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Another 60 Starlink satellites are set for launch on Wednesday to transmit Internet signals to future SpaceX consumers, as the company seeks regulatory approval to fly the 4,400 relay stations in the first phase of network deployment to higher altitudes. drops from previously planned.
SpaceX’s Starlink network is a multi-billion dollar program designed to cover the planet with broadband connectivity, serving a wide range of consumers in homes, businesses, schools and hospitals. The network, which could eventually have thousands of satellites, is also designed to provide connectivity to airplanes and ships, and the US Army. USA It is testing the Starlink service to assess its military usefulness.
“With performance that far exceeds that of traditional satellite Internet, and a global network with no limits on land infrastructure limitations, Starlink will offer high-speed broadband Internet to locations where access has been unreliable, expensive or completely unavailable “SpaceX says.
SpaceX has launched 360 Starlink satellites on six Falcon 9 rockets since last May. Another 60 are slated for launch Wednesday at 3:37 p.m. EDT (1937 GMT) from Platform 39A at NASA’s Kennedy Space Center in Florida.
With a pre-flown first stage and a recycled payload fairing, the Falcon 9 rocket will be powered by super-chilled, densified kerosene and liquid oxygen boosters that will start around 35 minutes before takeoff.
There is a 90 percent chance of acceptable weather conditions for the launch on Wednesday, according to a perspective released by the 45th US Army Weather Squadron. USA In Cape Canaveral. SpaceX says it brought forward the launch a day after Thursday to take advantage of the good weather forecast.
The Falcon 9’s engine controller will control the ignition of the rocket’s nine Merlin 1D main engines about three seconds before takeoff. The engines will start at full speed and the holding clamps will open to allow the 229-foot-tall (70-meter) launcher to take off from platform 39A with 1.7 million pounds of thrust.
Heading northeast, the Falcon 9 rocket will exceed the speed of sound in about a minute, then shutdown its first-stage engines for about two and a half minutes on the mission. The 15-story first-stage propeller will separate and attempt a propulsive landing on the SpaceX drone parked several hundred miles northeast of Cape Canaveral in the Atlantic Ocean.
The Falcon 9’s second stage will fire its single Merlin engine to launch the 60-quarter-ton Starlink satellites into orbit. At the beginning of the second stage of burns, the rocket will drop its shell-shaped nasal covering once it has risen above the dense lower layers of the atmosphere.
SpaceX’s two fairing recovery ships will also be at the station in the Atlantic Ocean east of Charleston, South Carolina, to try to trap the two fairing halves in giant nets for possible reuse on a future mission.
The mission’s fairing on Wednesday was previously launched last August with the Israeli communications satellite Amos 17 and recovered at sea. The first leg assigned to Wednesday’s flight is a veteran of three previous launches and landings, including SpaceX’s Crew Dragon capsule pilotless test flight in March 2019.
If everything goes as planned, the second stage of the Falcon 9 will shutdown its engine nearly nine minutes after takeoff, injecting the Starlink satellites into a preliminary elliptical orbit that extends more than 200 miles (300 km) above Earth.
The Starlink 60 spacecraft will deploy from the upper Falcon 9 stage all at once over the North Atlantic Ocean about 14 minutes into the mission.
Each of the quarter-ton Starlink satellites is expected to deploy a solar array wing and activate a krypton ion thruster to begin climbing to a 341-mile (550-kilometer) altitude operational orbit, where they will join hundreds of other Starlink nodes launched since last May.
SpaceX has modified the architecture of the Starlink network several times. More recently, SpaceX on Friday filed a request with the Federal Communications Commission proposing to operate more satellites in lower orbits than previously authorized by the FCC.
The first phase of the Starlink network will include 1,584 satellites that orbit 341 miles (550 kilometers) above Earth in planes inclined 53 degrees to the equator. That part of the constellation, which SpaceX intends to launch until the end of the year, remains unchanged in the SpaceX app.
SpaceX previously had the FCC regulatory approval to operate another 2,825 satellites in higher orbits between 690 miles (1,110 kilometers) and 823 miles (1,325 kilometers) of altitude, in orbital planes inclined 53.8, 70, 74 and 81 degrees to the equator.
