The world’s most powerful in-service launch vehicle roared aloft for its third mission overnight, delivering no fewer than 24 payloads for U.S. government, military and civilian customers into several different orbital locations. SpaceX’s triple-cored Falcon Heavy—whose 27 Merlin 1D+ first-stage engines generate some 5.1 million pounds (2.3 million kg) of propulsive yield at liftoff, took flight from historic Pad 39A at the Kennedy Space Center (KSC) in Florida at 2:30 a.m. EDT Tuesday, about three hours into a four-hour “window”, after delaying from 11:30pm to complete additional ground system checkouts.
Riding the coattails of the Heavy’s triumphant maiden test flight in February 2018 and its first commercial outing last April, last night’s mission achieved its own raft of “personal bests” for SpaceX, launching for the first time in the hours of darkness and reusing the same set of side-mounted boosters from its most recent flight.
As outlined in AmericaSpace’s preview article, this mission has demonstrated the Heavy’s gargantuan payload-to-orbit capability far closer to the max than either of its two previous flights. All told, 24 payloads from the Air Force, NASA, the National Space Organization of Taiwan and various arms of civilian and military academia were aboard the giant booster for its middle-of-the-night climb to orbit. These included the $165 million Space Test Program (STP)-2, contracts for which were signed back in December 2012 between SpaceX and the Air Force Space and Missile Systems Center (SMC) at Los Angeles Air Force Base in El Segundo, Calif.
“SMC procured the mission to provide spaceflight for advanced research and development satellites,” noted SpaceX in its online press kit. “The STP-2 mission will…perform 20 commanded deployment actions and place 24 separate spacecraft in three different orbits.” The Heavy’s haul includes payloads devoted to meteorology, ionospheric physics, climatology, geodesy, space weather, radio occultations, the deployment of large inflatable structures and novel telescope designs, a group of NASA-sponsored cubesats to investigate greener fuels and evaluate an ultra-precise atomic clock and The Planetary Society’s long-awaited LightSail-B to explore the usefulness of sunlight as a propulsion source.
Launching super-heavylift boosters in the hours of darkness is nothing new, and the now-retired Space Shuttle fleet scored more than 30 nocturnal flights during its three decades of operational service, firstly in August 1983 and latterly in April 2010. Added to that tally, the mammoth Saturn V—the most powerful rocket ever brought to operational status—staged a single night launch in December 1972 to boost Apollo 17 astronauts Gene Cernan, Ron Evans and Jack Schmitt towards the Moon. But last night would mark the first night launch of a Falcon Heavy and the spectacle was expected to be, well, spectacular.
The spectacle got underway last week, when the 230-foot-tall (70-meter) booster was trundled horizontally from its assembly building to Pad 39A and on 20 June underwent a customary Static Fire Test of its first-stage engines. It was then returned to the assembly building for the final integration of its multi-faced cargo—including the 8,100-pound (3,700 kg) Integrated Payload Stack (IPS)—and returned to the pad early Monday morning. Photographs from inside the assembly building, tweeted by SpaceX, made the vehicle look like an oversized toy, but no one was placed under any illusion, for as night fell on Monday evening one of the largest and most powerful rockets ever built stood ready for flight.
The weather, too, was virtually ready, with U.S. Air Force 45th Weather Squadron at Patrick Air Force Base forecasting Monday’s opening launch attempt with a 70-percent likelihood of acceptable weather, which then improved to 80% by Monday afternoon.
However, a beginning-of-window launch would not come to pass. “Targeting T-0 of 2:30 a.m. EDT for Falcon Heavy launch of STP-2,” SpaceX tweeted. “Team completed additional ground system checkouts. Vehicle and payload continue to look good.”
Shortly after 1:30 a.m. EDT Tuesday, the SpaceX Mission Director verified the “Go” to begin loading the three Falcon Heavy boosters with liquid oxygen and a highly refined form of rocket-grade kerosene, known as “RP-1”. The process continued until the final minutes before launch and at T-90 seconds the flight computers carried out their final checks. All was well. “This is the Mission Director,” came the clipped call at T-45 seconds. “Go for Launch.” Piercing the dark Florida sky like a blowtorch, the Falcon Heavy ponderously rose from the same pad that, almost five decades ago, saw Cernan, Evans and Schmitt begin their voyage to the Moon.
Just less than three minutes into its climb, the two side-mounted boosters—tail-numbered B1052 and B1053, both of which were chalking up their second respective launches, having previously powered the most recent Falcon Heavy aloft in April—were expended and jettisoned. In a sight which has become commonplace since December 2015, but which still never fails to thrill, they descended back to Earth and, via a ballet of engine burns and the deployment of hypersonic grid fins, alighted like a pair of synchronized ballet dancers on the adjacent pads of Landing Zones (LZ)-1 and 2 at the Cape.
In the meantime, the never-before-flown B1057 core continued for another minute or so, shutting down at 3.5 minutes after leaving Earth. It too commenced a rapid descent, with an expectation that it would touch down smoothly at 11 minutes into flight on the Autonomous Spaceport Drone Ship (ASDS) in the Atlantic Ocean. However, it proved too tough an ask on this challenging mission and B1057 missed the drone ship.
Of course, SpaceX always cautions against placing too much emphasis on the success of these visually spectacular, “gee-whiz” events and the focus of last night’s mission was getting the STP-2 payload safely to orbit…or, rather, orbits…for the Falcon Heavy’s second stage was required to execute no fewer than four discrete burns to accomplish its job.
The first burn was the longest, running for around five minutes, with the successive three burns executed respectively at an hour, two hours and some 3.5 hours into the mission. The latter three firings were due to run for around 30 seconds apiece and the engine cutoff after each burn was to be punctuated by a batch of payload deployments. The final spacecraft was slated to depart the Heavy’s payload fairing at three hours and 34 minutes after launch.
Looking ahead, the Falcon Heavy currently boasts at least four confirmed missions—two for commercial customers, two for the Department of Defense—through 2022. Scheduled for launch “late” in Fiscal Year 2020, the $130 million Air Force Space Command (AFSPC)-52 classified mission was firmly added to the Heavy’s books last October, in what Lt. Gen. Arnold Bunch, Jr., military deputy for the Office of the Assistant Secretary to the Air Force for Acquisition, described as the result of across-the-board financial savings both in “competition and also with commercial demand signal”. And more recently, in February 2019, contracts were signed between SpaceX and the Department of Defense to fly the $100 million AFSPC-44 aboard the Heavy “by February 2021”.
Commercial clients include a pair of contracts signed last October with Viasat, Inc., of Carlsbad, Calif., and the joint Swedish-U.S. firm Ovzon, to deliver two communications satellites to orbit. The former contract calls for the launch of one of three high-throughput ViaSat-3 Ka-band satellites in the 2020-2022 timeframe, with the Falcon Heavy expected to lift the payload “closer than usual” to its targeted 22,370-mile-high (36,000 km) geostationary altitude. Meanwhile, the small Ovzon-3 mobile broadband communications satellite—which will likely be co-manifested with another larger payload—is slated to fly in the fourth quarter of 2020.
Both will benefit from the Falcon Heavy’s immense lifting capabilities. In particular, ViaSat-3 utilizes electric propulsion and would ordinarily require months to get itself on-station, but the Heavy will accomplish “near-direct injection” of the payload. Ovzon CEO Per Wahlberg described SpaceX’s offer of a Heavy launch as a “very competitive solution” and one which “will gain us access to space in a timely and reliable manner”.