Loss of two Pléiades Neo Earth imaging satellites in European Vega C rocket failure – Spaceflight Now

Illustration of a Vega C rocket with the Zefiro 40 second stage launched. Credit: Arianespace

The last two spacecraft in the new Pleiades Neo Earth-observation fleet of four Airbus satellites and costing 600 million euros each crashed into the Atlantic Ocean shortly after launching from French Guiana on Tuesday night, the victim of the failure of a European Vega C rocket.

The Vega C launch operator, Arianespace, confirmed that the mission failed to place the two Pléiades Neo optical imaging satellites into orbit. The initial focus of the failure investigation was the Vega C rocket’s second stage.

The 114-foot (34.8-meter) rocket lifted off from the Guyana Space Center at 8:47:31 p.m. EDT Tuesday (0147:31 GMT Wednesday) with the Pléiades Neo 5 and 6 Earth imaging satellites for Airbus Defense and Void. The target was a sun-synchronous polar orbit.

Vega C’s powerful solid-fuel P120C first-stage booster burned in approximately two and a half minutes, producing a million pounds of thrust to accelerate the rocket into the upper atmosphere. Heading north from the coast of South America, the rocket dumped the spent first-stage engine casing and launched the Zefiro 40 second-stage engine to continue climbing into space.

But Arianespace said in a press release that the rocket encountered a problem about 2 minutes and 27 seconds into liftoff, close to the start of the Zefiro 40 engine.

“After take-off and nominal ignition of P120C, which is Vega’s first stage, a pressure drop was observed on Zefiro 40, which is Vega’s second stage,” said Stefan Israel, CEO of Arianespace. And after this low pressure, we noticed a deflection in the trajectory and a very strong anomaly. Unfortunately, we can say that the mission was lost.

Telemetry from the missile showed the vehicle losing speed about three and a half minutes into flight, when the Zefiro 40 VegaC was supposed to propel it to higher speeds. The missile appeared to reach a peak height of about 360,000 feet, or 110 kilometers. Tracking data indicated that the rocket re-entered the atmosphere over the Atlantic Ocean, with the final measurement showing Vega C about 570 miles (917 kilometers) north of the spaceport before it likely disintegrated due to heating and aerodynamic forces.

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“I want to deeply apologize to our customers, Pléiades Neo and Airbus Defense and Space, for this failure tonight,” Israel said. “And we will now have to work with all of our partners to better understand why Zefiro 40 was not operating properly tonight, resulting in the failure of the mission.”

A European Vega C rocket on the launch pad in French Guiana, hours before liftoff on the doomed mission with Pleiades Neo satellites 5 and 6. Credit: ESA/CNES/Arianespace/JM Guillon

The second stage of the Zefiro 40, like other solid-propellant booster stages of the Vega C, is produced by the main contractor for the rocket, the Italian airline Avio. The second stage engine was designed to burn its supply of 40 tonnes (36 metric tons) of pre-filled solid fuel in about 90 seconds.

Tuesday night’s launch was the first commercial flight of the upgraded European Vega C rocket, following Vega C’s flawless inaugural test flight on July 13.

The Vega C rocket replaces the first and second stages of the old solid-fuel Vega rocket with wider, heavier engine casings. The third stage engine is unchanged, and the liquid-fueled restartable fourth stage has the same type of engine but carries more fuel. The upgraded Vega C is longer than the original configuration of the Vega rocket, and has a larger payload capacity provided by the Swiss company Beyond Gravity, formerly known as RUAG Space.

The Zefiro 40’s wider second stage on the Vega C rocket replaces the Zefiro 23 engine on the base model of the Vega rocket, adding 50% more solid fuel and generating 293,000 pounds of thrust.

The European Vega family has now suffered three failures in 22 flights. The three failures occurred in the last eight Vega launches, after 14 consecutive successful flights since the Vega launcher entered service in 2012.

