How did the Earth get a mini-moon?
Astronomers first spotted the object, now known as 2020 SO, in September
After further analysis of her movement and veryclose proximity to the object (only 50,000 km) on December 1, NASA was able to confirm that this object is a relic of the early space era. Namely the Centaur booster rocket, which was once called the American workhorse in space. Now SO 2020 is about to make another close approach to Earth on February 2, 2021. This time, the object will travel further, but still within 0.58 lunar distances (220,000 km). After that, in March 2021, the Earth's gravity will cease to affect the object.
For Earth, this will no longer be a mini-moon. Instead, 2020 SO will revolve around the Sun.
How to see the 2020 SO approaching Earth?
Earthlings have a chance to see 2020 SO online as part of the Virtual Telescope Project.
The live broadcast is scheduled for the night from 1 to 2February 2021, starting at 22:00 UTC (that's February 1st at 16:00 Central Time, 17:00 Eastern Time, 14:00 North American Pacific Time; convert UTC to your time). That's when 2020 SO will be presented at its best in front of robotic telescopes.
How did scientists figure out that the mini-moon is a rocket booster?
Astronomers first spotted the object on Sept. 17 using the Pan-STARRS1 1.8-meter telescope in Haleakala, Hawaii.They gave it the designation — 2020 SO — and added it as an asteroid to the Apollo group of JPL's small body database.
Apollo asteroids are a group of near-Earth asteroids whose orbits intersect the Earth's from the outside. Asteroids of this group regularly cross theAt the same time, it is important to understand that not all asteroids of the Apollo group necessarily cross theEarth's orbit: In most cases, the intersection takes place only in the projection on the plane of the ecliptic, and in space the orbits only intersect. But there are also quite a few asteroids in the Apollo group that actually cross theA striking example is the asteroid (1566) Icarus, which, after approaching Mercury, changed its orbit so much that in the late 1960s scientists seriously predicted its fall into the Indian Ocean, but which eventually flew close to Earth at a distance of 6.36 million km.
After finding the object, it quickly became clear thatSO 2020 has some features that set it apart from regular asteroids. According to NASA / JPL calculations, the object flew past the Earth's moon at a speed of 3,025 km / h, or 0.84 km per second. This is an extremely low speed for an asteroid.
The calculations also showed a visible “slowasteroid "orbiting the Sun every 1.06 years (387 days). The low relative speed, as well as the Earth-like orbit, suggest that this is an artificial object launched from our planet. Radar images showed 2020 SO to have an elongated shape that is estimated to be between 6 and 14 m, which is the size of the Atlas LV-3C Centaur-D (approximately 12 m).
Confirmation that SO 2020 really wasLost and Found Rocket Booster, derived from data collected at NASA's Infrared Telescope Laboratory in Maunakey, Hawaii. Orbit analysis was also performed at the Center for the Study of Near Earth Objects (CNEOS) at NASA / JPL (Pasadena, California). It was this rocket that launched the ill-fated Surveyor 2 spacecraft to the Moon in 1966.
This 1964 photograph shows the overclockingthe Centaur rocket before connecting to the Atlas booster. A similar Centaur was used during the launch of Surveyor 2 two years later and is currently known as 2020 SO ... a new temporary mini-moon for Earth. Image courtesy of NASA / JPL-Caltech
Lunar accident
Paul Chodas, NASA Facilities Center Manager,Near Earth, the Jet Propulsion Laboratory (JPL) first suggested that the object could be lost by the Surveyor 2 launch vehicle. This robotic spacecraft was to become the second lunar lander in the American Surveyor program without a crew to explore the Earth satellite.
A model of the ill-fated Surveyor 2 lander that crashed on the Moon in 1966. Image courtesy of NASA / JPL-Caltech
The device was launched on September 20, 1966 from CapeCanaveral, Florida, aboard the Atlas-Centauri rocket. The investigation revealed that the accident occurred in the Central Gulf region, just 130 km from the intended landing site. During the maneuver, one correction engine failed to ignite, and due to unbalanced thrust, the ship began to fall onto the lunar surface. All attempts to save the mission failed. Contact with the spacecraft was lost at 9:35 UTC on September 22. The spacecraft was intended to land in the Central Gulf, but due to an accident, the spacecraft fell into the Copernicus crater. The exact location of the ship disaster is unknown. The spacecraft was scheduled to land on the lunar surface at 3:18 UTC on September 23, 1966. Its weight at impact was 292 kg, the speed was about 2.6 km/s.
Unlike some modern missileboosters (which return to Earth and land on ships at sea), the Surveyor 2 rocket booster remained in space and was lost. It appears to have been knocked off its original trajectory by a slight but constant pressure from sunlight.
As it turns out, the defunct launch vehicle, now known as 2020 SO, has passed Earth unnoticed several times in the past, including in 1966, shortly after launch.
Previously, such mini-moons were observed near the Earth?
This is not the first time the Earth has had a mini moon.
Space is filled with small asteroids.From time to time, one of these space rocks is temporarily captured by our planet's gravity and then thrown back into the solar system as a whole. The two confirmed mini-satellites are 2006 RH120 (in low Earth orbit from 2006 to 2007) and 2020 CD3 (in our orbit from 2018 to 2020).
In addition, this is not the first time scientists have mistaken space debris for an asteroid.
WT1190F entering the Earth's atmosphere south of Sri Lanka on November 13, 2015. Image courtesy of IAC / UAE / NASA / ESA.
Another small object that was originallywas considered an asteroid - WT1190F, discovered in October 2015 while approaching Earth. Its trajectory suggested it was about to enter Earth's atmosphere near Sri Lanka in the Indian Ocean, something that happens to normal asteroids several times a year.
On November 13, 2015, WT1190F was decaying in our atmosphere, and scientists were able to analyze its light using spectroscopy.
Analysis showed that the object could have been a component of a spacecraft, or part of a spent rocket, another wandering piece of space debris returning home.
In the case of SO 2020, his return home will not last long. After March, the spent rocket body will again be sent into a large solar orbit.
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