Sixty more satellites for SpaceX’s Starlink global Internet network streaked into orbit Monday night from Cape Canaveral, including one spacecraft to test an experimental dark coating to address scientists’ concerns that the thousands of the quarter-ton, flat-panel satellites will impede astronomical observations.
The launch of 60 more spacecraft for the Starlink project, which SpaceX sees as a core business area in the coming years, makes the company the operator of the largest fleet of commercial satellites, surpassing the previous mark set by Planet, an operator of Earth-imaging nanosatellites.
SpaceX wants to begin limited Internet service through the Starlink network later this year, then expand to global service to beam Internet signals to consumers in far-flung locales outside the reach of terrestrial wired broadband connections. Users on airplanes, ships and the U.S. military could also be Starlink customers.
Blazing a similar trail to two previous Starlink satellite launches last year, a SpaceX Falcon 9 rocket lifted off from pad 40 at Cape Canaveral at 9:19:21 p.m. EST Monday (0219:21 GMT Tuesday) and turned on a northeasterly heading over the Atlantic Ocean.
Nine kerosene-fueled Merlin 1D engines on the base of the first stage powered the rocket off the launch pad with 1.7 million pounds of thrust.
After two-and-a-half minutes, the nine main engines shut down and the first stage separated to begin descent maneuvers toward a landing on SpaceX’s drone ship “Of Course I Still Love You” in the Atlantic Ocean.
The first stage — flying for the fourth time on Monday night’s mission — nailed its landing on the drone ship, marking the 48th time SpaceX has successfully landed a Falcon booster since the company’s first rocket recovery in 2015. An attempt to catch one half of the Falcon 9’s clamshell-like payload fairing in a net fastened to an ocean-going vessel was unsuccessful, SpaceX said.
The Falcon 9’s second stage ignited its Merlin engine two times to place the 60 Starlink satellites into an orbit with a target altitude of 180 miles (290 kilometers) and an inclination of 53 degrees to the equator. SpaceX confirmed the Falcon 9 injected the payloads close to the planned orbit.
Retention rods holding the 60 flat-panel Starlink spacecraft to the Falcon 9 rocket released at 10:20 p.m. EST (0320 GMT) to allow separation of the satellites.
Retention rods holding the 60 Starlink satellites to the Falcon 9’s second stage have been released. The 60 spacecraft are floating away from the Falcon 9 rocket as it soars at an altitude of nearly 200 miles south of Australia. https://t.co/KNZ3rpnyfs pic.twitter.com/Hu8OIrtqqd
— Spaceflight Now (@SpaceflightNow) January 7, 2020
An on-board camera view showed the 60 satellites deploy from the Falcon 9’s second stage. The Starlink relay stations were expected to begin dispersing in the coming days, while SpaceX control teams perform tests and activate the satellites’ krypton-fed ion thrusters to begin maneuvering toward their planned operating altitude of 341 miles (550 kilometers).
The launch Monday kicked off a brisk pace of launches by SpaceX planned for 2020.
Gwynne Shotwell, SpaceX’s president and chief operating officer, said last month the company could perform as many as 35 to 38 launches this year from three launch pads in Florida and California. That figure does not include potential test flights of SpaceX’s next-generation Starship vehicle.
The bulk of SpaceX’s missions in 2020 will add satellites to the company’s Starlink constellation of broadband satellites.
SpaceX plans to operate the initial block of 1,584 Starlink satellites in orbits 341 miles above Earth. The company has regulatory approval from the Federal Communications Commission to eventually field a fleet of up to 12,000 small Starlink broadband stations, and has hinted in additional regulatory filings that it could seek to operate up to 42,000 Starlink spacecraft.
In response to concerns from astronomers, Shotwell said one of the 60 satellites set for launch Monday will test a new less-reflective coating designed to reduce the brightness of the spacecraft. The first 120 satellites were brighter than expected, raising worries from scientists that thousands of Starlink craft could interfere with astronomical observations.
The satellites are especially bright soon after launch, when they are bunched together and flying at lower altitudes.
“During orbit raise, the satellites are closely clustered together and their solar arrays are positioned in a special low-drag configuration, making the satellites appear visible from the ground just after deployment,” said Lauren Lyons, a SpaceX engineer who co-hosted the company’s webcast of Monday night’s launch. “However, once the satellites reach their operational altitude and begin on-station service, their orientation changes and the satellites become significantly less visible.
