After a little under three months without a mission from Florida’s launch pads, SpaceX is set to launch a Falcon 9 rocket Monday morning. Liftoff from SLC-40 at the Cape Canaveral Air Force Station is scheduled for 9:50 to 10:01 AM EST (14:50 to 15:01 UTC) with the preferred launch time being 09:56 AM EST (14:56 UTC). The mission will carry the first group of operational Starlink satellites to orbit.
The launch is the first from Cape Canaveral since the final ULA Delta IV Medium mission on August 22, and the first SpaceX launch since AMOS-17 on August 6. The mission is the 9th Falcon 9 launch this year, and the 11th SpaceX launch of 2019.
For Monday’s Starlink L1 launch window, the US Air Force’s 45th Weather Squadron predicts an 80% chance of acceptable weather. Should the launch require a delay to Tuesday, for any reason, the Air Force predicts a 70% chance of favorable weather.
New Reusability Milestones
After launch, the first stage of Falcon 9 will attempt a propulsive landing on Of Course I Still Love You, an Autonomous Spaceport Drone Ship (or ASDS), about 629 kilometers downrange in the Atlantic Ocean. The droneship departed Port Canaveral, towed by tug Hawk, on November 7.
The first stage of this mission is B1048.4, which is in line to become the first Falcon 9 core to launch 4 missions. The stage previously launched the Iridium-7 and SAOCOM-1A missions out of Vandenberg Air Force Base in California, followed by the Nusantara Satu mission from Florida.
The first stage successfully completed a pre-launch static fire test on November 5.
In another reuse milestone for SpaceX, the Starlink L1 mission will reuse the payload fairing from the Arabsat-6A Falcon Heavy mission, launched on April 11. This is the first time ever that a rocket payload fairing will be flown on two missions.
The payload fairing protects the satellites from aerodynamic forces during ascent through the dense parts of Earth’s atmosphere. Once the rocket reaches a high enough altitude, the fairing splits in half and falls back to Earth under parafoils.
In yet another first, SpaceX will attempt to recover both fairing halves via ship, using the GO Ms. Tree and GO Ms. Chief fairing recovery vessels.
The fairing supporting this mission previously flew on Falcon Heavy’s Arabsat-6A mission pic.twitter.com/iTgqqtl1pW
— SpaceX (@SpaceX) November 5, 2019
The fairing halves to be reused on Starlink L1 were not caught by fairing recovery ships after Arabsat-6A, but were retrieved from the ocean surface in good enough condition for reflight.
The first successful catch of a fairing half occurred on June 25 when GO Ms. Tree caught one fairing half from the STP-2 Falcon Heavy mission.
Since then, SpaceX has added a second fairing recovery ship to their fleet, GO Ms. Chief, in order to catch both fairing halves. Starlink L1 will be the first mission supported by GO Ms. Chief.
The two fairing-catching ships departed Port Canaveral on November 8 and will be stationed approximately 730 kilometers downrange.
Beginning the Operational Starlink Constellation
Inside the payload fairing for this launch are 60 Starlink satellites destined for Low Earth Orbit. The satellites are the first group of operational satellites for SpaceX’s satellite internet constellation following the launch of 60 test satellites on May 23.
The operational satellites most notably include Ka-band antennas, which were omitted from the test satellites. The operational satellites are also designed to be completely destroyed upon reentry, whereas about 5% of a Starlink test satellite’s components are expected to survive reentry.
Each satellite has a liftoff mass of 227 kilograms, which amounts to 13,620 kilograms of payload total. This matches the first dedicated Starlink mission as the heaviest payload SpaceX has ever launched.
After launch, the satellites will use their Krypton-fueled Hall thrusters to maneuver into their operational orbits. The first phase of Starlink deployment is planned to include 1,584 satellites in 550 kilometer altitude orbits, inclined 53 degrees. Additional deployment phases to different orbital altitudes will follow the completion of phase one.
On November 7, the Federal Communications Commission (FCC) granted SpaceX a Special Temporal Authority (STA) to change the deployment altitude of the satellites. Instead of deploying into a 440 kilometer orbit, like the 60 test satellites launched in May, the operational satellites will be deployed into a 280 kilometer orbit.
After launch, SpaceX will establish contact with each satellite and confirm each spacecraft’s health before maneuvering them to 350 kilometer orbits. Any satellites not functioning properly after launch will be left in the initial 280 kilometer orbit to naturally deorbit. Satellites that pass their health checks will use the 350 kilometer orbit to drift to their orbit planes, where they will then maneuver up to their operational altitude of 550 kilometers.
SpaceX did not late on Sunday that one of the satellites may not make it to an operational orbit, but that issue won’t halt the launch.
Team is go for launch of 60 Starlink sats tomorrow—heaviest payload to date, first re-flight of a fairing, and first Falcon 9 to fly a fourth mission. Watching 1 sat that may not orbit raise; if not, 100% of its components will quickly burn up in Earth’s atmosphere pic.twitter.com/OrI8L0ntFK
— SpaceX (@SpaceX) November 11, 2019
After the Starlink L1 launch, SpaceX will turn their focus towards a slate of upcoming Cape Canaveral launches. Next up is the CRS-19 Cargo Dragon mission to the International Space Station, scheduled to occur no earlier than December 4.
Also upcoming is the JCSAT-18/Kacific-1 satellite, launching no earlier than December 15. Finally, the Crew Dragon In-Flight Abort test is also targeted to launch in the near term, on a schedule that is heavily dependent on a successful static fire test of the spacecraft’s abort motors.
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