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 on Twitter.

SpaceX’s third Starlink satellite deployment mission in five days is set for launch at 6:20 a.m. EDT (1020 GMT) Wednesday from NASA’s Kennedy Space Center in Florida. A Falcon 9 rocket will carry 53 more Starlink internet satellites into orbit.

The commercial space company wheeled the Falcon 9 rocket to pad 39A on Tuesday, then raised the rocket vertical in preparation for liftoff just before sunrise Wednesday.

SpaceX aims to recover the first stage booster, making its fifth trip to space, on the deck of the drone ship “A Shortfall of Gravitas” a few hundred miles northeast of Cape Canaveral.

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

Helium pressurant will also flow into the rocket in the last half-hour of the countdown. In the final seven minutes before liftoff, the Falcon 9’s Merlin main engines will be thermally conditioned for flight through a procedure known as “chilldown.” The Falcon 9’s guidance and range safety systems will also be configured for launch at 6:20:10 a.m.

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

The rocket will exceed the speed of sound in about one minute, then shut down its nine main engines two-and-a-half minutes after liftoff. The booster will release from from the Falcon 9’s upper stage, then fire pulses from cold gas control thrusters and extend titanium grid fins to help steer the vehicle back into the atmosphere.

Two braking burns slowed the rocket for landing on the drone ship around 400 miles (650 kilometers) downrange approximately eight-and-a-half minutes after liftoff.

SpaceX’s Falcon 9 rocket stands on pad 39A Tuesday night. Credit: Spaceflight Now

The booster — tail number B1052 — is set for launch 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-stick Falcon 9 rocket. It’s flown twice — on Jan. 31 and March 9 — as a Falcon 9 first stage.

The landing of the first stage on the drone ship will occur just prior to shutdown of the upper stage engine. The rocket’s upper stage will coast halfway around the world before reigniting its Merlin-Vacuum upper stage engine about 45 minutes into the mission, paving the way for separation of the 53 Starlink satellites at T+plus 59 minutes, 17 seconds.

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

The Falcon 9’s guidance computer aims to deploy the satellites in a near-circular orbit ranging in altitude between 189 miles and 197 miles (305 by 318 kilometers), at an orbital inclination of 53.2 degrees to the equator. The satellites will use on-board propulsion to do the rest of the work to reach a circular orbit 335 miles (540 kilometers) above Earth.

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

Credit: Spaceflight Now

After Wednesday’s mission, designated Starlink 4-18, SpaceX will have 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 functioning as of this week, according to a list maintained by Jonathan McDowell, an astrophysicist who closely tracks spaceflight activity.

ROCKET: Falcon 9 (B1052.5)

PAYLOAD: 53 Starlink satelllites (Starlink 4-18)

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

LAUNCH DATE: May 18, 2022

LAUNCH TIME: 6:20:10 a.m. EDT (1020:10 GMT)

WEATHER FORECAST: 80% chance of acceptable weather; Low risk of upper level winds; Low risk of unfavorable conditions for booster recovery

BOOSTER RECOVERY: “A Shortfall of Gravitas” drone ship east of Charleston, South Carolina

LAUNCH AZIMUTH: Northeast

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

LAUNCH TIMELINE:

T+00:00: Liftoff T+01:02: Maximum aerodynamic pressure (Max-Q) T+02:30: First stage main engine cutoff (MECO) T+02:33: Stage separation T+02:40: Second stage engine ignition T+02:47: Fairing jettison T+06:15: First stage entry burn ignition (three engines) T+06:34: First stage entry burn cutoff T+08:01: First stage landing burn ignition (one engine) T+08:23: First stage landing T+08:45: Second stage engine cutoff (SECO 1) T+45:23: Second stage restart T+45:25: Second stage engine cutoff (SECO 2) T+59:17: Starlink satellite separation

MISSION STATS:

155th launch of a Falcon 9 rocket since 2010 163rd launch of Falcon rocket family since 2006 5th launch of Falcon 9 booster B1052 135th Falcon 9 launch from Florida’s Space Coast 49th SpaceX launch from pad 39A 143rd launch overall from pad 39A 97th flight of a reused Falcon 9 booster 47th dedicated Falcon 9 launch with Starlink satellites 21st Falcon 9 launch of 2022 21st launch by SpaceX in 2022 20th orbital launch based out of Cape Canaveral in 2022

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