Nineteen days after its most recent mission, SpaceX has successfully delivered a pair of commercial payloads toward Geostationary Transfer Orbit (GTO), at an altitude of about 22,300 miles (35,900 km). The Upgraded Falcon 9 successfully rose from Space Launch Complex (SLC)-40 at Cape Canaveral Air Force Station, Fla., at 10:29 a.m. EDT Wednesday, 15 June, right on the opening of a 44-minute “window.” Within the next 35 minutes, the Eutelsat 117 West B and ABS-2A communications satellites were deployed on behalf of the French-led European Telecommunications Satellite Organisation and Bermuda-headquartered Asia Broadcast Satellite. Despite the success of the primary mission, the secondary “experimental” objective of bringing the Upgraded Falcon 9’s first stage onto the deck of the Autonomous Spaceport Drone Ship (ASDS) in the Atlantic Ocean appeared to have succumbed to a “hard” landing and failure.
“I am proud of the entire professional team here on the Space Coast who worked together flawlessly to make this mission a success,” said Brig. Gen. Wayne Monteith, Launch Decision Authority for today’s mission and commander of the 45th Space Wing at Patrick Air Force Base, Fla. “Congratulations to SpaceX. Assured access to space is a challenging endeavor and today’s launch once again clearly demonstrates the collaborative efforts required for mission success. The 45th Space Wing team continues to shape the future of America’s space operations and serve as the ‘World’s Premier Gateway to Space.’”
In spite of an 80-percent likelihood of acceptable conditions on both Tuesday and Wednesday, SpaceX opted to press ahead with a launch attempt on the second of these two days, tracking at T-0 at 10:29 a.m. EDT. SpaceX told AmericaSpace that the 48-hour delay to last week’s Delta IV Heavy mission—laden with the National Reconnaissance Office’s NROL-37 satellite—led to Eastern Range issues which made Wednesday a more opportune target for the opening launch attempt. The 45th Weather Squadron at Patrick Air Force Base noted in its Tuesday morning summary that an approaching mid-level “trough,” digging into the Florida Panhandle, was expected to increase instability and trigger widespread convection over the Space Coast during the afternoon and evening. “On launch day, stronger and deeper southwest flow will delay the development and progression of the East Coast Sea Breeze until after the end of the morning launch window,” it was explained. “During the launch window, light southwest winds will allow for cumulus development over the Spaceport due to strong surface heating.”
All told, this produced a favorable outlook for Wednesday’s window, which ran from 10:29 a.m. through 11:13 a.m. EDT. The primary meteorological concern was a threat posed by cumulus clouds. Against this backdrops, SpaceX controllers gathered at their consoles in Hawthorne, Calif., early Wednesday, and pressed smoothly into several hours of pre-launch checkouts of the 229-foot-tall (70-meter) Upgraded Falcon 9. Today’s mission marked the sixth flight in less than six months by this latest incarnation of SpaceX’s Falcon 9 fleet, which undertook its maiden voyage last December. The Upgraded Falcon 9 benefits from structural enhancements to its airframe, as well as a “densified” load of cryogenic propellants and an enhanced Merlin 1D+ suite of engines. All told, this has enabled a higher payload-to-orbit capability and prior to today’s launch, four of the first five Upgraded Falcon 9 first stages successfully landed on solid ground or on the deck of the Autonomous Spaceport Drone Ship (ASDS).
Coming just 19 days after the 27 May launch of the heavyweight Thaicom-8 communications satellite to Geostationary Transfer Orbit (GTO), today’s mission seems to reinforce frequent predictions by SpaceX to achieve regular launches, approximately every three weeks or so. The booster was erected at Space Launch Complex (SLC)-40 at Cape Canaveral Air Force Station and completed its standard Static Fire Test of the nine Merlin 1D+ engines of the first stage over the weekend. By this stage, as outlined in AmericaSpace’s preview article, the East Coast-based ASDS—affectionately nicknamed “Of Course I Still Love You”—had also departed Port of Cape Canaveral, bound for a location about 410 miles (680 km) offshore in the Atlantic Ocean.
At 38 minutes before the 10:29 a.m. opening of Wednesday’s launch window, the SpaceX Launch Director polled his team for a “Go/No-Go” decision to begin tanking the Upgraded Falcon 9 with liquid oxygen and a highly refined form of rocket-grade kerosene, known as “RP-1.” Passing satisfactorily through a string of “Go” calls, fueling of the mammoth booster with 1.1 million pounds (500,000 kg) of liquid oxygen and RP-1 got underway. “Fueling completes just a minute or so before the ignition of the nine Merlin engines,” noted AmericaSpace’s Launch Tracker, run by Mike Barrett. “This is to ensure that the propellant is maintained at the correct temperature.”
During this period, the Eutelsat 117 West B and ABS-2A communications satellites—stacked one atop the other inside the Upgraded Falcon 9’s 43-foot-long (13-meter) Payload Fairing (PLF)—were transferred to internal batteries, which would power them through ascent until their solar arrays unfurled in orbit. As detailed in AmericaSpace’s preview, the satellites are near-identical to the Eutelsat 115 West B and ABS-3A duo, which were transported to GTO aboard a Falcon 9 v1.1 booster, last March. The Eutelsat payload, positioned uppermost on the stack and flying on behalf of the French-led European Telecommunications Satellite Organisation, was destined to be deployed first, about 30 minutes after launch, with Asia Broadcast Satellite’s ABS, in the lowermost position, would be released into space about five minutes later.
