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SpaceX rocket, Starlink satellite launch from platform 39A – Spaceflight Now

Live coverage of the countdown and launch of a SpaceX Falcon 9 rocket from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. The Starlink 4-18 mission launched SpaceX’s next batch of 53 Starlink broadband satellites. Follow us Twitter.

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SpaceX’s third Starlink satellite deployment mission in five days launched at 6:59 a.m. EDT (1059 GMT) Wednesday from NASA’s Kennedy Space Center in Florida. A Falcon 9 rocket launched 53 more Starlink internet satellites into orbit.

The commercial space company brought the Falcon 9 rocket to Pad 39A on Tuesday, then raised the rocket upright in preparation for liftoff just after sunrise Wednesday.

SpaceX recovered the first-stage booster, making its fifth trip to space, on the deck of the unmanned spacecraft “A Shortfall of Gravitas” a few hundred miles northeast of Cape Canaveral.

Stationed inside a firing room at Kennedy’s launch control center, the SpaceX launch team began loading supercooled densified kerosene and liquid oxygen propellants into the 229-foot-tall (70-meter) Falcon 9 vehicle at T-minus 35 minutes.

Pressurized helium also flowed into the rocket in the last half hour of the countdown. In the last seven minutes before liftoff, the Falcon 9’s Merlin main engines were thermally conditioned for flight through a procedure known as “relaxation.” The Falcon 9’s range and guidance safety systems were also set for the 6:59:40 a.m. launch.

After liftoff, the 229-foot-tall (70-meter) Falcon 9 rocket vectored its 1.7 million pounds of thrust, produced by nine Merlin engines, to head northeast over the Atlantic Ocean.

The rocket exceeded the speed of sound in about a minute and then shut down its nine main engines two and a half minutes after liftoff. The booster was released from the Falcon 9 upper stage, then fired pulses from the cold gas control thrusters and extended titanium grid fins to help steer the vehicle back into the atmosphere.

Two braking bursts slowed the rocket to land on the drone around 400 miles (650 kilometers) about eight and a half minutes after liftoff.

SpaceX’s Falcon 9 rocket sits on pad 39A Tuesday night. Credit: Space Flight Now

The booster, tail number B1052, launched on its fifth mission. It debuted as a side booster on two flights of SpaceX’s triple-core Falcon Heavy rocket in April and June 2019, then engineers converted it to fly as a booster stage on the single-spar Falcon 9 rocket. Heading into Wednesday’s mission, the booster had flown twice, on January 31 and March 9, as a Falcon 9 first stage.

The landing of the first stage on the drone occurred just before the upper stage engine shut down. The rocket’s upper stage circled halfway around the world before re-igniting its Merlin-Vacuum upper stage engine approximately 45 minutes into the mission, paving the way for the separation of all 53 Starlink satellites at T+plus 59 minutes, 17 seconds.

Retainer rods released from Starlink’s payload stack, allowing flat satellites to fly free from the Falcon 9 upper stage in orbit. The 53 spacecraft will deploy solar arrays and execute automated activation steps, then use krypton-fueled ion engines to maneuver into their operational orbit.

The Falcon 9’s guidance computer was intended to deploy the satellites in a nearly circular orbit with an altitude of between 189 miles and 197 miles (305 by 318 kilometers), with an orbital inclination of 53.2 degrees relative to the equator. The satellites will use onboard propulsion to do the rest of the work and reach a circular orbit 540 kilometers (335 miles) above Earth.

The Starlink satellites in Saturday’s mission will fly in one of five orbital “layers” used in SpaceX’s global Internet network. After reaching their operational orbit, the satellites will enter commercial service and begin transmitting broadband signals to consumers, who can purchase Starlink service and connect to the network with a SpaceX-provided ground terminal.

Credit: Space Flight Now

Following Wednesday’s mission, designated Starlink 4-18, SpaceX has launched 2,653 Starlink satellites to date, including spacecraft that were decommissioned or suffered failures. More than 2,300 of those satellites are in orbit and operational as of this week, according to a list maintained by Jonathan McDowell, an astrophysicist who closely follows spaceflight activity.

ROCKET: Falcon 9 (B1052.5)

USEFUL LOAD: 53 Starlink satellites (Starlink 4-18)

LAUNCH SITE: LC-39A, Kennedy Space Center, Florida

RELEASE DATE: May 18, 2022

LUNCH TIME: 6:59:40 a.m. EDT (10:59:40 GMT)

WEATHER FORECAST: 80% chance of fair weather; Low risk of high winds; Low risk of unfavorable conditions for reinforcement recovery

BOOSTER RECOVERY: Unmanned boat “A Shortfall of Gravitas” east of Charleston, South Carolina

LAUNCH AZIMUTH: northeast

TARGET ORBIT: 189 miles by 197 miles (304 kilometers by 318 kilometers), 53.2 degrees of incline

LAUNCH SCHEDULE:

  • T+00:00: Takeoff
  • T+01:02: Maximum aerodynamic pressure (Max-Q)
  • T+02:30: First stage main engine cut-off (MECO)
  • T+02:33: Separation of stages
  • T+02:40: Second stage engine ignition
  • T+02:47: Fairing Removal
  • T+06:15: First stage inlet burn ignition (three engines)
  • T+06:34: First stage entrance burn cut
  • T+08:01: First stage landing burn ignition (single engine)
  • T+08:23: Landing first stage
  • T+08:45: Second stage motor cut-off (DRY 1)
  • T+45:23: Restart of the second stage
  • T+45:25: Second stage engine cutoff (DRY 2)
  • T+59:17: Separation of Starlink satellites

MISSION STATISTICS:

  • 155th launch of a Falcon 9 rocket since 2010
  • 163rd launch of the Falcon rocket family since 2006
  • Fifth Falcon 9 B1052 booster launch
  • 135th launch of the Falcon 9 from the Florida Space Coast
  • SpaceX’s 49th launch from Pad 39A
  • 143rd overall launch from Pad 39A
  • Flight 97 of a repurposed Falcon 9 booster
  • Launch number 47 of the Falcon 9 with Starlink satellites
  • 21st Falcon 9 launch of 2022
  • 21st SpaceX launch in 2022
  • 20th orbital launch based at Cape Canaveral in 2022

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Follow Stephen Clark on Twitter: @StephenClark1.

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