Follow the key events of the Falcon 9 rocket’s ascent to orbit with the second set of 10 next-generation satellites for Iridium’s voice and data relay fleet.
The 229-foot-tall (70-meter) rocket will lift off Saturday at 1:25:14 p.m. PDT (4:25:14 p.m. EDT; 2025:14 GMT) from Vandenberg Air Force Base in California.
Data source: SpaceX
T-0:00:00: Liftoff
After the rocket’s nine Merlin 1D engines pass an automated health check, the Falcon 9 is released from Space Launch Complex 4-East at Vandenberg Air Force Base, California.
T+0:01:09: Max-Q
The Falcon 9 rocket reaches Max Q, the point of maximum aerodynamic pressure. The first stage’s nine Merlin 1D engines produce about 1.7 million pounds of thrust.
T+0:02:24: MECO
The Falcon 9’s nine Merlin 1D engines shut down.
T+0:02:28: Stage 1 Separation
The Falcon 9’s first stage separates from the second stage moments after MECO.
T+0:02:35: Stage 2 Ignition
The second stage Merlin 1D vacuum engine ignites for an approximately 6-and-a-half-minute burn to inject the Iridium Next satellites into a parking orbit.
T+0:03:16: 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+0:05:48: Stage 1 Entry Burn
A subset of the first stage’s Merlin 1D engines ignite for an entry burn to slow down for landing. A final landing burn will occur just before touchdown.
T+0:07:45: Stage 1 Landing
The Falcon 9 rocket’s first stage booster touches down on SpaceX’s drone ship in the Pacific Ocean.
T+0:09:04: SECO 1
The Merlin 1D vacuum engine turns off after placing the Iridium satellites in a temporary parking orbit, beginning at 43-minute coast in space.
T+0:52:06: Stage 2 Restart
The Falcon 9’s second stage engine ignites again for a 3-second burn to circularize its orbit.
T+0:52:09: SECO 2
The Merlin 1D vacuum engine shuts down after reaching a target orbit about 388 miles (625 kilometers) high with an inclination of 86 degrees.
T+0:57:10: Begin Iridium Deployments
The 1,896-pound (860-kilogram) Iridium Next satellites begin deploying from their two-tier dispenser on the Falcon 9 rocket’s second stage, separating at intervals of approximately every 90 seconds.
T+1:12:00: End Iridium Deployments
The last of the 10 Iridium Next satellites will separate from the rocket.
Photos captured by remote cameras placed at launch pad 39A show SpaceX’s Falcon Heavy rocket soaring skyward Thursday evening atop more than 5 million pounds of thrust.
The Crew Dragon mission was delayed a day due to cumulus clouds, but had enough clearance to allow for a launch on August 1. The Falcon 9 rocket lifted off from Launch Complex 39A at 11:43 a.m. EDT (1543 UTC).
Mitsubishi Heavy Industries, the prime contractor for Japan’s H-2B rocket, said Friday that engineers concluded a fire on the launch pad during a countdown earlier this month was most likely sparked by static electricity and stimulated by oxygen. The H-2B rocket launch has been rescheduled for Tuesday to start a resupply mission to the International Space Station.
