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SpaceX is counting down to the launch of 51 more Starlink Internet satellites and a payload that will use a Spaceflight-built orbital transport vehicle to maneuver into a different orbit to test broadband technology for Boeing. Liftoff from Space Launch Complex 40 at the Cape Canaveral Space Force Station on a Falcon 9 rocket is set for 10:09 p.m. EDT on Sunday (0209 GMT Monday), marking SpaceX’s 40th launch of the year. There is an 80 percent chance of favorable weather for a launch opportunity Sunday night, according to the US 45th Weather Squadron. The main payload for Sunday night’s mission, named Starlink 4-20, is SpaceX’s next batch of Starlink internet satellites. The rocket will lift 51 Starlink spacecraft levels, fewer than the number carried on a typical Starlink launch from Florida, to accommodate a payload. The secondary passenger is the Sherpa-LTC chemically propelled transport orbital vehicle that rides the Starlink payload stack inside the Falcon 9’s payload fairing. Built by Spaceflight, a Seattle-based spacecraft developer and launch broker, the orbiter Sherpa-LTC transporter is designed to carry small satellites and host experiments at different altitudes and inclinations after an initial ride into orbit by a large rocket. The Sherpa-LTC Orbital Transport Vehicle on Starlink Mission 4-20 will carry Boeing’s Varuna Technology Demonstration Mission, or Varuna-TDM. The mission is designed to demonstrate technologies and perform in-orbit performance tests for a V-band communications system, a proposed constellation of 147 satellites to provide broadband connectivity to U.S. commercial and government users. The Varuna-TDM mission will provide prospective users of the broadband satellite constellation “an opportunity to evaluate the performance of V-band communications links and ascertain their characteristics and acceptability for specific applications,” Boeing said. The mission patch for the Sherpa-LTC mission shows a rendering of the Orbital Transport Vehicle built by Spaceflight. Credit: Spaceflight The Falcon 9 rocket will deploy the Sherpa-LTC launch vehicle with the Varuna technology demonstration mission into a near-circular orbit at an average altitude of about 192 miles (310 kilometers) above Earth, at an inclination of 53.2 degrees to the equator. Sherpa-LTC will first deploy approximately 49 minutes into the flight, followed by separation of the 51 Starlink satellites at T++ 72 minutes. Spaceflight’s solar-powered transport orbiter will perform a series of burns to reach a circular orbit 620 miles (1,000 kilometers) above Earth, where the Varuna technology demonstration mission will launch. The Varuna technology demonstration payload was designed and built by Astro Digital, which also provided the command and control system for the Sherpa-LTC orbital transport vehicle. The Sherpa-LTC vehicle uses a bi-propellant, “green” or non-toxic propulsion system developed by Benchmark Space Systems. “The transportation capabilities of Sherpa-LTC combined with the reliability and consistency of Starlink missions create an ideal solution for the customer’s unique mission needs,” said Curt Blake, CEO and president of Spaceflight. “Our OTV eliminates the obstacles that make it more difficult for spacecraft to access unusual orbits in LEO and beyond. We look forward to continuing to provide innovative, cost-effective and reliable space transportation services for our customers and partners like Astro Digital.” With Starlink mission 4-20 on Sunday, SpaceX launched 3,259 Starlink Internet satellites, including prototypes and test units that are no longer operational. Sunday night’s launch will be SpaceX’s 59th mission dedicated primarily to carrying Starlink internet satellites into orbit. Located inside a launch control center just south of the Cape Canaveral Space Force Station, SpaceX’s launch team will begin loading supercooled, condensed kerosene and liquid oxygen propellants into the 229-foot-tall (70-meter) Falcon 9 vehicle in T-minus 35 minutes . Compressible helium will also flow into the rocket during the last half hour of the countdown. In the final seven minutes before liftoff, Falcon 9’s Merlin main engines will be thermally