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July 26 news, last weekend, SpaceX successfully launched three rockets in a rapid launch mode within three days after obtaining approval from the Federal Aviation Administration (FAA) to resume launch activities.FalconNo.9Rocket, sending 67 Starlink internet satellites into orbit.

At 1:45 a.m. local time on Saturday, a Falcon 9 rocket blasted off from the launch site at the Kennedy Space Center in Florida. It was a normal rocket launch, SpaceX's 73rd rocket launch of the year, the Starlink 10-9 mission to put 23 broadband internet satellites into orbit. However, after a rare malfunction during the launch of the Falcon 9 rocket earlier this month, this rocket was a return to flight for SpaceX and put the world's most active rocket booster back into service.

By all accounts, the launch was an excellent one. The rocket's first-stage booster, B-1069, successfully landed on a drone ship in the Atlantic Ocean after entering orbit for the 17th time. More than an hour after launch, the rocket's second stage released its payload as planned, and the spacecraft carrying the Starlink satellites will use its onboard thrusters to reach its scheduled operating altitude in the coming weeks.

On July 11, a Falcon 9 rocket failed during a launch of a Starlink satellite from the Vandenberg Space Force Base in California. Minutes after the first and second stage of the rocket separated, unusual ice accumulation was discovered on the Merlin Vacuum engine that powers the second stage of the rocket. According to SpaceX, the Merlin Vacuum engine successfully completed its first ignition after the second stage of the booster separated. However, during this time, a liquid oxygen leak near the engine caused the ice accumulation observed in the live webcast.

Engineers and technicians quickly determined the cause of the leak was aspaceshipA crack developed in the sensing wire of a liquid oxygen system pressure sensor. SpaceX said in a statement before Saturday's launch that the crack in the wire was caused by fatigue caused by high loads generated by engine vibration and loose clamps.

The leak of liquid oxygen caused by the rupture of the sensor wire caused the engine to overcool and reduced the amount of ignition fluid required for the second ignition of the Merlin engine, making it difficult to start the engine. Ultimately, the engine had a hard start and multiple components were damaged. The rocket could not reach the planned orbit, and the satellite was released into an orbit below the planned altitude and burned up in the Earth's atmosphere within a few days.

SpaceX said the failed sensor wire was redundant and not used by the flight safety system, and that a backup sensor on the engine could replace its function. In the short term, engineers will remove the sensor wire from the Falcon 9's second-stage booster engine.

The sensor wire was installed at a special request from a customer for another mission, SpaceX executive Sarah Walker said at a news conference Thursday. It has two connection points instead of one, which could make it more susceptible to vibrations that could cause tiny cracks, compared with other commonly used sensor wires.

Quick Recovery SpaceX identified the cause of the launch anomaly within hours of the incident and worked with the FAA to quickly find a solution, and the company received permission to resume launch last Thursday.

“It was incredible how quickly the team was able to determine the cause of the incident and take the appropriate corrective actions to ensure success,” Walker said.

Before the rocket launch failure on the evening of July 11, SpaceX had not experienced any mission failure in the past 297 Falcon 9 rocket launches. The last launch failure dates back to the explosion of the Amos 6 launch pad in September 2016. The interval from the failure to the go-around is almost unprecedented in the history of space flight.

SpaceX launched a second batch of Starlink satellites from the Cape Canaveral Space Station early Sunday, sending an additional 23 satellites into orbit. A few hours later, a third Falcon 9 rocket lifted off from the Vandenberg Space Force Base in California.

NASA is also counting on a Falcon 9 rocket to launch a Northrop Grumman Cygnus cargo spacecraft to the International Space Station on August 3. A SpaceX Crew Dragon spacecraft will then carry three NASA astronauts and one Russian cosmonaut to the International Space Station around August 18.

For this reason, NASA participated in the investigation of the Falcon 9 rocket's second-stage launch failure. NASA Commercial Manned Program Manager Steve Stich said SpaceX did an excellent job in determining the root cause of the failure, and then quickly checked the manned Dragon spacecraft and the Falcon 9 rocket's first-stage booster to ensure that there were no other sensors that could cause similar problems.

