Researchers at the Institute of Astronomy in Hawaii are scanning the night sky in September 2020 when something appears that completely bamboozles them. It’s an object speeding through the heavens quite close to Earth which they observe with the massive Pan-STARRS1 telescope. This device is designed to detect space objects that could pose a risk to our planet. Worryingly, this mysterious and unidentified item might just fit the bill.
The Pan-STARRS1 telescope is set near the top of the 10,000-foot-high Haleakala Crater on the Hawaiian Island of Maui. A couple of days after the anomalous object was first spotted, Paul Chodas, who’d been alerted by the Hawaiian observatory, set to work studying this enigmatic phenomenon. He works at NASA’s Jet Propulsion Laboratory in Pasadena, California as manager of the Center for Near Earth Object Studies.
At this point exactly what this object was remained anybody’s guess. An asteroid, a random lump of space junk? Or how about an alien spaceship from another galaxy? Okay, the first two were both plausible while the third option was, to say the least, a bit of a stretch. But the fact was that at this early stage, scientists had no ready explanation for this unexplained object in the night sky.
But what was already emerging was that this object was acting in ways not normally seen from your standard asteroid from space. While observing the object, Dr. Chodas had noticed something decidedly peculiar about it. Your common or garden asteroid usually follows a path through space that is tilted in relation to the orbit of the Earth around the Sun. But this body was on the same plane as our planet’s path around the solar giant.
Another peculiarity was that 2020 SO, as the object came to be known, was not traveling through the heavens at the type of speed normally observed with asteroids. It was progressing at roughly 1,500mph, much slower than they normally zoom through space. So Dr. Chodas was finding it less and less likely that this was actually an asteroid. But if that was true, then just what exactly was this strange visitor?
Close passes of the Earth by asteroids, or at least of the planet’s atmosphere, are not unusual. Plus there is any amount of space junk, the leftovers of historic space missions, circling high above the planet. Let’s take a look at asteroids first. They’re lumps of rock which may have traveled through space for millions, or even billions of years.
Most asteroids orbit the Sun, just as Earth does. They are what remains of the formation of the Solar System – the Sun and the planets – about 4.6 billion years ago. According to NASA there are more than 1 million such objects. That sounds an impressively high number but in fact if you took all of the asteroids and lumped them together, you’d get something less than half the size of our Moon.
Most asteroids are found in what’s known as, predictably, The Asteroid Belt, which lies between the planets Mars and Jupiter. The largest such object in the solar system is Vesta which has a diameter of 329 miles. By contrast, some asteroids have a span of only about 30 feet. When one of these enters the Earth’s atmosphere, it usually burns up and that is called a meteoroid, a meteor, or most commonly, a shooting star.
But there’s another type of shooting star, distinct from a meteoroid. That’s a meteorite. This is an asteroid that partially survives its descent through our atmosphere so that its remnants strike the Earth. The best-known meteorite was the one that struck the Earth roughly 66 million years ago causing such a cataclysm that it resulted in the extinction of the dinosaurs.
So although most meteors or meteorites are harmless, not all are. And that’s why the Center for Near Earth Object Studies exists. You’ll remember that this agency’s boss, Dr. Chodas, was the man who recognized that 2020 OS did not seem like an ordinary asteroid. Although as you’ll recall, he wasn’t sure at all exactly what it really was.
In any case, the organization that Dr. Chodas heads has a very important mission. Staff at the agency keeps an eye on the skies and when they spot an asteroid they make an assessment of the object’s likely trajectory. If Earth is going to be struck by a dangerously large asteroid, it’s the Near Earth Objects Center that will sound a warning.
As we noted earlier, apart from an asteroid, there was one other plausible explanation for the object that the Hawaiian researchers spotted in September 2020: space junk. According to the U.K.’s Natural History Museum in London, since humans first started launching things into space in the 1950s, thousands of pieces of space debris have been left to orbit around the planet.
Redundant satellites, bits of launch rockets, even just fragments of paint are all circling the planet. In fact, the museum has noted that there are 34,000 bits of junk larger than 4 inches across including some 3,000 inactive satellites drifting aimlessly in orbit around Earth. And there are literally millions of smaller bits of trash traveling in circles, trapped by the planet’s gravitational pull.
