The base stage of the long 5B march is likely to hit Earth’s atmosphere in the coming days.
China launched its first space station late Wednesday, but the mission launcher also entered orbit and was moving unexpectedly slowly back to Earth.
Long March 5, a type of the largest missile in China, You started successfully Tianhe unit, weighing 22.5 tons local time, Wenchang, Thursday. Tianhe separated from the bomber’s initial stage after 492 seconds of flight and directly entered the planned initial orbit.
The Long March 5B was developed specifically to launch space station modules in near-Earth orbit and uniquely uses a base stage and four side boosters to place their payload directly into near-Earth orbit.
However, this basic phase is also in orbit and will likely re-enter uncontrollably in the next few days or weeks as the increased interaction with the atmosphere pulls it back to Earth. If so, it would be one of the biggest cases of uncontrolled re-entry of spacecraft and could land on a populated area.
Most of the early stages of expendable missiles do not reach orbital velocity, are in the atmosphere, and land in a pre-defined return zone. Some of the second, larger stages lead to low burning in orbit to reduce the time in orbit and the possibility of colliding with other spacecraft or an immediate return to the atmosphere.
There has been speculation that the Long March 5B core will require an active maneuver to thwart itself, but that doesn’t appear to be happening. At a press conference in Wenchang on Thursday, Wang Jue, commander in chief of the Long March 5B Launch Vehicle, said:Chinese) That the second Long March 5B had seen improvements at the first launch, but the potential Deorbit maneuver was not mentioned.
Ground penetrating radars, which the US military uses to track spacecraft and other objects in space, have detected an object and classified it as the body of a Long March 5B missile. The base stage 2021-035B now identified is about 30 meters long and five meters wide, is in orbit at an altitude of 170 x 372 kilometers, and is moving at speeds of over seven kilometers per second.
A potential land for amateurs NB From the rocket core, which shows regular flashes indicating that it is rolling over and therefore not under control.
There are no TLEs yet to start Vega. TLE is another element for Tianhe Burning B, which confirms that the slow decay rate is the CZ-5B base level. pic.twitter.com/0dVkUkcpjA
– Jonathan McDowell (@ planet4589) 30. April 2021
On the maiden launch of the Long March 5B, the first stage reached orbit six days later and returned to orbit uncontrollably. Re-entry was made across the Atlantic Ocean according to information from the 18th Space Force Space Observation Squadron.
Had the event occurred 15 to 30 minutes earlier, the debris, which had not been damaged by the return heat, might have fallen onto American soil. the incident The face of criticism from the NASA administrator at the time Jim Bridenstein.
Unexpected return
It is impossible to predict where and when the new Long March 5B will land. Its orbit will continue to narrow as atmospheric clouds make it denser. The speed of this process depends on the size and density of the object. Variables include changes and fluctuations in the atmosphere, which are themselves influenced by solar activity and other factors.
The rocket’s high velocity means that it orbits the Earth approximately every 90 minutes. Changing the return time by just a few minutes will result in a return point thousands of miles away.
The inclination of the Long March 5B base stage at 41.5 degrees means that the missile body will pass slightly north of New York, Madrid, Beijing and even southern Chile and Wellington, New Zealand, and can re-enter at any point during that stage. Area.
The most likely event is that the wreck will survive the intense heat of re-entry into oceans or uninhabited areas, but the risk of personal injury or property damage remains.
Said space observer Jonathan McDowell Space News The previous launch of the Long March 5B was the largest uncensored comeback in decades and the fourth largest ever. “The base stage at Long March 5B is seven times larger than the second stage of the Falcon 9, which was highly publicized a few weeks ago when it returned through Seattle and dumped some pressure tanks in Washington state.”
McDowell said he hoped China would improve the performance of the initial stage in closing the controlled orbit after separating from Tianhe. “I think by current standards it is unacceptable to appeal them without supervision,” McDowell said.
“Since 1990, no more than 10 tons have been intentionally put into orbit to get out of control.” The Long March 5B base stage is believed to have a “dry matter” or, if fuel-free, mass of about 21 tons without the four side boosters.
Holger Krag, head of the European Space Agency’s Office of Space Security Programs, says from her experience that the average mass is around 100 tons. Re-entry In a way that cannot be controlled in general. “This affects about 50-60 single events every year.”
“It is always difficult to determine the amount of mass remaining and the number of fragments without knowing the body design, but a reasonable ‘general rule’ is about 20-40% of the original dry matter.”
Components made of heat-resistant materials such as stainless steel or titanium tanks and the thrusters can come into contact with the ground. The rest of the objects fall vertically after they slow down and move at full speed.
The largest and most famous incident was the re-entry of NASA’s 76-ton ship Skylab in 1979, with uncontrolled wreckage scattered across the Indian Ocean and western Australia.
Entering again at night can lead to stunning views, as well Another re-entry The second stage Falcon 9 with its wreck, fortunately does not cause any damage.
The Chinese space laboratory Tiangong-1, which weighed 8 tons, has achieved great fame Uncontrolled re-entry In 2018 the successor was Tiangong-2 far Censored fashion in 2019.
