A Long March 5B missile, carrying a Chinese space station unit, fell into low Earth orbit and is now in danger of collapsing again.
The rocket successfully launched the Tianhe unit last week, which will become the living quarters for the future China Space Station (CSS). Unfortunately, the 30-meter missile also reached orbit and is now one of the largest launches ever for uncontrolled reentry.
It is uncommon for rockets to reach the speed needed to reach orbit, but they currently travel around the world about once every 90 minutes, or seven kilometers every second. It passes as far north as New York, Madrid and Beijing, and as far south as Chile and New Zealand.
There are concerns that the missile may land in a populated area; The last time a Long March missile was launched in May 2020, debris was reported to have landed on villages in Ivory Coast.
While it is likely that the missile will fall into the ocean – simply due to the large percentage of the land covered by water – astronomers believe that some parts of the missile will survive upon return.
That would be “the equivalent of crashing a small plane scattered over 100 miles away,” according to Jonathan McDowell, an astrophysicist at Harvard University’s Center for Astrophysics.
At the moment, it is very difficult to predict the fall of the missile, but it is expected to return to Earth on May 10. Once the exact day is confirmed, experts can apparently narrow down the landing time to a six-hour window.
“The base stage in Long March 5B is seven times larger than the second stage of Falcon 9 which caused a lot of press attention a few weeks ago when it entered again over Seattle and dumped pressure tanks in Washington state,” he said. “I think according to current standards, it is unacceptable to allow it to enter again without supervision. Since 1990, no more than 10 tons have been deliberately left in orbit to come back unattended again.”
Adam SmithMay 4, 2021 12:22
Long March 5B: Tracking the missile
For now, the missile remains within those parameters, but it has fallen further today. At 10:00 GMT, when the missile was over Africa, it dropped nearly 160 kilometers.
Amateur observations from the ground show regular flashes of the missile in the night sky, indicating that it is not under any control.
It is possible that a large portion of the missile will collapse when destroyed, but some debris will remain.
“It is always difficult to assess how much mass remains and how many fragments there are without knowing the object’s design, but a reasonable ‘general rule’ is about 20-40 percent of the original dry mass,” Holger Krag, head of the ESA’s space safety program office, said.
Adam SmithMay 4, 2021 12:10