SpaceX tested a Falcon 9 rocket at NASA’s Kennedy Space Center on Saturday in preparation for liftoff on Sunday with the company’s next batch of 53 Starlink internet satellites.
Launch pad test fires were once a regular part of every SpaceX launch campaign, but the company is phasing out static test fires for most missions as the Falcon 9’s launch rate has increased to an average of one flight per week.
Just hours after launching a Falcon 9 rocket with 46 Starlink broadband satellites from Vandenberg Space Force Base in California, SpaceX launched another Falcon 9 from pad 39A at Kennedy Space Center on Friday to prepare for launch on Sunday. with 53 other internet relay nodes.
But first, the SpaceX launch team readied the rocket for a static firing test on Saturday morning.
Kerosene and liquid oxygen flowed into the Falcon 9 approximately 35 minutes before ignition time. SpaceX engineers in Firing Room 4 at Kennedy’s Launch Control Center observed and managed the operation.
The Merlin engines ran for about 7 seconds at 9 a.m. EDT (1300 GMT) Saturday as hydraulic hold-down clamps held the Falcon 9 firmly to the ground. The engines revved up to generate 1.7 million pounds of thrust, briefly sending an exhaust plume out of the flame trench.
SpaceX drained the rocket’s boosters after the test firing, and the company confirmed the mission was on track for liftoff Sunday at 9:38 a.m. EDT (1338 GMT). The mission will mark SpaceX’s 33rd launch of the year and the 53rd launch dedicated to the Starlink network.
Friday’s launch from California was Falcon 9’s 32nd launch of 2022, breaking the company’s record of 31 launches in one year set in 2021.
Including Saturday’s static firing, SpaceX has conducted a test firing on the launch pad ahead of six of 33 Falcon 9 missions so far this year. SpaceX conducted pre-launch test firings before each Falcon 9 launch through 2020, then gradually decreased the use of static firings.
SpaceX used to require a static firing whenever an engine was removed between flights from one of its Falcon 9 reusable boosters. This requirement changed to performing a pre-launch firing test only when three engines or more are removed between missions, according to a report published last month by Aviation Week & Space Technology.
Static firings were originally part of every SpaceX launch campaign to ensure engineers spotted any issues with the rocket before launch day. But SpaceX has improved its performance by launching in time as test firings have become less common.
A last-minute abort before a scheduled launch in California earlier this week was the first time a Falcon 9 launch had been erased from the terminal countdown by a technical issue since December 2020. SpaceX has recorded 62 consecutive launches of December 2020 to this month without an aborted countdown caused by a rocket issue.
And SpaceX has completed 141 consecutive successful missions since an explosion during a static firing test in 2016 destroyed a Falcon 9 rocket and Israel’s Amos 6 communications satellite.
SpaceX continues to test the brand new Falcon 9 rockets on a test bed at the company’s facilities in central Texas after the boosters left their factory in Hawthorne, California.
The launch of the Starlink 4-25 mission on Sunday will put SpaceX’s next 53 Starlink internet satellites into low Earth orbit. The Falcon 9 will depart from pad 39A and head northeast over the Atlantic Ocean, flying on a path parallel to the east coast of the United States.
The rocket’s first-stage booster will shut down approximately two and a half minutes into the mission. After separating from the upper stage at the edge of space, Falcon 9’s first stage will head for SpaceX’s drone ship “A Shortfall of Gravitas” stationed approximately 400 miles (650 kilometers) downriver. Atlantic Ocean, using cold gas thrusters and a titanium grid fins to help control its flight path.
Engine burns will slow the rocket down to land on the drone. The flying booster on Starlink mission 4-25, known as B1062, will launch on its eighth trip to space. It debuted with the launch of a US military GPS navigation satellite in November 2020 and launched the fully private Inspiration4 and Axiom-1 crew missions in September 2021 and April this year.
Most recently, the booster flew on June 8 with Egypt’s Nilesat 301 geostationary communications satellite.
As the first stage descends for landing on Sunday, Falcon 9’s upper stage will burn for about six minutes to place 53 flat-packed Starlink satellites into a transfer orbit of between 144 and 210 miles (232 kilometers by 338 kilometers) , at an inclination of 53.2 degrees from the equator.
Falcon 9’s reusable payload fairing will jettison when the second stage burns. A recovery vessel is also stationed in the Atlantic to recover the two halves of the nose cone after they splash down under the parachutes.
The satellites – each weighing more than a quarter ton – will separate from the rocket’s upper stage at T+ plus 15 minutes and 24 seconds. Four retention rods will be dropped to allow satellites to fly freely from Falcon 9 into orbit. The rods hold the spacecraft to the rocket during ascent through space.
The Starlink satellites will deploy their solar arrays and use ion propulsion to reach their operational altitude of 335 miles (540 kilometers). Orbit climb maneuvers typically take a few weeks to a few months, depending on the targeted orbital plan for each spacecraft.
SpaceX launched 2,904 Starlink satellites for Sunday’s mission, including prototypes and earlier spacecraft designs that are no longer in service. The company says its Starlink broadband service is currently available in 36 countries around the world.
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