A new satellite has become one of the 20 brightest stars in the sky

A new satellite has become one of the 20 brightest stars in the sky

Observing a BlueWalker 3 pass from Oukaimeden Observatory on November 16, 2022. The bright star in the lower left is Zeta Puppis.
Enlarge / Observing a BlueWalker 3 pass from Oukaimeden Observatory on November 16, 2022. The bright star in the lower left is Zeta Puppis.

CLEOsat/Oukaimeden Observatory/IAU CPS/AE Kaeouach

Last month, a Texas-based company announced that it had successfully deployed the largest ever commercial communications satellite into low Earth orbit.

This BlueWalker 3 demonstration satellite measures almost 65 square meters, or about a third of the size of a tennis court. Designed and developed by AST SpaceMobile, the vast BlueWalker 3 satellite is intended to demonstrate the ability of standard mobile phones to connect directly to the Internet via satellite. Large satellites are needed to connect to mobile devices without an antenna on the ground.

In this emerging field of direct-to-mobile connectivity, which seeks to provide Internet service beyond the reach of terrestrial cell towers, AST competes with Lync, another company that has also launched demonstration satellites. Additionally, larger players such as Apple and a team from SpaceX and T-Mobile have announced plans to provide direct connectivity services.

So, while there are many more such satellites to come, AST stands out right now because it is the first to launch an exceptionally large satellite, and it plans to start launching operational “BlueBird” satellites. “end of 2023.

IAU Concerns

Since the launch of BlueWalker3 in September, astronomers have tracked the satellite and their alarm has been heightened after its antenna was deployed last month. According to the International Astronomical Union, post-deployment measurements showed that BlueWalker 3 had an apparent visual magnitude of around 1 at its maximum, which is almost as bright as Antares and Spica, the 15th and 16th brightest stars. of the night sky.

For the past few years, astronomers have been concerned about megaconstellations, like SpaceX’s Starlink satellites. Although there are more of them – there are more than 3,000 Starlink satellites in orbit – they are much smaller and much less bright than the types of satellites AST plans to launch. Eventually, AST plans to launch a constellation of 168 large satellites to provide “substantial” global coverage, a company spokesperson said.

However, only one is enough for astronomers. “BlueWalker 3 is a big change in the constellation satellite question and should give us all a reason to pause,” said Piero Benvenuti, director of the International Astronomical Union.

The astronomers’ organization is also concerned about the potential for radio interference from these “cell towers in space”. They will transmit strong radio waves at frequencies currently reserved for terrestrial cell phone communications, but are not subject to the same radio quiet zone restrictions as terrestrial cellular networks. This could have serious implications for research in radio astronomy – which has been used to discover cosmic microwave background radiation, for example – as well as work in related fields.

Astronomers are currently building their radio astronomy observatories in remote areas, away from interference from cell towers. They fear that these large satellites transmitting radio waves will interfere in unpopulated areas.

AST responds

A spokesperson for AST issued a statement to Ars that the impact of its satellites must be weighed against the “universal good” of cellular broadband for people on Earth. However, the company also said it was willing to work with astronomers to address their concerns.

“We look forward to using the latest technologies and strategies to mitigate possible impacts on astronomy,” the AST statement read. “We are actively working with industry experts on the latest innovations, including next-generation anti-reflective materials. We are also engaged with NASA and certain working groups within the astronomical community to participate in advanced industrial solutions , including potential operational interventions.”

To that end, AST said it is committed to avoiding broadcasts within or adjacent to the National Radio Quiet Zone in the United States, which is a large land area that includes parts of West Virginia. and Virginia, as well as additional radio astronomy sites.

A US-based astronomer who focuses on light pollution, John Barentine, told Ars he welcomes the company’s efforts to tackle radio interference. He also appreciates all efforts to mitigate the effects on optical astronomy. However, Barentine warned, there is no recourse for astronomers but to take AST and other companies at face value due to a lack of regulatory oversight.

“Overtures from commercial space operators who pledge that their activities in space will not adversely affect astronomy are being made in the absence of any meaningful regulatory oversight that mandates mitigation measures,” a- he declared. “AST SpaceMobile’s stated intentions are laudable, but at this time these are just words. I therefore reserve judgment pending the company’s actions.”

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