Falcon 9 B1051 makes final flight on Galaxy-31 & 32 mission

by Lee Kanayama

After a delay caused by Hurricane Nicole, SpaceX launched its 52nd mission of 2022 with the Intelsat Galaxy-31 & 32 satellites using a flight-proven Falcon 9 to a geostationary transfer orbit (GTO). Falcon 9 first-stage booster B1051-14 made its final flight on this mission.

Falcon 9 launched from Space Launch Complex 40 (SLC-40) at the Cape Canaveral Space Force Station (CCSFS) on Nov. 12 at the opening of a two-hour launch window at 11:06 AM EST (16:06 UTC).

Galaxy-31 & 32 is SpaceX’s third overall mission for Intelsat. The near-identical satellites are Intelsat’s third and fourth satellites to clear the C-band 300-400 MHz range for the FCC’s 5G Rollout. This mission was SpaceX’s first expendable Falcon 9 flight since Crew Dragon’s In-Flight Escape Demonstration in January 2020.

B1051: A Historic Booster

With SpaceX recently completing its 51st launch of 2022, this year has marked many firsts for the company. To achieve these firsts, SpaceX has used flight-proven boosters to keep up with its busy cadence and prove reusability. One booster has continued to prove to SpaceX that boosters with high-flights work and can work as well as its younger siblings; B1051-14 will be making its last flight on this mission.

B1051 is one of the fleet leader of the Falcon 9 fleet, having previously supported 13 missions. The booster first supported the uncrewed SpaceX Demo-1 mission in March 2019, carrying the first Dragon 2 spacecraft to the ISS. A few months later, in June 2019, SpaceX moved B1051 to Vandenberg Space Force Base (VSFB) to support the RADARSAT Constellation mission after B1050 made an unexpected splashdown.

B1051-1 launches the SpaceX Demo-1 mission in March 2019. (Credit: Brady Kenniston for NSF)

B1051 made its third flight on the Starlink v1.0 L3 mission from SLC-40 in January 2020. It became the third Falcon 9 booster to launch from all three launch sites. With SpaceX losing two first-stage boosters in the first quarter of 2020, the company was down to three active boosters (B1049, B1051, and B1059). B1051 made its fourth flight in April from LC-39A on the Starlink v1.0 L6 mission to return SpaceX to regular flights.

In August and October 2020, B1051 made its fifth and sixth flights on two Starlink missions. In December, B1051 marked a milestone in the Falcon 9 fleet supporting the commercial SiriusXM-7 mission on its seventh flight. This flight was the first time a booster with more than four flights supported a commercial mission and the first booster to support five missions in a single year.

In March 2020, older booster B1049 became the fleet leader, becoming the first booster to launch and land five, six, and seven times. At the beginning of 2021, B1051 took over as fleet leader during the Starlink v1.0 L16 mission. This flight had many milestones, including the first eighth flight of a booster, the fastest turnaround at 38 days, and the first flight of a new booster milestone not preceded by a static fire test. It supported the first ninth flight of a booster two months later on Starlink v1.0 L21.

Two months later, B1051 made history again, becoming the first Falcon 9 to reach ten flights on Starlink v1.0 L27. As the first booster to reach this milestone, it proved a Falcon 9 could support 10+ flights without significant refurbishment. After completing this flight, B1051 underwent major inspections and moved to VSFB. In December 2021, B1051 supported the first 11th flight of a Falcon 9 on Starlink Group 4-4 from VSFB. Following the flight, SpaceX transported B1051 back to CCSFS for the final time.

Falcon 9 (B1051-10) supports Starlink v1.0 L27. (Credit: Stephen Marr for NSF/L2)

In March 2022, it supported the first 12th flight of a booster on the Starlink Group 4-12 mission. B1051 was overtaken as the fleet leader on Jun. 17, with B1060 becoming the first booster to support 13 flights. B1051 held the title of fleet leader for one year, four months, and 28 days, the longest time a booster has held the title of fleet leader in the SpaceX fleet.

A month after B1060 became the fleet leader, B1051 supported its 13th flight on Starlink Group 4-22. After supporting 4-22, SpaceX took B1051 off the SpaceX drone ship Just Read the Instructions (JRTI) at Port Canaveral and moved it to HangarX to prepare for its final flight. B1051 had its recovery hardware removed and a second stage installed for its next flight. The booster will have a turnaround of 118 days.

