At 12:12pm EST (17:12 UTC), SpaceX is set to launch a Falcon 9 rocket for the Starlink Group 4-11 mission from SLC-4E at Vandenberg Space Force Base in California.
Falcon 9 will launch a total of 50 Starlink satellites during the mission. Starlink is SpaceX’s satellite constellation designed to provide broadband internet around the globe.
The first stage of the Falcon 9 rocket will attempt a landing on the autonomous spaceport drone ship Of Course I Still Love You.
The booster for this mission will be B1063-4, which has flown a total of three previous flights. Starlink Group 4-11 will be the fourth mission for this booster.
The first flight for B1063-4 was the launch of Sentinel-6A Michael Freilich on November 21, 2020 from SLC-4E. The booster subsequently landed at LZ-4 (Landing Zone-4) minutes later.
The booster was then used on the Starlink V1 L28 mission, which launched on May 26, 2021. This time, the booster launched from SLC-40 at Cape Canaveral in Florida. It then landed on the drone ship Just Read The Instructions downrange in the Atlantic Ocean.
The most recent launch for B1063-4 was the launch of NASA’s DART (Double Asteroid Redirection Test) payload from SLC-4E on November 24, 2021. The booster then landed on Of Course I Still Love You in the Pacific.
The launch site:
The launch site for the mission, Space Launch Complex-4E (East), also known as SLC-4E was originally built as a launch facility for the Atlas-Agena D rocket, and was constructed along the neighboring SLC-4W.
Later on, the launch site was modified for the Titan family of launch vehicles. SLC-4E was the host of Titan IIID, Titan 34D, and Titan IV launches. The final Titan launched in the form of a Titan IV from SLC-4E on October 19, 2005.
The site was then refurbished to be capable of launching Falcon 9 rockets for SpaceX. The company launched their first mission from SLC-4E on September 29, 2013 with Falcon 9 v1.1. Neighboring SLC-4W was demolished by SpaceX and is now Landing Zone-4 .
The most recent launch from SLC-4E was a Falcon 9 on February 2 on the NROL-87 mission for the National Reconnaissance Office.
— Pauline Acalin (@w00ki33) February 8, 2022
In preparation for the launch, Of Course I Still Love You departed the Port of Long Beach in California on February 22 while under tow by Tug Scorpius. The recovery ships GO Quest and NRC Quest will also be stationed downrange of the launch site. NRC Quest will recover the two payload fairing, while GO Quest will provide support for the drone ship.
NRC Quest was previously used by SpaceX as the Dragon 1 recovery ship on the West Coast.
Prior to launch day, Falcon 9 was rolled out from the Horizontal Integration Facility and erected on the pad. At 35 minutes prior to liftoff, the launch autosequence will start. Simultaneously, fueling will begin on the Falcon 9 starting with RP-1 kerosene on both the first and second stages. At the same time, LOX (Liquid Oxygen) will begin flowing into the first stage booster.
The T-20 minute vent will occur next. At the same point in the countdown, RP-1 loading will be complete on the second stage. Around 16 minutes prior to launch, LOX loading on the second stage will begin.
In order to protect the nine Merlin 1D engines on the Falcon 9, the first stage engines will be chilled down. This process will prevent thermal shock at ignition. The Merlin 1D engine is a gas-generator cycle engine that runs on RP-1 and LOX. Previous versions of that engine have been used on past variants of the Falcon 9 and the first stage of the Falcon 1.
At around T-4 minutes and 30 seconds, the TE (Transporter Erector) will retract to 77.5 degrees for launch. The TE at SLC-4E has a different design compared to the ones at SpaceX’s other launch sites at SLC-40 and LC-39A in Florida.
A minute prior to launch, the Falcon 9 will enter a milestone known as startup, when the vehicle takes control of the terminal count. At T-3 seconds, the nine Merlin 1D engines will ignite.
At T0, the holddown clamps on the launch pad will release the Falcon 9, and it will begin its journey to low earth orbit. As it ascends, the launch vehicle will pitch downrange.
Following the shutdown of the nine engines on the second stage, the second stage will separate from B1063-4 at T+2 minutes and 40 seconds. The single Merlin MVac engine on the second stage will then ignite as the second stage continues to ascend. Seconds later, two stiffener rings at the end of the MVac engines will separate.
Around eight minutes 50 seconds after launch, booster B1063 will land on Of Course I Still Love You, situated in the Pacific Ocean. At the same time, the Merlin MVac engine will shut down, placing the Starlinks into a 53.2 degree orbit.
At T+53 minutes 39 seconds, the second stage will reignite for a single second to place the stack into their final
Around one hour two minutes after launch, the second stage of the Falcon 9 will release the 50 Starlink satellites into their final drop-off orbit at 306 x 316 km. After checkouts by SpaceX, the satellites will individually raise their orbits to join the operational satellites in higher orbits in the Starlink constellation.
(Featured image: A Falcon 9 launches for the NROL-87 mission from SLC-4E on February 2. Credit: Jack Beyer for NSF/L2)
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