December 16, 2019

Successful launch continues deployment of SpaceX’s Starlink network


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SpaceX’s Falcon 9 rocket took off from Cape Canaveral at 9:56 a.m. EST (1456 GMT) Monday. Credit: Steven Young/Spaceflight Now

Sixty upgraded satellites for SpaceX’s Starlink broadband network rocketed into orbit Monday from Florida’s Space Coast, debuting performance enhancements and notching new firsts in SpaceX’s list of rocket reuse accomplishments.

SpaceX’s second batch of Starlink satellites joined 60 previous broadband-beaming spacecraft in orbit after deployment from a Falcon 9 rocket Monday, adding to a network that may eventually include thousands of satellites broadcasting high-speed Internet signals from space.

The 229-foot-tall (70-meter) Falcon 9 climbed away from Cape Canaveral’s Complex 40 launch pad at 9:56 a.m. EST (1456 GMT), turned toward the northeast and soared through scattered clouds on a gorgeous Veterans Day morning.

Nine kerosene-fueled Merlin 1D engines powered the Falcon 9 with 1.7 million pounds of thrust, sending the rocket into the sky with a thundering sendoff. It was the first launch to take off from a Cape Canaveral launch pad since Aug. 22, and SpaceX’s first satellite launch since Aug. 6.

The Falcon 9’s first stage shut down and detached from the rocket’s second stage around two-and-a-half minutes into the flight. Moments later, the Falcon 9’s second stage lit its single Merlin powerplant to propel itself into orbit with the Starlink payloads, then the rocket’s nose cone opened and fell away, revealing the Starlink satellites after transiting through the thick, lower layers of the atmosphere.

The first stage booster returned to a propulsive landing on SpaceX’s drone ship “Of Course I Still Love You” holding position around 400 miles (650 kilometers) downrange from Cape Canaveral in the Atlantic Ocean, roughly due east of Charleston, South Carolina. The rocket completed its fourth mission, following three previous launches and landings — two last year, and one in February that helped loft into space an Indonesian communications satellite and the Israeli Beresheet moon lander.

Monday’s launch was the first time SpaceX flew a Falcon 9 booster on a fourth mission. It also marked another first for SpaceX, which demonstrated its capability to reuse a payload fairing recovered from a previous launch.

The bulbous payload shroud protects satellites during the first few minutes of flight, then drops away from the rocket in two halves. The fairing halves flown Monday originally launched on a Falcon Heavy mission April 11, then parachuted into the Atlantic Ocean, where SpaceX teams pulled them from the sea for inspections, refurbishment and reuse.

SpaceX planned to attempt to catch both fairing halves with two specially-outfitted boats Monday. But managers ordered the ships to port due to concerns about rough seas.

SpaceX now has two fairing recovery ships in its fleet, both equipped with giant nets to catch composite fairing halves as they gently fall to the sea under parachutes. The fairings also carry cold gas thrusters to control their descent.

On previous missions, SpaceX has tried to catch one fairing half using a single boat. The company successfully caught one piece of the fairing for the first time after a July 25 launch of a Falcon Heavy rocket.

Pursuing the prime objective of Monday’s mission, the Falcon 9’s second stage engine switched off about nine minutes after launch, and the rocket coasted over Europe and the Middle East before reigniting its engine at around 10:41 a.m. EST (1541 GMT) to circularize its orbit. The Falcon 9 aimed for an altitude of around 174 miles (280 kilometers) for deployment of the Starlink satellites, and a member of SpaceX’s launch team confirmed the rocket achieved an on-target orbit.

The Falcon 9 sent commands at 10:56 a.m. EST (1546 GMT) to release retention pins holding the Starlink satellites to the launcher, and live video from a camera on-board the rocket showed the 60 flat-panel spacecraft receding in the blackness of space.

Sixty Starlink satellites separated from the Falcon 9 rocket about one hour after launch Monday. The spacecraft deployed in one piece, then will disperse over the coming hours and days. Credit: SpaceX

The satellites, but at a SpaceX facility in Redmond, Washington, are designed to gradually disperse over the coming hours and days. Ion thrusters fed by krypton fuel will maneuver the satellites into operational 341-mile-high (550-kilometer) orbits inclined 53 degrees to the equator.

SpaceX says 1,440 of the satellites are needed to provide Internet service over the “populated world,” a service level the company says could be achieved after 24 launches.

The Starlink network could offer service for northern parts of the United States and Canada after six launches, according to SpaceX.

SpaceX could launch thousands more Starlink satellites if merited by market demand. The Federal Communications Commission has authorized SpaceX to operate nearly 12,000 Starlink satellites broadcasting in Ku-band, Ka-band and V-band frequencies, with groups of spacecraft positioned at different altitudes and in various planes in low Earth orbit.

