Falcon Heavy launches largest ever geostationary satellite

by Ian Atkinson

For its third flight this year, Falcon Heavy conducted the record-breaking launch of EchoStar 24. Also known as Jupiter 3, this payload will be the heaviest satellite launched to a geostationary transfer orbit, massing 9.2 tonnes. As such, Falcon Heavy needed to expend its center core to gain additional performance, like what has been done on several recent missions.

Falcon Heavy was scheduled to lift off from Kennedy Space Center’s Launch Complex 39A at 11:04 PM EDT on July 26 (03:04 UTC on July 27). However, an abort was called with less than a minute remaining in the countdown. Another attempt on Friday occurred without issue.

Although the core will be expended, the two side boosters will perform return-to-launch site landings at SpaceX’s Landing Zones 1 and 2.

2023 is turning out to be the busiest year so far for Falcon Heavy — which has always been a low-flight cadence rocket. Following its demo mission in 2018 and two operational missions in 2019, it was not until three years later in 2022 that SpaceX’s most powerful rocket took to the skies once more.

In just the first half of this year, the vehicle flew twice — once for the United States Space Force on the USSF-67 mission, and the other for ViaSat. The latter mission was notable for being the first and only fully-expendable Falcon Heavy, needing maximum performance to deliver ViaSat-3 Americas and two secondary payloads to a near-geostationary orbit.

Jupiter 3 did not use the full expendable performance of the rocket, although it did have a mission kit on the second stage that enabled it to perform a third burn that would place the satellite closer to its final destination. The satellite was deployed into a geostationary transfer orbit (GTO) — less demanding than a near-geostationary orbit. A geostationary transfer orbit has an apogee, or its highest point, approximately 35,000 kilometers above Earth’s surface, and a perigee, or lowest point in its orbit, around 200 kilometers up.

This particular GTO lowered the inclination from 28 degrees to 10 degrees, and also raised the perigee of the transfer orbit to 8000 kilometers. This put the satellite in approximately a GTO-1000 orbit, with the satellite needing to use its onboard propulsion to provide a further 1000 m/s of velocity to reach geostationary orbit (GEO). It is more common to place the payload into an orbit in the range of 1500 to 1800 m/s from GEO, with some previous launches of heavy satellites on Falcon 9 leaving the payload more than 2000 m/s from GEO.

Jupiter 3 is a demanding payload for the launch vehicle. The satellite has a mass of 9,200 kilograms, making it both the heaviest geostationary satellite and heaviest commercial satellite ever launched, breaking the current record by nearly two tonnes.

This immense mass is due to the hardware needed to support the satellite’s high bandwidth. With a capacity of 500 gigabits per second, Jupiter 3 will double the throughput of the current two-satellite Jupiter fleet.

The Jupiter satellite fleet — owned and operated by Hughes — is aimed at delivering space-based internet to customers on Earth. This service, called HughesNet, provides connectivity to airplanes, ocean vessels, rural communities, and impoverished regions around the world. Jupiter 3 in particular will operate from the 95 degrees West slot in geostationary orbit, allowing it to serve the North and South American continents.

With its high capacity, Jupiter 3 will enable rural customers to reach download speeds of up to 100 megabits per second, comparable to average download speeds from SpaceX’s Starlink satellite internet service. Of course, the two services differ greatly in latency, with HughesNet having an average latency of roughly 600 milliseconds due to its high orbit, compared to Starlink’s 60 milliseconds. This makes a difference in high-paced internet activities like gaming but will have a lesser effect on more mundane tasks.

To support the immense satellite, Jupiter 3 is loaded with nearly 3,500 kilograms of propellants and powered by two seven-panel solar arrays. The propellant will be used for both raising the satellite into a geostationary orbit as well as stationkeeping throughout its approximately 20-year service life.

To prepare for its flight, Jupiter 3 was encapsulated inside Falcon Heavy’s fairing and trucked to the Horizontal Integration Facility at Launch Complex 39A. Once inside the hangar, the fairing was rotated horizontally to be integrated onto the Falcon Heavy launch vehicle. Currently, Falcon 9 and Falcon Heavy only support horizontal payload integration. However, vertical integration methods have been proposed and will eventually need to be constructed for some upcoming NASA and United States government payloads.

