Alien space object 2020 SO was discovered on September 17, 2020, approaching Earth. On November 8, it slowly drifted into Earth’s sphere of gravity to become a new mini-moon. It will escape again in a new orbit around the sun in March 2021. During that time it will make 2 large loops around our planet. In this image, the Earth is the blue dot. The moon’s orbit is the yellow circle. The 2020 SO trajectory is the pink line in a loop. Image via Phoenix7777 / Wikimedia Commons.
Astronomers saw the object now known as 2020 SO for the first time last September. Orbit models quickly showed that both the slow speed and the trajectory were of the approaching object unusual. The models showed that the Earth would capture this object – temporarily – as a new mini-moon. And that’s what happened. 2020 SO has been in orbit since November 8. After further analysis of its motion – 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 of the early space age, a Centaur rocket supercharger in the top flight, once called America’s workhorse in space. Now, 2020 SO is about to get close to Earth again on February 2, 2021. It will go further away this time, but still within 0.58 lunar distances (140,000 miles or 220,000 km). Then, in March 2021, Earth’s gravity will give up its grip 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 say goodbye, live: come to our home!
EarthSky 2021 lunar calendars still available! Order now.
The live feed is scheduled for the night of February 1, 2021, starting at 10:00 PM UTC (that’s February 1 at 4:00 PM Central, 5:00 PM East, 2:00 PM Pacific in North America; translate UTC to your time). That’s when, Gianluca said, 2020 SO will be at its best above the Virtual Telescope’s robotic telescopes in central Italy. See the poster below for details and read more about this event via Virtual Telescope.
Poster of the February 1, 2021 online event, via Virtual Telescope.
Astronomers first imaged the object on Sept. 17 using the 71-inch (1.8-meter) Pan-STARRS1 telescope in Haleakala, Hawaii. They gave it its name – 2020 SO – and added it as an Apollo-type asteroid in the JPL Small-Body Database.
However, 2020 SO soon turned out to have some features that distinguish it from common asteroids. According to calculations by NASA / JPL, the object flew past Earth’s moon at a speed of 1,880 miles per hour (3,025 km / h) or 0.84 km per second (0.5 mi / sec). That’s an extremely slow speed for an asteroid.
These calculations also show that the apparent “slow asteroid” orbits the sun every 1.06 years (387 days). Its slow relative speed, along with its Earth-like orbit, both suggest it is an artificial object launched from our planet. Radar images showed that 2020 SO had an elongated shape estimated to be between 20 and 45 feet (6 to 14 meters), which corresponds to the dimensions of an Atlas LV-3C Centaur-D (about 41 feet or 12 meters).
Confirmation that SO 2020 was indeed a lost-and-found rocket booster came from data collected at NASA’s Infrared Telescope Facility in Maunakea, Hawaii, and from orbit analyzes conducted at the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Pasadena, California. This particular rocket launched the ill-fated Surveyor 2 spacecraft towards the moon in 1966.
Paul Chodas, manager of NASA’s Near Earth Object center at the Jet Propulsion Laboratory (JPL) in Pasadena, California, first suggested the object could be Surveyor 2’s lost rocket booster. Surveyor 2 was a robotic spacecraft launched to the moon on September 20, 1966. It was intended to be the second lunar lander in the unmanned American Surveyor program to explore the moon. The spacecraft launched into space atop an Atlas LV-3C Centaur-D rocket from Cape Kennedy, Florida.
A mid-course correction error caused ground controllers to lose contact with the vessel three days later after a thruster failed to ignite. The malfunction caused the spacecraft to topple and eventually crash near the Moon’s Copernicus crater.
Unlike some of today’s rocket boosters (which return to Earth and land on ships at sea), Surveyor 2’s rocket booster remains in space and has been lost. It appears to have been pushed from its original orbit by a small but continuous pressure of sunlight.
As it turns out, the defunct booster – now known as 2020 SO – had passed Earth unnoticed several times in the past, including a close approach in 1966, not long after it launched.
This 1964 photo shows a Centaur missile in the upper stage before being attached to an Atlas booster. A similar Centaur was used two years later during the launch of Surveyor 2 and is currently known as 2020 SO… a new temporary mini-moon for Earth. Image via NASA / JPL-Caltech.
Launch of an Atlas LV-3C Centaur-D on June 30, 1964. Image via AstroNautix.
A model of the ill-fated lander Surveyor 2, which crashed to the moon in 1966. Image via NASA / JPL-Caltech.
How could we have lost an entire 12-meter rocket? Space archaeologist Alice Gorman of Flinders University in Australia told ScienceAlert that – before our modern era of reusable rockets – the rockets that launched spaceships into space were surprisingly easily lost. She said:
There are so many factors in the space environment, such as 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 lose sight of them very easily. And if they do something unpredictable, and you look the wrong way, you don’t know where it’s going. It’s quite amazing how many things have disappeared.
NASA explained that the pressure from the sun’s radiation caused the object to change its orbit:
The pressure exerted by sunlight is small but continuous, and has a greater effect on a hollow object than on a solid object. A used missile is essentially an empty tube and therefore a low-density, large-area object. Thus, it will be pushed by the pressure of the solar radiation more than by a solid, high-density rock, just as an empty soda can will be pushed more by the wind than a small rock.
This animation shows the orbit of 2020 SO as it was captured by Earth’s gravity on November 8, 2020. It will escape in March 2021. Its movement has accelerated a million times faster than real-time. Image via NASA / JPL-Caltech.
This isn’t the first time the Earth has recorded a minimoon.
As you may already realize, space is packed with tiny asteroids. Occasionally, one of these space rocks is temporarily captured by our planet’s gravity, before being ejected back into the solar system in general. Two confirmed mini moons are 2006 RH120 (in orbit between 2006 and 2007) and 2020 CD3 (in our orbit between 2018 and 2020).
It’s also not the first time we’ve mistaken space junk for an asteroid.
Another small object initially thought to be an asteroid was WT1190F, detected in October 2015 approaching Earth. Its trajectory suggested it was about to penetrate Earth’s atmosphere near Sri Lanka, in the Indian Ocean, an event that happens several times a year with common asteroids.
When WT1190F disintegrated in our atmosphere on November 13, 2015, scientists analyzed the light through spectroscopy.
This analysis suggested that the object could be part of a spacecraft or part of a used rocket, another floating piece of space junk returning home.
In the case of SO 2020, the return home will not take long. After March, the spent rocket body will be underway again, returning to a larger orbit around the sun. Who knows how long we’ll keep up this time?
2020 SO is not the first object thought to be an asteroid, later realized to be man-made space junk. Here is an object tagged WT1190F entering Earth’s atmosphere south of Sri Lanka on Nov. 13, 2015. Image via IAC / UAE / NASA / ESA.
In short, an “asteroid” spotted in September 2020 became a new mini-moon to Earth in November. In early December, NASA confirmed that the object is a lost missile from the Surveyor 2 mission, originally launched from Earth more than 50 years ago. Now 2020 SO is about to make a final approach to Earth. That will happen on February 2. The night before, February 1, you can view this object online.
Via NASA
Via ScienceAlert
Via Popular Mechanics
Via virtual telescope
