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SpaceX talks results of ‘DarkSat’ coating aimed at reducing brightness of Starlink satellites

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SpaceX successfully launched another batch of Starlink satellites into space on March 18, the fourth such launch this year. That brings the total number of internet-beaming satellites to 362, which includes two experimental ones. But ever since the initial batch got off the ground, astronomers and skywatchers have voiced concerns over the apparent brightness of the satellites.

That’s because the satellites appear in the night sky as a train of bright white dots marching across the sky. The sight is alarming to scientists who depend on clear skies in order to peer deep into space. Their concern is this: if the satellites are already interfering with telescope observations, what’s going to happen when there are 42,000 in orbit?

Initially, SpaceX has said its Starlink network will consist of 1,584 satellites, all operating in low Earth orbit. But the company has approval from the Federal Communications Commission for 12,000 satellites and could seek permission to launch 30,000 more. And they’re not the only company with space internet ambitions; OneWeb and Amazon have similar constellations planned.

SpaceX says it’s building satellites four times faster than OneWeb, by far its closest competitor. (SpaceX/Arianespace)

To help assuage their concerns, SpaceX decided to test out an experimental coating that would reduce the brightness of its satellites. SpaceX tested it out on a previous launch, on one individual satellite, aptly named “DarkSat”.

During the live broadcast of the most recent Starlink mission, SpaceX representatives said that the experiment was somewhat successful and that the coating did help to reduce the satellite’s brightness. But SpaceX wanted to try other means to see which technique was the more effective.

“Preliminary results show a notable reduction,” said Jessica Anderson, one of the hosts of the webcast. But just how effective it is remains to be seen.

Astronomers in Chile measured the DarkSat’s brightness and compared it to the rest of the Starlink satellites. The findings show that the DarkSat was about 55% dimmer, which is good news for certain telescopes. Other telescopes, like the upcoming Vera Rubin Observatory will need the brightness reduced even further as the sensitive optics would be greatly affected by the satellites zooming across the sky.

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Starlink satellites trail across images from DECam Credit: Cliff Johnson/Clara Martínez-Vázquez/DELVE Survey

Astronomers ran computer simulations that showed that the Starlink satellites would not only show up as pronounced streaks across images, but would saturate the pixels in the detectors, causing other ghost-like artifacts to appear. Observatories like the Vera Rubin would need the satellites to be at least 10-20% darker to mitigate their effects.

During the broadcast, Anderson also explained that the company was looking into other ideas that could reduce the satellites’ reflectivity even further.

One of those other ideas is a sunshade. SpaceX didn’t divulge too many details, other than the fact the technology would be used on a future mission and that it would deploy like a patio umbrella from the satellite. How that compares to the coating on the DarkSat remains to be seen.

 

I write about space, science, and future tech.

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Tesla Roadster event gets delayed due to unfavorable weather

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Credit: Tesla

Tesla is delaying its event for the Roadster, moving it from this Thursday, October 1, to Thursday, October 15, due to unfavorable weather.

The company has said it has been tracking the weather for this Thursday closely with local meteorologists, and because the event can only be held outside, Tesla is making the call to delay it:

“We’ve been tracking the weather closely with local meteorologists, but given the severe conditions predicted & because this event can only be held outdoors, we’ve made the difficult decision to reschedule. New date is October 15. Additional details to follow.”

We are sure that this is bringing back PTSD for some Tesla fans, and we know it is not ideal, but this also reveals some things about the event. Tesla said that this can only be held outdoors, meaning it bodes well for the rumors that the vehicle could potentially hover.

Some believe that this was essentially confirmed by the FAA airspace restriction they were granted, but this could have been for a drone show or to keep drones from spying on the event.

Tesla Roadster is available for order once again following brief hold

The Roadster event has been long-awaited, and it is unfortunate that the weather is going to keep us all waiting a little bit longer.

The Tesla Roadster will be unveiled in Waco, Texas.

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SpaceX turned a heralding moment for Starship into its greatest

Starship reached orbit despite losing an engine, deployed 26 Starlink V3 satellites on Flight 14.

