The promising satellite internet network offered by SpaceX with its Starlink project has already given its users the first joys, but it is not all good news: astronomers continue to protest about this deployment.
Hundreds of them already protested months ago and indicated that the huge number of satellites threatens future astronomical discoveries. SpaceX modified those that were launched a posteriori to reduce their albedo or reflectivity , but the measure has not completely satisfied the experts.
An artificial constellation that worries astronomers
The first round of satellites that SpaceX launched consisted of objects 99% brighter than the rest of the objects in low Earth orbit, but things looked much worse considering that 12,000 of those satellites are expected to serve, although the total number could amount to 42,000 of these items.
Musk indicated in March 2020 that Starlink “will not cause any impact on the astronomical discoveries, zero”, but even so SpaceX ended up responding to the criticism and applied a special paint layer to reduce the albedo or reflectivity to the radiation that these satellites receive. and that makes space exploration difficult. This new iteration became known as Starlink-1130 (or ‘DarkSats’, ‘dark satellites’) and began launching in early 2020.
A recent study has analyzed how both these satellite and the original version (Starlink-1113) behaved before different wavelengths used for astronomical exploration, and effectively verified that those who use this special layer reduce the albedo in half in certain cases. , but that, they say, is not enough.
Thus, although it offers notable improvements in the observation of the ultraviolet region, the layer causes the surface temperature of the satellites to increase and that creates problems in the exploration that uses intermediate infrared wavelengths.
SpaceX is expected to launch a new iteration of these satellites dubbed ‘VisorStats’ soon , but the impact of these models on astronomical observation is unknown.
For astronomers one option would be to change the orbit of operation of these satellites, which are located 547 km from our planet. Competing service OneWeb places its satellites at 1,200 km, which would make the effect of these artificial constellations much less. It seems difficult for SpaceX to consider that alternative, so we will have to wait to see if the new iterations of its Starlink really alleviate the problem.
Via | Gizmodo