SpaceX's third Block 5 Falcon 9 booster shows off its well-worn octaweb and Merlin engines after a successful launch debut and recovery. (Pauline Acalin)

SpaceX test-fires Falcon 9 Block 5 booster for upgraded rocket’s fifth launch

After a couple of weeks of mysterious delays, SpaceX is once again back in the saddle for its next orbital mission and has successfully completed Falcon 9’s routine prelaunch wet dress rehearsal and static fire. This rocket will launch Telstar 19V’s (launched in July) sister communications satellite Telstar 18V to a high-energy transfer orbit at 11:28 PM EDT, September 8 (03:28 UTC, September 9).

SpaceX’s static fire testing – conducted once in Texas with just the first stage and once at the launch site with the upper stage attached – is very nearly identical to a real launch, save for the fact that the rocket is not allowed to actually lift off from the pad, and only ignites its main engines for a handful of seconds.

Falcon 9 B1049 seen mid-static fire on September 5th.

Almost entirely unique to SpaceX in the launch industry, Falcon 9 and Falcon Heavy are perhaps the only operational (orbital-class) rockets in the world to still conduct routine test fires of integrated segments, including both boosters, upper stages, and even Dragon spacecraft thrusters (both Crew and Cargo variants). Other launch providers like ULA, Arianespace, and Roscosmos will typically test engines individually, but that testing is often not even routine – spot checks more than anything systematic.

In fact, SpaceX’s system of hardware testing as extraordinarily extensive. Aside from test firing integrated boosters and upper stages, SpaceX doubles down on that testing both at the launch site and in Texas. Prior to integrated testing, essentially all rocket engines (sea-level Merlin 1Ds, vacuum Merlin 1Ds, SuperDraco thrusters, Draco thrusters, and Falcon’s cold gas maneuvering thrusters) are hot-fire (or cold-fire, in the case of the cold gas thrusters) tested in Texas after completing assembly in Hawthorne.


After that, the individual rocket engines and thrusters are shipped back to Hawthorne, integrated into their Dragon, Falcon upper stage, or Falcon booster parent rocket, and then shipped back to Texas once more for integrated test-fires, shipped to their launch site, and test-fired yet again (in the case of Falcon 9 and Heavy, not Dragon). This extraordinarily systematic testing apparatus is without a doubt unique to SpaceX, with the only closest comparison being found in small launch startup Rocket Lab, which is also extensively vertically integrated, including in-house tests of all engines prior to shipment.

Much like modern aircraft (particularly airliners) routinely test all critical systems prior to takeoff, particularly a full-thrust engine check with brakes applied, SpaceX and Rocket Lab are explicitly attempting to replicate in spaceflight the sort of practices that have helped to make air travel perhaps the safest and most reliable method of transportation ever created by humans.

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SpaceX test-fires Falcon 9 Block 5 booster for upgraded rocket’s fifth launch
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