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SpaceX’s Starship reached orbit for the first time on Monday, and for a few nail-biting minutes it looked like it wouldn’t. During ascent on Flight 14, one of Ship 41’s six Raptor engines shut down early, and SpaceX’s livestream host Dan Huot told viewers the team had decided not to commit to orbit. Minutes later, after what Huot described as a lot of conversation in the control room, the final poll came back in favor, and a roughly 19 second burn of a single Raptor pushed the ship into orbit about 170 miles up.

The reversal matters because SpaceX had written the exit ramp into the mission plan. The company said it would only fire the orbital insertion burn if flight controllers confirmed enough backup hardware remained for the deorbit burn, a condition Teslarati laid out ahead of the flight. Losing an engine was exactly the scenario that rule was built for.

Pressing forward fits Elon Musk’s history. Falcon 1 failed three straight times before its fourth launch reached orbit in 2008, with SpaceX nearly out of money, and Starship was developed by flying prototypes until they broke. What changed this year SpaceX going public, and with $SPCX sliding below its IPO price in July when Flight 13 slipped, the short interest climbed significantly, as Teslarati reported at the time. A Starship potentially lost today with revenue generating next-gen Starlink satellites aboard would have landed directly on shareholders.

That pressure showed up after orbit. SpaceX cut a flight planned to last nearly 10 hours to about three, moving splashdown from west of Chile to the North Pacific near Hawaii. SpaceX gave no reason, though Musk said this month the company was being extremely cautious about debris risk. The single Raptor for deorbit worked, and Ship 41 completed its flip and landing burn before breaking apart in the water, an outcome SpaceX expected. Musk has structured SpaceX’s governance to shield long term bets from market pressure.

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The payload is the bigger business story. Musk posted that all 26 Starlink V3 satellites deployed and are “operating nominally.” Each V3 is rated for about 1 Tbps of downlink and 160 Gbps of uplink, so this single launch adds roughly 26 Tbps, about 10 times what a Falcon 9 load of V2 Mini satellites adds. The V3 is too large for Falcon 9, making Starship the only vehicle that can build out the planned 100,000 satellite constellation, at up to 60 per flight once it reaches routine service. Unlike the 20 V3 units on Flight 13, which reentered on a suborbital path, these will raise their orbits and could begin serving customers within weeks and bring in hundreds of millions of additional dollars in projected Starlink revenue.

SpaceX has already begun winding down Falcon 9 Starlink launches from Florida in favor of Starship. Reported targets put Flight 15 as early as October 19, leaving about three weeks to diagnose Monday’s engine shutdown before the next orbital attempt.

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Tesla Cybercab fleet doubles to well over 100 units

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(Credit: Teslarati)

Tesla quietly doubled the size of its Cybercab fleet within the Robotaxi program in Austin, Texas, over the weekend to well over 100 units.

The move not only establishes more of the steering-wheel-less and pedal-less vehicles within the ride-sharing fleet Tesla has been operating for a year, but it also solidifies a more robust Robotaxi fleet as a whole.

Riders started receiving notifications from the Robotaxi app that stated: “Cybercab fleet has doubled: more rides available.”

Tesla first launched rides in the Cybercab in early September, although the Robotaxi fleet has been active for over a year, as rides began last Summer. Cybercab is truly Tesla’s most crucial vehicle release yet, as it is the first car any company has built that is geared toward full-fledged and end-to-end autonomy, never needing human intervention for anything.

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Only available in Austin at the current time, Cybercab has two seats and has been spotted testing around various U.S. states and regions; Tesla plans to deploy the Cybercab in various U.S. cities in the coming months as a best-case scenario.

Tesla Cybercab gets initial tie-in to localized, in-house cathode plant

The availability of the Cybercab has doubled from just 58 units last Monday to 125 the following Friday. Marking a substantial increase in Cybercab availability, the additional ride-sharing units are more than welcome, as wait times for Cybercabs, especially, were quite high.

The dramatic increase is a sign that demand for Robotaxi is growing and Tesla is feeling more confident that its driverless ride-hailing suite, especially its Full Self-Driving software, is able to handle any traffic situation without explicit direction or supervision from a human being.

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