13.07.2024

A screenshot from the July 11, 2024, livestream of a Falcon 9 launch shows the rockeet that failed and resulted in falling Starlink satellites. The flight marked the first mission failure for a SpaceX Falcon 9 rocket in 7 years. Image via SpaceX livestream.

FAA grounds Falcon 9 after engine explodes mid-flight

The Falcon 9 rocket – the workhorse of the SpaceX fleet – was grounded indefinitely by the Federal Aviation Administration (FAA) on Friday, July 12, 2024, following an engine explosion after a liftoff Thursday night. The space-bound Falcon 9 lift vehicle exploded unexpectedly about an hour after liftoff from Vandenberg Space Force Base. The liftoff took place at 7:25 p.m. PDT (02:25 UTC on July 12). The malfunction left the rocket’s cargo – 20 Starlink v.2 mini satellites – unable to reach their intended orbit. The satellites are expected to fall back to Earth, possibly as early as this weekend or early next week.

So the rare failure means skywatchers should start looking for falling Starlink debris.

As of July 12, 2024, SpaceX has launched the Falcon 9 70 times this year. That translates to more than half of the 137 orbital launches made worldwide this year.

Until Wednesday’s failure, the Falcon 9 has flown 364 successful missions overall. The British news agency Reuters commented it was the 1st failure of a SpaceX Falcon 9 in seven years.

Rare Falcon 9 RUD

SpaceX said in a statement that a leak in the vehicle’s second stage engine caused the malfunction:

Falcon 9’s second stage performed its 1st burn nominally, however a liquid oxygen leak developed on the second stage. After a planned relight of the upper stage engine to raise perigee – or the lowest point of orbit – the Merlin Vacuum engine experienced an anomaly and was unable to complete its second burn.

SpaceX CEO Elon Musk announced the RUD – euphemistic company jargon for a rapid unscheduled disassembly – on X.com (formerly Twitter):

Luckless satellites being dragged to Earth fast

SpaceX officials said via X.com they were able to regain communication with some of the satellites. Then controllers sent instructions to fire onboard thrusters to raise their low orbits. But, the company said, it isn’t counting on success:

Unless the satellites gain enough speed, they will tumble into a fiery reentry. CEO Musk was more blunt about the likelihood of recovery. He tweeted his pessimism:

We’re updating satellite software to run the ion thrusters at their equivalent of warp 9. Unlike a Star Trek episode, this will probably not work, but it’s worth a shot.

Starlink satellites falling

Each time the doomed satellites pass closest to Earth, they lose about 3.1 miles (5 km) of altitude. The drag of the planet’s atmosphere is slowing them down. And inevitably it will bring them down.

According to the AP report on the incident, SpaceX has not given a time when the falling Starlink satellites will begin reentering. Unconfirmed rumors on X.com say to expect them within three days.

When a falling Starlink satellite burns, it does so messily. SpaceX designed the satellites to disintegrate completely on reentry. They said:

At this level of drag, our maximum available thrust is unlikely to be enough to successfully raise the satellites. As such, the satellites will reenter Earth’s atmosphere and fully demise. They do not pose a threat to other satellites in orbit or to public safety.

The FAA doesn’t agree. In a 2023 report to Congress, the agency said falling Starlink debris could kill or maim:

By 2035, if the expected large constellation growth is realized and debris from Starlink satellites survive reentry, the total number of hazardous fragments surviving reentries each year is expected to reach 28,000, and the casualty expectation, the number of individuals on the ground predicted to be injured or killed by debris surviving the reentries of satellites being disposed from these constellations, would be 0.6 per year, which means that one person on the planet would be expected to be injured or killed every two years.

CNN reported SpaceX called the FAA’s assertion “preposterous, unjustified, and inaccurate.”

When will Falcon 9 fly again?

AP reported on Friday that SpaceX must fix the engine problem before the Falcon 9 can fly again. The setback will likely send the company into high gear, as their launch calendar is crammed.

A SpaceX statement issued Thursday night says SpaceX expects a quick return to flight:

SpaceX will perform a full investigation in coordination with the FAA, determine root cause, and make corrective actions to ensure the success of future missions. With a robust satellite and rocket production capability, and a high launch cadence, we’re positioned to rapidly recover and continue our pace as the world’s most active launch services provider.

Meanwhile, the FAA said a full fix and perhaps a new license will be required to get the Falcon 9 flying:

A return to flight is based on the FAA determining that any system, process, or procedure related to the mishap does not affect public safety. In addition, SpaceX may need to request and receive approval from the FAA to modify its license that incorporates any corrective actions and meet all other licensing requirements.

The next scheduled flight of the Falcon 9 was to happen in mid-July. It’s now on hold. The vehicle was to carry Space Norway’s pair of Arctic Satellite Broadband Mission satellite constellations to orbit. The satellites – made by Northrop Grumman – will provide commercial broadband and protected military communications.

Falling Starlink satellites aren’t new

More than 6,000 Starlink satellites are currently in low Earth orbit. But some Starlink satellites have failed to reach their intended orbit before now. In 2022, 40 Starlink satellites made an early reentry when a geomagnetic storm hit the day after their launch, increasing their drag. Here’s a video of a Starlink satellite reentering over Puerto Rico, to give you an idea of what to look for.

Bottom line: A SpaceX Falcon 9 launched Thursday night exploded. It was carrying a Starlink satellites that failed to reach their proper orbit and are now expected to make a fiery reentry.

Quelle: EarthSky