The modified plan submitted to the FCC by SpaceX provides for Ku-band and Ka-band satellites in the next phase of the Starlink network, all operated at altitudes between 335 miles (540 kilometers) and 354 miles (570 kilometers) with inclinations of 53.2, 70 and 97.6 degrees.
The application covers 4,408 Starlink satellites, one less than SpaceX provided in the previous architecture.
In documentation submitted Friday to the FCC, SpaceX said a lower altitude will bring satellites closer to Starlink consumers and allow the network to “deliver low-latency broadband to underserved and underserved Americans who are on par with the service that was previously only available in urban areas. “
The change will also improve the Starlink service for users of the US government. USA In the polar regions and will allow for faster network deployment, SpaceX said.
Starlink flying satellites in lower orbits will help ensure they re-enter the atmosphere in a shorter time in the event of a failure. And the spacecraft will transmit signals at reduced power levels because they are closer to Earth, which SpaceX said will allow the Starlink fleet to comply with limits to reduce radio interference with other ground and satellite wireless networks.
Last week’s request to modify the SpaceX FCC license is the latest in a series of tweaks to the Starlink architecture. Before the first launch of 60 Starlink satellites last year, SpaceX received FCC approval to migrate the positions of the fleet’s first 1,584 satellites from 714 miles (1,150 kilometers) to 341 miles (550 kilometers).
In December, the FCC granted a request from SpaceX to reconfigure the distribution of Starlink satellites on different orbital planes. SpaceX said the request was intended to expand Starlink coverage faster in the United States without the need for more satellites.
SpaceX wrote in the FCC filing on Friday that the Starlink network is still on track to start serving American consumers this year.
At lower altitudes, Starlink satellites will fly in a region with more space traffic. SpaceX says its Starlink spacecraft can maneuver to avoid collisions with other objects in orbit, and it releases orbital data on Starlink satellites so that other operators can also perform evasive maneuvers.
Astronomers have also expressed concern about the brightness of Starlink satellites, which could interfere with images from the Earth’s telescope, particularly around sunrise and sunset.
Starlink satellites reflect more sunlight than SpaceX or astronomers anticipated before Starlink’s first dedicated launch last year. The American Astronomical Society and other groups are working with SpaceX to try to limit the impacts of satellites on astronomy.
“SpaceX is committed to promoting all forms of space exploration, which is why it has already taken a number of proactive steps to ensure it does not materially affect optical astronomy,” the company wrote in Friday’s request to the FCC, which does not count. with authority regulations on the brightness of satellites. “SpaceX is working with American and international astronomy organizations and observatories to scientifically measure the real impact of their satellites.”
Flying more Starlink satellites at lower altitudes could make relay nodes appear brighter from the ground, but there will be fewer Starlink satellites visible in the sky at the same time. The spacecraft at lower altitudes will also spend less time illuminated by sunlight.
One of the 60 Starlink satellites launched on January 6 had a new darker coating meant to reduce the reflectivity of the spacecraft. SpaceX said last month that preliminary data indicated a “noticeable reduction” in the brightness of that satellite, which has been dubbed “DarkSat.”
Beyond this (blackout) treatment, SpaceX is developing new mitigation efforts that it plans to test in the coming months, “SpaceX wrote in Friday’s FCC filing.” In addition, SpaceX will make available satellite tracking data for astronomers can better coordinate their observations with our satellites. “
One change SpaceX is studying is the addition of an umbrella, or visor, to deploy like an umbrella on Starlink satellites to reduce the amount of sunlight shining on the spacecraft.
Beyond the 4,400 Ku-band and Ka-band satellites covered in Friday’s application for a modified FCC license, SpaceX plans to launch an additional 7,500 V-band data relay stations in orbits around 214 miles (345.6 kilometers) above sea level. . The FCC has already approved SpaceX to operate the V-band network.
SpaceX’s next Starlink launch after Wednesday could happen as early as mid-May on another Falcon 9 rocket mission from Cape Canaveral.
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Follow Stephen Clark on Twitter: @ StephenClark1.
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