SpaceX launches third batch of 60 Starlink broadband satellites, reviving concerns

SpaceX’s Falcon 9 rocket rises from its launch pad, sending Starlink satellites into space. (SpaceX via YouTube)
SpaceX’s Falcon 9 rocket rises from its launch pad, sending Starlink satellites into space. (SpaceX via YouTube)

SpaceX sent a fresh batch of 60 Starlink broadband satellites into orbit tonight on a Falcon 9 rocket, executing a mission that aims to give the California-based company the world’s biggest commercial satellite constellation.

When added to the previous two 60-satellite launches, the Starlink tally comes to 180 satellites. Some of SpaceX’s previously launched satellites are no longer in service; nevertheless, the launch was expected to push Starlink past Planet’s constellation of roughly 140 Earth-imaging satellites.

SpaceX’s facility in Redmond, Wash., is playing the lead role in building Starlink satellites. Eventually, SpaceX aims to have thousands of the satellites in low Earth orbit — but the prospect of having so many spacecraft in orbit has sparked concerns about the effect on astronomical observations and space traffic jams.

Tonight’s liftoff from Cape Canaveral Air Force Station in Florida came at 9:19 p.m. ET (6:19 p.m. PT), marking the first orbital launch of 2020.

Minutes after launch, the Falcon 9’s first-stage booster fell away from the second stage and landed itself on a drone ship dubbed “Of Course I Still Love You,” stationed hundreds of miles offshore in the Atlantic Ocean.

About 45 minutes after launch, SpaceX tried to catch half of the rocket’s nose cone, or fairing, in a giant catcher’s-mitt net that was rigged on top of a ship called Ms. Tree. The attempt came close but missed, SpaceX reported.

Meanwhile, the second stage and its payload continued onward to orbit. A little more than an hour after launch, the stacked-up satellites were deployed like a deck of cards spread across a playing table. The physics behind that deployment will allow the satellites to spread out in a 180-mile-high (290-kilometer-high) orbit.

Once the satellites are checked out, their orbits are to be raised to an operational altitude of 342 miles (550 kilometers).

During the early stages of their flight, the satellites’ solar panels make them visible from the ground as a string of lights passing through the sky. SpaceX says their brightness will dim as the panels are reoriented. Even so, astronomers have voiced concerns about the rise of light and radio pollution in the night sky, spoiling their sensitive observations. The topic is due to come up this week in Hawaii at the winter meeting of the American Astronomical Society.

To address the concerns, SpaceX is experimenting with coatings that would reduce the satellites’ reflectivity. One of the 60 spacecraft launched tonight was given the darkening treatment to see how the satellite’s performance will be affected.

Space traffic management is another concern. SpaceX says it shares high-fidelity tracking data with other satellite operators to reduce the risk of collision. But last September, a close encounter involving a Starlink satellite and a European wind-monitoring satellite demonstrated that the system may not be foolproof.

SpaceX says Starlink was created to provide broadband internet access to the billions of people around the world who are currently underserved — and bring in the revenue that billionaire founder Elon Musk says will be required to fund his vision of building a city on Mars. The company plans to start offering limited service as early as this year.

When it comes to satellite broadband from low Earth orbit, or LEO, SpaceX isn’t likely to be the only game in town. The London-based OneWeb consortium is also planning to put a LEO constellation into operation this year, starting with the Arctic. Canada’s Telesat has similar ambitions. And Amazon has plans for a 3,236-satellite constellation of its own, known as Project Kuiper.

Check in with the Heavens Above website or follow Dave Dickinson on Twitter to find out about sighting opportunities for the third batch of Starlink satellites.

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source: yahoo.com