The Globalstar-2 FM15 spacecraft, built by Thales Alenia Space, is part of the Globalstar second-generation Low Earth Orbit (LEO) communications satellite constellation. While Globalstar-2 FM15’s 24 sisters have been deployed between 2010 and 2013, it remains on Earth as a ground-based backup spacecraft until now. Now, when the existing satellites start to show their age, it will be launched into the field to strengthen the network.
Globalstar uses its constellation of satellites to provide voice and data communications around the world. The company’s first-generation satellite constellation, deployed between 1998 and 2000, consists of 48 operational satellites and in-orbit spares. The second-generation system was originally designed with 32 satellites, but was later scaled down to the 24 currently in orbit.
These second-generation satellites – including FM15 – are based on Thales’ Extended Lifetime Bus 1000 (ELiTeBus-1000) platform, which has an expected operational life of 15 years. The 24 satellites already in orbit were launched by Soyuz-2-1a/Fregat rockets in groups of six. Globalstar plans to replace the satellites with a third-generation spacecraft that will be used in phases starting in 2025. Earlier this year, the company awarded a contract with Canada’s MDA to build the first 17 replacement satellites.
FM15 is part of an initial batch of 25 satellites procured for Globalstar’s second-generation satellite constellation. The company had intended to order more satellites as spares. However, after a contract dispute between the two companies in 2011, Thales turned down orders for another six spacecraft. This makes FM15 the only spare satellite available to Globalstar, which has been retained to this day. Launching FM15 will help keep the constellation operational until the MDA-built satellites begin to come online.
The Globalstar-2 satellite has a mass of 700 kilograms, far less than the carrying capacity of SpaceX’s Falcon 9 rocket. Additionally, the Falcon 9’s first stage booster landed on the Autonomous Spaceport Drone Ship (ASDS) downstream of Cape Canaveral.
ASDS is typically used when rockets carry heavier payloads or are aimed at higher orbits, where performance constraints prevent it from flying in a Return To Launch Site (RTLS) fashion.
These factors led to rumors that a secret U.S. government payload also boarded the rocket during Sunday’s launch, entering orbit with Globalstar-2 FM15.
If so, it’s an unusually high degree of secrecy: For most classified launches, the agency responsible is at least identified, and the launch is announced — often with an unclassified mission name, such as U.S. National The name of the NRO Launch (NROL) used by the Reconnaissance Office (NRO) mission.
Images of the secondary booster on the coast stage show a rather unique setup on the adapter.
One notable exception to this practice in the past was a Falcon 9 launch in January 2018. That launch carried a satellite called Zuma, built by Northrop Grumman for an undisclosed U.S. government customer. The Falcon performed the RTLS mission and successfully launched Zuma into the planned low-Earth orbit at an inclination of about 51°.
However, as part of the payload, Northrop Grumman provided their own separation mechanism to attach the Zuma to the rocket. The mechanism reportedly failed to work. This means that while the Falcon rocket deorbits itself to safely dispose of itself, the satellite is still attached to the Falcon’s final stage, which burns up on re-entry into Earth’s atmosphere.
Since Globalstar’s constellation operates in a 52° orbit, if FM15 has a common passenger — possibly a successor or replacement for Zuma, the rocket won’t have to make particularly significant adjustments to its orbit to deploy the two satellites in on its planned track. Zuma’s launch, on the other hand, does not require ASDS for recovery — although this could be explained by the additional presence of Globalstar satellites and the need to deploy the satellites to different orbits.
Two NRO launches in recent years have flown to similar orbits, both on Falcon 9 rockets. NROL-76 launched in May 2017, and NROL-108, consisting of two satellites, launched in December 2020. It is unclear whether the tasks are related, and observers speculate that they may be technology demonstrators.
It’s also possible that the second payload could be another lightweight satellite — or several smaller satellites — giving the Falcon 9 more performance for orbital maneuvers. This could allow it to unload its secret cargo to a completely different orbit after first dropping the Globalstar spacecraft into its planned orbit.
In any case, if the secrecy of Sunday’s launch is not officially acknowledged, the first signs of Falcon 9’s deployment into orbit may come from amateur satellite watchers posting their observations to mailing lists such as SeeSat-L middle.
Before payloads can be observed in orbit, however, they first have to get there. SpaceX lifted off from Spaceport 40 at Cape Canaveral Air Force Station on Sunday’s mission using a Falcon 9 rocket.
The Falcon 9 is a two-stage rocket consisting of a reusable first stage booster and an expendable second stage. The payload fairing — which can also be recovered and reused — encapsulates the satellite in the nose of the rocket. SpaceX launched the first Falcon 9 in June 2010, and the rocket has successfully completed more than 150 missions since then, only one of which has failed.
During the early stages of the flight, nine Merlin-1D engines developed in-house by SpaceX powered the rocket’s first stage. After liftoff from SLC-40, the rocket rolled and tilted in a northeast direction to align with its target orbit. After about 70 seconds of flight, it passed Max-Q, the zone of maximum dynamic pressure, and entered supersonic speed at the same time.
The stage that powers Sunday’s mission is the booster B1061-9. Already a veteran with eight launches, it flew for the first time in November 2020. Its first two missions were dedicated to NASA’s Commercial Crew Program (CCP), assisting the program in its first mission to the International Space Station by propelling the Crew Dragon spacecraft Resilience and Endeavour into orbit on their respective Crew-1 and Crew-2 missions Operates crew rotation flights.
The booster made its first uncrewed launch in June 2021, when it helped SiriusXM deploy the SXM-8 communications satellite, and then the cargo Dragon mission CRS-23 in August. The fifth launch of B1061 deployed NASA’s Imaging X-ray Polarization Probe (IXPE) last December. The booster has since conducted one Starlink launch and two most recent multi-payload transport missions in April and May.
The B1061-9, which powered Sunday’s mission, flew for about 2 minutes and 31 seconds before its engines shut down: an event known as a main engine shutdown (MECO). Classification occurs approximately four seconds later, the Falcon’s second stage continues to orbit with its payload, and B1061-9 begins its return to Earth. The second stage fired its single Merlin Vaccum (MVac) engine, a vacuum-optimized version of the Merlin-1D, about 8 seconds after staging.
The fairing halves detached from the rocket at T+2:54, completing their job of protecting the payload during atmospheric climb. After re-entry, each fairing half will deploy a parachute as it descends into the Atlantic Ocean, where SpaceX’s recovery ship will pick them up and send them back ashore for future reuse.
The second stage completed a series of three burns before deploying the GlobalStar payload at T+1:53:21. If any unannounced hitchhiking payloads were actually deployed on Sunday’s mission, it’s unclear whether they separated before or after GlobalStar.
B1061-9 returned to Earth as the second stage continued toward orbit to accomplish the primary objective of Sunday’s mission. After staging, it oriented itself and deployed grid wings that would help guide it as it fell back into the atmosphere. Since the drone ship has been positioned so close to the ground that no pick-up burn is required for this mission, it only needs to perform entry and landing burns for this flight.
Entry burn helps reduce heating of the platform during re-entry, during which the thrusters use three Merlin-1D engines. Shortly before touchdown, the middle engine was fired again for the landing burn, and at the same time, the B1069-9 was slowed down for a soft landing on the deck.