SpaceX and our space debris problem
It’s been a bit of a hectic month for SpaceX, Elon Musk’s rocket and satellite internet company.
The bad news: A solar storm knocked 40 of its Starlink satellites back to Earth. They go to burn into Earth’s atmosphere, costing the company up to $100 million and casting new doubts on Musk’s grand plans for satellite internet in addition to those recently voiced by China and Nasa. The good news? All of those reports that a SpaceX rocket was about to crash into the moon were false: the rocket belongs to someone else.
The error highlights the growing problem of all the trash we as a planet throw into space and how we deal with it (or not, as the case may be). Not everything we send arrives, and some is lost. This is especially true once it leaves Earth orbit, as no one is officially tracking our space junk there. Basically, we leave that to a handful of dedicated astronomers who do it as a hobby.
One of these astronomers is Bill Gray. He developed software called Project Pluto, which is used to track objects in space. A few weeks ago he announcement this part of a SpaceX Falcon 9 rocket would crash into the moon on March 4. Lots of news stories followed (Musk-related disasters tend to grab headlines), but any hope that Musk would have knocked an ankle back to earth a few days ago. Gray announced that he had made a mistake: the wayward object is most likely the recall of the Chinese Chang’e 5-T1. rocketlaunched in 2014.
Perhaps surprisingly, this case of mistaken identity isn’t hard to make, even for the relatively few people who track this stuff all the time. Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, explained that it is difficult to determine the exact trajectory of an uncontrolled object in space. There are many variables that can alter the trajectory of the object, and even a small change adds up with time and distance.
Also, and this is the heart of the matter, we don’t really track these things anyway.
We have a good idea of what orbits the Earth, especially if these objects send signals back to us or if they are able to endanger anything or anyone in Earth orbit (or on the Earth herself). And we know where important science stuff like space telescopes, deep space weather satellitesand probes are.
But a piece of space junk – an abandoned rocket stage, let’s just say – floating well beyond Earth’s orbit is more of a curiosity than a concern. Since there are no rules for tracking the things we launch into deep space, the only information we might have is the launch data and observations of astronomers catching it on its merry way through the night sky, assuming it’s even close enough to be visible.
The rocket confusion happened years ago, Gray told The New York Times. He calculate the orbit of an object first observed in March 2015 and found that it had passed the moon about a month earlier. This matched what he believed to be the flight path of a recent SpaceX launchso Gray was fairly certain the object was a discarded rocket booster from that launch.
It wasn’t until he announced that a SpaceX rocket was going to crash into the moon that he realized it wasn’t launched to the moon at all, so it probably wasn’t the object. But China’s Chang’e 5-T1 rocket launched in October 2014 was sent to the moon, making it the most likely new (and current) suspect. Also helpful, McDowell said: An amateur radio satellite from Luxembourg hitchhike on this rocket booster, providing several days of orbital data. Once the SpaceX rocket was ruled out, they realized they were probably looking at the Chinese rocket instead.
While this all sounds like a disturbing amount of guesswork, luckily when it comes to things that could crash into Earth, we’re a little more diligent. The personal interest, as well as the knowledge of this probably happened to dinosaurs, is a powerful motivator. This is why, since 1998, NASA has operated the Center for Near-Earth Object Studies, which tracks potentially dangerous objects so that we can identify and, if necessary, stop collisions that would otherwise be catastrophic. Specifically, the center monitors asteroids and comets that are large enough and will pass close enough to our planet — less than 4.6 million miles is considered “close” — to pose a potential threat to it.
Other than that, NASA told Recode that it’s really about tracking space debris only when that debris could endanger NASA assets. The Center for Near-Earth Object Studies ended up helping determine who the rocket likely belongs to, but that was only in response to the attention it garnered about its impending demise. The United States Space Force also tracks orbital debris but did not respond to request for comment on whether or how it tracks debris in lunar orbit.
“Things that are more than, say, 100,000 kilometers away? Space Force doesn’t care,” McDowell said. “That’s a low enough traffic volume. There is no real risk of them hitting each other.
It won’t be the first time a man-made object has crashed on the moon. While the deliberate smashing of objects into planetary bodies seems more in the fictional realm of a James Bond villain, Commander CobraWhere Georges Méliès, it happens. last November, NASA launched a rocket in an asteroid to see if we can knock asteroids off course if one threatens to hit Earth. And, in 2009, Nasa launched a rocket into a lunar crater to see if there was water in the crater. And there are several other missions on various planets of several countries which end with the spaceship crashing on the orbiting bodies after running out of fuel or completing their missions.
Unintentional accidents are rarer, but we had a fairly recent example in 2019, when an Israeli company’s lunar mission ended with the lander crashing, possibly knocking thousands of tardigrades who were with him. Whoops. Before that, we had not had an accidental lunar crash since 1971. At least, not one that we know of.
“It’s probably not the first time this has happened,” McDowell said. “It’s just the first time we’ve paid enough attention to notice it.”
What we think now is that the Chang’e 5-T1 rocket booster is expected to hit the moon on March 4 at around 7:30 a.m. If you’re hoping to see it, you’re out of luck: it will reach the far side of the moon, which means it won’t be visible to us now or ever. The rotation of the moon is locked with the earth, so we always see the same side. But it is possible that some of the objects in lunar orbit get an image of the crater they leave. NASA told Recode that its lunar orbiter would not be able to see the impact, but would look for the crater. It could take “weeks or months” to find it.
McDowell said he hopes this incident will make the general public aware of the gaps in our knowledge regarding man-made objects floating in deep space, wherever they may be. He would like to see an international database of all launches with their trajectories, as well as funding for at least one person to track them. This is going to be especially important in the decades to come, as the amount of lunar traffic grows and so does the number of countries and private companies that create it. Now we have a chance to prepare for later.
“It gets confusing out there. Let’s get organized,” McDowell said.
As for the location of that SpaceX rocket that was initially blamed for the upcoming lunar crash? We can only guess. Maybe we’ll see it again someday, but no one seems to know for sure.
This story was first published in the Recode newsletter. register here so as not to miss the next one!