Falcon 9 rocket test-fired for Axiom commercial crew mission

A Falcon 9 rocket fires its engines Wednesday at the Kennedy Space Center. Credit: Spaceflight Now

SpaceX rolled a Falcon 9 rocket and Dragon capsule to their launch pad Tuesday and test-fired the booster’s engines Wednesday at the Kennedy Space Center, setting up for launch Friday of four private space fliers on a 10-day mission to the International Space Station.

The 215-foot-tall (65-meter) rocket emerged from its hangar with the Dragon Endeavour spacecraft Tuesday afternoon. Shortly after nightfall, SpaceX raised the Falcon 9 vertical on its launch mount over the flame trench at pad 39A.

Early Wednesday, the four men who will ride the Dragon capsule into orbit participated in a dress rehearsal for launch day. They rode to the pad in Tesla SUVs, just as they will Friday, and put on their custom-made SpaceX pressure suits before riding an elevator up the launch pad tower and walking across the crew access arm to board the Dragon spacecraft.

The dress rehearsal is a customary step before all SpaceX astronaut launches, giving the crew members and their ground support team an opportunity to practice their procedures before the real countdown.

SpaceX followed the crew practice run with a hold-down test-firing of the Falcon 9’s Merlin 1D main engines at 2 p.m. EDT (1800 GMT) Wednesday.

The all-private crew mission is the first flight to the space station without a management role filled by a government space agency, such as NASA or Russia’s Roscosmos. Axiom Space, a Houston-based company, is overseeing the mission after contracting with SpaceX for the launch and transportation, and cinching agreements with NASA to provide accommodations at the space station.

Axiom plans to launch a series of additional crew missions to the International Space Station, then launch its own private module to link up with the outpost in late 2024. The private firm eventually aims to detach the module to form the centerpiece of a standalone research lab that could be used by NASA and commercial customers.

A SpaceX Falcon 9 rocket and Crew Dragon spacecraft stand on pad 39A in preparation for Axiom’s Ax-1 private crew mission. Credit: Stephen Clark / Spaceflight Now

Commander Mike Lopez-Alegria, a retired NASA astronaut who has spent nearly 258 days in space, will command the Ax-1 mission. Lopez-Alegria is an Axiom employee, and his three crewmates are paying their way to the space station as Axiom customers.

Larry Connor, head of a real estate investment firm and an experienced private pilot, will serve as co-pilot of the Crew Dragon Endeavour spacecraft. The other private astronauts are Mark Pathy, an investor and philanthropist from Canada, and Eytan Stibbe, an entrepreneur, venture capitalist, and a former F-16 fighter pilot in the Israeli Air Force.

The crew trained for the mission in Houston and at SpaceX’s headquarters in Hawthorne, California.

The Ax-1 mission will last about 10 days, with roughly eight days on the space station, where Lopez-Alegria, Connor, Pathy, and Stibbe will perform experiments, participate in educational and public relations outreach activities, and enjoy their time in orbit.

Their arrival at the station will temporarily raise the size of the station crew to 11 people. Landing of the Ax-1 mission is tentatively scheduled for April 18, when the Dragon spacecraft will splash down under parachutes off the coast of Florida.

SpaceX will then launch the next long-duration crew to the space station no earlier than April 23 on the company’s brand new Crew Dragon Freedom spacecraft. That mission, under contract to NASA, will launch ferry three U.S. astronauts and an Italian-born European Space Agency astronaut to the space station for a mission set to last nearly five months.

With Lopez-Alegria, Connor, Pathy, and Stibbe safely out of the Dragon capsule and away from the launch pad, SpaceX’s ground team loaded super-chilled, densified propellants into the Falcon 9 rocket Wednesday afternoon for a test-firing of the booster’s nine Merlin main engines.

Kerosene and liquid oxygen flowed into the Falcon 9 beginning about 35 minutes prior to ignition time. SpaceX engineers in Firing Room 4 of the Launch Control Center at Kennedy observed and managed the operation.

The Merlin engines fired for approximately 7 seconds while hydraulic hold-down clamps kept the Falcon 9 firmly on the ground. The engines throttled up to generate 1.7 million pounds of thrust, briefly sending a plume of exhaust out of the flame trench.

SpaceX’s Crew Dragon Endeavour spacecraft on top of a Falcon 9 rocket on Launch Complex 39A. Credit: SpaceX

With the static fire test complete, SpaceX planned to drain the propellants from the Falcon 9. Engineers will analyze data collected during the test-firing to make sure all systems performed well.

A launch readiness review is scheduled Thursday, where mission managers will give final approval to proceed with the countdown Friday. Liftoff is scheduled for 11:17 a.m. EDT (1517 GMT).

The Falcon 9 and Dragon spacecraft will head northeast from Florida’s Space Coast to line up with the space station’s orbital track. Flying parallel to the U.S. East Coast, the Falcon 9 will shed its first stage about two-and-a-half minutes into the mission, allowing the booster to descend back to a landing on a drone ship in the Atlantic Ocean.

The reusable booster flying on the Ax-1 mission is making its fifth trip to space, following two missions that carried U.S. military GPS navigation satellites, the Inspiration4 private crew mission, and, most recently, a flight to deploy Starlink internet satellites in January.

The rocket’s single-engine upper stage will fire more than six minutes to place the Dragon spacecraft and four crew members in a preliminary orbit. The Dragon will separate from the rocket a few minutes later, open its nose cone to reveal its docking mechanism, then execute a series of Draco thruster burns to fine-tune its path to the space station.

The Dragon capsule will dock with the zenith, or upward-facing, port on the space station’s Harmony module around 6:45 a.m. EDT (1045 GMT) Saturday, assuming the mission takes off Friday, beginning about eight days of activities on the orbiting complex.

There’s an 80% chance of favorable weather for launch of the Ax-1 mission Friday, according to the U.S. Space Force’s 45th Weather Squadron at Cape Canaveral. Axiom and SpaceX have backup launch opportunities Saturday and Sunday.

A cold front is predicted to move through the area Thursday, bringing drier and cooler conditions to Central Florida. “The primary launch weather concern Friday is any lingering mid-level cloudiness,” the forecast team wrote Wednesday morning.

There is a moderate risk of unfavorable upper level wind shear, and adverse weather conditions along the Falcon 9’s ascent corridor northeast over the Atlantic Ocean. SpaceX officials will watch the downrange weather to ensure it is acceptable for landing of the first stage booster, and safe enough for the Dragon capsule to splash down in the event of an in-flight abort.

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Follow Stephen Clark on Twitter: @StephenClark1.