China News Service, Beijing, April 16 (Ma Shuisha) The flight crew of Shenzhou 13 returned to the ground safely on the 16th. This is the first time that the Shenzhou manned spacecraft has adopted a rapid return plan.

How was the astronaut return date set?

How can astronauts' "trip home" be shortened?

Why is it 5 laps back?

What "Tiangong Specialties" did the three astronauts bring back?

Shao Limin, deputy technical manager of the manned spacecraft system project of the Fifth Academy of China Aerospace Science and Technology Corporation, answered media interviews.

How was the astronaut return date chosen?

  In order to return to the ground during the day, the flight crew of Shenzhou 13 began preparations for the return on the evening of the 15th.

When it comes to the selection of the return date, Shao Limin pointed out that the first thing to do is to ensure that the flight path passes through the landing site, otherwise it will definitely not be possible to return on this day.

  "After the spacecraft is transferred to independent flight, we have to wait for the spacecraft to pass the landing site." Shao Limin said that the Shenzhou spacecraft actually has lateral maneuverability, but the excessive maneuverability requires high propellant, so the researchers chose to use Time is exchanged for space, wait until the spacecraft passes the circle above the landing field, and then start the return procedure.

  He pointed out that the trajectory problem is the most important factor. In addition, the staff also considered the weather factors, but the requirements for the weather during the return process of the spacecraft are not as high as those during the launch, and the weather can be predicted.

How to shorten the "trip home" of astronauts?

  According to reports, it takes 1.5 hours for the spacecraft to fly around the earth. This time, the Shenzhou 13 spacecraft was compressed from the original dozen or so laps to 5 laps, which greatly shortened the astronaut's "trip home" and further improved the The return experience of astronauts.

Shao Limin pointed out that the flight crew of Shenzhou 13 has been in orbit for 6 months. If they return to the ground in a relatively small spaceship for another day, the comfort level will be reduced. Shortening the return time of the spacecraft will also meet the needs of astronauts.

  Shao Limin said that compared with the return process of the Shenzhou 12 spacecraft, the return procedure of the Shenzhou 13 spacecraft has not changed much except for the 5-lap fast return plan, which still involves the separation of the assembly, the maintenance and measurement of the orbit before the return, and the orbit module. Steps such as separation from the return capsule, separation of the propulsion module from the return capsule, and re-entry into the atmosphere.

  How can I reduce the number of laps while doing the pinning?

Shao Limin said that ground researchers optimized the return process and carried out the original serial work in parallel to shorten the astronauts' waiting time in the Shenzhou spacecraft's return cabin.

For example, moving the orbital measurement before return to before the assembly is separated, shortening the steps that originally required two laps to complete to only one lap, saving flight time, but the return process has not changed qualitatively.

  It should be emphasized that the return time is not as short as possible.

Shao Limin pointed out that the short return time means that the spacecraft will quickly pass the landing site. If there is an abnormal situation after the separation of the combination, it may be too late to deal with it, but it will lead to a longer waiting time.

Therefore, 5 laps is a compromise, which can not only achieve the goal of the shortest return time, but also take into account the task indicators.

What "Tiangong Specialties" did the astronauts bring back?

  Shao Limin said that the use of the fast return scheme makes the rhythm of the flight control more compact, and the front and rear connections are more tense, thus putting more pressure on the flight control personnel, but it does not affect the software and hardware configuration of the spacecraft itself.

For the Shenzhou 13 spacecraft, the biggest test is to return safely after a long flight.

  This is the first time the Shenzhou spacecraft has been in orbit for 6 months.

"Extending the docking time can compress the number of launches, reduce the risks brought by launch and return, and reduce engineering costs." Shao Limin said, but the longer the spacecraft flies, the higher the probability of failure, and the ground cannot fully simulate the In the orbit environment, to ensure the reliability of the spacecraft's life, it must pass the on-orbit verification, which is not only more scientific, but also makes the researchers more confident and confident.

  During the entire return process, the astronauts are mainly responsible for the transfer and installation of materials, and do not require special operations and maintenance of the spacecraft.

Shao Limin said that the Shenzhou spacecraft can control the flight independently without the participation of astronauts. The astronauts mainly solve the things that cannot be operated on the ground, such as transferring the goods that need to be brought back to the ground, closing the cabin door, putting on pressure suits, and fixing themselves on the ground. on the seat.

  Talking about what the Shenzhou 13 astronaut crew will bring back, Shao Limin said, "That's a lot", such as the astronauts' on-orbit records, video photos they took, experimental samples, some space station equipment, etc. "We are still in the key technology verification stage, and some situations are not as expected, so astronauts need to bring them back to the ground for analysis." (End)