The second stage booster of the rocket planned for the manned space mission Crew 9 will be tested at the SpaceX factory in McGregor, Texas in the coming days to verify that the corrective actions taken by the company do not have unintended consequences.

"The rocket will be doing a second-stage booster fire test around July 30, which is actually to check some modifications to the rocket due to the anomaly," Stich said on Friday. "We have been following up on the investigation conducted by the FAA, and SpaceX has been very transparent, and our team has participated in the investigation and tracked all adjustments to the booster."

NASA has yet to formally approve a SpaceX launch mission for next month, but the successful return of the Falcon 9 rocket to space over the weekend will undoubtedly play a major role in the final decision.

Boeing engineers also had a busy weekend, successfully firing all 27 maneuvering thrusters on the Starliner spacecraft currently docked at the International Space Station.

These tests verified the good performance of the Reaction Control System (RCS) thrusters that had experienced early problems and confirmed that a known helium leak in the spacecraft's propulsion system remained stable and had not worsened.

The tests also demonstrated that the thrusters will function properly when the spacecraft eventually returns to Earth.

“The purpose of the single pulse firings was to confirm the performance of each thruster,” Boeing said. “Between each firing, the team checked the real-time data and all thrusters were operating normally at peak thrust ratings.

Boeing said: "The helium system remains stable. In addition, the RCS oxidizer isolation valve, which had not been fully seated, was operated multiple times during Saturday's test and is now operating normally."

The Starliner spacecraft launched on its first crewed test flight on June 5. Crew members Barry Wilmore and Sunita Williams were initially expected to stay in space for about eight days.

However, the mission has now lasted nearly two months due to the need to resolve thruster issues and five helium leaks, one of which was detected before launch and the remaining four occurred while the spacecraft was docked with the International Space Station.

NASA is expected to hold a major review later this week to evaluate the test data and determine whether the spacecraft is ready to bring Wilmer and Williams safely back to Earth.

As for the manned space mission of SpaceX and the Falcon 9 rocket, the company's head Walker said on Friday that the second-stage booster engine will only ignite once during the manned flight, which means that the liquid oxygen leak problem that caused the Starlink launch failure will not affect the manned mission. But in any case, the parts that caused the leak will be removed.

"I have every confidence in the team and that NASA is fully engaged in the response," said Nick Hague, a Crew 9 member and veteran astronaut who has experienced a Russian Soyuz launch abort. "When the team decided to go, I was excited to get on a rocket again."

He added that the crew was training at SpaceX headquarters in Hawthorne, California, the day after the Falcon 9 launch anomaly, and "from the beginning, they were communicating and telling us everything they knew."

The Federal Aviation Administration (FAA), which is responsible for reviewing launch permits, agreed with SpaceX's analysis of the failure and concluded that there were "no public safety implications."

"This public safety decision means that Falcon 9 rockets can resume flying while the overall investigation is ongoing, provided all other licensing requirements are met," the FAA said in a statement.

In addition to providing an update on SpaceX's recent Falcon 9 rocket launch plans, Walker also discussed an unexpected issue in which fragments of the Crew Dragon spacecraft's service module did not completely burn up during re-entry into the atmosphere, and some of them fell to the ground.

The service module of the Crew Dragon spacecraft is equipped with solar cells to power the spacecraft in space and deliver external space station payloads to orbit in an unsealed environment. Before re-entering the atmosphere, the service module is discarded. The crew module of the spacecraft is equipped with a heat shield, exits orbit by igniting the braking rocket, and finally splashes down accurately in the ocean. The service module continues to fly in a low orbit and eventually re-enters the atmosphere in an uncontrolled manner.

In early programs, engineers expected the entire service module to burn up during re-entry, but on several missions, relatively large charred fragments survived atmospheric re-entry.

The returning Crew Dragon and the recently launched Cargo Dragon have splashed down off the Florida coast, in the Gulf of Mexico or in the Atlantic Ocean.

Walker said SpaceX now plans to move all spacecraft splashdowns to the Pacific Ocean off the west coast of the United States. Now, the service module will be jettisoned after the deorbit rocket is launched, ensuring that its re-entry point in the atmosphere is roughly the same as the crew module and cargo module, that is, farther from the shore. (Chenchen)