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SpaceX launched Boeing's test spacecraft and 51 more Starlink satellites

Falcon 9 rocket launched 51 internet satellites and a Boeing's Varuna TDM

Starlink G4-20 launch (Credit: SpaceX)

September 4, 2022 The SpaceX Falcon9 v1.2 FT Block 5 rocket number B1052.7 with fifty-one Starlink V1.5 satellites and a Spaceflight Inc's Sherpa-LTC orbital transfer vehicle launched from Space Launch Complex 40 (SLC-40) at Cape Canaveral Space Force Station in Florida. The instant launch window is at 22:09 ET (02:09:40 UTC on Sept. September 5th). The payloads were deployed in 236 × 329 km, inclined at 53.2 degrees.

Falcon 9 B1052-7 Landing on JRTI (Credit: SpaceX)

The 'core' of the first stage of this mission previously launched Arabsat-6A, STP-2, COSMO-SkyMed Second Generation FM2, the South Korean lunar probe KPLO and two Starlink missions. After separating the stages, the core will land on the Just Read the Instructions droneship, which will be parked in the Atlantic Ocean, towed by the fairing recovery support vessel 'Doug'.


Elon Musk's internet satellites (totaling 15,657 kg, specimens 1425 to 1475) are part of the 'Group 4-20', to join the specimens already established in their working orbits. The satellites will be released in a single block into the initial target orbit of approximately 230 km inclined at 53.2°, to then separate and proceed to their final orbits of 540 km.


Boeing's Varuna Technology Demonstration Mission (Varuna-TDM, from 180kg total mass to 140kg without propellant) will test V-band communications equipment for a proposed constellation of 147 non-geostationary broadband satellites. The satellite will be ejected from Spaceflight's Sherpa-LTC2-type space tug (“OTV”) into an orbit of 1056 km, inclined at 54°. It will elevate orbit through two starts on a Hohmann trajectory to its operational orbit to operate for a period of up to two years. At the conclusion of the mission, it will perform the out-of-orbit burn to reduce the perigee to 300 km until re-entry.

Sherpa LTC-2 / Varuna Technology Demonstration Mission

The spacecraft consists of the Sherpa-LTC 2 orbital transfer vehicle with an integral bi-propellant propulsion system and solar array arrangement, and guidance and control equipment housed in two modules built by Astro Digital and bolted to the transfer vehicle's support ring. These modules are the command and control system (CCS) and the V-band payload module.

The Sherpa's chemical propulsion system uses Benchmark Space Systems' Polaris powertrain with “green” propellants. The oxidant is high test peroxide (HTP) and isopropyl alcohol (IPA) is the fuel fed using nitrogen gas as a pressurizer. This dual-mode bipropellant system with four independently controlled engines. The HTP can be used as a monopropellant in low-thrust mode or combined with the IPA in high-thrust mode. Each thruster can provide up to 22 N of thrust individually; when operated together, all four produce up to 88 N of thrust. With the ability to command the thrusters independently, the Sherpa can steer without the need for tipping.

Relations between Spaceflight and SpaceX shaken

Spaceflight has relied on SpaceX launches for its expanding lineup of next-generation space tugs. The first of these was a Sherpa-FX, which has no propulsion, which made its debut as part of the Transporter-1 hitchhiking mission in January 2021. The Transporter-2 mission then launched a Sherpa-FX2 and a Sherpa-LTE – the Spaceflight's first electric-powered OTV later that year in June. After the Sherpa-LTC was removed from SpaceX's Transporter 3 flight in January 2022, Spaceflight planned to launch a Sherpa-FX on its next shared flight in April.

However, SpaceX decided to remove the tug from its Transporter-4 after concerns about environmental factors that would affect the satellites installed on the OTV. About a week later, Muks' company said it would no longer work with Spaceflight after the currently manifested missions. Spaceflight CEO Curt Blake declined to discuss Spaceflight's relationship with SpaceX, or what his last OTV would be to fly with the company.

To broaden its options, Spaceflight announced on August 8 an agreement to launch future space tugs on Arianespace's Vega rockets, including its next-generation Vega C. Blake said he has signed an agreement to use Vega with Italy's SAB Launch Services – which also provides services on other European launchers – to cover launches starting next year.

Blake said Spaceflight is "very close to identifying details" for Vega customers and missions that would use Sherpa, with the first launch likely in late 2023 or early 2024. Spaceflight and SAB are also partnering to deliver customers access to shared integration and storage facilities in Europe and the United States. Blake said Spaceflight is in talks with "several" other launch providers and "approaching finalizing deals to launch OTVs on multiple rockets."


All times are approximate

hh:min:ss – Events

00:00:00 Takeoff

00:01:12 Max Q (peak moment of mechanical stress on the rocket)

00:02:29 1st stage main engine cutoff (MECO)

00:02:33 1st and 2nd stages separated

00:02:39 2nd stage engine ignition

00:03:13 Fairing Jettison

00:08:05 Start of 1st stage input ignition

00:06:36 1st stage re-entry ignition completed

00:08:05 Start of 1st stage landing ignition

00:08:27 1st stage landing

00:08:45 2nd stage engine Cutoff (SECO-1)

00:45:25 2nd Ignition of the 2nd stage engine (SES-2)

00:45:27 2nd Engine Cut-Off 2nd Stage (SECO-2)

00:49:28 Spaceflight's Sherpa-LTC is Deployed

01:12:23 Starlink satellites are Deployed


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