About 3% of SpaceX’s Starlink satellites may have failed. That’s not too bad, but across a 42,000-spacecraft constellation it could spark a crisis.

BY Mojgan October 20, 2020 Air & Space ، Science ، Space ، Technology 8 views
SpaceX, the rocket company founded by Elon Musk, plans to surround Earth with Starlink satellites and provide global high-speed, low-latency internet service from orbit. SpaceX; Kevork Djansezian/Getty; Business Insider

SpaceX is launching satellites into space by the dozens to realize Starlink, a globe-encircling constellation of spacecraft that beam affordable, high-speed internet across Earth.

So far, the scheme — envisioned by SpaceX founder Elon Musk — seems to be working. The aerospace company even plans to open a public beta test across the northern US and southern Canada, Musk tweeted on October 8, possibly within the next few months.

“Other countries to follow as soon as we receive regulatory approval,” he added.

However, the unprecedented project has left a trail of seemingly unresponsive spacecraft in its wake. All of the satellites are designed to be maneuverable in space using an ion engine, and even deorbit themselves back to Earth. But satellites with malfunctioning communication or propulsion systems can fly uncontrolled and pose a hazard to other satellites, and even astronauts, circling Earth.

SpaceX launched its first batch of 60 prototypes in May 2019 and, to date, has flown 775 total Starlink internet satellites. But so far around 3% of those spacecraft may have failed, according to data collected by Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics.

“I would say their failure rate is not egregious,” McDowell told Business Insider. “It’s not worse than anybody else’s failure rates. The concern is that even a normal failure rate in such a huge constellation is going to end up with a lot of bad space junk.”

Some of those failures may be intentional tests, but how many (if any) is not publicly known because SpaceX hasn’t released such information. As a result, astronomers like McDowell have resorted to analyzing satellite-movement data gleaned from SpaceX and the US government, showing which Starlink satellites have fallen back toward Earth and which ones are not maneuvering. (The 3% apparent failure rate does not include 45 satellites that SpaceX is known to have intentionally deorbited.)

The first batch of 60 high-speed Starlink internet satellites, each weighing about 500 pounds, flat-packed into a stack prior to their launch aboard a Falcon 9 rocket on May 23, 2019. 
SpaceX via Twitter

SpaceX has permission from the US government to launch nearly 12,000 Starlink satellites, though it’s asked to launch 30,000 more for a total of nearly 42,000. In either case, SpaceX is on track to form a “megaconstellation” that outnumbers all prior spacecraft ever launched by humanity. If 3% of the maximum planned Starlink constellation fails, that could mean 1,260 dead, 550-pound satellites the size of a desk aimlessly circling the planet.

There were about 3,200 nonfunctional satellites in Earth’s orbit as of February, according to the European Space Agency. Many of these dead spacecraft regularly threaten to collide with others and create a space-debris crisis. This week, for example, satellite trackers flagged a “very high risk” close pass between a dead satellite and a discarded rocket body, with one company calculating a 10% chance of collision. (They didn’t collide, after all.)

SpaceX says its satellites will naturally deorbit, or burn up in Earth’s atmosphere, if their propulsion systems don’t work. But that process can take up to five years, according to Starlink’s website. In the meantime, defunct satellites rocket around Earth faster than a bullet, with nobody to steer them away from other spacecraft that may fly in their path.

SpaceX did not acknowledge Business Insider’s requests for comment. However, in filings to the Federal Communications Commission, SpaceX has downplayed the risk, stating that it “views satellite failure to deorbit rates of 10 or 5 percent as unacceptable, and even a rate of 1 percent is unlikely.”

If 1% of its satellites did fail with no capacity to maneuver, the company said, “there is approximately a 1 percent chance per decade that any failed SpaceX satellite would collide with a piece of tracked debris.”

The company also claimed that its practices “effectively eliminate the chance that such rates will ever occur.”

Dead satellites can collide and build up a space-debris crisis

A simulation of space debris created by India’s “Mission Shakti” anti-satellite missile test on March 27, 2019. 
Analytical Graphics Inc.

