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A strange 2020 SO space object was discovered on September 17, 2020, as it approached Earth. On November 8, it slowly drifted into Earth’s gravitational dominance sphere, becoming a new mini-moon. It will escape again into a new orbit around the sun in March 2021. During this time it will make 2 large loops around our planet. In this image, the Earth is the blue point. The orbit of the moon is the yellow circle. The 2020 SW trajectory is the pink loop line. Image via Phoenix7777 / Wikimedia Commons.
Astronomers first noticed the object now known as 2020 SO last September. Orbit models quickly showed that the low speed and trajectory of the approaching object was unusual. The models showed that Earth would capture this object – temporarily – as a new mini-moon. And that’s what happened. 2020 SO has been in orbit around Earth since November 8. After further analysis of its movement – and a very close approach to the object (only 30,000 miles, 50,000 km, or 0.13 lunar distances) on December 1 – NASA was able to confirm that the object is a relic. from the start of the space age, a Centaur top-stage rocket thruster, once called America’s workhorse in space. Now 2020 SO is set to make another close approach to Earth on February 2, 2021. It will pass further this time, but still within 0.58 lunar distance (140,000 miles or 220,000 km). Subsequently, in March 2021, Earth’s gravity will relinquish its hold on the object.
It will no longer be a mini moon for Earth. Instead, it will orbit the sun.
You have the chance to see 2020 SO online. The virtual telescope project in Rome will show the object online on the night of February 1. Italian astronomer Gianluca Masi wrote:
We’ll say goodbye to you, live: join us from the comfort of your own home!
EarthSky 2021 lunar calendars still available! Order now.
The live stream is scheduled for the night of February 1, 2021, starting at 10:00 p.m. UTC (i.e. February 1 at 4:00 p.m. Central, 5:00 p.m. East, 2:00 p.m. Pacific in North America; translate UTC to your time) . That’s when, Gianluca said, 2020 SO will be at its best above the robotic telescopes of the Virtual Telescope in central Italy. See the poster below for more details and learn more about this event via the Virtual Telescope.
Poster of the February 1, 2021 online event, via Virtual Telescope.
Astronomers first sighted the object on September 17 using the 71-inch (1.8-meter) Pan-STARRS1 telescope in Haleakala, Hawaii. They gave it its designation – 2020 SO – and added it as an Apollo-type asteroid in the JPL Small-Body database.
However, 2020 SO was quickly seen to have certain characteristics that set it apart from regular asteroids. According to NASA / JPL calculations, the object passed the Earth’s moon at a speed of 1,880 miles per hour (3,025 km / h) or 0.84 km per second (0.5 mph). This is an extremely slow speed for an asteroid.
These calculations also show the apparent “slow asteroid” orbiting the sun every 1.06 years (387 days). The low relative speed, as well as the Earth-like orbit, both suggest it as an artificial object launched from our planet. Radar images showed that 2020 SW had an elongated shape estimated to be 20 to 45 feet (6 to 14 meters), which corresponds to the dimensions of an Atlas LV-3C Centaur-D (approximately 41 feet or 12 meters).
Confirmation that SO 2020 was indeed a lost and found rocket thruster came from data collected at NASA’s infrared telescope facility in Maunakea, Hawaii, and orbit analyzes conducted at the Center for Near-Earth Object. Studies (CNEOS) at the NASA Jet. Propulsion laboratory in Pasadena, California. This particular rocket launched the ill-fated Surveyor 2 spacecraft to the moon in 1966.
Paul Chodas, director of the NASA Near-Earth Object Center at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., First suggested that the object could be the lost rocket propellant from Surveyor 2. Surveyor 2 was a robotic spacecraft that was launched to the moon on September 20, 1966. It was supposed to be the second lunar lander in the US Surveyor program unequipped to explore the moon. The spacecraft exploded in space on top of an Atlas LV-3C Centaur-D rocket from Cape Kennedy, Florida.
