SpaceX to launch Starlink v1.0 L23 mission

SpaceX is ready to launch yet another batch of 60 Starlink satellites on the Starlink v1.0 L23 mission. Liftoff from Space Launch Complex 40 (SLC-40) at the Cape Canaveral Space Force Station is targeted for April 7 at 12:34 PM EDT (16:34 UTC).

This will be the third time a Falcon 9 first stage will fly a seventh mission, the tenth Falcon 9 flight of the year, and the first in April. This flight will likely be the last SpaceX mission prior to the Crew-2 launch later this month.

Booster Reuse and Launch Preparation

SpaceX is using a flight proven Falcon 9 Block 5 booster, B1058-7 – with the “-7” signifying the stage’s seventh flight. This is the third time a booster will be used on a seventh flight.

B1058 is one of five Falcon 9 boosters introduced in 2020. It first supported the Crew Demo-2 mission in May 2020, becoming the first SpaceX rocket to launch crew into space. It then supported the ANASIS-II mission in July 2020, when it achieved the fastest Falcon 9 booster turnaround at the time with 51 days between launches. 

It later supported the Starlink v1.0 L12 mission in October 2020, followed by the SpaceX CRS-21 mission in December 2020, the first launch of a Cargo Dragon 2 spacecraft. In 2021, B1058 supported the Transporter-1 rideshare mission in January and the Starlink v1.0 L20 mission in March.

Falcon 9 B1058-6 launches the Starlink v1.0 L20 mission in March 2021 – via Stephen Marr for NSF/L2

This time, B1058 will have a turnaround time of 27 days and 8 hours. This makes Starlink v1.0 L23 the second fastest turnaround for Falcon 9, just barely beat by B1060 on the Starlink v1.0 L18 mission at 27 days and 4 hours.

However, this launch will give B1058 the fastest average turnaround time at 52 days. These fast turnaround records help SpaceX rapidly reuse Falcon 9 boosters in support of Starlink and other missions.

B1058 will attempt to land on the SpaceX autonomous spaceport drone ship Of Course I Still Love You (OCISLY), which is stationed ~633 kilometers downrange. OCISLY left Port Canaveral on April 3 to support Starlink v1.0 L23.

This mission will also use a flight proven set of payload fairings. One fairing half, the passive half, supported the Starlink v1.0 L12 mission in October 2020.

The other half, the active half, supported the AMOS-17 mission in August 2019, the Starlink v1.0 L6 mission in April 2020, and the Starlink v1.0 L15 mission in November 2020. This will be the second time a fairing half has flown four missions. 

Once the fairings separate from the Falcon 9, they will be recovered by the fairing recovery vessel Shelia Bordelon.

This time around, SpaceX did not conduct a static fire test prior to launch. Since Starlink v1.0 L8 with B1059-3, several missions have not required a static fire test due to the reliability of the flight proven first stage boosters. For non-Starlink missions, the launch customer can request a static fire test before a launch.

Launch

At T-38 minutes, a final Go/No-Go poll is conducted for propellant loading. Three minutes later, the auto-launch sequence starts, beginning RP-1 fuel and Liqud Oxygen (LOX) begin loading on the first stage and RP-1 loading on the second stage.

Second stage RP-1 loading then completes at T-20 minutes, before LOX loading begins at T-16 minutes.

At T-7 minutes, the Falcon 9 begins engine chill to ensure there were no thermal shocks to the engines at ignition. At T-4 minutes, the transporter/erector retracts to 88.2 degrees for launch.

All propellant loading completes at T-2 minutes. At T-1 minute, Falcon 9 enters “startup” and the flight computer takes control of the countdown. At the same time, both stages begin to pressurize for flight.

Three seconds before liftoff, the engine controller commands the first stage engines to ignite. 

Once its engines are at full thrust and verified to be healthy, the hydraulic hold-down clamps release the Falcon 9, and the transporter/erector retracts to 45 degrees as the vehicle lifts off.

Falcon 9 B1058-5 launches the Transporter-1 mission in January 2021 – via Thomas Burghardt for NSF/L2

A few seconds later, the Falcon 9 begins a pitch program, to fly northeast from Cape Canaveral towards a 53 degree inclined orbit. At T+1 minute 12 seconds, the Falcon 9 reaches Max-Q, where the aerodynamic forces are at their peak.

At T+2 minutes 33 seconds, the nine first-stage engines shut down, followed by stage separation a few seconds later. The single Merlin Vacuum engine on the second stage then ignites.

The first stage then deploys its grid fins and begins a flip maneuver to prepare for re-entry. At around T+3 minutes, the payload fairings separate. 

After six minutes into the flight, the first stage reignites three of its engines to slow down and protect itself from reentry. The entry burn lasts around 20 seconds.

A couple of minutes later, the first stage reignites a single engine to land on OCISLY. If successful, this will be the 79th first stage landing for Falcon 9. The first stage will then be taken back to Port Canaveral to begin inspections and refurbishments for its eighth flight.

While the first stage is landing, the second stage shuts down its engine and enters its initial parking orbit. It will then coast for about 45 minutes before restarting its Merlin Vacuum engine for just a single second. That second burn will place the Falcon 9 and 60 Starlink satellites into a 260 x 280 kilometer orbit. 

Falcon 9 B1058-1 lands after supporting the Crew Demo-2 mission in May 2020 – via SpaceX

After the burn is complete, the second stage will begin to a slow spin in preparation for Starlink deployment. After the spin has started and another 15-minute coast is complete, the 60 Starlink satellites will separate from the second stage. The Starlink satellites will then begin maneuvering to their 550 kilometer operational orbits. 

Starlink

Starlink is SpaceX’s low Earth orbit satellite internet constellation that aims to deliver fast, affordable, and low latency service where internet is currently either unavailable or expensive. 

The Starlink constellation is set to consist of five orbital shells, with the Starlink v1.0 L23 mission continuing to build the first. This shell will consist of 1,584 satellites in the aforementioned 550 kilometer altitude, 53 degree inclination orbit. The first of these satellites were launched in November 2019, and the first shell will be completed with the Starlink v1.0 L28 mission. 

Once the shell is complete, Starlink will provide coverage to over 80% of the Earth’s surface.

Each of the v1.0 Starlink satellites weighs 260 kilograms and is designed to be compact. The satellites are equipped with a Hall-effect Krypton Ion Thruster to maneuver in space. 

Since May 2019, 1,445 Starlink satellites have launched into space, of which 1,319 are still in orbit.

Starlink v1.0 L23 will likely be the final launch before SpaceX begins to focus on the Crew-2 mission, lifting off from LC-39A on April 22.

(Lead photo of B1058-2 prior to ANASIS-II – via Stephen Marr for NSF)

The post SpaceX to launch Starlink v1.0 L23 mission appeared first on NASASpaceFlight.com.

About the author