Two days later than planned, SpaceX’s 25th Falcon 9 of the year roared aloft from Space Launch Complex (SLC)-40 at Cape Canaveral Air Force Station, Fla., at 11:30 a.m. EST Sunday. Within nine minutes of breaking the shackles of Earth, blackened and scorched from yet another high-energy descent, the veteran B1051 first stage—embarking on a record-tying seventh flight for a Falcon 9 core—alighted smoothly on the deck of the Autonomous Spaceport Drone Ship (ASDS), “Just Read the Instructions”, in the Atlantic Ocean.
And 32 minutes into flight, the heavyweight SXM-7 high-powered broadcasting satellite was deployed on the first leg of its long trek up to Geostationary Orbit, some 22,300 miles (35,900 km) above the Home Planet.
Including this morning’s liftoff, the 25 flights have been conducted using only 11 Falcon 9 cores. Two of those cores have logged three launches, a further two have done four and today’s outing by B1051 makes it the first booster to record a fifth mission in a single calendar year.
Launch of SXM-7 was originally targeted for a two-hour “window” on Friday, with a highly favorable weather outlook, and fueling of the Falcon 9 with liquid oxygen and a highly-refined form of rocket-grade kerosene (known as “RP-1”) proceeded without incident. But only 30 seconds prior to the scheduled 12:55 p.m. EST launch time, the ominous words “Hold, Hold, Hold” echoed over the countdown net and the clock was halted.
“Standing down from today’s launch attempt to perform additional ground system checkouts,” SpaceX later tweeted. “Teams are working toward no earlier than Sunday, 13 December for next launch attempt of SXM-7.”
Weather for both Sunday and Monday, at first glance, appeared considerably more dicey, with an increasing onshore flow expected to yield only a 60-percent probability of acceptable conditions at T-0. “The front in the Gulf is forecast to wash out across North Florida on Sunday, leaving unsettled conditions across the Spaceport for a late Sunday morning launch attempt,” noted the 45th Weather Squadron in its Saturday morning update.
“The primary concerns will be Cumulus Clouds associated with showers in the vicinity of the Spaceport. Increasing high clouds are currently expected to be too cold for a Thick Cloud Layer concern. A second and stronger system is forecast to move across the southeastern U.S. late Sunday into Monday.” Both launch windows on Sunday and Monday were timed to open at 11:22 a.m. EST and close at 1:21 p.m. EST.
Primary payload for today’s launch is the 15,000-pound (7,000 kg) SXM-7 high-powered broadcasting satellite, bound for Geostationary Orbit and an expected 15-year operational lifetime. Provided by New York-headquartered SiriusXM Holdings, Inc., the satellite will support Digital Audio Radio Service (DARS) capability.
Contracts to build SXM-7 (and its twin, SXM-8, targeted to fly atop another Falcon 9 next year) were signed with Space Systems/Loral (SS/L)—now a subsidiary of Maxar Technologies—back in July 2016. Both are based upon the tried-and-true SSL-1300 “bus” and can generate more than 20 kilowatts of electrical power and feature large unfurlable S-band antenna reflectors to broadcast to radios without the need for large ground-based dishes.
When it enters active service, SXM-7 will replace an earlier satellite, XM-3, which is now nearing the end of its lifetime, having been placed into orbit way back in March 2005.
“SiriusXM provides an unparalleled variety of audio entertainment for radio listeners in North America,” said John Celli, then-president of SS/L at the time of the July 2016 contract award. “We have a long history of working with SiriusXM to develop some of the world’s most advanced satellites, which broadcast to cars and radios for the home, office, and mobile devices. We are honored to be selected to build two additional satellites that will reinforce and augment the fleet’s capability.”
SXM-7 arrived at Cape Canaveral Air Force Station in mid-October 2020, where it underwent functional testing and fueling, ahead of encapsulation aboard the Falcon 9. “SXM-7 will deliver the highest power density of any commercial satellite on-orbit,” noted Maxar, “sending more than 8,000 watts of content to the Continental U.S., Canada, Puerto Rico and the Caribbean, increasing the quality of signal for SiriusXM subscribers.”
This morning’s on-time liftoff made SXM-7 only the second SpaceX-launched geostationary payload in 2020, following July’s ANASIS-II, and all told the Hawthorne, Calif.-headquartered provider has placed no fewer than 34 communications satellites into orbit since December 2013. This figure has included the first commercial comsats provided by Turkmenistan, Bulgaria and Bangladesh.
Ignition of B1051’s nine Merlin 1D+ first-stage engines came on time and the 230-foot-tall (70-meter) Falcon 9 powered away from SLC-40 under a total of 1.5 million pounds (680,000 kg) of thrust. A little over two minutes later, its job done, B1051 separated from the stack and commenced an intricate descent, controlled by engine burns and hypersonic grid-fins, to alight smoothly on the deck of the ASDS. It was the fifth pinpoint landing of a booster on “Just Read the Instructions” since June, which was moved to support an increased-tempo East Coast flight manifest after having previously welcomed home seven Falcon 9 cores between January 2017 and January 2019.
With B1051 gone, the baton passed to the Falcon 9’s second stage, whose single Merlin 1D+ Vacuum engine burned for almost six minutes to deliver SXM-7 towards GTO. Payload separation was confirmed about 32 minutes after launch. Returning from its latest flight, B1051 is now one of only two Falcon 9 cores—the other being the recently-landed B1049—to have launched as many as seven times.
First used to deliver SpaceX’s uncrewed Demo-1 mission of Crew Dragon to the space station in March 2019, it went on to pull double duty at Vandenberg Air Force Base, Calif., the following June, when it launched Canada’s three-satellite Radarsat Constellation Mission (RCM). B1051 went on to launch four batches of Starlinks—a total of 237 satellites—as well as the BlackSky Global-7 and Global-7 imaging satellites between January and October 2020. Flying again today with SXM-7, it becomes the first Falcon 9 core to record as many as five launches in a single calendar year.
Coming up next, perhaps as soon as Thursday, another booster is slated to lift the highly secretive NROL-108 payload to orbit on behalf of the National Reconnaissance Office. Launching from historic Pad 39A at the Kennedy Space Center (KSC) in Florida, NROL-108 will represent SpaceX’s fourth fully classified mission since May 2017.