Abandoned or lost pieces of equipment that are left at lower attitudes soon burn up in the atmosphere as they’re pulled towards Earth. But pieces of junk at more than about 22,000 miles above the planet’s surface will remain in pointless orbit for centuries or even millennia. There is a risk that new satellites might collide with old dead ones. But experts say it’s small, roughly a one in 10,000 chance.
The problem is hardly helped by the fact that the likes of India, the USA and China have found a purpose for redundant satellites. They have used them for missile target practice. The resulting impact and explosion creates thousands more bits of space garbage. So space junk might seem a fairly remote problem, but it’s a real one. For example, the International Space Station had to take evasive action thrice during 2020 to avoid space detritus.
So given that serious scientists were unlikely to give credence to any suggestion of an alien spacecraft, what was this mysterious object? Evidence from Dr. Chodas’s observations of 2020 SO began to point in one, rather surprising, direction. As we’ve seen, because of the way the object was orbiting around the Sun and the Earth, early on he was fairly sure that he wasn’t looking at an asteroid.
Dr. Chodas had discovered that the path that 2020 SO had taken was unlike that of an asteroid by using a computer simulation of its orbit around the Sun and the Earth. Then he had an inspiration. Why not try throwing the simulation into reverse in an attempt to work out the origin of the object? And that is just what he did.
In effect, Dr. Chodas was making 2020 SO travel back through time – and the results were startling. This backwards simulation showed that the object had been quite close to Earth back in 1966. As the scientist told The New York Times newspaper in December 2020, the body had then been “close enough that it could have originated from the Earth.”
Dr. Chodas quickly went public with his unexpected finding. He emailed colleagues around the world with a message describing the hunch generated by his backward simulation. He informed his peers that he believed the mystery object might actually be a part of a 1966 NASA space vehicle, Surveyor 2. That unmanned mission to the Moon had gone spectacularly wrong.
NASA’s Surveyor mission series consisted of seven unmanned exploratory launches to the Moon, with the first blasting off from Cape Canaveral, Florida in May 1966. The Surveyor 1 spacecraft was powered by an Atlas-Centaur rocket and made the first ever successful soft landing on the surface of the Moon, by the U.S. or indeed anyone else. The purpose of the Surveyor missions was to scout out conditions on the Moon in preparation for the manned Apollo missions that would follow.
Surveyor 1 was regarded as a great accomplishment and NASA, it’s been said, had been optimistic about its second Surveyor mission, which launched in September 1966. Like its predecessor – which had transmitted 11,000 images back to Earth – it was hoped Surveyor 2 would beam back many more photographs of the lunar terrain.
Mike Dinn had been the deputy director of the monitoring station at Tidbinbilla, Australia, which tracked Surveyor 2 as it sped towards the Moon. He recalled the mood back in 1966 to The New York Times in December 2020, “We fully expected Surveyor 2 to be a complete success.”
Surveyor 2’s launch went off smoothly. The one-ton spacecraft, like Surveyor 1, was blasted into space atop an Atlas D first stage and a second-stage Centaur booster rocket. Its planned destination was an area called Sinus Medii. But as the spacecraft traveled towards the Moon, at a critical moment in the flight something went wrong with one of Surveyor 2’s three booster engines.
What NASA had planned was that there would be a blast of the three thrusters for just short of ten seconds during the journey to the Moon. This would correct the course of Surveyor 2, ensuring that it would land on the chosen destination spot. But while two of the jets ignited as planned, one remained dead. This pushed the ship into an uncontrolled tailspin.
Desperately trying to correct the malfunction, ground control at the mission center tried to fire up the uncooperative rocket no fewer than 39 times. But it was all to no avail. The spacecraft lost communication with Earth and began to tumble towards the Moon’s surface. A NASA press release just after the event described what had happened.
The press release read, “For more than 24 hours, engineers at the Jet Propulsion Laboratory attempted to correct an out-of-control tumbling condition which began during the midcourse trajectory correction….Early today it also was apparent that the major objectives of the mission could not be met.” The stricken spacecraft crashed into the Moon’s surface, near the Copernicus Crater.
