Block 5 Falcon 9 roars spaceward with Bangabandhu-1 satellite
CAPE CANAVERAL, Fla. — In the sunny afternoon skies of Florida, SpaceX launched what it calls the final major upgrade of its Falcon 9—the Block 5. The rocket’s mission was to send the Bangabandhu-1 geostationary communications satellite into orbit for the country of Bangladesh.
Liftoff took place at 4:14 p.m. EDT (20:12 GMT)—the opening of a 127-minute launch window—May 11, 2018, at at Kennedy space Center’s Launch Complex 39A. This was the second attempt to get the booster off the ground as the previous day’s attempt resulted in a scrub after an automated abort within a minute of liftoff. SpaceX later said that the onboard computer triggered the abort because of an “artifact” from an improperly reset test sequence.
With the flight rescheduled for 24 hours, the 45th Space Wing predicted a 30 percent chance of weather violating launch criteria with the primary concern being thick clouds. However, those never materialized and the launch countdown proceeded quietly without problems.
“Today we watched SpaceX make history again with their new generation Falcon 9 Block 5 rocket,” the 45th Space Wing said in a statement on its Facebook page. “The Bangabandhu-1 communications satellite was the first launch off Pad 39 since Falcon Heavy. They continue to make strides in what is possible from the Eastern Range. Rural neighborhoods in and across Bangladesh will have the ability to access direct-to-home television programming.”
Bangabandhu-1 is Bangladesh’s first geostationary communications satellite. It was built by France-based Thales Alenia Space on behalf of the Bangladesh Telecommunication Regulatory Commission. The 7,700-pound (3,700-kilogram) satellite was built on Thales Alenia Space’s Spacebus 4000B2 spacecraft platform and sports some 14 standard C-band transponders and 26 Ku-band transponders.
It has two deployable solar panels that generate about six kilowatts of power and is designed to be operational in geostationary orbit for some 15 years at the 119.1 degrees East orbital slot to provide direct-to-home services, video distribution and very small aperture terminal communications across Bangladesh, according to SpaceX’s mission press kit.
While the mission was to send Bangabandhu-1 into space, perhaps the star of the launch was the newly-upgraded Falcon 9.
Block 5 upgrades
The 229-foot (70-meter) tall, two-stage orbital launcher sported a number of upgrades including increased thrust and more thermal protection around the nine Merlin 1D engines at the base of the first stage to help with reentry heating during recovery maneuvers. Moreover, the base of the rocket that houses the engines, called the “octoweb,” is now bolted on, rather than welded.
Altogether, the company has stated in the past that some 100 or more chances have been made to the vehicle. The most visible of these are the black landing legs, interstage and raceway—a protected path that carries cables and piping down the side of the rocket. Those areas are coated with a special heat resistant material, SpaceX said.
“The key to Block 5 is that it’s designed to do 10 or more flights with no refurbishment between each flight—or at least not scheduled refurbishment between each flight,” said SpaceX CEO Elon Musk during a media conference call before the launch. “The only thing that needs to change is you reload propellant and fly again.”
Musk said he believes the Block 5 design is capable of at least 100 flights before being retired. In fact, he said SpaceX plans to launch a Block 5 Falcon 9 twice within 24 hours sometime in 2019.
“It’s going to take some requirements—we’re going to be very careful and deliberate about this—but that will be I think truly remarkable to launch an orbit-class rocket—the same orbit-class rocket—twice in one day,” Musk said. “Because there’s only so much work you could even do in one day and a bunch of it consists of transporting the rocket from its landing site back to the launch site, mounting a new satellite on the rocket and loading propellant and going—and doing all of that within 24 hour period, while maintaining a very high level of mission assurance, is extraordinarily difficult.”
The flight of the Falcon
Part of that speed will be enabled by a new version of the Falcon 9’s launch countdown timeline. The previous version of the vehicle had the loading of rocket grade kerosene (RP-1) at minus 70 minutes and the loading of liquid oxygen at minus 35 minutes.
For the Block 5, the company began loading RP-1 in both stages and liquid oxygen in the first stage at minus 35 minutes. At minus 16 minutes, loading of liquid oxygen into the second stage began.
