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May 07, 2023

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Watch our live coverage of the countdown and launch of a SpaceX Falcon 9 rocket

Watch our live coverage of the countdown and launch of a SpaceX Falcon 9 rocket on the Starlink 6-4 mission at 5:56 a.m. EDT (0956 UTC) on June 3 from Space Launch Complex 40 at Cape Canaveral Space Force Station, Florida. Follow us on Twitter.

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SpaceX plans to launch a Falcon 9 rocket from Cape Canaveral just before sunrise Sunday with 22 upgraded Starlink internet satellites, the first of two SpaceX missions scheduled to lift off from Florida's Space Coast in less seven hours.

The first of the two launches is scheduled to take off from pad 40 at Cape Canaveral Space Force Station at 5:56 a.m. EDT (0956 UTC). A 229-foot-tall (70-meter) Falcon 9 rocket will loft 22 second-generation Starlink internet satellites into orbit on a mission SpaceX calls Starlink 6-4.

A little more than six hours later, at 12:12 p.m. EDT (1612 UTC), another Falcon 9 is set for liftoff a few miles up the coast from pad 39A at NASA's Kennedy Space Center. That mission will send an unpiloted Cargo Dragon supply ship on a flight to the International Space Station.

But the weather forecast is iffy for both launch opportunities. There's a 50% chance of acceptable weather conditions for launch of the Starlink 6-4 mission before sunrise Saturday, then a 60% chance of bad weather for the midday launch time for the Cargo Dragon mission.

If both missions launch as scheduled, it would be the shortest turnaround between two space launches on Florida's Space Coast since 1966.

The Starlink 6-4 mission will continue launching SpaceX's new Starlink V2 Mini satellite platform fitted with improved phased array antennas, capable of four times the communications capacity of earlier generations of Starlink satellites, known as Version 1.5. The Starlink satellites beam internet signals to consumers around the world.

SpaceX delayed the Starlink 6-4 mission from June 1 after a transporter carrying the Falcon 9's payload fairing containing the batch of Starlink satellites ran into an electrical line at the Florida spaceport. The incident briefly knocked out electricity at Kennedy Space Center on May 27, and power flashes were visible in the sky over the launch base.

The transporter was carrying the Starlink satellites inside their payload fairing from a processing facility to the Falcon 9's hangar at pad 40. It wasn't clear whether SpaceX swapped out the Starlink satellites and payload fairing that struck the electrical lines for a new set of spacecraft. The payload fairing containing the satellites slated for launch Sunday traveled from SpaceX's Roberts Road facility at Kennedy Space Center to the hangar at pad 40 on Friday.

SpaceX technicians at the pad 40 hangar planned to rotate the fairing horizontal and connect it with the Falcon 9 rocket, then roll the entire launch vehicle to the pad and raise it vertical in preparation for Sunday morning's countdown.

Despite their name, the Starlink V2 Mini satellites are nearly times as massive and more than four times larger than the older Starlink V1.5 satellites. Like all Starlink launches, the Falcon 9 rocket will released the new batch of internet satellites into an orbit below their final operating altitude. The satellites will then use on-board propulsion to raise their orbits to an altitude of more than 300 miles (500 kilometers).

The "Mini" moniker refers to SpaceX's plans to launch an even larger full-size Starlink V2 satellite design on the company's huge new Starship rocket. The Starship has nearly 10 times the payload lift capability of a Falcon 9 rocket, with greater volume for satellites, too.

The full-size Starlink V2s will be capable of transmitting signals directly to cell phones. But with the Starship rocket not yet operational following its first full-scale test flight in April, SpaceX began launching second-generation satellites on Falcon 9 rockets and developed the V2 Minis to fit on the company's existing launch vehicles.

The first group of 21 Starlink V2 Mini satellites launched Feb. 27 on a Falcon 9 rocket, but some of those spacecraft were decommissioned and intentionally steered back into the atmosphere due to technical problems. Elon Musk, SpaceX's founder and CEO, said the first batch of Starlink V2 Mini satellites were "experiencing some issues, as expected." SpaceX planned to thoroughly test the satellites before boosting them above the altitude of the International Space Station to their final operating orbit.

SpaceX continued launching older-model Starlink V1.5 satellites on a series of missions in March and April, before resuming deployment of the bigger, more capable Starlink V2 Mini satellites with a Falcon 9 launch April 19. Since then, SpaceX has launched four missions with the older Starlink V1.5 satellites before switching back to the larger V2 Minis again for a May 19 launch.

In addition to improved communications capability, the Starlink V2 Mini satellites have more efficient, higher-thrust argon-fueled propulsion systems. Argon is cheaper than the krypton gas SpaceX used to fuel ion engines on the older-generation Starlink V1.5 satellites.

"This means Starlink can provide more bandwidth with increased reliability and connect millions of more people around the world with high-speed internet," SpaceX said before the first launch of Starlink V2 Mini satellites in February.

Each Starlink V2 Mini satellite weighs about 1,760 pounds (800 kilograms) at launch, nearly three times heavier than the older Starlink satellites. The are also bigger in size, with a spacecraft body more than 13 feet (4.1 meters) wide, filling more of the Falcon 9 rocket's payload fairing during launch, according to regulatory filings with the Federal Communications Commission.