adjusted for flight through a process known as “chilldown.” The Falcon 9’s range guidance and safety system will also be configured for launch. After liftoff, the Falcon 9 rocket will transfer its 1.7 million pounds of thrust — generated by nine Merlin engines — to head northeast over the Atlantic Ocean. The rocket will exceed the speed of sound in about a minute, then shut down its nine main engines two and a half minutes after liftoff. The booster stage will release from the Falcon 9’s upper stage and then fire pulses from cold gas control thrusters and extended titanium mesh fins to help propel the vehicle back into the atmosphere. Two brake burns slowed the rocket for a landing on the Just Read the Instructions drone ship about 400 miles (650 kilometers) down range about eight and a half minutes after liftoff. The first stage for Sunday’s launch is called B1052 in SpaceX’s inventory. The booster will make its seventh space flight. That vehicle flew as a side booster on two Falcon Heavy rocket missions in 2019 and was then converted to fly as a first stage on the Falcon 9 rocket, starting earlier this year. Falcon 9’s reusable payload fairing will drop during the second stage burn. A recovery ship is also on station in the Atlantic to recover the two halves of the nose cone after they splash down under parachutes. The landing of the first stage on Sunday’s mission will come moments after the Falcon 9’s second-stage engine shuts down to deliver the Starlink satellites into a preliminary transfer orbit. A second upper stage burn approximately 45 minutes after launch will place the payloads on the proper orbit for separation. After the Sherpa-LTC payloads are released, the upper stage will release restraint rods from the Starlink payload stack, allowing the flat-pack satellites to fly free from the Falcon 9 upper stage into orbit. The 51 spacecraft will deploy solar arrays and run through automated activation steps, then use krypton-fueled ion engines to maneuver into their operational orbit. The satellites will use onboard propulsion to do the rest of the work to reach a circular orbit 335 miles (540 kilometers) above Earth. The Starlink satellites will fly in one of five orbital “shells” at different inclinations for SpaceX’s global Internet network. After reaching their operational orbit, the satellites will enter commercial service and begin broadcasting broadband signals to consumers, who can purchase Starlink service and connect to the network with a ground terminal provided by SpaceX. ROCKET: Falcon 9 (B1052.7) PAYLOAD: 51 Starlink and Sherpa-LTC satellites (Starlink 4-20) LAUNCH LOCATION: SLC-40, Cape Canaveral Space Station, Florida START DATE: September 4, 2022 START TIME: 10:09 p.m. EDT (0209 GMT) WEATHER FORECAST: 80% chance of acceptable weather. Low risk of upper level winds. Low risk of adverse conditions for recall recovery RECOVERY AID: ‘Just Read the Instructions’ drone ships east of Charleston, South Carolina LAUNCH AZIMUTH: Northeast TARGET ORBIT: 188 miles by 196 miles (304 km by 316 km), inclination 53.2 degrees LAUNCH SCHEDULE:

T+00:00: Take off T+01:12: Maximum aerodynamic pressure (Max-Q) T+02:29: First stage main engine shutdown (MECO) T+02:33: Scene separation T+02:39: Second stage engine ignition (SES 2) T+03:13: Fairing jettison T+06:05: Ignition of first stage inlet combustion (three engines) T+06:36: Cutoff of first stage inlet combustion T+08:05: Landing burn ignition first stage (one engine) T+08:27: First stage landing T+08:45: Second stage engine cut-out (SECO 1) T+45:25: Second stage engine ignition (SES 2) T+45:27: Second stage engine cut-out (SECO 2) T+49:28: Sherpa-LTC split T+1:12:23: Separation of Starlink satellites

SHIPPING STATISTICS:

174th launch of a Falcon 9 rocket since 2010 182nd launch of the Falcon rocket family since 2006 7th release of Falcon 9 booster B1052 149th Falcon 9 launch from Florida’s Space Coast 96th Falcon 9 launch from pad 40 151st overall launch from pad 40 116th flight of a reused Falcon 9 booster Exclusive 59th Falcon 9 launch with Starlink satellites 2022 Falcon 9 40th launch 40th launch from SpaceX in 2022 38th orbital launch attempt based at Cape Canaveral in 2022

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