From there, the countdown continued as previous flights had. The nine Merlin 1D engines began chilling to condition themselves for launch at minus seven minus. One minute before liftoff, the rocket’s tanks pressurized to flight levels. At 45 seconds, the launch director verified the vehicle was “go” for launch.
Some three seconds before lifting skyward, the nine Merlin 1D engines at the base of the Falcon 9 ignited and spooled up to full thrust. Once the onboard computers verified all the engines were working as designed, the latches at Launch Complex 39A released the vehicle and it rose toward space.
The rocket began a slow rise before quickly speeding up. It cleared the strongback and tower in about eight seconds. Within just over a minute into the flight, it passed the speed of sound and reached the moment of peak mechanical stress, and area called Max Q.
Two minutes, 31 seconds after liftoff, the Falcon 9’s first stage finished its job and its engines cut off as planned. In a span of just five seconds, the first and second stages separated, and the second stage’s lone vacuum-optimized Merlin 1D engine ignited to finish the job of sending Bangabandhu-1 spaceward.
Three minutes, 37 seconds into the flight, the two payload fairing halves separated.
The second stage continued its first burn until about 8 minutes 19 seconds into the ascent before cutting off after achieving a low-Earth parking orbit where it coasted for about 20 minutes.
Meanwhile, the first stage with all of the upgrades of the Block 5, continued on its suborbital trajectory toward SpaceX’s drone ship, Of Course I Still Love You, downrange in the Atlantic Ocean.
Just over six minutes after leaving Florida, the booster performed a short entry burn, utilizing three engines, to ease itself back into the thicker portion of Earth’s atmosphere.
With its titanium grid fins, the booster continued guided itself toward the small drone ship in the Atlantic Ocean. Then, some seven-or-so minutes into the flight, the stage performed a final landing burn to softly touch down on the deck of Of Course I Still Love You.
This was the 25th overall successful booster core landing—the 14th on a drone ship. SpaceX recovery personnel will now spend the next several days safing the booster and towing it back to Port Canaveral where it will be offloaded, inspected and presumably prepared for another flight after appropriate inspections and refurbishment.
In space, some 28.5 minutes after leaving the Sunshine State, the second stage with its Bangabandhu-1 payload ignited for a second time. It’s minute-long burn placed it and the satellite into a geostationary transfer orbit.
A couple minutes later, some 34 minutes after liftoff, the Bangabandhu-1 satellite separated and was sent on its way. In the coming days weeks and months, the spacecraft will use its onboard propellant and thrusters to circularize its orbit and move into its slot in geostationary orbit. It will also unfold its two solar panels and antennas.
A heavy 2018 manifest
This was the 54th flight of a Falcon 9, which first debuted nearly eight years ago in June 2010. It was also SpaceX’s ninth flight of 2018, including the triple-core Falcon Heavy mission in February. Last year, 2017, the company launched 18 rockets and had orbited five by the same point in the year.
“We’re on track to be double our launch rate last year, which was a record launch rate for us,” Musk said. “In fact, I believe Falcon 9 was the most launched rocket worldwide of 2017. And, if things go well, which is a caveat, then SpaceX will launch more rockets than any other country in 2018.”
In keeping with its breakneck pace, SpaceX is set to send another Falcon 9 spaceward in less than 10 days on May 19. This will occur on the other side of the continent at Vandenberg Air Force Base in California and involve using a previously-flown Falcon 9 to send five Iridium NEXT satellites into orbit along with NASA’s Gravity Recovery and Climate Experiment Follow On (GRACE-FO) mission.
Just five days after that, if schedules hold, SpaceX is expected to send the SES-12 communications satellite into orbit, also on a previously-flown Falcon 9. This time, it will be at Cape Canaveral Air Force Station’s Space Launch Complex 40, just a few miles south of Kennedy Space Center’s Launch Complex 39A.
So, in a span of two weeks, SpaceX could launch three rockets from three different pads for four different customers.
While the next several missions will utilize an older version of the Falcon 9, it is unclear when the next Block 5 launch will be. The company has several Block 4 boosters in its inventory that SpaceX only expects to fly a total of two times. If past is prologue, they’ll likely be expended on their second flight in order to test the limits of booster landing technology.
Video courtesy of SpaceX
Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.