In spite of ominous weather conditions at Cape Canaveral Air Force Station, Fla., which required a slight, 10-minute adjustment of the targeted T-0 launch time, SpaceX has successfully executed its fifth Falcon 9 v1.1 mission of 2014. Liftoff of the two-stage vehicle, carrying the AsiaSat-6 telecommunications satellite into geostationary transfer orbit, took place at precisely 1:00 a.m. EDT Sunday, 7 September, from Space Launch Complex (SLC)-40 at the Cape, turning night into day across the Florida landscape. This year is shaping up to be a banner 12 months for SpaceX, marking the first time in its history that it has launched more than three missions and gradually cementing the reliability credentials of Elon Musk’s Hawthorne, Calif.-based launch services organization.
As described in AmericaSpace’s AsiaSat-6 preview article, the mission was originally targeted to fly on 26 August, but was initially postponed by 24 hours, following the explosion of the Falcon 9 Reusable Development Vehicle (F9R Dev) on 22 August and the need for SpaceX engineers “to review the circumstances that caused the test vehicle to auto-terminate to confirm that there is not a risk to orbital flight.” Rescheduled for 27 August, the second effort to get AsiaSat-6 airborne was called off about 10 hours before the opening of the launch window and the mission was delayed by up to two weeks, reportedly to allow additional verifications of “the Falcon 9 fault detection and recovery logic, with particular focus on highly improbable corner-case failure scenarios.”
At length, the 45th Weather Squadron revealed Thursday, 4 September, that a launch attempt would be made on Sunday, 7 September, and this was subsequently confirmed by both SpaceX and AsiaSat on Friday afternoon. With a 70 percent likelihood of acceptable meteorological conditions—and key concerns centering upon the possibility of violating the Thick Cloud Rule—the launch was scheduled to occur during an expansive “window,” extending from 12:50 a.m. until 4:04 a.m. EDT.
Shortly after 8:40 p.m. EDT Saturday, SpaceX management kicked off the lengthy process of loading liquid oxygen and a highly refined form of rocket-grade kerosene (known as “RP-1”) into the propellant tanks of the Falcon 9 v1.1, in order to feed its nine Merlin-1D first stage engines. The cryogenic nature of the oxygen—whose liquid state exists within a temperature range from -221.54 degrees Celsius (-368.77 degrees Fahrenheit) to -182.96 degrees Celsius (-297.33 degrees Fahrenheit)—required the engines’ fuel lines to be chilled down, in order to avoid thermally shocking and fracturing them. Within an hour, by 9:35 p.m. EDT, all propellants were fully loaded aboard the vehicle.
As expected, the Thick Cloud Rule reared its ugly head, with the Eastern Range declaring itself “Red” (“No Go”) at 10:50 p.m. However, with conditions expected to revert to “Green” as temperatures cooled following a stormy day at the Cape, SpaceX slightly adjusted its T-0 time to 1:00 a.m. EDT Sunday. The standard Go-No Go poll of all stations at T-13 minutes took place promptly at 12:47 a.m., producing a flurry of rapid-fire “Go” calls across the board, and this set up the countdown for its “terminal” phase at T-10 minutes. During this phase, the Merlin-1D engines were chilled, ready for their ignition sequence, and at 12:53 a.m. AsiaSat-6 was transferred to internal power, and the rocket itself transitioned to its on-board batteries. All external power utilities from the Ground Support Equipment (GSE) were disconnected, and at 12:55 a.m. the approximately 90-second process of retracting the “strongback” away from the vehicle got underway. The Flight Termination System (FTS)—tasked with destroying the Falcon 9 v1.1 in the event of a major accident during ascent—was placed onto internal power and armed.
By T-2 minutes and 15 seconds, the first stage tanks had reached flight pressure. “Range Green!” came the call from SpaceX’s Range Operations Co-ordinator (ROC), clearing the weather as the last remaining issue in an otherwise flawless countdown. The Merlin-1D engines were purged with gaseous nitrogen, and, at T-60 seconds, SLC-40’s “Niagara” deluge system of 53 nozzles was activated, flooding the pad surface and flame trench with 30,000 gallons (113,500 liters) of water, per minute, to suppress acoustic waves radiating from the engine exhausts. At T-3 seconds, the nine Merlin-1D engines roared to life, ramping up to a combined thrust of 1.3 million pounds (590,000 kg). Following computer-commanded health checks, at the stroke of 1:00 a.m. the Falcon 9 v1.1 was released from SLC-40 to commence SpaceX’s fifth mission of 2014, turning night into day across the Cape.
Immediately after clearing the SLC-40 tower, the rocket executed a combined pitch, roll, and yaw program maneuver to establish itself onto the proper flight azimuth to inject AsiaSat-6 into geostationary transfer orbit. Eighty seconds into the ascent, the vehicle surpassed the speed of sound and experienced a period of maximum aerodynamic stress (colloquially known as “Max Q”) upon its airframe. At about the same time, the Merlin-1D Vacuum engine of the second stage underwent its own chill-down protocol, ahead of its own ignition later in the ascent phase. At 1:02 a.m., 130 seconds after liftoff, two of the first-stage engines throttled back, under computer command, in order to reduce the rate of acceleration at the point of Main Engine Cutoff (MECO).