Deviating from every previous Falcon Heavy launch, SpaceX opted not to perform a static fire test. A static fire is a pre-launch rehearsal where the vehicle — usually without the payload on top — is rolled out onto the launch pad, loaded with propellants, and subjected to a launch-like countdown. At T0, the engines ignite for a brief firing before shutting down. The rocket is then rolled back into the Horizontal Integration Facility for final work.

Omitting a static fire has not been uncommon for Falcon 9 missions, especially those flying a flight-proven booster. However, this is a unique move for Falcon Heavy, as every prior launch had a pre-flight static fire.

This is likely due to the two side boosters B1064 and B1065 having already flown twice before. And although the center core B1074 is brand new, the Falcon rocket family has been extremely reliable, having a stretch of over 200 successful launches in a row, likely playing into the omission of a static fire.

With the Jupiter 3 satellite and its fairing integrated on top, Falcon Heavy was rolled out onto the launch pad at Launch Complex 39A and raised to vertical ahead of launch.

The countdown began around T-10 hours with the vehicle being powered up. At T-50 minutes, all three first-stage boosters began to be filled with a refined form of kerosene known as RP-1. Around five minutes later, liquid oxygen (LOX) began flowing in as well.

The second stage then followed, with RP-1 loading commencing at T-35 minutes and LOX around T-18.5 minutes.

Propellant loading continued until just a few minutes before liftoff to ensure it was as chilled and dense as possible, giving the vehicle the best possible performance.

At T-7 minutes, the 27 first-stage Merlin 1D engines were chilled as a small amount of LOX was trickled through their plumbing. This is to avoid thermal shock at ignition when LOX and RP-1 begin flowing through the engine in earnest.

When the count reached T-1 minute, the vehicle itself took control of the countdown followed by the propellant tanks being pressurized for flight.

At T-3 seconds, first-stage ignition commenced, as the boosters ignited in a staggered pattern to avoid inducing extreme stress on the vehicle. With engines and vehicle systems operating nominally, Falcon Heavy lifted off from Pad 39A at T0.

Less than a minute after leaving the ground, the vehicle reached max-Q, the moment of maximum aerodynamic forces.

Falcon Heavy boosters B1064 and B1065 on Landing Zones 1 and 2 at Cape Canaveral Space Force Station after the USSF-67 mission earlier this year. (Credit: SpaceX)

The side boosters were the first components to detach from the vehicle, shutting down and separating two and a half minutes after liftoff. B1064 and B1065 flip and reignited three of their nine Merlin 1D engines to boost back to Cape Canaveral. The same three engines reignited twice more — once for the entry burn to slow down the boosters and protect them from re-entry heating, and again for the landing burn. The two cores landed at Landing Zones 1 and 2, ready for minor refurbishments ahead of their next flight.

The center core burned for around a minute and a half longer, further accelerating the second stage and Jupiter 3 payload. The center core, like on the past three Falcon Heavy missions, was expended to offer additional performance to the payload.

The core and second stages separated, followed shortly after by second-stage ignition and payload fairing separation. Like most recent Falcon missions, the fairings deploy a parachute and land softly in the Atlantic Ocean to be recovered and reused.

Stage two injected itself and Jupiter 3 into a near-circular low-Earth parking orbit, where they coasted together prior to the second stage reigniting. Once it has reached the correct position in space, the second stage ignited its Merlin 1D vacuum engine for the second time, accelerating Jupiter 3 to a geostationary transfer orbit.

After a final coast of nearly 3 hours, the upper stage lit one more time to put the satellite closer to its destination. Jupiter 3 was then deployed from the second stage, and will use its onboard propulsion to reach its final geostationary orbit.

2023 is set to be the busiest year yet for Falcon Heavy. Jupiter 3 was its third flight this year, with up to two more missions left on the roster before 2024. NASA’s Psyche mission will be the vehicle’s next launch, whose complex flight profile means it must fly between October 5 and 23 of this year or it will be delayed again by around a year. Currently, the spacecraft is on track for launch.

(Lead image: Falcon Heavy on LC-39A. Credit: Sawyer Rosenstein for NSF)

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