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Investigators blamed the 2019 launch accident on a “thermal structural failure” in the Zefiro 23 Vega rocket’s second stage. The launch failure in 2020 was traced to misplaced cables on the Vega rocket’s liquid-fueled upper stage, called the Attitude and Vernier Upper Module.

The Vega rocket had racked up four consecutive successful launches, including the debut of Vega C, ahead of Tuesday night’s ill-fated mission.

The missing satellites on the Vega C rocket were the third spacecraft and the fourth in a quartet of Earth observation satellites built and owned by Airbus. The first two Pléiades Neo satellites launched in 2021 on separate Vega rockets, but Airbus has put the third and fourth spacecraft of the constellation on the same mission to take advantage of the carrying capacity of the heavier Vega C rocket.

File photo of the Zefiro 40 second stage engine stack prior to the first Vega C launch. credit:
ESA-Manuel Pedoussaut

The Pléiades Neo satellites feature improvements to two of Airbus’ first-generation Pléiades Earth-observation satellites launched in 2011 and 2012. Airbus says it has fully funded the development of the Pléiades Neo satellites, with the intention of selling the images commercially to private companies and users. government officials. The company announced the Pléiades Neo program in 2016, and Airbus has assembled the Pléiades Neo spacecraft at its facility in Toulouse, France.

The four satellite program was expected to cost Airbus around 600 million euros, or roughly $700 million.

The Pléiades Neo satellites can produce optical images of the Earth’s surface with a resolution of 11.8 inches, or 30 centimeters, according to Airbus. This is good enough to resolve features like vehicles and road signs. The first two Pléiades satellites launched more than a decade ago have a resolution of 19.6 inches, or 50 centimeters.

Airbus has released images from the first two Pléiades Neo satellites showcasing their capabilities, depicting lava flows from volcanic eruptions, large-scale music and sporting events, and views of planes and missiles at airports and spaceports.

The imaging resolution of Airbus’ four Pléiades Neo satellites is comparable to that provided by Maxar’s six WorldView Legion observation satellites, which are due to begin launching next year. The companies are competitive, providing the highest resolution Earth observation imagery in the global commercial market.

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With the help of laser-satellite communications links, the Pléiades Neo satellites will be able to quickly respond to mission requests within half an hour, according to Airbus.

A single Pléiades Neo satellite, using a new agile pointing capability enabled by moment-of-control gyroscopes, can rotate in tandem to monitor the same location every two days. Once all four satellites are in orbit, the constellation will be able to image any location on Earth twice a day.

Each Pléiades Neo spacecraft is designed to operate for at least 10 years. A single Pléiades Neo satellite can collect images covering an area of ​​nearly 200,000 square miles (500,000 square kilometers) per day, says Airbus.

The Pléiades Neo 5 and 6 satellites are stacked one on top of the other before being encased inside the payload fairing of a Vega C rocket. Credit: ESA/CNES/Arianespace/P. Boudon

Applications of the Pléiades Neo imagery include urban planning, city management, climate change assessments, and pollution impact identification. Satellites can also be tasked with assessing damage from natural disasters, and the images also have military applications.

The Vega C rocket aims to put the Pléiades Neo 5 and 6 satellites into a polar or north-south orbit, orbiting about 385 miles (620 kilometers) above Earth.

Europe’s Vega rocket family is designed to carry small to medium-sized satellites into orbit. Developed in partnership between Avio and the European Space Agency, the Vega C rocket is capable of towing up to 5,070 pounds (2.3 metric tons) of payload mass into a 435-mile (700 km) polar orbit, more than the model’s capacity. The base for the Vega missile is 3,300 lb (1.5 metric tons).

The European Space Agency and the European Commission reached an agreement with Arianespace last month to launch five satellites of the European Earth-observing Copernicus system on Vega C rockets. The new deal increased Arianespace’s backlog to 15 Vega missions, including 13 Vega C missions and two more launches with the original Vega rocket configuration.

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Follow Stephen Clark on Twitter: @employee.

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