SpaceX Falcon 9 launches JCSAT-18/Kacific-1

by Ian Atkinson

SpaceX launched its Falcon 9 rocket with JCSAT-18/Kacific-1 on Monday. The launch, the 77th for the Falcon 9, saw the commercial communications satellite lofted to a geostationary transfer orbit (GTO). The 1-hour 28-minute launch window opened at 7:10 PM EST on December 16, with an on-time liftoff.

Falcon 9 Launch:

This mission represented the quickest turnaround between launches for any SpaceX launch pad – in this case, Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station.

The last launch from SLC-40 was CRS-19, a cargo resupply mission for the International Space Station. CRS-19 launched on December 5, only 11 days prior to JCSAT-18/Kacific-1’s planned launch date.

The previous record was between the CRS-18 and Amos-17 flights – a gap of just over 12 days. After its renovation in 2017 – following the September 2016 on-pad Falcon 9 explosion – SLC-40 was rated for a minimum turnaround time of seven days.

JCSAT-18/Kacific-1’s launch flow began with the static fire test – a complete rehearsal of the launch countdown. Ahead of a static fire test, the vehicle – without its payload or fairing attached – is rolled out onto the launch pad and raised vertical. The propellant tanks on the first and second stages are filled, and the test culminates with a brief firing of the nine Merlin 1D engines on the first stage.

In the early morning of December 13, the Falcon 9 was rolled out and raised vertical on the launch pad at SLC-40. Following fueling and the quick engine firing, SpaceX confirmed a successful test later in the day.

The first stage of this specific Falcon 9 – B1056.3 – has flown twice before. The “56” in its name indicates that it was the 56th first stage core produced, and the “.3” at the end designates that this will be its third mission.

B1056 first flew in May 2019 on the CRS-17 mission. After its landing on SpaceX’s droneship Of Course I Still Love You, its landing legs were retracted and locked back into position – a first for core stage recovery. Previously, the landing legs on first stages were removed following landing.

The stage flew for a second time in July 2019 for the CRS-18 mission. B1056 was planned to fly again for CRS-19 – which would have made it the first time a NASA mission used a twice-flown booster. However, for unknown reasons, that mission was later reassigned to the brand-new B1059.

B1056.3 – along with the second stage – launched JCSAT-18/Kacific-1 into an eccentric geostationary transfer orbit. Once the satellite reached that orbit, it will use its own thrusters to reach a circular geostationary orbit – nearly 36,000 kilometers above Earth’s surface.

The payload for this mission is a communications satellite named JCSAT-18/Kacific-1, based on the Boeing 702MP satellite bus. The satellite will be owned and operated by two different companies – SKY Perfect JSAT Corporation and Kacific Broadband Satellites. By sharing the satellite bus, the two operators were able to split the costs of construction and launch.

JCSAT-18/Kacific-1 just after it arrived at Cape Canaveral for final pre-launch processing. Credit: Kacific

The JCSAT-18 payload features Ku-band conventional and spot beams that will provide phone and broadband internet connectivity to Northern and South East Asia, the Northern Pacific, and parts of southern Alaska.

The Kacific-1 payload features 56 Ka-band narrow beams to provide broadband internet to South East Asia – including New Zealand. According to the company, almost all of the 56 beams have been booked by customers. The payload will bring high-speed connectivity to the region, with a 550-600ms latency and an overall system capacity of 60Gbps.

Kacific-1 will be the first in a series of satellites for Kacific. The company plans to place future satellites in different orbital positions to increase both the area of coverage and bandwidth capacity.

The total mass of the satellite is 6800kg – on the upper end of the Falcon 9’s GTO capabilities. Due to the satellite’s high mass and the performance required to reach a geostationary transfer orbit, the first stage made a downrange landing approximately eight minutes after liftoff on SpaceX’s droneship Of Course I Still Love You.

This was successful.

SpaceX not only attempted a first stage recovery but also tried to catch both fairing halves for the first time.

Their two fairing recovery vessels – named GO Ms. Tree and GO Ms. Chief – were stationed approximately 789km downrange in the Atlantic Ocean, 138km further than the droneship and its support crew.

Due to the fairings using steerable parachutes to slowly descend toward the recovery area, their recovery attempt took place around 45 minutes after launch. Each ship is designed to catch one fairing half in their large net. Should the fairings miss the nets, the crews can still recover them from the ocean.

This was the case for this mission as both fairings landed in the water.

A double fairing recovery was planned to be attempted on the first Starlink v1.0 launch in November 2019 – however, rough seas caused the attempt to be called off.

SpaceX has previously recovered numerous fairing halves – usually scooping them out of the ocean after a recovery ship missed the catch. The first fairings reused on a mission – those from the Arabsat-6A Falcon Heavy mission, and reflown on Starlink v1.0 Launch 1 – were recovered after landing in the ocean.

SpaceX caught their first fairing half in a net on June 25, 2019, using GO Ms. Tree after the STP-2 Falcon Heavy mission. GO Ms. Chief has not caught a fairing yet.

A complete fairing costs $6 million – about 10% of the Falcon 9’s cost. As the frequency of Starlink launches ramps up in 2020, demand for fairings will increase as well. Reusing fairings will reduce the need to produce new ones, allowing SpaceX to save money and time.

Following the JCSAT-18/Kacific-1 mission, SpaceX plans to close out 2019 with the second operational Starlink launch, currently scheduled for December 30.

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