Only a handful of days after successfully returning domestic crew launch capabilities to U.S. soil for the first time since July of 2011, SpaceX continued to steam ahead with its 2020 launch campaign lofting another batch of satellites for the company’s Starlink internet constellation. The eighth flight of Starlink satellites launched on a flight-proven Falcon 9 rocket from Cape Canaveral’s Space Launch Complex 40 at 9:25 pm Eastern time on Wednesday (01:25 UTC on Thursday).
This mission, also known as Starlink v1.0 L7, marked SpaceX’s eighth orbital launch of the year so far, and the ninth total launch (including the successful suborbital Crew Dragon In-Flight Abort test that took place on January 19. This was also the 86th launch of the company’s workhorse Falcon 9, and the 94th total launch for SpaceX since their formation in 2002.
The first stage of the Falcon 9 rocket that launched the Starlink v1.0 L7 mission is B1049.5. The designation stems from SpaceX’s internal booster numbering scheme, with “B1” marking a first stage booster, “049” indicating that it is the 49th Falcon core built, and “.5” showing that the booster was configured for its fifth launch and landing attempt.
The booster previously launched the Telstar 18V spacecraft in September 2018, the Iridium NEXT-8 mission in January 2019, and two previous Starlink missions in May 2019 and January 2020, respectively. With a successful launch on Wednesday, B1049.5 will become only the second Falcon core to fly five times, with B1048 being the first to reach this milestone in March.
These reflights are made possible because of the upgraded Falcon 9 Block 5, which features improved thermal protection on the engine section, landing legs, raceways, and interstage; heat-resistant titanium grid fins, more robust engine valves, and retractable landing legs. These upgrades were implemented in order to further optimize booster reusability and reduce refurbishment times and costs, with the capability to perform up to 10 flights before requiring significant refurbishment. The Block 5 version of Falcon 9 debuted in May 2018, and has flown on 29 missions to date.
Falcon booster B1049.5 successfully completed a static fire test – a short firing test of a rocket’s engines – on the launch pad at SLC-40 at Cape Canaveral Air Force Station on May 13 in preparation for the Starlink v1.0 L7 mission.
A Falcon 9 has roared on LC-40 signaling what appears to be a nominal static fire ahead of another Starlink mission. Of course, waiting for @SpaceX to confirm nominal status. #Starlink pic.twitter.com/WEJiBozzVi
— Julia (@julia_bergeron) May 13, 2020
The launch was originally set to occur no earlier than May 17. However, due to an Eastern Range scheduling conflict, the formation of Tropical Storm Arthur off of the coast of Florida, the lack of droneship availability, and a dwindling window of time to turnaround the droneship “Of Course I Still Love You” between missions, SpaceX decided to stand down from launching Starlink until after the launch of the Crew Dragon Demo-2 mission with NASA astronauts Bob Behnken and Doug Hurley on board had taken place.
As a result, “Of Course I Still Love You” (OCISLY, for short) was assigned to the Demo-2 mission after previously being assigned to Starlink. Luckily, since this time, SpaceX has managed to solve the problem of droneship availability, thanks to the formal addition of a new member to the East Coast recovery fleet.
After several months of refurbishment and extensive upgrades, SpaceX’s droneship Just Read the Instructions (JRTI) will mark her beginning of service in the Atlantic Ocean with an attempt at a successful recovery of B1049.5 as part of the Starlink v1.0 L7 mission.
Not to be confused with the original Just Read the Instructions used in 2015, JRTI started service in the Pacific Ocean during early 2016, beginning with the Jason-3 mission. Although the primary mission was a success, the booster failed to land successfully, and due to the lack of launches from Vandenberg, it would be almost one year later until the next landing attempt. However, starting with Iridium-1, every West Coast droneship landing was a success.
With the introduction of a West Coast landing zone, LZ-4, and the completion of the Iridium constellation, the main driver behind needing a west coast droneship, SpaceX found a more useful way to deploy their West Coast droneship.
In order to support SpaceX’s busy 2020 manifest, JRTI was moved from the West Coast to the East Coast via the Panama Canal. Along the way, she stopped in Fourchon, Louisiana—where she was built—for a several month-long refurbishment and upgrade process. She finally arrived in Port Canaveral on December 10, 2019, where she was berthed next to her sister Of Course I Still Love You (OCISLY). JRTI, which arrived carrying cargo intended to be outfitted on both droneships, was fitted out over the following months and officially entered service on May 30 when she was deployed for service.
Arrival in Florida:
When JRTI arrived in port, her deck was filled with cargo including 6 new azimuth thrusters and 12 diesel generator units. She sat much higher in the water than OCISLY due to having no ballast.
