September 28, 2021

Falcon 9 launch timeline with SXM 8


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SpaceX’s Falcon 9 rocket is set for liftoff from Cape Canaveral early Sunday, heading due east over the Atlantic Ocean to deliver the SXM 8 radio broadcasting satellite into orbit around 32 minutes later.

The 229-foot-tall (70-meter) rocket is poised for launch from pad 40 at Cape Canaveral Space Force Station in Florida during a one-hour, 59-minute launch window opening at 12:26 a.m. EDT (0426 GMT) Sunday.

Perched atop the rocket is the SXM 8 radio broadcasting satellite, a spacecraft manufactured by Maxar Technologies in Palo Alto, California, and owned by SiriusXM.

After deployment from the upper stage of the Falcon 9 rocket in an elliptical transfer orbit, the SXM 8 spacecraft will use its on-board thrusters to boost itself into a circular geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) over the equator.

Based on Maxar’s 1300-series satellite bus, SXM 8 will provide radio programming to SiriusXM’s subscribers across North America.

The Falcon 9 first stage booster set to loft the SXM 8 payload has two previous flights to its credit, both of which were Crew Dragon missions carrying astronauts to the International Space Station.

The timeline below outlines the launch sequence for the Falcon 9 flight with SXM 8.

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 Complex 40.
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+0:01:00: Mach 1

The Falcon 9 rocket reaches Mach 1, the speed of sound.
The Falcon 9 rocket reaches Mach 1, the speed of sound, as the nine Merlin 1D engines provide more than 1.7 million pounds of thrust.

T+0:01:12: Max Q

The Falcon 9 rocket reaches Max Q, the point of maximum aerodynamic pressure.
The Falcon 9 rocket reaches Max Q, the point of maximum aerodynamic pressure.

T+0:02:33: MECO

The Falcon 9’s nine Merlin 1D engines shut down.
The Falcon 9’s nine Merlin 1D engines shut down.

T+0:02:36: Stage 1 Separation

The Falcon 9’s first stage separates from the second stage moments after MECO.
The Falcon 9’s first stage separates from the second stage moments after MECO.

T+0:02:44: First Ignition of Second Stage

The second stage Merlin 1D vacuum engine ignites for an approximately 6-minute burn to put the rocket and SES 9 into a preliminary parking orbit.
The second stage Merlin-Vacuum engine ignites for a five-and-a-half-minute burn to put the rocket and Turksat 5A spacecraft into a preliminary parking orbit.

T+0:03:23: 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.
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+0:06:31: Stage 1 Entry Burn Begins

A subset of the first stage’s Merlin 1D engines begin an entry burn to slow down for landing. A final landing burn will occur just before touchdown.

T+0:08:12: SECO 1

The second stage of the Falcon 9 rocket shuts down after reaching a preliminary low-altitude orbit. The upper stage and SES 9 begin a coast phase scheduled to last more than 18 minutes before the second stage Merlin vacuum engine reignites.
The second stage of the Falcon 9 rocket shuts down after reaching a preliminary low-altitude orbit. The upper stage and SXM 8 begin a coast phase scheduled to last 18 minutes before the second stage Merlin vacuum engine reignites.

T+0:08:40: Stage 1 Landing

The Falcon 9 rocket’s first stage booster touches down on SpaceX’s drone ship “Just Read the Instructions” in the Atlantic Ocean.

T+0:26:07: Second Ignition of Second Stage

The Falcon 9's second stage Merlin engine restarts to propel the SES 9 communications satellite into a supersynchronous transfer orbit.
The Falcon 9’s second stage Merlin engine restarts to propel the SXM 8 communications satellite into an elliptical transfer orbit.

T+0:26:51: SECO 2

The Merlin engine shuts down after a short burn to put the SES 10 satellite in the proper orbit for deployment.
The Merlin engine shuts down after a short burn to put the SXM 8 satellite in the proper elliptical orbit with an apogee of about 12,000 miles (20,000 kilometers).

T+0:31:42: SXM 8 Separation

The SES 9 satellite separates from the Falcon 9 rocket in an orbit with a predicted high point of about 39,300 kilometers (24,400 miles), a low point of 290 kilometers (180 miles) and an inclination of 28 degrees. Due to the 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.
The SXM 8 satellite separates from the Falcon 9 rocket into an elliptical transfer orbit, on the way to a perch in geostationary orbit.

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Follow Stephen Clark on Twitter: @StephenClark1.


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