.gov/news/news196.html and http://www.jpl.nasa.gov/asteroidwatch.
context_page_description: A flyby is a spaceflight operation in which a spacecraft passes in close 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.
context_section_description: Flyby is also sometimes loosely used to describe when, for example, an asteroid approaches and coasts by the Earth.
  This was also the term for when a comet did a flyby of Mars in 2014.
  P/2016 BA14 was radar imaged at distance of 2.2 million miles (9 lunar distances) from Earth in 2016, during its flyby. This enabled the size of the nucleus to be calculated to about 1 km in diameter.
  On December 16, 2018 the short period comet 46P/Wirtanen had its closest approach of Earth, coming within  7.1 million miles (one of its closest approaches to Earth).
caption: During an asteroid flyby of Earth, sometimes they are imaged by radar. Animation of 2014 JO25, which had an Earth flyby in 2017