SpaceX Conducts Preburner Test Of Starship SN20's Vacuum-Optimized Raptor Engine

Evelyn Arevalo by Evelyn Arevalo October 19, 2021

SpaceX Conducts Preburner Test Of Starship SN20's Vacuum-Optimized Raptor Engine

Featured Image Source: Tesmanian.com

SpaceX teams continue to prepare Starship SN20 and Super Heavy Booster 4 for an orbital flight attempt. The vehicles will undergo a separate pre-flight testing campaign to ensure each prototype is ready for a spaceflight to orbit and back. The SN20 spacecraft will be propelled to orbit by rocket Booster 4, it will liftoff from South Texas, fly across Florida Straits, and reenter Earth’s atmosphere to soft-land in the ocean off the northwest coast of Kauai, Hawaii, near a U.S. military base. Booster 4 will return to land in the Gulf of Mexico, approximately 20 miles from Starbase at Boca Chica Beach. It is unclear when the company will conduct the ambitious orbital flight test, they are still pending regulatory approval from the Federal Aviation Administration (FAA). The test is designed to assess the spacecraft’s performance and gather all kinds of data that will enable the company to develop a fully-reusable launch system.

The FAA is conducting an environmental assessment of SpaceX operations at Boca Chica and invited the public to give their opinions on Starship activities in the South Texas region. The Administration is also accepting public comments via email until November 1st. More Information: FAA Hosts First Public Virtual Hearing On SpaceX's Environmental Review For Starship Program, Invites Public To Participate In Wednesday Hearing. After their assessment concludes, then the agency can provide SpaceX with a Starship flight license for the orbital test flight. 

On Monday night, SpaceX ignited Starship SN20’s Raptor engine as part of the vehicle’s preflight test campaign. Raptors are fueled by a combination of cryogenic liquid methane (propellant) and liquid oxygen (oxidizer). The stainless-steel vehicle will be equipped with six Raptors, three are vacuum-optimized engines (also known as 'R-Vac) for propulsion in space. These engines have a much larger nozzle than sea-level Raptor engines used for atmospheric flight.

According to local sources, SpaceX performed a preburner test yesterday of a single R-Vac engine installed underneath the Starship SN20 spacecraft prototype. Engineers briefly fired the R-Vac engine for a couple of seconds at the Starbase launch pad. The Raptor engines have a preburner which is a small combustion chamber designed to drive the turbopumps, which pump fuel into the preburners. Methane and oxygen pass through the Raptor's turbopumps and their exhaust is combined in the main combustion chamber to ignite the engine. Spaceflight photographers set up Live cameras that captured the moment when Starship SN20 R-Vac took its first fiery breath, shown below. During the orbital flight, Starship will utilize six engines, all the engines are expected to undergo similar testing.

A Boca Chica Village resident received a letter from SpaceX this evening, stating that they plan to conduct a full static-fire test on Wednesday, October 20. During the static-fire, engineers will ignite Starship SN20’s R-Vac engine at high thrust for a few seconds as the vehicle remains grounded to the test mount. –“To Residents or Occupants Boca Chica Village: SpaceX will conduct Space Test Activities on October 20, 2021 from 5:00pm to 12:00am,” the company wrote, “Approximately 10 minutes prior to the activity, you will be provided notice by the sounding of a police siren in Boca Chica Village. There may be more than one instance during that time period where you will hear a siren notification. There is a risk that a malfunction of the SpaceX vehicle during these activities will create an overpressure event that can break windows. Therefore, in order to protect Public Health and Safety, it is recommended that you consider temporarily vacating yourself […] Thank you for your ongoing cooperation,” the letter reads.

 

Featured Image Source: Tesmanian.com / @JaneidyEve via Twitter





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