SpaceX Melts New Rocket Engine During Test Shows Fiery Video

Ramish Zafar
The Starship SN9 prototype during a hot-fire test in January 2021. Image: SpaceX

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As part of its campaign to develop a new engine lineup for a new launch vehicle system, aerospace launch services provider Space Exploration Technologies Corporation (SpaceX) is busy testing new engines in its facilities in McGregor, Texas. SpaceX is currently developing Starship, which is a new rocket that aims towards satisfying several different mission profiles and is built around conducting interplanetary missions aimed at eventually establishing a human presence on Mars.

Starship, currently waiting completion of a review by the Federal Aviation Administration (FAA), will use SpaceX's brand new Raptor full flow stage combustion Methane fueled rocket engines, and despite not having conducted a full test flight of the new launch system, SpaceX is moving ahead with developing a new engine dubbed as the Raptor 2 by the company's chief executive officer Mr. Elon Musk.

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SpaceX Raptor 2 Appears To Have Similar Problem To Earlier Variants Of The First Generation Raptor Engine

So far, SpaceX has conducted five Starship tests that have relied on the system's upper or first stage also dubbed as Starship. The full system consists of a Super Heavy booster and Starship, and it measures a whopping 120 meters tall when Starship is stacked on top of the Super Heavy.

SpaceX's five tests saw only one vehicle survive the demonstration, and only two managed to successfully land vertically. All these vehicles used the first generation Raptor engines, yet SpaceX upgraded the engines on some of them as it incorporated lessons from earlier failures.

The first test which used the prototype dubbed SN8, succesfully reigniteed its Raptors mid-air but failed to succesfully land due to low thrust. SpaceX's chief Mr. Elon Musk explained later that the landing failure occured due to low fuel pressure. This also resulted in the Raptor engine emitting green flames seconds before it crash landed, which is a key fact for the latest SpaceX engine tests as well.

Green flames emanating from the Raptor engine were the December 2020 test that perhaps SN8 wouldn't come out of its test flight in a single piece. Image: SpaceX

Now, with the FAA evaluating SpaceX's rocket test facilities in Boca Chica, Texas, the company is busy testing the second generation Raptor engine dubbed as Raptor 2 in McGregor, Texas. A video of this test shared by video journalist Adam Cucker on his YouTube channel shows the engine emitting volumes of exhaust for 24 seconds before starting to throw out green flames. The test took place on January 14th, 2022, and it is not the first time SpaceX has tested what Cucker believes is the Raptor 2 in McGregor.

The SpaceX Raptor 2 emitting green smoke during a test in McGregor, Texas earlier this month according to footage shared by Adam Cuker on YouTube. Image: SpaceX Raptor 2 Test (Green Flash)/YouTube

SpaceX Raptor 2 Tests Indicate Higher Chamber Pressure Creating Difficulties For Company

The green flames are due to the copper components inside the engine melting due to a malfunction. Such an event takes place when there is insufficient fuel in an engine's combustion chamber, which results in excess Oxygen melting the innards. A rocket engine uses fuel and liquid Oxygen to generate thrust, and for the Raptor, SpaceX uses Methane as a fuel.

Additionally, the January 14th test is not the first time that the company has tested the Raptor 2. According to a statement made by Mr. Musk on the social media platform Twitter, all Raptor tests conducted since late December will be of the second generation engines, and Cuker has shared recordings of seven tests so far, with the first one dated December 19th, 2021 - the same day Musk confirmed that all proceeding Raptor tests will be Raptor 2. This test ran for a 144 seconds, but judging by the exhaust levels, it did not fully throttle up the engine. The exhaust levels appear to be higher for the latest test run, insinuating that the problems occurred as SpaceX ramped up the Raptor 2 to generate more thrust.

When compared to the first-generation Raptor, the newer engine uses similar fuel but has a higher combustion chamber pressure and a wider throat. For a rocket engine, the chamber pressure is the value at which the oxidizer and the fuel are mixed and then ignited. The resulting by-products are then forced through a throat to generate a countering force against gravity to generate lift. This force is generally referred to as thrust and the first-generation Raptor is capable of generating 225 metrictons in thrust 330 bar chamber pressure.

In comparison, the Raptor 2 aims at increasing thrust by roughly 9% to 245 tons at 321 bar pressure due to its wider throat. Musk has also stated that the engine is operating at 330 bar consistently, indicating that successive tests have increased its chamber pressure. SpaceX plans to introduce the new engines on its Starship prototypes soon, and the FAA expects that its environmental review will be finished by the end of next month.

You can take a look at the full video of the latest SpaceX Raptor 2 rocket engine test here:

For more on the Raptor and Raptor 2 engines, take a look at:

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