“While it’s really cool to catch a glimpse of those satellites from the ground, they can sometimes be a distraction for astronomers,” Lyons said. “So on this flight, Starlink is testing an experimental darkening treatment on one satellite in order to further reduce the light reflection off the satellites.”
SpaceX is seeking to strike a balance between astronomers’ concerns and the company’s ambitions for the Starlink network. Skywatchers will gauge the effectiveness of the new experimental coating to determine if it reduces the reflectivity of the satellite, and SpaceX wants to ensure the treatment does not impact the performance of the spacecraft.
“We also make satellite tracking data available to astronomers so they can better coordinate their observations with our satellites,” Lyons said. “These measures, along with our work with leading astronomy groups, will enable SpaceX to bring Internet access to underserved and unserved populations around the world without materially impacting the use of the night sky.”
SpaceX says it hopes to begin regional broadband service to Canada and the northern United States with the partially-complete Starlink constellation by the middle of this year, once it has launched 12 Starlink missions. Starlink service for Internet consumers worldwide will come after 24 launches, according to Shotwell.
“Twelve launches gets us connectivity with no gaps down to a latitude of roughly 25 degrees … And then 24 missions gets us global coverage with no data gaps,” Shotwell said last month. “So what’s preventing us from providing service? Getting the right number of satellites up in orbit. We will start offering service (mid-2020) because we have those 12 launches.”
SpaceX has not announced pricing for the Starlink service.
“All I know is you will be far happier with the value of the Starlink service than you are with your current service,” Shotwell said in December. “You will, for sure, get way more bandwidth for the same price, or way more bandwidth for less … You’ll be far happier with this. The value will be far greater (than with current Internet service providers).”
She said SpaceX is building about seven Starlink satellites per day at a factory in Redmond, Washington. Low-volume production of SpaceX’s ground user terminals is also underway in California, Shotwell said.
SpaceX is still working out its strategy for commencing Starlink commercial services.
“Between now and June … we’re going to have to figure that out,” Shotwell said last month. “We will do presales like Tesla has done. The initial experience will be bumpy. We’ll have early customers be part of that journey with us. We’re not going to fib and say it’s going to be the best thing ever. When you get service, it’s going to be great. But it will be bumpy for a while.
The U.S. military has a contract with SpaceX to demonstrate the Starlink network’s ability to deliver data to the cockpit of airplanes, the first of what SpaceX hopes will be a lucrative business selling bandwidth to the Defense Department.
“I think we probably will mature as a provider, and it should not be bumpy, really in ’21. By ’21, I think we probably will have figured out most of the problems.”
SpaceX is gearing up for at least one more Starlink launch from Cape Canaveral using a Falcon 9 rocket later this month.
But first, the company’s Florida team will perform an in-flight test of the abort system the Crew Dragon commercial crew capsule on the ship’s final demonstration launch before NASA clears SpaceX to launch astronauts to the International Space Station.
The Crew Dragon in-flight abort test will take off from pad 39A at NASA’s Kennedy Space Center aboard a modified Falcon 9 rocket. Once it reaches the stratosphere, the crew capsule — flying without astronauts this time — will trigger its launch escape engines to propel itself away from the Falcon 9, verifying the ship’s ability to carry crews away from a failing rocket.
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Follow Stephen Clark on Twitter: @StephenClark1.
Scientists Unearth the Mystery of Mirror World to Solve the Hubble Constant Problem – AZoQuantum
According to a new study, an unseen ‘mirror world’ of particles that interacts with the universe solely through gravity might be the key to solving a crucial cosmological issue—the Hubble constant problem.
The Hubble constant is the current rate of cosmic expansion, but the rate predicted by cosmology’s standard model is far slower than the rate discovered by the most accurate local observations. Many cosmologists have attempted to resolve this difference by altering the present cosmological paradigm.
The objective is to do so without jeopardizing the consistency of standard model predictions with many other cosmological phenomena, such as cosmic microwave background.