However, SpaceX is not alone in pushing to launch large numbers of internet satellites. OneWeb has already launched 74 satellites for its planned constellation of 48,000, and Amazon aims to launch more than 3,200 for its Kuiper fleet. It’s unclear how many dead satellites those constellations might also leave in orbit.

Since nobody can maneuver them, failed satellites sometimes hurtle toward other spacecraft — including the International Space Station and its crew of astronauts.

Even if a satellite crashes into another satellite with no humans on board, it can create perilous conditions. 

“We replace two satellites with essentially two shotgun blasts of debris,” Dan Ceperley, the CEO of satellite-tracking company LeoLabs, told Business Insider in January. That month, two dead satellites almost crossed paths and exploded into hundreds of thousands of bits of debris.

It wouldn’t have been the first such explosion, and it doesn’t take many to exacerbate the debris problem. In 2007, China tested an anti-satellite missile by blowing up one of its own weather satellites. Two years later, one American and one Russian spacecraft accidentally collided. Those two events alone increased the amount of large debris in low-Earth orbit by about 70%. India conducted its own anti-satellite missile test in 2019, and the explosion created an estimated 6,500 pieces of debris larger than an eraser.

All in all, more than 500 such “fragmentation events” have created nearly 130 million bits of debris in Earth’s orbit. Those chunks of debris zip around the planet at more than 17,500 mph, or roughly 10 times the speed of a bullet.

That’s not only a problem for robotic spacecraft, but ones carrying people. Just last month, a piece of debris careened within a mile of the football field-sized space laboratory. To avoid a collision, mission controllers fired the thrusters of an attached Russian cargo spaceship to maneuver the station out of possible harm’s way. The three crew members sealed themselves inside an ISS segment with a Soyuz spaceship, so they could escape if the debris struck.

A space-debris hit to space shuttle Endeavour’s radiator found after one of its missions. The entry hole is about 0.25 inches wide, and the exit hole is twice as large. 

If the space-junk problem gets extreme, a chain of collisions could spiral out of control and surround Earth in a practically impassable field of debris. This possibility is known as the Kessler syndrome, after Donald J. Kessler, who worked for NASA’s Johnson Space Center and calculated in a 1978 paper that it could take hundreds or even thousands of years for such debris to clear up enough to make spaceflight safe again.

“It is a long-term effect that takes place over decades and centuries,” Ted Muelhaupt, who leads The Aerospace Corporation’s satellite system analysis, previously told Business Insider. “Anything that makes a lot of debris is going to increase that risk.”

The sheer number of objects in Earth’s orbit may already be having a Kessler-like effect, as Rocket Lab CEO Peter Beck described last week.

An illustration of space junk. Satellites and debris are not to scale. 

“This has a massive impact on the launch side,” he told CNN Business, adding that rockets “have to try and weave their way up in between these [satellite] constellations.”

Starlink is already a space-debris hazard 

SpaceX has barely launched 2% of its planned constellation, but it has already had a close call.

In September 2019, the European Space Agency had to maneuver one of its spacecraft at the last minute to avoid possibly colliding with a Starlink satellite. The chance of that crash was 1 in 1,000. While that may sound low, NASA routinely moves the ISS for chances of 1 in 100,000.

The ESA said it had to move its satellite because SpaceX had “no plan to take action.” SpaceX said it missed the ESA emails about the issue due to a “bug” in its communications systems.

An illustration of SpaceX’s Starlink satellite internet constellation in orbit around Earth. 

Overall, close approaches like that seem to be happening more frequently.

“We are seeing recently a decided uptick in the number of conjunctions,” Dan Oltrogge, an astrodynamicist at Analytical Graphics, Inc, where he uses a software that has been assessing conjunction data since 2005, recently told Business Insider. “And it looks to be very well aligned with the new large-constellation spacecraft that have been launched.”

As new satellite constellations launch, regulatory agencies like the FCC may need to evaluate how many dead spacecraft they’re willing to accept.

“What is an acceptable failure rate?” McDowell asked. “That, I’m maybe not competent to have an opinion on.”


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