On January 13, GO Pursuit, which had previously served SpaceX as a fairing recovery vessel, delivered 2 more thrusters and 4 cylinder-shaped housing tubes, bringing the complement of new thrusters to 8, or 4 per droneship.
JRTI arrived without her old positioning thrusters attached. These now older-model thrusters are similar to the ones still installed on OCISLY (the thrusters on JRTI were less powerful) and are visible in port because they fold up out of the water.
It is understood that both ships are receiving more powerful thrusters to combat extreme currents when they are far downrange on Starlink missions. The Gulf Stream current has been putting a strain on OCISLY’s thrusters.
The new thrusters are visibly much larger. They output significantly more power, and thus require more powerful generator units on deck. Unlike the older model thrusters, they are fixed inside of their housing pods and are not retractable.
To give an idea of the upgraded droneship’s power, the four new thrusters likely give JRTI twice as much power as Hawk, a tug that normally tows OCISLY.
Work to install the new thrusters started in early February. During a several month-long process, the deck of Just Read the Instructions played host to a flurry of activity as it served as a staging point for the new hardware.
The most visible additions to the deck of JRTI are the 6 new diesel generators, along with their assorted electrical equipment.
The housing pods and their respective thrusters were joined atop stands on the deck of JRTI, and from there they were lowered to their final position on the side of the ship.
As part of her upgrades, JRTI required her own “Octagrabber,” a massive tracked robot used to secure landed boosters to the deck of a droneship.
First put into service on OCISLY in 2017, Octagrabber provides a safer alternative to manually securing a booster, which involves a team of technicians boarding the droneship and manually attaching jacks and chains. This method can be dangerous especially during rough sea conditions. Octagrabber, on the other hand, remotely drives out from the safety of its “garage,” stops directly underneath the booster, and raises 4 hydraulic arms that attach to each of the Falcon’s hold-down points.
After the Arabsat-6A mission, Octagrabber was also modified to be compatible with Falcon Heavy center cores, which have a slightly different hold-down system.
A few miles from Port Canaveral at SpaceX’s Cidco Road manufacturing complex, a second Octagrabber was manufactured for use on JRTI.
As technicians ready JRTI to become operational, another crew has been quietly working on Ocatgrabber 2.0 at the Cidco Rd. facility in Cocoa, FL. Today the booster stabilizing robot has arms raised. They may be close to delivery day. #JRTI #SpaceXFleet pic.twitter.com/d9sa2qOADl
— Julia (@julia_bergeron) May 17, 2020
On the morning of May 13, Just Read the Instructions left Port Canaveral for the first time. Under the power of tug Eagle, she was towed a few miles offshore where she successfully completed her first sea trial.
After returning, more work was quickly completed. Much of the deck was cleared and, several days later, another sea trial was conducted. Following this sea trial, JRTI was returned to port so that preparations—including the installation of her new Octagrabber—could be made for supporting her first mission on the East Coast.
Entering Service and the Future:
Amidst the post-launch excitement of Demo-2, Just Read the Instructions departed Port Canaveral with tug Finn Falgout in support of the latest Starlink mission.
With two launch pads, and now two operational droneships on the east coast, SpaceX can now theoretically achieve a higher launch cadence than before. The company is also now able to perform a rare type of Falcon Heavy recovery—one where the center core is expended, but both side boosters land far downrange on droneships.
However, these new capabilities may not be fully realized right away, as having an upgraded JRTI finally in service means the company can afford to take OCISLY out of service to receive her own set of upgrades.
In addition, SpaceX still only has one droneship support ship, GO Quest. This could complicate recovery additions, as GO Quest (currently the longest-serving ship in SpaceX’s fleet) is necessary for transporting the crews that are crucial to ensuring the success of Falcon 9 recoveries at sea. For this mission, GO Quest opted not to return home to Port Canaveral after supporting Demo-2; rather, the ship resupplied in North Carolina in order to meet Just Read the Instructions at the Starlink landing zone in time.
Starlink v1.0 L7 Payload:
With JRTI and her support crew on station in the landing zone about 630 kilometers (394 miles) downrange in the Atlantic, that enabled a successful landing of Falcon 9 core B1049.5 to take place after launching the next batch of Starlink satellites to low Earth orbit.
Falcon 9 B1049.5 lands on JRTI!
Five landings for this booster. JRTI makes her first East Coast catch! pic.twitter.com/YCtenuPpb4
— Chris B – NSF (@NASASpaceflight) June 4, 2020
60 Starlink internet satellites will be launched on Wednesday’s mission. The v1.0 L7 mission will be the seventh launch of operational satellites, and the eighth batch of 60 spacecraft when accounting for the Starlink v0.9 mission, launched in May 2019.