The issue that scholars like Francis-Yan Cyr-Racine, assistant professor in the Department of Physics and Astronomy at the University of New Mexico, Fei Ge, and Lloyd Knox at the University of California, Davis, have been seeking to answer is if such a cosmic scenario exists.
Cosmology, according to NASA, is the scientific study of the universe’s large-scale characteristics. Cosmologists investigate topics such as dark matter and dark energy, as well as whether there is only one universe or a multiverse. Cosmology encompasses the entire cosmos, from conception to death, and is full of mysteries and intrigue.
Cyr-Racine, Ge, and Knox have now identified a previously overlooked mathematical characteristic of cosmological models that, in theory, might allow for a quicker expansion rate without affecting the mainstream cosmology model’s most accurately proven other predictions.
Most dimensionless cosmic observables are substantially invariant when gravitational free-fall rates and photon-electron scattering rates are scaled uniformly.
Basically, we point out that a lot of the observations we do in cosmology have an inherent symmetry under rescaling the universe as a whole. This might provide a way to understand why there appears to be a discrepancy between different measurements of the Universe’s expansion rate.
Francis-Yan Cyr-Racine, Assistant Professor, Department of Physics and Astronomy, University of New Mexico
The study was published in Physical Review Letters.
This finding suggests a new way to reconcile measurements of the cosmic microwave background and large-scale structure with high Hubble constant H0 values by discovering a cosmological model in which the scaling transformation can be demonstrated without violating any measurements of values not protected by symmetry.
This effort has paved the way for a novel approach to tackling a difficult challenge. Additional model development might provide uniformity to the two remaining constraints: the inferred primordial deuterium and helium abundances.
Researchers are driven to an incredibly fascinating conclusion if the universe is somehow leveraging this symmetry: there is a mirror universe that is remarkably identical to ours but unseen, except through the gravitational influence on this world.
The “mirror world” dark sector would lead to efficient scaling of gravitational free-fall speeds while maintaining the accurately calculated mean photon density now reported.
“In practice, this scaling symmetry could only be realized by including a mirror world in the model—a parallel universe with new particles that are all copies of known particles. The mirror world idea first arose in the 1990s but has not previously been recognized as a potential solution to the Hubble constant problem”, stated Cyr-Racine.
He further explained, “This might seem crazy at face value, but such mirror worlds have a large physics literature in a completely different context since they can help solve important problem in particle physics. Our work allows us to link, for the first time, this large literature to an important problem in cosmology.”
Researchers are also asking if the Hubble constant gap could be caused in part by measurement mistakes, in addition to looking for missing elements in the present cosmological model.
While this is still a possibility, it is worth noting that the disparity has grown in importance as higher-quality data has been included in the analysis, suggesting that the data is not to be blamed.
According to Cyr-Racine, “It went from two and a half Sigma, to three, and three and a half to four Sigma. By now, we are pretty much at the five-Sigma level. That is the key number which makes this a real problem because you have two measurements of the same thing, which if you have a consistent picture of the universe should just be completely consistent with each other, but they differ by a very statistically significant amount.”
He concluded, “That is the premise here and we have been thinking about what could be causing that and why are these measurements discrepant? So that is a big problem for cosmology. We just don’t seem to understand what the universe is doing today.”
Cyr-Racine, F., et al. (2022) Symmetry of Cosmological Observables, a Mirror World Dark Sector, and the Hubble Constant. Physical Review Letters. doi:10.1103/PhysRevLett.128.201301.
NASA Voyager 1 Space Probe From the '70s Afflicted by Mysterious Glitch – CNET
NASA’s 45-year-old Voyager 1 spacecraft is a marvel. It’s cruising along outside our solar system and still staying in touch with Earth. But it’s presented its team with what NASA is calling a “mystery.” It’s operating normally but sending back some odd telemetry data.
The issue likely traces to Voyager 1’s attitude articulation and control system (AACS), which handles its orientation in space, including the task of keeping its antenna pointed at Earth
“All signs suggest the AACS is still working, but the telemetry data it’s returning is invalid. For instance, the data may appear to be randomly generated, or does not reflect any possible state the AACS could be in,” NASA’s Jet Propulsion Lab said in a statement Wednesday.
The data isn’t making sense, but Voyager 1 is maintaining a clear line of communication with home and the problem hasn’t triggered a protective “safe mode.”