The larger, heavier satellite platform means a Falcon 9 rocket can only launch around 22 Starlink V2 Mini payloads at a time, compared to more than 50 Starlink V1.5s on a single Falcon 9 launch.

The two deployable solar panels on each Starlink V2 Mini satellite span about 100 feet (30 meters) tip-to-tip. The previous generation of Starlink V1.5 satellites have a single solar array wing, with each spacecraft measuring about 36 feet (11 meters) end-to-end once the solar panel is extended.

The enhancements give the Starlink V2 Mini satellites a total surface area of 1,248 square feet, or 116 square meters, more than four times that of a Starlink V1.5 satellite.

The Federal Communications granted SpaceX approval Dec. 1 to launch up to 7,500 of its planned 29,988-spacecraft Starlink Gen2 constellation, which will spread out into slightly different orbits than the original Starlink fleet. The regulatory agency deferred a decision on the remaining satellites SpaceX proposed for Gen2.

Specifically, the FCC granted SpaceX authority to launch the initial block of 7,500 Starlink Gen2 satellites into orbits at 525, 530, and 535 kilometers, with inclinations of 53, 43, and 33 degrees, respectively, using Ku-band and Ka-band frequencies. SpaceX started launching older-design Starlink V1.5 satellites into the orbits approved for the Gen2 constellation in December.

The FCC previously authorized SpaceX to launch and operate roughly 4,400 first-generation Ka-band and Ku-band Starlink spacecraft that SpaceX has been launching since 2019. SpaceX is nearing completion with launches to populate the first-generation Starlink network.

With the launch Sunday, SpaceX will have sent 528 Starlink Gen2 satellites into orbit, including Starlink V1.5 and Starlink V2 Mini spacecraft. After this mission, SpaceX will have deployed 4,543 Starlinks satellites in all, including test units no longer in service. More than 4,100 Starlink satellites are currently in orbit, according to Jonathan McDowell, an astrophysicist and space expert who catalogs spaceflight activity.

During the Sunday's early morning countdown, SpaceX's launch team will be stationed inside a launch control center just south of Cape Canaveral Space Force Station to monitor key systems on the Falcon 9 rocket and at the launch pad. SpaceX will begin loading super-chilled, densified kerosene and liquid oxygen propellants into the Falcon 9 vehicle at T-minus 35 minutes.

Helium pressurant will also flow into the rocket in the last half-hour of the countdown. In the final seven minutes before liftoff, the Falcon 9's Merlin main engines will be thermally conditioned for flight through a procedure known as "chilldown." The Falcon 9's guidance and range safety systems will also be configured for launch.

After liftoff, the Falcon 9 rocket will vector its 1.7 million pounds of thrust — produced by nine Merlin engines — to steer southeast over the Atlantic Ocean. The Falcon 9 rocket will exceed the speed of sound in about one minute, then shut down its nine main engines two-and-a-half minutes after liftoff. The booster stage will separate from the Falcon 9's upper stage, then fire pulses from cold gas control thrusters and extend titanium grid fins to help steer the vehicle back into the atmosphere.

Two braking burns will slow the rocket for landing on the drone ship "Just Read the Instructions" around 400 miles (640 kilometers) downrange approximately eight-and-a-half minutes after liftoff. The reusable booster, designated B1078 in SpaceX's inventory, will fly on its third trip to space Sunday.

The Falcon 9's reusable payload fairing will jettison during the second stage burn. A recovery ship is also on station in the Atlantic to retrieve the two halves of the nose cone after they splash down under parachutes.

Landing of the first stage on Sunday's mission will occur just as the Falcon 9's second stage engine cuts off to deliver the Starlink satellites into a preliminary parking orbit. Another upper stage burn 54 minutes into the mission will reshape the orbit ahead of payload separation.

Separation of the 22 Starlink spacecraft, built by SpaceX in Redmond, Washington, from the Falcon 9 rocket is expected about 65 minutes after liftoff.

The Falcon 9's guidance computer aims to deploy the satellites into an orbit at an inclination of 43 degrees to the equator, with an altitude ranging between 195 miles and 200 miles (314-by-323 kilometers). After separating from the rocket, the 22 Starlink spacecraft will unfurl solar arrays and run through automated activation steps, then use their argon-fueled ion engines to maneuver into their operational orbit.

ROCKET: Falcon 9 (B1078.3)

PAYLOAD: 22 Starlink V2 Mini satellites (Starlink 6-4)

LAUNCH SITE: SLC-40, Cape Canaveral Space Force Station, Florida

LAUNCH DATE: June 4, 2023

LAUNCH TIME: 5:56 a.m. EDT (0956 UTC)

WEATHER FORECAST: 50% chance of acceptable weather; Low risk of upper level winds; Low risk of unfavorable conditions for booster recovery

BOOSTER RECOVERY: "Just Read the Instructions" drone ship northeast of the Bahamas

LAUNCH AZIMUTH: Southeast

TARGET ORBIT: 195 miles by 200 miles (314 kilometers by 323 kilometers), 43.0 degrees inclination

LAUNCH TIMELINE:

MISSION STATS:

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Follow Stephen Clark on Twitter: @StephenClark1.