The International Space Station (ISS) has had a busy week. First, a spacewalk had to be called off because coolant water got everywhere in the airlock. The astronauts then had to take cover in the spaceship they were in because there was a report of potentially dangerous space junk coming toward them.

The pieces were made when an old satellite broke apart. Resurs-P1 was a Russian commercial Earth observation satellite that was used until 2021, when it was turned off because some of its equipment stopped working. It wasn’t meant to deorbit, so it just kept going around in a circle about 355 kilometers (221 miles) above our heads. It would have burned up and lost altitude in the end, but on Wednesday, something else happened.

LeoLabs, a company that tracks satellites, says that the satellite broke into more than 100 pieces that can be tracked. The ISS is farther away than their orbit; it is between 413 and 422 kilometers (257 and 262 miles) high. Even so, some of the debris could still hit the ISS, so the astronauts were told to stay inside as a safety measure.

LeoLabs has detected a debris-generating event in Low Earth Orbit.

Early indications are that a non-operational Russian spacecraft, Resurs P1 (SATNO 39186), released a number of fragments between 13:05 UTC 26 June and 00:51 UTC 27 June.

— LeoLabs (@LeoLabs_Space) June 27, 2024

Starting around 8:45 p.m. EDT on Wednesday, June 26, NASA told crews on the space station to take cover in their own spacecraft as a standard safety measure after learning that a satellite had broken up near the station earlier that day. NASA wrote in a blog post that Mission Control kept an eye on the path of the debris and after about an hour, the crew was told they could leave their spacecraft and normal operations returned to the station.

LeoLabs said Thursday afternoon that they were tracking at least 180 pieces of debris, and they expect that number to go up. The sudden breaking apart of the satellite is still not clear, but LeoLabs hopes to be able to figure it out.

Update: We are now tracking at least 180 fragments resulting from this event.

We expect this number to increase in the coming days. We are actively analyzing the debris cloud to characterize it, identify a potential cause, and estimate the impact.

More details to follow. https://t.co/tp3GC9Ti5s

— LeoLabs (@LeoLabs_Space) June 27, 2024

It’s possible that Resurs-P1 was hit by another piece of space junk, which caused a swarm of debris. The object Resurs-P1 is not small; it’s about the size of a van. A van that is going 5 miles per second (8 km/h). It’s very fast, so even a small thing hitting it would do a lot of damage.

A collision of space junk is a big problem because it could cause the Kessler Syndrome, which is a chain reaction of debris that blocks access to a certain orbital region. A lot of people want satellites to have a plan for deorbiting right now to avoid this kind of thing.

People have been interested in the Antikythera mechanism for more than 120 years, and new research has shed more light on this amazing machine in recent years. The pieces that are still there show that it was probably used to figure out things like eclipses and where the planets were in the sky. With some statistical methods that are often used in gravitational wave research, astronomers from the University of Glasgow have found more proof that it is linked to the Moon.

Professor Graham Woan and Dr. Joseph Bayley each used a different method after an interesting X-ray analysis of the object was done years ago. Some people don’t know how many holes are in one of the rings, which is thought to be a calendar. There is only a small piece of the ring left, and it’s hard to say for sure what it is because it spent 2,000 years underwater.

Based on the X-ray data, Woan and Bayley used bayesian statistics to determine how many holes there were in the rings. The most likely number was either 354 or 355 holes, they found. Around 354 days make up a lunar calendar. Based on the research, this number is 100 times more likely than 360 holes, which is what the Egyptian solar calendar has. This means that a 365-hole ring, which would be like a real solar year, is very unlikely.

“Towards the end of last year, a colleague showed me data that YouTuber Chris Budiselic had collected. Budiselic was trying to make a copy of the calendar ring and was looking into ways to find out how many holes it had,” Professor Woan said in a statement. “I thought it was an interesting problem that I might be able to solve in a new way over the Christmas break, so I started using some statistical methods to find the answer.”

The Markov Chain Monte Carlo and nested sampling methods were used. These are common ways to figure out how likely one result is given incomplete data. These techniques lead us to believe that the whole ring was 77.1 millimeters across and had either 354 or 355 holes spaced 0.028 millimeters apart.

“Previous research had suggested that the calendar ring probably followed the lunar calendar, but the two methods we used in this project make it much more likely that this was the case,” Dr. Bayley said. “It’s made me appreciate the Antikythera mechanism and the work and care that Greek craftsmen put into making it even more. To punch the holes so precisely, they would have needed to be measured very accurately and punched with a very steady hand.”

The study has been written up in The Horological Journal.

The first samples ever taken from the far side of the moon have been opened by scientists in China.

Chang’e 6 softly landed on the far side of the moon on June 1. It was the second time China had done this, and they are still the only country to have done it.

China just landed a probe on the far side of the Moon – this time nearer the south pole, to gather volcanic samples using a scoop and drill, and blast them back to Earth. They've partnered with Sweden, France and Italy. Proving the tech needed to land Chinese astronauts by 2030. pic.twitter.com/Yf5wW8EQMK

— Chris Hadfield (@Cmdr_Hadfield) June 2, 2024

The lander brought something back for the European Space Agency (ESA): a negative ion detector. This detector has already picked up negative ions as they are thrown up by the lunar surface.

Author Martin Wieser said in a statement, “These observations on the Moon will help us better understand the surface environment and act as a pathfinder to explore negative ion populations in other airless bodies in the Solar System, from planets to asteroids and other moons.”

But the main goal of the mission is to bring back the first samples from the far side of the Moon. On Tuesday, the China National Space Administration (CNSA) landed in the Inner Mongolia desert to do just that. It was flown to Beijing on Wednesday, and at the China Academy of Space Technology, it was opened.

Researchers from all over China who have applied for access will sort the samples before they are studied. Scientists from around the world might be able to use this after two years, according to Space.com.

“One of the most fundamental questions in lunar research”—what geologic activity is responsible for the differences between the two sides of the Moon—is what Zongyu Yue, a geologist at the Chinese Academy of Sciences, told the South China Morning Post. This is what the samples are meant to do.

Even though it’s called the “dark side” of the moon, the far side gets about the same amount of sunlight. But there are big differences between them, which we found out when we started traveling through space.

The Moon’s far side has many craters, but not as many deep basins and “lunar seas” as its near side. In 2012, the Gravity Recovery and Interior Laboratory mission measured that the far side’s crust was thicker. It also seems to be more conductive, which is strange.

There are several ideas about how the sides got to be so different. One is that Earth used to have two moons that orbited it and crashed into each other early in its history. Another is that a dwarf planet later crashed into a smaller Earth moon.

You can study the far side of the moon from space, but there’s nothing better than taking samples yourself. Scientists hope that the samples will help them figure out how the moon formed. They also think that the samples might contain water, oxygen, and hydrogen that can be used for future missions.