Finally, at 1:02:41 a.m., the seven remaining first-stage engines were shut down and the lower component of the Falcon 9 v1.1 separated from the rapidly ascending stack. The turn then came for the restartable second stage, whose single Merlin-1D Vacuum engine—with a maximum thrust of 180,000 pounds (81,600 kg)—roared to life at 1:02:49 a.m. to continue the boost to deliver AsiaSat-6 into orbit. Thirty seconds into its burn, the 43-foot-tall (13.1-meter) payload fairing was jettisoned, exposing the satellite to the space environment for the first time. Finally, the Merlin-1D Vacuum shut down at 1:09:35 a.m., after which the stack coasted for 17 minutes, prior to a restart at 1:26 a.m. The second burn lasted approximately one minute and served to raise the orbital apogee to geostationary altitude. AsiaSat-6 was released into free flight a few minutes later at 1:32 a.m.
Built by Space Systems/Loral (SS/L), the cube-shaped satellite weighs 8,100 pounds (3,700 kg) and represents one of the largest and most powerful AsiaSats ever inserted into orbit. Following initial checkout, AsiaSat-6 will be positioned at 120 degrees East longitude. It will be operated by the Asia Satellite Telecommunications Company Ltd., headquartered in Hong Kong, and 14 of its 28 high-powered C-band transponders will be leased to Thaicom—under a $171 million, 15-year contract, signed in December 2011—who will market them as “Thaicom-7.” The satellite is equipped with one “global” beam and one “regional” beam, providing region-wide coverage of Asia, Australasia, Central Asia, and the Pacific Islands, with enhanced power and look angles over Pacific Rim countries.
AsiaSat selected SS/L in November 2011 to build its AsiaSat-8 and AsiaSat-6 platforms, both of which are expected to support 15-year operational lifetimes. Based upon the LS-1300 “bus,” with a pair of deployable solar arrays and batteries, both satellites breezed through thermal vacuum tests last December and underwent dynamic tests and Compact Antenna Test Range (CATR) tests in January-February 2014. The latter allowed engineers to measure antenna and payload performance and demonstrate their compliance with spacecraft specifications. “These critical tests are essential,” AsiaSat reported in December 2013, “in order to achieve the highest quality and reliability of the spacecraft before shipment to the SpaceX launch pad at Cape Canaveral.”
The arrival of AsiaSat-6 marks the tenth in a series of satellites, which can trace its ancestry back almost a quarter-century. AsiaSat-1, launched atop a Chinese Long March-3 booster in April 1990, had an interesting back story, for it was originally the Westar VI communications satellite, delivered into an improper orbit by shuttle mission 41B in February 1984 and triumphantly retrieved and returned to Earth by the 51A shuttle crew the following November. AsiaSat-2 followed in November 1995, also aboard a Long March rocket, after which the third (AsiaSat-3) and fourth (AsiaSat-3S) satellites in the series were delivered by Russian Proton-K boosters in December 1997 and March 1999. The latter replaced the decomissioned AsiaSat-1 from May 1999 and is today the oldest member of the fleet still in operational status. Kicking off the 21st century, AsiaSat-4 rode an Atlas IIIB from Cape Canaveral in April 2003, followed by AsiaSat-5 atop a Proton-M/Briz-M from Baikonur in August 2009, AsiaSat-7 in November 2011, and AsiaSat-8 in August 2014.
AsiaSat-5 entered the headlines in the summer of 2014, during the World Cup coverage from Brazil, when it delivered the first-ever live telecast of the international football competition in 4K resolution. Commonly (though not strictly accurately) known to the general consumer as “ultra-high-definition television” (UHDTV), 4K produces horizontal resolution of close to 4,000 pixels, more than four times higher than standard HDTV and capable of 60 frames per second. AsiaSat-5 delivered live 4K coverage of the Colombia-Uruguay Round of 16 match on 28 June, followed by the Germany-France quarter-final on 4 July and the final, between Germany and Argentina, on 13 July. According to AsiaSat, the worldwide number of 4K television households is expected to rise from 2.2 million at the end of 2013 to as high as 66.2 million by the end of 2018. Moreover, the Asia-Pacific region is forecasted to become the single largest 4K television market by 2016, accounting for 42 percent of global 4K television households.
As with its sibling, AsiaSat-8, launched on 5 August, the geostationary requirement of the AsiaSat-6 mission required the maximum performance capability of the Falcon 9 v1.1 and consequently the booster was not equipped with extendible landing legs and did not perform a “propulsive return-over-water” and controlled splashdown. The next attempt to perform such a maneuver will be made during the launch of the fourth dedicated Dragon cargo mission (SpX-4) to the International Space Station (ISS), which was originally scheduled for launch on 19 September, but which may suffer some slippage in the wake of the AsiaSat-6 delays.