Post by Andrei Tchentchik on Oct 27, 2020 12:17:48 GMT 2
(.#562).- SpaceX seeks to make Starlink satellites less visible.
How SpaceX seeks to make Starlink satellites less visible.
By: Brice Louvet, science editor
April 30, 2020
Astronomers criticizing the light pollution emitted by Starlink satellites, Elon Musk is currently looking for a way to make them less visible. In this spirit, new “sun visors” will soon be tested.
Satellites that divide
You may have witnessed, during the nights of Thursday to Sunday, remarkable passages of the last “train” of Starlink satellites, around 22h. While many marveled at the time, evoking a disturbing but very impressive phenomenon, others, on the other hand, condemned the experiment, arguing that all these batches of satellites were, in the end, going to hinder nocturnal observations.
Truth be told, many astronomers are concerned because capturing photographs of dimly lit objects usually requires several hours of exposure time. Point your telescope at the wrong place at the wrong time and you can be sure that the “Starlink” satellites will spoil the rendering.
Astronomers are already raising concerns that "only" half a thousand Starlink satellites have been deployed so far. But let's not forget that SpaceX officially plans to launch 12,000 of these instruments in Low Orbit (LEO). In addition, license applications filed last year with the International Telecommunication Union (ITU) suggest that Elon Musk plans to offer 30,000 additional satellites in the coming years.
As a reminder, mankind has only launched 9,400 objects into orbit since the dawn of the space age in 1957. And the earth’s environment already looks quite polluted.
The “DarkSat” option
Well aware of these concerns, Elon Musk has been thinking for several months about different ways to make these satellites less bright in the night sky.
With this in mind, SpaceX has already tested several measures. On January 6 in particular, as part of the deployment of a new batch of satellites, one of the instruments was covered with an "experimental obscuration treatment". A kind of black paint aiming to blend it into the decor.
But if observations seem to show that this "DarkSat" is indeed much darker than its other congeners in orbit, it is obviously not yet enough to appease the concerns of astronomers.
Furthermore, the simple act of painting satellites in black seems very risky. "It's not something you do lightly," Giorgio Savini, director of the University College London Observatory, told Business Insider a few months ago, talking about "temperature regulation" issues. .
The dark paint absorbs solar heat more effectively. As a result, a satellite will heat up enormously in the presence of our star, before cooling as soon as it enters the shadow of the Earth. Constraints that necessarily lead mechanical structures to expand and then contract.
A batch of Starlink satellites ready to be deployed in orbit.
Credits: Official SpaceX Photos / Flickr
New “sun visors” soon tested
But SpaceX is currently considering a second solution. This Wednesday, April 22, in response to a Twitter subscriber who wished him good luck on his latest launch of Starlink satellites, Elon Musk notably discussed the design of new "sun visors" aimed at reducing "solar reflection on the bodies of satellites "
Again, little information has been circulated, but it is believed to be structures made of "extremely radio-transparent" dark foam, so as "not to affect phased array antennas". The satellites equipped with these new sun visors will be deployed during the next launch (number 8) scheduled for May. Hoping this time that the technique works.
As a reminder, the objective of this Starlink constellation is to provide broadband Internet access to the entire planet. With approximately 40 million subscribers by 2025, Elon Musk estimates that it will be able to generate revenue ten times greater than the activity of SpaceX launchers, and thereby finance future expeditions to Mars.
F I N .
How SpaceX seeks to make Starlink satellites less visible.
By: Brice Louvet, science editor
April 30, 2020
Astronomers criticizing the light pollution emitted by Starlink satellites, Elon Musk is currently looking for a way to make them less visible. In this spirit, new “sun visors” will soon be tested.
Satellites that divide
You may have witnessed, during the nights of Thursday to Sunday, remarkable passages of the last “train” of Starlink satellites, around 22h. While many marveled at the time, evoking a disturbing but very impressive phenomenon, others, on the other hand, condemned the experiment, arguing that all these batches of satellites were, in the end, going to hinder nocturnal observations.
Truth be told, many astronomers are concerned because capturing photographs of dimly lit objects usually requires several hours of exposure time. Point your telescope at the wrong place at the wrong time and you can be sure that the “Starlink” satellites will spoil the rendering.
Astronomers are already raising concerns that "only" half a thousand Starlink satellites have been deployed so far. But let's not forget that SpaceX officially plans to launch 12,000 of these instruments in Low Orbit (LEO). In addition, license applications filed last year with the International Telecommunication Union (ITU) suggest that Elon Musk plans to offer 30,000 additional satellites in the coming years.
As a reminder, mankind has only launched 9,400 objects into orbit since the dawn of the space age in 1957. And the earth’s environment already looks quite polluted.
The “DarkSat” option
Well aware of these concerns, Elon Musk has been thinking for several months about different ways to make these satellites less bright in the night sky.
With this in mind, SpaceX has already tested several measures. On January 6 in particular, as part of the deployment of a new batch of satellites, one of the instruments was covered with an "experimental obscuration treatment". A kind of black paint aiming to blend it into the decor.
But if observations seem to show that this "DarkSat" is indeed much darker than its other congeners in orbit, it is obviously not yet enough to appease the concerns of astronomers.
Furthermore, the simple act of painting satellites in black seems very risky. "It's not something you do lightly," Giorgio Savini, director of the University College London Observatory, told Business Insider a few months ago, talking about "temperature regulation" issues. .
The dark paint absorbs solar heat more effectively. As a result, a satellite will heat up enormously in the presence of our star, before cooling as soon as it enters the shadow of the Earth. Constraints that necessarily lead mechanical structures to expand and then contract.
A batch of Starlink satellites ready to be deployed in orbit.
Credits: Official SpaceX Photos / Flickr
New “sun visors” soon tested
But SpaceX is currently considering a second solution. This Wednesday, April 22, in response to a Twitter subscriber who wished him good luck on his latest launch of Starlink satellites, Elon Musk notably discussed the design of new "sun visors" aimed at reducing "solar reflection on the bodies of satellites "
Again, little information has been circulated, but it is believed to be structures made of "extremely radio-transparent" dark foam, so as "not to affect phased array antennas". The satellites equipped with these new sun visors will be deployed during the next launch (number 8) scheduled for May. Hoping this time that the technique works.
As a reminder, the objective of this Starlink constellation is to provide broadband Internet access to the entire planet. With approximately 40 million subscribers by 2025, Elon Musk estimates that it will be able to generate revenue ten times greater than the activity of SpaceX launchers, and thereby finance future expeditions to Mars.
F I N .
