SpaceX launched Japan’s JCSAT-16 communications satellite in the early hours of Sunday via a Falcon 9 rocket, with lift off occurring from SLC-40 at Cape Canaveral at the start of a two-hour launch window that opened at 01:26 local time (05:26 UTC). Once again, a return of the first stage to SpaceX’s drone ship was successful.
Making its eighth launch of the year, the Falcon 9 delivered JCSAT-16 into a geosynchronous transfer orbit. It was the second mission that SpaceX have flown for JCSAT-16’s operator, Sky Perfect JSAT Corporation, following the successful launch of JCSAT-14 in May.
Sky Perfect JSAT is Japan’s largest commercial satellite operator, with a fleet of communications satellites stationed between 82 and 162 degrees East. It was formed in October 2008 by the merger of JSAT Corporation, Sky Perfect Communications and Space Communications Corporation (SCC).
JSAT continues to operate two series of satellites; the JCSAT series was inherited from JSAT Corporation, while its Superbird line were originally operated by SCC.
The JCSAT-16 spacecraft was constructed by Space Systems/Loral, under a two-satellite contract which was announced in April 2014.
The second satellite, JCSAT-15, is scheduled for launch aboard an Ariane 5 later this year.
JCSAT-16 is based on Loral’s SSL-1300 bus and has a mass of around 4,600 kilograms (10,000 lb). Powered by twin solar arrays, the satellite carries a payload of Ku and Ka-band transponders.
JCSAT-16 will serve as an on-orbit spare for JSAT’s fleet, joining the existing JCSAT-RA spacecraft in this capacity. It had been intended to be stationed at a longitude of 150 degrees East, on standby should its services be needed. However, it is now expected to be pressed into action immediately after the launch of the Superbird 8 satellite was delayed by up to two years.
Superbird 8 had been scheduled for launch last month, but was damaged en-route to the launch site; a tarpaulin was left covering vents on its shipping container, which prevented the container being maintained at a constant pressure while in flight.
Superbird 8 was intended to operate at a longitude of 162 degrees East, replacing the sixteen-year-old Superbird B2 which has already exceeded its design life.
JCSAT-16 will occupy this position until Superbird 8 has been repaired and launched – which is currently expected to be 2018 – before reverting to its reserve role. JCSAT-16 is designed to provide fifteen years of service – a typical lifespan for a modern communications satellite.
Sunday’s launch made use of SpaceX’s Falcon 9 rocket, making its twenty-eighth flight since its 2010 debut.
A two-stage vehicle, the Falcon is powered by ten Merlin-1D engines; nine on the first stage, with the tenth – in a vacuum-optimised configuration – powering the second stage.
The first stage is designed to be recovered, making a powered descent following separation, with a view to eventual reusability. The Falcon 9 has been revised twice since its original form that was used for the first five missions.
Early flights used Merlin-1C engines; with those on the first stage arranged in a square grid. From the sixth launch onwards the Falcon 9 v1.1 configuration was used, introducing the Merlin-1D and rearranging the first stage engines into an octagonal, or “OctaWeb” pattern.
This upgrade also stretched both stages of the vehicle, increasing its performance to allow early propulsive recovery tests. Where mission requirements allowed, the v1.1 would fly with deployable landing legs attached to demonstrate this component and aid in descent tests, which initially saw the stage make a controlled descent into the ocean.
Three late v1.1 launches saw the rocket attempt a landing atop SpaceX’s Autonomous Spaceport Drone Ship (ASDS), a barge adapted to accommodate first stage recovery at sea.
The first two of these attempts came after launching the CRS-5 and CRS-6 Dragon missions in early 2015, using the first “Just Read the Instructions” barge; in both cases the stages reached their landing targets but toppled over and exploded after landing.
A recovery attempt was also to have been made during the CRS-7 launch. However, the vehicle disintegrated before first stage separation; the Falcon 9’s only outright launch failure to date.
A further revision, known unofficially as the “Full Thrust” Falcon 9, or the “Falcon 9 v1.2”, was introduced in December 2015 with the launch of eleven Orbcomm communications satellites. Officially, SpaceX only calls the rocket the “Falcon 9”.
The v1.2 uses supercold liquid oxygen to oxidise its RP-1 propellant, its lower temperature than the liquid oxygen used previously allows more to be carried in the same tank capacity, providing further performance increases over the v1.1. The vehicle also boasts uprated first stage engines and a further-stretched second stage.
The increased performance of the v1.2 configuration allows the first stage to attempt a landing on most missions, including those targeting geosynchronous transfer orbits such as Sunday’s.
On missions with a significant performance margin – such as the Orbcomm launch – the first stage can now return to Cape Canaveral under its own power rather than needing to put down at sea using the ASDS.
The December launch marked the first successful recovery of the Falcon’s first stage, which successfully touched down at Cape Canaveral’s Landing Zone 1; the former Launch Complex 13 to the south of the Falcon 9’s launch pad.
Since the introduction of the Full Thrust configuration, it has been used for all launches except the Jason 3 ocean research satellite, which was deployed by the last Falcon 9 v1.1 in January 2016.
That launch saw the third attempt to land the v1.1’s first stage, using a second barge also named “Just Read the Instructions” off the coast of California, following liftoff from Vandenberg Air Force Base.