B1060-14 was the first booster with more than ten flights to support a commercial mission. B1051 was the second to support a commercial mission with 14 flights and the first expendable Falcon 9 mission since January 2020.

SpaceX transported B1051 to the Horizontal Integration Facility (HIF) at SLC-40 on Nov. 4. At the HIF, B1051 was integrated on the Strongback Transporter/Erector (T/E), and the encapsulated payloads were attached shortly after. The SpaceX teams rolled out the Falcon 9 to SLC-40 for launch and raised the rocket vertical on Nov. 11.

Intelsat’s Galaxy-31 & 32 Satellites

Galaxy-31 & 32 are two near-identical satellites owned and operated by the commercial satellite operator Intelsat. The company was founded in 1964 as the International Telecommunications Satellite Organization, or Intelsat, to own and manage international broadcasting services with multiple participating countries. Intelsat launched its first satellite in 1965, Intelsat I (Early Bird), as the world’s first commercial communication satellite.

In the following decades, Intelsat began launching satellites using primarily Atlas and Delta rockets to provide global commercial telecommunication services. As Intelsat’s satellites grew larger, Intelsat started to launch its satellites on Ariane, Titan, Proton, Chang Zheng, Zenit, and Falcon launch vehicles.

During the launch of Intelsat-6 3 (Intelsat 603), the Commercial Titan III solid motor kick stage failed to separate from the second stage, leaving the satellite in a useless low Earth orbit (LEO). Intelsat would task NASA to boost the satellite to a GTO. NASA completed the mission using Space Shuttle Endeavour on its first flight during STS-49. Intelsat 603 completed 23 years in orbit before it was retired.

Intelsat 603 separates from Space Shuttle Endeavour after successfully replacing its perigee stage. (Credit: NASA)

In the 1980s, the Hughes Space and Communications Company, later merging with PanAmSat, started the Galaxy communications satellite fleet. The Galaxy communications satellites provided telecommunication services to the United States. Intelsat became privatized in 2001 and merged with PanAmSat five years later.

Since then, Intelsat has continued to launch satellites to expand its global coverage. Recently, Intelsat scored a historic first with Northrop Grumman’s Mission Extension Vehicle (MEV)-1 and the 19-year-old Intelsat 901 satellite. After lasting six years longer than its 13-year lifespan, Intelsat moved the Intelsat 901 orbit into a graveyard orbit, with Intelsat-37e taking its place. The MEV-1 launched in October 2019 to rendezvous with the 901 satellite.

MEV-1 docked with Intelsat 901 on Feb. 25, 2020, becoming the first time two commercial satellites docked and mission extension services were offered to a geostationary satellite. MEV-1 moved the satellites to replace the aging Intelsat 907 satellite for five years. A second MEV docked with the Intelsat 10-01 satellite in 2021.

MEV-1 20-meters away from Intelsat 901 before docking. (Credit: Northrop Grumman)

On Nov. 7, 2022, Intelsat announced an order for the Intelsat-45 satellite from SWISSto12. Intelsat will be the first commercial satellite operator to use the SWISSto12 HummingSat satellite bus. SWISSto12, under a partnership with ESA, will use HummingSat to create a satellite just a tenth of the size of conventional satellites to launch as a rideshare payload with satellites going to GEO. Intelsat-45 will provide Ku-band satellite services with a launch in 2025.

Along with satellite operator SES, Intelsat has been launching satellites to clear the 300-400 MHz C-band spectrum above the United States per the FCC’s plan to roll out 5G services. As a part of Intelsat’s plan to clear that spectrum, the company ordered seven satellites from manufacturers Maxar and Northrop Grumman. Intelsat ordered six satellites, four from Maxar and two from Northrop Grumman, in 2020. The company ordered a seventh satellite from Maxar a few months later. Maxar has built nearly 60 satellites for Intelsat since the 1970s.

Intelsat selected SpaceX to launch five of the seven satellites. For this mission, Intelsat requested Galaxy 31 & 32 to be launched to a higher transfer orbit, requiring an expendable mission. Falcon 9 (B1037) supported its first Intelsat launch in 2017 in an expendable configuration on the Intelsat-35e mission. Galaxy 31 & 32 will be the third overall launch for Intelsat by SpaceX and its second expandable launch for Intelsat.

The two satellites ordered from Northrop Grumman are based on the GEOStar-3 satellite bus and were named Galaxy 33 & 34. Galaxy 33 & 34 were launched on a Falcon 9 (B1060-14) on Oct. 8, 2022. The duo is currently in GEO conducting testing to begin operation.