Each satellite has a launch mass of approximately 260 kilograms (573 pounds), thereby adding up for a total of 15,600 kilograms (34,392 pounds) of payload. The operational Starlink missions are the heaviest payloads that SpaceX has launched to date.
The satellites will be initially deployed into an elliptical low Earth orbit, with a 53 degree inclination. After launch, SpaceX will conduct data reviews of each satellite to ensure that they are in working order before proceeding with orbit raising operations. One these checkouts are complete, the operational satellites will use their Krypton-fueled Hall thrusters to raise their orbit to the operational 550 kilometers (342 miles) altitude, while those that do not function properly after launch will remain in the initial deployment orbit to quickly deorbit.
On this mission, SpaceX launched a single Starlink satellite with a deployable sun shade or visor, nicknamed “VisorSat”. This visor will deploy during satellite separation from Falcon 9, and will attempt to block sunlight from reflecting off of a majority of the satellite body, thereby reducing the satellite’s intrinsic brightness as seen from the ground.
This visor will be implemented on all future Starlinks as a means of mitigating the reflectivity of the satellites while on orbit, as well as avoiding any thermal issues due to black-colored materials. Previous attempts at diminishing the satellite’s brightness by darkening the phased arrays and parabolic antennas (as was the case with a “DarkSat” launched in early 2020) still allowed some light to reflect, including in the infrared spectrum.
The Starlink v1.0 L7 mission is part of the initial deployment phase for the Starlink constellation, which will consist of 1,584 satellites. Additional phases consisting of additional satellites will soon follow. SpaceX hopes to launch two batches of satellites per month in 2020.
The countdown began at T-38 minutes to liftoff, when the launch director conducted a “go/no-go” poll for propellant loading. When all conditions were clear to proceed, loading of RP-1 fuel into both stages of the Falcon 9 rocket began 35 minutes before launch, along with liquid oxygen (LOX) loading into the first stage. LOX loading into the second stage began at the T-16 minute mark.
At 7 minutes before liftoff, the LOX pre-valves on the nine Merlin 1D engines on the first stage opened to allow super-chilled liquid oxygen to flow through the engine and condition the turbopumps for ignition, in a step known as “engine chill”. This assists in preventing thermal shock, which could damage the engines upon startup.
The final minute of the countdown saw Falcon 9’s onboard flight computers carry out their remaining checks on the launch vehicle and pressurize its propellant tanks for flight. At T-45 seconds to liftoff, the launch director gave the final “go” for launch.
At T-3 seconds, the nine Merlin 1D engines on the first stage ignited, with liftoff occurring at T-0 following a quick final check on the vehicle’s health by the onboard flight computers.
After lifting off from Cape Canaveral’s SLC-40, Falcon 9 began to pitch downrange as it accelerated towards orbital velocity. The vehicle passed through the region of maximum aerodynamic pressure, or “Max-Q”, at around a minute and 12 seconds into the flight. This is the point during launch when the mechanical stresses on the rocket are at their greatest.
The first stage engines continued to burn until the T+2 minute 32 second mark, when all nine engines shut down simultaneously in an event known as Main Engine Cutoff, or MECO. Shortly afterward, the first and second stages of Falcon 9 separated, and the vacuum-optimized Merlin engine on the second stage ignited and began to propel the 60 Starlink satellites to their initial orbit.
Falcon 9’s 5-meter diameter protective payload fairing deployed at 3 minutes and 11 seconds into the flight. Both fairing halves descended back to Earth to be recovered by SpaceX’s two fairing recovery vessels, GO Ms. Tree and GO Ms. Chief. These recovery attempts occurred at around 45 minutes after launch.
While the second stage and payload continued to orbit, Falcon core B1049.5 conducted its own set of maneuvers to attempt a propulsive landing on the deck of “Just Read The Instructions”. The completion of the booster’s entry burn is occurred at the T+7 minute 4 second mark, with a landing at 8 minutes and 42 seconds into the mission. This was successful.
Falcon 9’s upper stage and 60 Starlink satellites completed their only burn of the mission at 8 minutes and 58 seconds, with a short coast phase following after Second Engine Cutoff, or SECO.
The 60 Starlink satellites deployed 14 minutes and 54 seconds into the flight. This marked the completion of the launch phase of the mission, and will allow the spacecraft to begin maneuvering to their respective slots in low Earth orbit.
The Starlink v1.0 L7 mission was one of multiple launches on the schedule for SpaceX in June. The ninth launch of Starlink satellites on a Falcon 9 is tentatively scheduled to occur in June, while the third GPS Block III spacecraft will fly on a reusable Falcon 9 no earlier than June 30.
SpaceX hopes to launch 24 Starlink missions before the end of 2020.