The twin spacecraft Voyager 1 andlaunched in the 1970s and have long outlasted their expected lifespans. They’re both in interstellar space, which Voyager 1 and 2 project manager Suzanne Dodd describes as a “high-radiation environment that no spacecraft have flown in before.”
Voyager 1 is roughly 14.5 billion miles (23.3 billion kilometers) away from home. It takes a couple days to send a signal and then hear back, which adds to the challenge of understanding what’s going on. This leaves NASA with a whole lot of unknowns. Is the AACS the culprit or is another system experiencing a glitch? Will Voyager 1 be able to continue its science mission?
There are ways forward from this glitch. Voyager 1 may just live with it. Or a software fix or a switch to backup hardware could be the solution. NASA hopes both Voyagers will continue to send back science data beyond 2025.
Said Dodd, “A mystery like this is sort of par for the course at this stage of the Voyager mission.”
Boeing docks crew capsule to space station in test do-over – Phys.org
With only a test dummy aboard, Boeing’s astronaut capsule pulled up and parked at the International Space Station for the first time Friday, a huge achievement for the company after years of false starts.
With Starliner’s arrival, NASA finally realizes its longtime effort to have crew capsules from competing U.S. companies flying to the space station.
SpaceX already has a running start. Elon Musk’s company pulled off the same test three years ago and has since launched 18 astronauts to the space station, as well as tourists.
“Today marks a great milestone,” NASA astronaut Bob Hines radioed from the orbiting complex. “Starliner is looking beautiful on the front of the station,” he added.
The only other time Boeing’s Starliner flew in space, it never got anywhere near the station, ending up in the wrong orbit.
This time, the overhauled spacecraft made it to the right spot following Thursday’s launch and docked at the station 25 hours later. The automated rendezvous went off without a major hitch, despite the failure of a handful of thrusters.
If the rest of Starliner’s mission goes well, Boeing could be ready to launch its first crew by the end of this year. The astronauts likely to serve on the first Starliner crew joined Boeing and NASA flight controllers in Houston as the action unfolded nearly 270 miles (435 kilometers) up.
NASA wants redundancy when it comes to the Florida-based astronaut taxi service. Administrator Bill Nelson said Boeing’s long road with Starliner underscores the importance of having two types of crew capsules. U.S. astronauts were stuck riding Russian rockets once the shuttle program ended, until SpaceX’s first crew flight in 2020.
Boeing’s first Starliner test flight in 2019 was plagued by software errors that cut the mission short and could have doomed the spacecraft. Those were corrected, but when the new capsule awaited liftoff last summer, corroded valves halted the countdown. More repairs followed, as Boeing chalked up nearly $600 million in do-over costs.
Before letting Starliner get close to the space station Friday, Boeing ground controllers practiced maneuvering the capsule and tested its robotic vision system. Everything checked out well, Boeing said, except for a cooling loop and four failed thrusters. The capsule held a steady temperature, however, and had plenty of other thrusters for steering.
Once Starliner was within 10 miles (15 kilometers) of the space station, Boeing flight controllers in Houston could see the space station through the capsule’s cameras. “We’re waving. Can you see us?” joked Hines.
There was only silence from Starliner. The commander’s seat was occupied once again by the mannequin dubbed Rosie the Rocketeer, a space-age version of World War II’s Rosie the Riveter.
The gleaming white-with-blue-trim capsule hovered 33 feet (10 meters) from the station for close to two hours—considerably longer than planned—as flight controllers adjusted its docking ring and ensured everything else was in order. When the green light finally came, Starliner closed the gap in four minutes, eliciting cheers in Boeing’s control center. Applause erupted once the latches were tightly secured.
“These last 48 hours have just been a barnstorm, so it’s going to be very good to sleep tonight,” said Mark Nappi, vice president and director of Boeing’s commercial crew program.
It was a double celebration for NASA’s commercial crew program director Steve Stich, who turned 57 Friday. “What an incredible birthday it was,” he told reporters.
The space station‘s seven astronauts will unload groceries and gear from Starliner and pack it up with experiments. Unlike SpaceX’s Dragon capsule that splashes down off the Florida coast, Starliner will aim for a landing in New Mexico next Wednesday.
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