A US spacecraft that malfunctioned on its way to the moon will plunge back to Earth and burn up in a fireball over the South Pacific on Thursday night.
A fuel leak aboard the Peregrine lander made it challenging for space agencies to track the doomed spacecraft, but as the leak subsided in recent days, its path became more predictable.
Based on the latest calculations, the lander will re-enter Earth’s atmosphere around 2100 GMT on Thursday, with most of the spacecraft burning up east of Australia between New Caledonia and Fiji. The nearest populated place is Aneityum, the southernmost island of Vanuatu.
“The challenge with this particular object was the uncertainty of its exact orbital position due to the initial release of on-board fuel,” said Angus Stewart, the UK’s head of space surveillance and detection. Space Agency. “Once that ventilation stopped, the orbit became much more stable and we were able to successfully locate Peregrine.”
Predicting where and when space hardware will come down is especially difficult for satellites in low orbit, as they often surf through the atmosphere for a few laps of the planet before burning up. Because the Peregrine lander comes in at a steeper angle, there is much less uncertainty.
“You get infinitely better control over where and when it will come back in,” said Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
However, how much of the spacecraft will survive reentry is less clear. Peregrine travels much faster than a typical re-entry satellite, so will generate more heat as it shoots through the atmosphere. On the other hand, the steeper angle means it has less air to punch through.
As with all spacecraft crossing an increasingly congested low-Earth orbit, Peregrine poses some risk to other spacecraft, but the chance of a collision is slim. “Our analysis, based on data from international partners, did not identify a risk to other space objects from Peregrine,” Stewart said.
Peregrine launched on Jan. 8 aboard a Vulcan Centaur rocket from Cape Canaveral, Florida. The launch was flawless – not a given for a rocket’s first flight – but Peregrine developed a fuel leak shortly after being released from the rocket’s upper stage.
What caused the leak is unclear, but Astrobotic, the Pittsburgh firm that built the lander, believes a stuck valve led to a surge in helium pressure that ruptured the spacecraft’s oxidizer tank. The loss of propellant meant the lander had no chance of achieving a soft landing on the moon – a first for a private company – and as it edged towards lunar distance, it was soon pulled back on a collision course with the earth.
Astrobotic along with Nasa and other US agencies to ensure as safe a reentry path as possible. To push Peregrine toward the South Pacific, the spacecraft did 23 short burns with its main engine. Peregrine then turned so that the force of the leaking propellant helped send the doomed spacecraft out to sea.
Despite the low risk of Peregrine, concerns remain about the threat posed by space debris as launches become more frequent. Andy Lawrence, the regius professor of astronomy at the University of Edinburgh, said satellite launches were increasing exponentially and that many spacecraft that fell back to Earth did not burn up completely. “As well as the danger of large pieces landing in our gardens, it is increasingly likely that a small piece will hit an aircraft,” he said.