SpaceX set to launch its first “block 5” Falcon 9 rocket

SpaceX is readying an upgraded version of its Falcon 9 rocket for launch Thursday — the first of its kind. The “block 5” version of the booster incorporates numerous design changes to improve performance and safety, while allowing the company to refly first stages 10 times or more. The launch Thursday will boost Bangladesh’s first communications satellite into orbit.

Along with helping SpaceX streamline launch operations, the block 5 booster eventually will be used to launch astronauts to the International Space Station as well as high-priority national security payloads for the Pentagon. The block 5 upgrades are designed to meet the stringent safety requirements for such missions.

Following a first stage engine test firing last week, the revamped booster’s first flight is targeted for liftoff from historic pad 39A at the Kennedy Space Center at 5:47 p.m. EDT (GMT-4) Thursday, after slipping from the original time of 4:12 p.m. The launch window closes at 6:22 p.m. EDT. Forecasters are predicting an 80 percent chance of acceptable weather.

The goal of the flight is to launch the Bangabandhu 1 communications satellite, built by Thales Alenia Space in France to provide Ku-band and C-band television and data services across Bangladesh. Once in orbit and checked out by Thales, the satellite will be operated by the Bangladesh Telecommunication Regulatory Commission.

As has become common for SpaceX, the Falcon 9’s first stage will attempt to fly itself back to a landing on an offshore droneship after boosting Bangabandhu 1 out of the thick lower atmosphere. Going into Thursday’s launch, SpaceX’s landing record stood at 24 successful booster recoveries, 12 on land and 12 on droneships.

The block 5 Falcon 9 features a variety of upgrades to improve reliability and performance and to make it easier for SpaceX to refurbish the first stages for additional flights. SpaceX has re-launched 11 first stage boosters to date, but none have flown more than twice.

“Block 5 is designed for 10 or more flights with very limited refurbishment but should be capable of additional flights with further testing and possible additional refurbishment,” SpaceX President Gwynne Shotwell told Aviation Week and Space Technology magazine.

“It is the final substantial upgrade to the Falcon 9 design, although we may make minor upgrades as we continue to strive for rapid reusability and extremely high reliability.”

One of the most significant changes is the use of stronger high-pressure helium tanks, known as composite overwrapped pressure vessels, or COPVs, that are submerged in the rocket’s liquid oxygen propellant tanks. The helium is used to pressurize the propellant tanks and provide the muscle needed for steering.

A second stage COPV apparently ruptured during a pre-launch test Sept. 1, 2016, triggering a catastrophic explosion that destroyed a Falcon 9 and its satellite payload and heavily damaged the launch complex. The new tanks are designed to eliminate that failure mode and are required for NASA’s commercial crew program.

Other changes include improved heat shield insulation at the base of the rocket, a tougher “octaweb” first stage engine mounting framework, redesigned turbopump machinery to minimize or eliminate small cracks in critical components and improved insulation in other areas of the rocket.

Even the landing legs have been redesigned to allow engineers to retract them after touchdown. The legs had to be removed in previous versions of the rocket before a recovered booster could be hauled away for post-flight processing.

“Block 5 basically summarizes all that we learned on reusability,” Hans Koenigsmann, a senior SpaceX manager, told reporters before a launch last month. “We tried to summarize all of these lessons learned into a booster that then is able to fly and be recovered and fly again multiple times without a lot of refurbishment. That’s basically the key thing on block 5.”