In 2004, it was decided to convert the backup module into a real flight module,It was originally scheduled to be sent to the space station in 2007, but the situation has been continuous for 14 years, and tickets have to be skipped every year. It has been faced with the problem of the service life of instruments, engines and other components, and finally had to be launched, but this is still delayed from last summer to July this year.
During this period, its engine started abnormally, causing the international space station to flip 45 degrees. Then the International Space Station reset and returned to normal. NASA said it did not cause any danger.