SpaceX fires for rocket response record with next Starlink launch – Spaceflight Now

SpaceX’s Falcon 9 rocket lands on an unmanned spacecraft April 8 after launching the Ax-1 private crew mission. The same booster will be used again for the westbound Starlink 4-16 mission for liftoff on April 29. Credit: SpaceX

With a mission Friday to deploy more Starlink internet satellites, SpaceX will attempt to shave nearly a week off the company’s previous record for the shortest time between two launches of the same Falcon 9 booster.

The Falcon 9 rocket scheduled to blast off Friday from Cape Canaveral will be powered by a first stage that launched just 21 days earlier, with Axiom’s Ax-1 private astronaut mission to the International Space Station. SpaceX is about to break the 27-day rocket turnaround record set last year.

Fifty-three more Starlink Internet satellites are rigged atop the Falcon 9 rocket for liftoff from Pad 40 at the Cape Canaveral Space Force Station. The launch is scheduled for an instant shot at 5:27 pm EDT (21:27 GMT) on Friday. Meteorologists with the US Space Force, which runs the launch range at Cape Canaveral, are predicting an 80% chance of favorable weather for liftoff on Friday afternoon.

The mission, designed as Starlink 4-16, will be the 151st launch of a Falcon 9 rocket since SpaceX debuted its payload vehicle on June 4, 2010, and the 43rd Falcon 9 flight dedicated primarily to putting into orbit Starlink Internet repeater stations. The launch will be SpaceX’s 17th mission of the year and the sixth Falcon 9 launch in April, the most by SpaceX in a single month.

SpaceX has increased its launch cadence this year. Elon Musk, the company’s founder and CEO, said SpaceX aims to complete 60 Falcon 9 and Falcon Heavy flights by 2022, nearly double the 31 missions flown last year. The launch rate is maintained thanks to SpaceX’s reuse of booster rockets and payload fairings. Only one of the 17 Falcon 9 flights so far this year has used an entirely new rocket.

The booster flying on Friday’s mission, tail number B1062, landed on SpaceX’s unmanned spacecraft “A Shortfall of Gravitas” in the Atlantic Ocean after launch with the Ax-1 missions. The drone returned the rocket to port for inspections and minor repairs, then SpaceX integrated the booster stage with a new second stage and took the rocket to the hangar on pad 40.

Inside the hangar, SpaceX technicians docked the rocket with its payload of 53 Starlink satellites, already encapsulated inside the Falcon 9’s front deck. SpaceX planned to roll the fully assembled Falcon 9 onto the pad just north of the hangar on Thursday. , then raise it vertically for final launch preparations.

Like the most recent Starlink missions, Falcon 9 will aim for a near-circular orbit at an average altitude of 310 kilometers (192 miles) for the deployment of 53 compact spacecraft, each weighing just over a quarter ton.

A batch of Starlink satellites are deployed from a Falcon 9 rocket on a mission last year. Credit: SpaceX

The Falcon 9 rocket will head northeast from Cape Canaveral with nine kerosene-fueled Merlin 1D engines that will generate 1.7 million pounds of thrust. Two and a half minutes after liftoff, the booster will separate from the second stage and begin its descent back to the “Just Read the Instructions” drone in the Atlantic Ocean east of the Carolinas.

The booster, on its sixth trip into space, will arc to an altitude of nearly 400,000 feet before descending for a vertical booster landing on the floating platform about eight and a half minutes after launch.

The second stage will fire its single vacuum-optimized engine for two burns to place the Starlink satellites into the correct orbit for separation. The deployment of the Starlink satellites will occur over South Australia approximately 59 minutes after the mission.

Falcon 9 will release the satellites into an orbit inclined 53.2 degrees to the equator, one of five orbital “layers” used in SpaceX’s global internet network.

The Starlink satellites will expand solar arrays and use integrated ion thrusters to reach their operational orbit at an altitude of 540 kilometers (335 miles), where they will enter commercial service and begin transmitting broadband signals to consumers.

Going into Friday’s mission, SpaceX has launched 2,388 Starlink satellites to date, including spacecraft that were decommissioned or suffered failures. More than 2,100 of those satellites are in orbit and operational as of Thursday, according to a list maintained by Jonathan McDowell, an astrophysicist who tracks spaceflight activity.

That makes Starlink’s fleet the largest satellite constellation in the world, by a factor of almost five over the Internet satellite fleet owned by rival OneWeb.

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Follow Stephen Clark on Twitter: @StephenClark1.

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