Galaxy-31, 32, 35, 36, and 37 are the five satellites ordered from Maxar using the Maxar 1300-class satellite platform. Galaxy 37 is a larger satellite and will launch solo on a Falcon 9 in 2023. Galaxy-31 & 32 are the first two Maxar satellites to be launched. Galaxy-35 & 36 will launch on an Ariane 5 with a third satellite in December 2022.

Galaxy-31 & 32 launched in a dual-stacked configuration, allowing the two satellites to launch simultaneously. Recently, SES-20 & 21 launched using an Atlas V 531 in a similar configuration as Galaxy-31 & 32. SES is also clearing out the same C-band spectrum for the FCC.

Maxar delivered the satellites to CCSFS in October 2022. SpaceX encapsulated the two satellites in Falcon 9’s 5.2-meter payload fairing and moved them to the HIF for integration.

Launch operations began at T-38 minutes with an electronic go/no-go poll for propellant loading and launch. With a “go” given, the auto-launch sequence began at T-35 minutes with RP-1 loading on both stages and LOX loading on the first stage.

RP-1 loading on the second stage was completed just before 20 minutes before launch. LOX loading began on stage two four minutes later. At T-7 minutes, the Falcon 9 first stage chilled its engines with liquid oxygen to ensure there were no thermal shocks to the engines at ignition. The T/E retracted to the launch position of 88.2 degrees at T-4 minutes and 30 seconds.

Propellant loading was complete at T-2 minutes. Two significant events then occurred simultaneously a minute later: the flight computers entered “startup,” and the propellant tanks began to pressurize to flight levels. The launch director gave the final “go” for launch 45 seconds before liftoff.

At T-3 seconds, the nine first-stage engines were commanded to ignite. A second later, the engines ignited and began a final health check. Once the engines were verified healthy and producing full thrust, the hydraulic hold-down clamps and the T/E retracted, allowing liftoff.

Falcon 9 (B1062-7) supports the Nilesat-301 mission. (Credit: SpaceX)

Shortly after liftoff, Falcon 9 began a pitch maneuver due east to follow its proper flight profile. One minute and 12 seconds into the flight, Falcon 9 passeed Max-Q.

Once propellant levels were depleted, B1051 shut down its nine first-stage engines around two minutes and 43 seconds into the flight. Three seconds later, the second stage separated, and its single Merlin Vacuum (MVac) ignited for Second Engine Start (SES)-1. B1051 then safed its flight termination system ahead of a destructive plunge back into the atmosphere, ending its nearly four-year life.

With the vehicle outside the densest part of the Earth’s atmosphere, Falcon 9’s payload fairing separate three minutes and 32 seconds into the flight.

After reaching a low Earth parking orbit, the second-stage engine shut down just eight minutes into the flight. After an ~18-minute coast in orbit, SES-2 took place for its second and last burn. This 70-second burn placed the vehicle into a GTO. Once the burn was complete, Falcon 9 coasted for five minutes before releasing Galaxy-32. Another five-minute coast then took place before Galaxy-31 was released.

Galaxy-31 (left) and Galaxy-32 (right) in final preparations before delivery to CCSFS. (Credit: Maxar)

Once in GEO, Galaxy-31 will be located at 121 degrees West — replacing Galaxy-23 — with Galaxy-32 at 91 degrees West — replacing Galaxy-17. The two satellites will provide customers with C-band broadcasting communication services.

SpaceX still has more launches planned for November. NET mid-November, Falcon 9 will launch the Eutelsat-10B satellite to GTO on B1049-11’s final flight. In mid-November, Falcon 9 will launch the CRS-26 mission using the new Dragon C211 capsule. Falcon 9 will also launch the HAKUTO-R Mission 1 lunar lander around the same time as CRS-26.

In late November, SpaceX will launch its first of three batches of OneWeb satellites. Finally, a Starlink mission is expected sometime in November.

Next year, SpaceX will launch two Intelsat satellites. One is the Galaxy-37 satellite, and the other is Intelsat-40e/TEMPO. Intelsat-40e is a part of the Intelsat Epic satellite series with a hosted NASA payload called Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument to study pollution above the United States.

(Lead photo: Falcon 9 B1051-14 on its retirement flight with the Galaxy-31 & 32 satellites. Credit: Stephen Marr for NSF)

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