SpaceX’s Falcon 9 rocket is set for liftoff from Cape Canaveral early Thursday, heading due east over the Atlantic Ocean to deliver the Inmarsat 5 F4 communications satellite into orbit 32 minutes later.
The 229-foot-tall (70-meter) rocket is poised for launch from pad 39A at NASA’s Kennedy Space Center in Florida at 7:21 p.m. EDT (2321 GMT) Thursday at the opening of a 49-minute launch window.
Perched atop the rocket is the Inmarsat 5 F4 communications satellite, a spacecraft made by Boeing, ready to join Inmarsat’s Global Xpress network providing broadband connectivity to airline passengers and maritime crews. The rocket will place the satellite into a high-altitude “supersynchronous” transfer orbit.
The timeline below outlines the launch sequence for the Falcon 9 flight with Inmarsat 5 F4. On this mission, SpaceX does not plan to attempt a recovery of the rocket’s first stage booster due to the high performance required to place the heavy Inmarsat 5 F4 spacecraft into a high-altitude orbit.
The Falcon 9 does not carry landing legs or grid fins, which are not required for the expendable mission.
Data source: SpaceX
T-0:00:00: Liftoff
After the rocket’s nine Merlin engines pass an automated health check, hold-down clamps will release the Falcon 9 booster for liftoff from pad 39A.
T+0:01:13: Mach 1
The Falcon 9 rocket reaches Mach 1, the speed of sound, as the nine Merlin 1D engines provide more than 1.5 million pounds of thrust.
T+0:01:17: Max Q
The Falcon 9 rocket reaches Max Q, the point of maximum aerodynamic pressure.
T+0:02:45: MECO
The Falcon 9’s nine Merlin 1D engines shut down.
T+0:02:49: Stage 1 Separation
The Falcon 9’s first stage separates from the second stage moments after MECO.
T+0:02:56: First Ignition of Second Stage
The second stage Merlin 1D vacuum engine ignites for a nearly 6-minute burn to put the rocket and Inmarsat 5 F4 into a preliminary parking orbit.
T+0:03:35: Fairing Jettison
The 5.2-meter (17.1-foot) diameter payload fairing jettisons once the Falcon 9 rocket ascends through the dense lower atmosphere. The 43-foot-tall fairing is made of two clamshell-like halves composed of carbon fiber with an aluminum honeycomb core.
T+0:08:38: SECO 1
The second stage of the Falcon 9 rocket shuts down after reaching a preliminary low-altitude orbit. The upper stage and Inmarsat 5 F4 begin a coast phase scheduled to last more than 18 minutes before the second stage Merlin vacuum engine reignites.
T+0:26:59: Second Ignition of Second Stage
The Falcon 9’s second stage Merlin engine restarts to propel the Inmarsat 5 F4 communications satellite into a supersynchronous transfer orbit.
T+0:27:55: SECO 2
The Merlin engine shuts down after a short burn to put the Inmarsat 5 F4 satellite in the proper orbit for deployment.
T+0:31:48: Inmarsat 5 F4 Separation
The Inmarsat 5 F4 satellite separates from the Falcon 9 rocket in a supersynchronous transfer orbit. Due to a decision to burn the second stage nearly to depletion, there is some slight uncertainty on the orbital parameters based on the exact performance of the launcher.
SpaceX tested astronaut slidewire escape baskets and fire suppression capabilities Friday at launch pad 39A in Florida, demonstrating systems that would be activated in the event of an emergency before liftoff of a crewed mission.
SpaceX has delayed liftoff of its next cargo ship bound for the International Space Station until Friday, setting up a one-shot attempt to launch the commercial supply carrier from Cape Canaveral before a potential slip to late December due to high solar angles in orbit.
A nearly three-month stoppage of on-site work due to concerns about the spread of the coronavirus at NASA’s Marshall Space Fight Center in Alabama is expected to push back the launch of the IXPE X-ray astronomy satellite from May 2021 until some time later next year, a senior space agency official said.