At 10:16 a.m., the countdown passed T-13 minutes and a final “Go/No-Go” poll of all flight controllers again yielded a unanimous approval to press ahead. The Terminal Count was initiated at T-10 minutes, during which time the nine Merlin 1D+ engines were chilled, preparatory to their ignition sequence. “The engines must be thermally conditioned,” our Launch Tracker stressed, “to ensure that there are no sudden changes in temperature when the super-cold liquid oxygen starts to flow.” By 10:18 a.m., the process of loading RP-1 was entering its final stages, with liquid oxygen tanking expected to conclude a little over a minute before T-0.
All external power utilities from the Ground Support Equipment (GSE) was disconnected from the stack and at 10:24 a.m. the roughly 90-second process of retracting the “strongback” from the Upgraded Falcon 9 got underway. In tandem, the Flight Termination System (FTS)—tasked with destroying the vehicle in the event of an accident during ascent—was placed onto internal power and armed. Fueling concluded and the first-stage propellant tanks were verified at their proper flight pressures. The Merlins were purged with gaseous nitrogen and, at T-60 seconds, the “Niagara” deluge system of 53 nozzles was activated, flooding the pad and flame trench with 30,000 gallons (113,500 liters) of water per minute to suppress acoustic energy radiating from the engines. At the same time, the rocket entered “Startup” and its on-board computers assumed primary command of all critical functions.
At T-3 seconds, the Merlins roared to life, ramping up to their combined thrust of 1.5 million pounds (680,000 kg). Following computer-commanded health checks, the vehicle was released from SLC-40 and blazed into the crystal clear Florida skies at 10:29 a.m. Immediately after clearing the towers, the booster executed a combined pitch, roll, and yaw program maneuver to establish itself onto the proper flight azimuth for insertion of the Eutelsat 117 West B and ABS-2A combo into GTO.
Eighty seconds into the climb, the Upgraded Falcon 9 exceeded the speed of sound and experienced a period of maximum aerodynamic duress—colloquially known as “Max Q”—on its airframe. Concurrently, the Merlin 1D+ Vacuum engine of the second stage underwent a “chill-down” protocol, prior to its own pair of “burns,” late in the ascent, to deliver Thaicom 8 to orbit. At 10:31:38 a.m., about 2.5 minutes after liftoff, the first stage shut down and separated, with the Merlin 1D+ Vacuum engine igniting a few seconds later and generating 210,000 pounds (95,250 kg) of thrust. During the course of its first burn, which lasted a little over six minutes, the two-piece (or “bisector”) Payload Fairing was jettisoned, by means of a pair of pneumatic “pushers.” This exposed the Eutelsat/ABS duo to the space environment for the first time.
The stack then coasted for more than 16 minutes, ahead of the second burn at 10:54 a.m. This burn was much shorter than its predecessor—running for barely 65 seconds or so—but by the time of its conclusion the Eutelsat/ABS duo had been correctly positioned for transfer to GTO. Sitting atop the stack, Eutelsat 117 West B was deployed at 10:59 a.m., with ABS-2A following at 11:04 a.m., as both satellites kick off anticipated 15-year operational lifespans. The former is targeted for an orbital “slot” of 116.8 degrees West longitude, where it will provide expanded broadband, voice and data transmission, and video broadcasting services across 45 nations and territories in the Americas, whilst the latter will offer direct-to-home and cable television, as well as data networks and telecommunications coverage, across South Asia, Southeast Asia, Russia, Sub-Saharan Africa, and the Middle East and North Africa (MENA) region.
As the Eutelsat/ABS stack headed upward to a Geostationary Orbit which will provide them with a vantage point about 22,300 miles (35,900 km) above the Home Planet, efforts to return the Upgraded Falcon 9’s first stage back to the ASDS in the Atlantic Ocean were underway. Due to propellant restrictions imposed by the heavyweight and high-energy GTO trajectory, a Boost-Back burn was reportedly removed from the re-entry regime. SpaceX has taken to describing its ASDS landings as “experimental”—with the deployment of the primary payload considered the benchmark of mission success—and in the case of high-energy and high-velocity GTO missions this is especially the case.
That said, with four previous successful landings on solid ground or on the ASDS between December 2015 and May 2016, it was confidently expected that the first stage would reach the deck of the drone ship. At 10:32 a.m., only a few minutes after departing the Cape, the grid fins were deployed from the sides of the first stage to execute their critical role in guiding the booster back through the “sensible” atmosphere, toward the drone ship. The first stage executed its re-entry “burn” at 10:35 a.m. Ten minutes later, footage from the ASDS revealed that the rocket had executed its three-engine landing burn and had reached the deck.
However, obscured by a pall of smoke and flame, it remained unclear for some time whether the obviously “hard” landing had proceeded successfully or resulted in the loss of the vehicle. The bad news came at 11:04 a.m., when SpaceX CEO Elon Musk tweeted “Ascent phase & satellites look good, but booster rocket had a RUD on droneship.” An “RUD”—the somewhat comical “Rapid Unscheduled Disassembly”—confirmed fears that although the first stage reached its destination, it impacted too hard to be survivable. Mr. Musk followed up on these comments by noting that “Thrust was low on 1 of 3 landing engines,” adding that “High-G landings v sensitive to all engines at max.” He later tweeted that “Upgrades underway to enable rocket to compensate for a thrust shortfall on one of three landing engines. Probably get there end of year.”
This was disappointing, in view of the Upgraded Falcon 9’s near-flawless track record of securing intact landings. Last December, on its very first mission, the first stage alighted with precision on Landing Zone (LZ)-1 at the Cape, with three smooth touchdowns on the ASDS following in April and May 2016. Dovetailed into these successes was the “hard” landing of another Upgraded Falcon 9 first stage in March. Clearly, it has long been stressed by SpaceX that the greater energy and velocity requirements to get heavier and GTO-bound payloads aloft produces correspondingly smaller propellant availability for the re-entry and landing burns. Last month’s landing of the first stage from the JCSat-14 mission, though successful and intact, reportedly incurred “max damage.”