A mysterious bright light that crosses the sky before dawn. Around 6:05 local Spanish time (4:05 UT), a large number of early risers from much of the south and central-west of the peninsula were stunned on Monday to see what seemed to be a strange ball of fire on the horizon. Looking like a plane engulfed in flames or, to the most excited imaginations, an artifact from another civilization, it was actually the re-entry of the second stage of the recoverable Falcon 9 rocket with which the Space X company has put 51 into orbit new satellites of the Starlink constellation.
In addition to being observed by many people, the phenomenon was recorded by the detectors of the SMART project (Red de Bolides y Meteoros del Suroeste de Europa – Red SWEMN) in Calar Alto (Almería), Sierra Nevada, La Sagra (Granada), La Hita (Toledo) and Olocau, Ayora and Cullera (Valencia).
The rocket, which belongs to the Starlink 4-20 mission, was launched from Cape Canaveral (United States) on Monday at 2:32 p.m. Spanish peninsular time. In the images of the reentry, a cloud of gases can be seen coming from the propellants of the second stage of the Falcon 9. These propellants achieve the braking of said stage to deorbit it and cause its reentry, thus preventing it from remaining as space debris around our planet.
“Second-stage re-entry starts at about 1,600 meters per second. The thrusters slow it down even more during re-entry, to avoid very sharp interaction with the air as it moves into the denser layers of the atmosphere,” he explains. José María Madiedo, from the Institute of Astrophysics of Andalusia (IAA-CSIC).
braking effect
Although in the image the rocket looks like a ball of fire, “nothing has burned,” Madiedo stresses. “The braking effect has precisely this objective, so that this second stage survives and there is an option to recover it. However, the recovery of the second stage is more complicated than the first, so Space X has not always succeeded” , Add.
As he explains, the procedure for the re-entry of the Falcon 9 has been “totally normal”. Space X had publicly announced the launch and did a live online broadcast of the entire mission. That the reentry has been seen from Spain has been “a coincidence”, since the second stage left 51 satellites in orbit that it was transporting before passing over our country. “From that point on, the programmed re-entry begins, a phase in which they flew over neighboring areas, making it possible for the phenomenon to be seen from Spain,” says the expert.
The videos show the images collected by the different external cameras operated from the Calar Alto Observatory in Almería. These videos have been sped up to four times their actual speed.
Starlink is a huge constellation of satellites that promises to offer a totally independent internet connection with a quality never seen before and that reaches all corners of the planet. It has been criticized by many astronomers because it can increase space debris and contribute its lights to making the skies less and less pristine.