One of the first stage’s legs failed to deploy fully in what would otherwise have been a perfect landing, and again the vehicle toppled and exploded upon touchdown.
Since its introduction, landing attempts have been made with all launches of the Falcon 9 v1.2; mostly at sea. The second ASDS, named “Of Course I Still Love You”, replaced the original “Just Read the Instructions” in 2015; with the latter being converted back to a regular barge.
A new barge with the same name was converted to support launches from Vandenberg Air Force Base in California. In seven attempts to date with the v1.2, five successful landings have been made – two on land and three at sea aboard the ASDS.
The two failures both came on ASDS landings following geosynchronous missions, whose higher velocity represents a greater challenge in terms of achieving a successful landing.
The landing is an experimental objective of the launch, and its success or failure has no bearing on whether any particular launch is considered a success or failure; which is determined solely upon whether JCSAT-16 is delivered safely to its correct transfer orbit.
Sunday’s launch took place from Space Launch Complex 40 (SLC-40) at the Cape Canaveral Air Force Station (CCAFS); a former Titan III and IV launch facility which was first constructed in the 1960s.
Part of the Titan’s Integrate-Transfer-Launch (ITL) complex along with the nearby Complex 41 – now used by the Atlas V – and a shared processing facility which has been demolished, SLC-40 was used for 55 Titan launches between June 1965 and April 2003, including 26 Titan IIICs (all but four of which used the standardised Titan III(23)C version of the rocket); eight Titan III(34)Ds, four Commercial Titan IIIs, twelve Titan IVAs and five Titan IVBs.
The Falcon 9 has launched from SLC-40 since its maiden flight in 2010; Sunday’s will be the twenty-sixth Falcon launch from the pad, which was also used for a Dragon pad abort test launch in May 2015 which reached an apogee of about 1.5 kilometres (0.93 miles, 0.81 nautical miles). Including the abort test, Sunday’s mission is the eighty-second to lift off from SLC-40.
The use of supercold oxidizer limits Falcon to a short countdown in order to maintain the necessary temperature.
Fuelling began just thirty-five minutes before launch, following a poll around three minutes earlier. Once initial loading was completed the oxidiser tanks continued to be topped off as the countdown proceeded, replenishing the oxygen as it evaporated. Gaseous oxygen was vented.
Most milestones occur in the final ten minutes of the countdown, as the vehicle is fully configured for flight.
Engine chilldown began shortly after the ten-minute mark in the countdown. As the count continued, final motion tests of the rocket’s nozzles was conducted; in flight the engines are used to provide attitude control through thrust vectoring.
About five minutes before liftoff, the vehicle’s tanks were pressurized in preparation for retraction of the Strongback, a structure used to transport the Falcon from its hangar to the launch pad, raise it to the vertical position and provide a mast for support cables and umbilicals during the countdown.
Retraction of the strongback began about three minutes and twenty seconds before liftoff; taking about a minute to reach its fully-retracted position.
Shortly after the strongback began retracting, the rocket’s flight termination system – consisting of explosive charges which would function as a self-destruct should the rocket go off course – was switched to internal power and armed.
The Falcon 9 itself moved to internal power a little under two minutes before launch.
Final clearance to launch was given by US Air Force’s Range Control Officer (RCO) about two minutes before launch, and by SpaceX’s Launch Director at the ninety-second mark. In the last minute of the countdown the rocket was placed into startup mode, final pressurization occurred, and the launch pad water deluge system was activated.
Ignition of the Falcon’s nine first stage engines occurred three seconds before the end of the countdown, with vehicle being held down until the zero mark while the engines ramped up thrust and final checks were verified.
Falcon lifted off at T-0, beginning its ascent East over the Atlantic Ocean towards geosynchronous transfer orbit.
Seventy-eight seconds after liftoff the rocket passed through Max-Q – the area of maximum dynamic pressure, or stress, upon the vehicle.
The first stage burned for two minutes and 33 seconds before shutting down its engines; separating from the second stage three seconds later to begin its descent for landing.
Eight seconds after stage separation the second stage’s engine ignited for the first of two burns, lasting five minutes and 48 seconds to establish an initial parking orbit. Separation of the payload fairing from around the satellite at the nose of the rocket occurred during this first burn, approximately 48 seconds after ignition.
A coast phase of seventeen minutes and fifty-eight seconds separated the first and second burns of the second stage; the latter of which lasted 62 seconds to raise the orbit’s perigee towards geosynchronous altitude.
Separation of JCSAT-16 occurred four minutes and 41 seconds after the end of the second burn; or at 32 minutes, 13 seconds elapsed time.
Following its separation, the first stage performed its own series of manoeuvres to attempt a landing atop the Autonomous Spaceport Drone Ship (ASDS), “Of Course I Still Love You”.
Two burns made using a subset of the first stage engines; the first of these was an entry burn to slow the vehicle as it comes back into Earth’s atmosphere, while the second to make a powered landing atop the Drone Ship.
The landing burn used just one engine to reduce the stresses on the vehicle.
The entry burn took place around six-and-three-quarter minutes after liftoff, with landing a little over eight and a half minutes after launch.
Following Sunday’s launch, SpaceX will next be in action in early September with the launch of Israel’s Amos-6 communications satellite.
(Images via SpaceX and SSL).