Questions remain about Chinese rocket creating unusual twin craters on the moon

In November, we reported how the impact of China’s Long March rocket booster on the moon created an unusual double crater. In the case of a single booster producing twin craters, some researchers believe there must be an additional, possibly secret, payload on the front end of the booster (opposite the rocket motor). But that may not necessarily be the case.

Other researchers believe the extra mass is no secret, but could be inert structures such as payload adapters added to the rocket to support the primary mission payload.

Chang’e-5-T1 is an experimental robotic spacecraft launched by the China National Space Administration (CNSA) on October 23, 2014 to test the design of the return capsule planned for future Chang’e-5 missions, Chang’e Mission No. 5 is China’s first mission. Sample return efforts. Chang’e-5 landed on the moon in November 2020 and successfully collected lunar samples from the lunar storm sea area. The container returned to Earth on December 16, 2020.

Ahead of the country’s first sample return effort, the first in more than four decades, China wants to test the program and its sample return capsules. This is one of the T-1’s five mission objectives.

Philip Stock, an emeritus professor at the University of Western Ontario, said in an email to Universe Today that the rocket carried a “service module” satellite with a sample return capsule attached. It requires a fairly strong support structure (called a payload adapter) to support the mass against vibrations and acceleration during launch.

Stocker explained how the service module would orbit the moon and return to Earth, where it would release the capsule to test its re-entry survivability. The service module then returns to the Earth-Moon L2 point, where it remains for a few months before entering low lunar orbit, possibly for a gravity mapping mission. The service module remains in lunar orbit.

The combined mass of the service module and space capsule is 2,500 kilograms (2.5 tons), so it can’t just sit on top of a rocket’s fuel tank, Stock said.I can’t guess the quality [of the payload adapter] But it will be quite significant.

Payload adapters are available for medium payloads ranging from 135 kg (300 lb) to 225 kg (500 lb) or more.

Chang’e-5-T1 does have additional payloads, but they are small (known to be on board) and cannot account for a large enough mass to create a second crater. The two payloads are small radiation exposure experiments targeting bacteria and plants, and the first commercial payload from German space technology company OHB System, called the 4M mission (Manfred Memorial Moon Mission) in honor of the company’s The founder, Manfred Fuchs, passed away in 2014. The payload weighs only 14 kilograms but contains two scientific instruments: a radio beacon to test new methods of locating the spacecraft; and a radiation dosimeter (provided by Spanish company iC-Mlaga) to continuously measure radiation levels The entire satellite’s journey around the moon. The 4M mission is installed in the booster’s equipment bay.

Scott Tilley, a citizen scientist who monitors the orbits of satellites on Earth and the Moon, said there was no reason to suspect there was anything on board the rocket other than the 4M and common flight electronics. There will also be some additional mass to support the payload adapter and associated structures used to support the payload stack, which may be the limit of the rocket’s capabilities. Consider this is their first mission to the moon with a stacked payload. It can be more complex to install and secure than other more self-contained payloads.

The ongoing debate about the extra mass and what it might have been wouldn’t have ensued without two things: the unusual twin craters created by the booster impact, and denials by Chinese Foreign Ministry officials that the space debris and impact came from them rocket. They insist that the Chang’e 5T-1 rocket burned up when it returned to Earth in 2014. However, on March 1, 2022, the U.S. Department of Defense Space Command, which is responsible for tracking space debris in low-Earth orbit, issued a statement stating that China’s 2014 rocket never derailed.

Furthermore, Chinese officials have never commented on the nature of the twin craters.

The crater was photographed by NASA’s Lunar Reconnaissance Orbiter (LRO).

Typically, the mass of a spent rocket is concentrated on the engine end; the rest of the rocket stage consists mostly of an empty fuel tank, LRO Camera (LROC) principal investigator Mark Robinson wrote in June 2022 when the images were released.

A team of researchers at the University of Arizona discovered the errant booster (initially thought to be an asteroid) and by tracking its movement determined that it came from the Change 5-T1 mission. They also conducted spectral analysis of the object through ground telescopes during multiple flybys of the Earth, and ultimately showed that the object was the Long March 3C launch vehicle body in the Chang’e-5-T1 mission. They were able to roughly predict where and when the booster would hit the moon, which is why the LRO team could hunt through their data and easily find impact craters.

Everyone was surprised by the twin craters created by the impact. No other rocket body impact on the Moon produced a double crater, as shown in the crater images from the four Saturn rocket boosters of Apollo 13, 14, 15, and 17.

Researchers at the University of Arizona say there must be additional, undisclosed mass on the front end of the rocket’s main body.

The results of the Bayesian analysis mean that There may be extra mass at the front of the rocket body. Comparing pre- and post-impact images of this location, two different craters can be seen side by side, created by Change 5-T1 R/B. The twin craters support the hypothesis that there is additional mass at the front of the rocket body opposite the engine, beyond the published mass of the second permanently fixed payload.

When asked whether the payload adapter might be to blame for the excessive mass, team member Vishnu Reddy didn’t want to hazard a guess without more data.

He said it’s difficult to speculate on support structures because we don’t know of similar conditions for ordinary boosters sent to the moon.

Tilley told Universe Today that it is well known among amateur and professional satellite and rocket trackers that the China Space Administration has struggled in the past with the goal of having these types of boosters re-enter the Earth’s atmosphere or eject from the Earth and Moon. The system correctly disposes of the object.

Tilley explained that the Chinese expected the rocket to re-enter the Earth’s atmosphere and mentioned the details in a paper by LuxSpace, the company carrying out the 4M mission. But that didn’t happen, so it appears that part of their mission failed, which may be why the Chinese later denied it was their rocket.

Subsequently, however, recent missions such as the Chang’e-5 sample return mission had their boosters successfully re-enter the Earth’s atmosphere and be properly disposed of.

Another question about the impact is understanding the dynamics of why a single booster would create a double crater even if it had a lot of weight on both ends.

Regarding the twin craters, Vishnu explained, “I think the booster hit at a near-vertical angle, so the engines created the first crater and the second mass tipped over and formed the second crater.” However, Vishnu added that it is also possible that two craters would have formed if the booster was tumbling and happened to be horizontal at impact.

But like much of this unusual space drama story, questions remain.

That’s why we’ll leave the actual mechanism to a future paper, when we have better data to model it, Vishnu said.