Documents filed with the International Telecommunication Union last month suggested SpaceX could add another 30,000 Starlink satellites to the network, growing its total size to 42,000 spacecraft.

The Starlink network is rapidly becoming a core business area for SpaceX, which is competing with companies like OneWeb and Amazon’s Project Kuiper to deploy fleets of thousands of small satellites in low Earth orbit to beam broadband Internet signals from space to users around the world.

Developers of the so-called “mega-constellations” in low Earth orbit say their networks offer key advantages over traditional satellite Internet architectures, which relay on satellites in higher orbits, where radio transmissions — even traveling at the speed of light — take longer to reach.

Artist’s illustration of the distribution of satellites in SpaceX’s Starlink network. Credit: SpaceX

SpaceX has launched more satellites than either of its chief competitors — Amazon has not yet launched any — and the spacecraft that lifted off Monday will introduce new capabilities to the Starlink network.

“Since the most recent launch of Starlink satellites in May, SpaceX has increased spectrum capacity for the end user through upgrades in design that maximize the use of both Ka- and Ku-bands,” SpaceX wrote in a press kit for Monday’s launch. “Additionally, components of each satellite are 100% demisable and will quickly burn up in Earth’s atmosphere at the end of their life cycle — a measure that exceeds all current safety standards.”

SpaceX said the new Starlink spacecraft design can provide a 400 percent increase in data throughout per satellite, and each satellite carries double the number of steerable phased array broadband beams than on earlier Starlink platforms.

The first 60 Starlink satellites, which launched May 23, carried only Ku-band antennas. At the time, SpaceX said 95 percent of the materials in each of the first 60 satellites would burn up in the atmosphere after their missions were complete.

Gwynne Shotwell, SpaceX’s president and chief operating officer, said last month that the company plans to begin launching Starlink spacecraft equipped with inter-satellite laser crosslinks some time mid-to-late next year.

Three of the 60 satellites launched in May have stopped communicating with ground controllers, but SpaceX officials say they are pleased with the overall performance of the initial block of Starlink spacecraft.

The U.S. Air Force is testing Internet connections between aircraft and SpaceX’s Starlink satellites to evaluate the network’s suitability for future military use, and Elon Musk, SpaceX’s founder and CEO, said he sent a tweet last month through a Starlink satellite.

“We still have ways to go from tweets to 4K cat videos, but we are on our way,” joked Lauren Lyons, a SpaceX engineer who hosted the company’s webcast of Monday’s launch.

Skywatchers with clear skies at twilight could see the Starlink satellites passing overhead in a train-like formation after Monday’s launch, similar to observations of the first 60 satellites following their launch in May.

The satellites reflected more sunlight than expected, creating a shimmering spectacle and sometimes flaring to be as bright as the brightest stars in the sky. The satellites appeared to dim over time, and observations became less frequent as they spread out in their orbital plane.

The bright satellites drew the ire of many astronomers, who worried the addition of thousands of similarly-bright satellites could interfere with scientific observations using ground-based telescopes.

The Royal Astronomical Society said in June that the large number of broadband satellites proposed by SpaceX, Amazon, OneWeb and Telesat “presents a challenge to ground-based astronomy.”

“The deployed networks could make it much harder to obtain images of the sky without the streaks associated with satellites, and thus compromise astronomical research,” the society said in a statement.

The National Radio Astronomy Observatory, funded by the National Science Foundation, said in May it was working with SpaceX to “jointly analyze and minimize any potential impacts” on astronomical observations caused by radio transmissions coming from the Starlink satellites.

“These discussions have been fruitful and are providing valuable guidelines that could be considered by other such systems as well,” the NRAO said in a statement. “To date, SpaceX has demonstrated their respect for our concerns and their support for astronomy.”

The NRAO said it continued to monitor, analyze and discuss the “evolving parameters” of the Starlink system. The NRAO identified several proposals under consideration, including exclusion zones and other mitigations around the National Science Foundation’s current and future radio astronomy facilities.

SpaceX says it is actively working with leading astronomy groups from around the world to make sure their work is not affected by the Starlink satellites. Engineers are taking steps to make the base of future Starlink satellites black to “help mitigate impacts on the astronomy community,” SpaceX said.

But SpaceX says satellites launched Monday do not incorporate the change.

SpaceX says it will adjust Starlink orbits should it be necessary for extremely sensitive space science observations, and the company has touted the ability of its next-generation Starship vehicle to send giant astronomical telescopes into space.

“We have also proactively reached out to leading astronomy groups from around the world to discuss the Starlink mission profile, scientifically assess the impacts on astronomy activities and evaluate any helpful mitigations moving forward,” a SpaceX official said.

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Follow Stephen Clark on Twitter: @StephenClark1.


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