A mid-course correction failure caused ground controllers to lose contact with the craft three days later, after a thruster failed to ignite. The failure caused the spacecraft to fall and ultimately crash near the moon’s Copernicus Crater.
Unlike some rocket boosters today (which return to Earth and land on ships at sea), Surveyor 2’s rocket boosters remain in space and have been lost. It appears to have been pushed back from its original path by weak but continuous pressure of sunlight.
It turns out that the defunct booster – now known as 2020 SO – had gone unnoticed on Earth on several occasions in the past, including a close-up in 1966, shortly after launch.
This 1964 photograph shows a Centaur top stage rocket before it was mated to an Atlas booster. A similar Centaur was used at the launch of Surveyor 2 two years later and is currently known as 2020 SO… a new temporary mini-moon for Earth. Image via NASA / JPL-Caltech.
A launch of the Atlas LV-3C Centaur-D on June 30, 1964. Image via AstroNautix.
A model of the ill-fated Surveyor 2 lander, which crashed on the moon in 1966. Image via NASA / JPL-Caltech.
How could we have lost an entire 41-foot-long rocket? Space archaeologist Alice Gorman of Flinders University in Australia told ScienceAlert that before our modern era of reusable rockets, rockets that launched craft into space were surprisingly easy to lose. She says:
There are so many factors in the space environment, like gravitational factors and other things that affect motion, that it can be quite unpredictable at times.
You have to keep following these things, or you can just lose track of them very easily. And if they do something a little unpredictable, and you look the wrong way, then you don’t know where it went. It’s quite astonishing, the number of things that are missing.
NASA explained that the pressure of solar radiation caused the object to change its trajectory:
The pressure exerted by sunlight is weak but continuous, and it has a greater effect on a hollow object than on a solid object. A used rocket is essentially an empty tube and therefore is a low density object with a large area. Thus, it will be pushed by the pressure of solar radiation more than a mass of high density rock, just as an empty soda can will be pushed by the wind more than a small stone.
This animation shows the orbit of 2020 SW as it was captured by Earth’s gravity on November 8, 2020. It will escape in March 2021. Its motion has been accelerated a million times faster than real time. Image via NASA / JPL-Caltech.
This is not the first time that Earth has captured a mini moon.
As you may have noticed, space is filled with tiny asteroids. Every once in a while, one of these space rocks is captured, temporarily, by the gravity of our planet, before being sent back into the solar system as a whole. Two confirmed mini-moons are 2006 RH120 (in Earth orbit between 2006 and 2007) and 2020 CD3 (in our orbit between 2018 and 2020).
It’s not the first time we’ve confused space debris with an asteroid, either.
Another small object that was initially thought to be an asteroid was the WT1190F, detected in October 2015 as it approached Earth. Its trajectory suggested it was about to enter Earth’s atmosphere near Sri Lanka, in the Indian Ocean, an event that occurs with ordinary asteroids several times a year.
As WT1190F disintegrated in our atmosphere on November 13, 2015, scientists analyzed its light spectroscopically.
This analysis suggested that the object could be a spaceship component or part of a worn-out rocket, another piece of stray space debris returning home.
In the case of 2020 SO, her return home won’t last long. After March, the exhausted rocket body will be en route again, returning to a larger solar orbit. Who knows how long we’ll take it into account this time?
2020 SO is not the first object considered to be an asteroid, and later realized as a man-made space junk. Here is an object tagged WT1190F entering Earth’s atmosphere south of Sri Lanka on November 13, 2015. Image via IAC / UAE / NASA / ESA.
Conclusion: an “asteroid” spotted in September 2020 became a new mini-moon for Earth in November. In early December, NASA confirmed the object was a stray rocket from the Surveyor 2 mission, which was originally launched from Earth more than 50 years ago. Now 2020 SO is about to make one last close approach to Earth. This will happen on February 2. The night before, February 1, you can participate in an online consultation of this item.
Via NASA
Via ScienceAlert
Via popular mechanics
Via a virtual telescope
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