Despite this disappointing failure in the Surveyor mission plan, eventually it succeeded, with the other six unmanned flights to the Moon all passing off without major incident. The success of the Surveyor project can be judged by the fact that Apollo 11 was able to land men on the Moon in 1969. This feat was partially enabled by the information that the Surveyor spacecraft had previously collected.
As we’ve seen, Dr. Chodas seems to have been the first to theorize that the mysterious object first spotted in the skies in September 2020 was in fact part of the Surveyor 2 rocket. But it required more methodical sleuthing to pin down this hypothesis. Detailed analysis of 2020 SO was the next step.
Scientists around the world now began to work on studying this mysterious piece of possible space junk from Surveyor 2, hoping to get a positive I.D. Of course, that was no easy task: remember we’re talking about something that was only about 25 feet long. What’s more, it was floating through space many thousands of miles from Earth.
Confirmation that the object was almost certainly not a naturally formed asteroid came from measurements of its path. Researchers in Arizona and Spain confirmed that radiation from the Sun was subtly altering the object’s path. This would be extremely unlikely if the object was a piece of solid rock. But if it was a hollow piece of metal, the phenomenon would be entirely expected.
So it was looking increasingly likely that rather than an asteroid, or even an alien spaceship, this object was the remains of a booster rocket. But from which space mission had this rocket originated? Dr. Chodas suggested that it might be the Centaur rocket section from Surveyor 2. That had been jettisoned soon after the spacecraft had launched from Earth.
After separating from Surveyor 2, the Centaur booster had traveled on through space, past the Moon, and as far as anyone knew, onwards into oblivion. But if this piece of space debris was the Centaur, it had clearly started to orbit around the Sun in a full circle that also brought it close to Earth. Yet positive confirmation remained elusive.
One way of trying to identify the object was to view it using infrared telescopes. That confirmed once and for all that 2020 SO was not an asteroid and was metallic. Vishnu Reddy, an associate professor at the University of Arizona’s Lunar and Planetary Laboratory, led a team that analyzed data captured by the infrared telescope at Maunakea, Hawaii.
Quoted on the NASA website, Dr. Reddy said, “Due to extreme faintness of this object following [the] Center for Near Earth Object Studies prediction, it was a challenging object to characterize. We got color observations with the Large Binocular Telescope or LBT that suggested 2020 SO was not an asteroid.” But his work went further than that.
Dr. Reddy and his colleagues also compared the infrared signature of 2020 SO with that of 301 steel, the material used in Centaur rockets, and the match was close. But he wanted to be more precise than that – a near match just wasn’t good enough. The professor went on to describe the next stage of the painstaking research, which involved more infrared signal comparisons.
Dr. Reddy explained, “We knew that if we wanted to compare apples to apples, we’d need to try to get spectral data from another Centaur rocket booster that had been in Earth orbit for many years to then see if it better matched 2020 SO’s spectrum.” But this would be no simple task.
“Because of the extreme speed at which Earth-orbiting Centaur boosters travel across the sky,” Dr. Reddy said, “we knew it would be extremely difficult to lock on with the Infrared Telescope Facility long enough to get a solid and reliable data set.” But the scientists were determined to do just that. And early in December they succeeded with the help of a previously-identified defunct Centaur booster still in orbit when it was some 27,400 miles from Earth, the closest it would come.
The researchers focused on observing what they knew to be the remnants of a Centaur booster rocket from 1971. And they kept it in their sights for long enough to get sufficient data for comparison with the information they already had about 2020 SO. The result of the analysis of the two sets of data? A conclusive match.
So what had started out as a mere hunch by Dr. Chodas in September that 2020 SO was a piece of the rocket that had launched Surveyor 2 towards the Moon in 1966 was now accepted as fact. This piece of space junk definitely was not an asteroid. And nor was it a spaceship from another galaxy. It was indeed the Centaur booster rocket that had formed a key part of the sadly unsuccessful Surveyor 2 mission.
Sometime around the spring of 2021, the Centaur booster will pass beyond our planet and head off on its orbit around the Sun. But it won’t be the last time that this memorial to the failed NASA Surveyor 2 launch visits its home planet. The dead thruster is slated to swing around the Sun and head back towards Earth. As Dr. Chodas told the The New York Times, “In 2036, it’s coming back.”