ABANDONED MISSILE HITS THE MOON – SCIENTISTS
The booster missile can be seen tracking across the sky from right to left
Scientists who had expected the collision at 12:25 GMT say that part of the discarded rocket should have hit the far side of the moon by now. The three-ton missile part has been tracked for a number of years, but its provenance has been disputed. At first, astronomers thought it might have been owned by Elon Musk’s SpaceX, then said it was Chinese – something China denies, and the effects of the impact on the Moon were supposed to be slight. The rocket stage had dug a small hole and created a column of dust. in the coming days or weeks scientists hope to have confirmation. The rocket part of Earth was first seen in March 2015. It was spotted by a NASA-funded space survey in Arizona, but it quickly lost interest when it turned out that the object was not an asteroid. The rocket part is what’s known as “space junk” – devices that are thrown off missions or satellites without enough fuel or power to return to Earth. Some pieces are closer to us, just above Earth, but others, like this booster, are thousands of kilometers away in high orbit, far from Earth’s atmosphere. The European Space Agency estimates that there are now 36,500 pieces of space junk larger than 10 centimeters, and no space program or university officially tracks abyssal space junk. Observation space is expensive and the risk to humans from high-altitude debris in orbit is low. Therefore, it falls to a small handful of volunteer astronomers who spend their spare time doing calculations and estimating orbits. They send emails and alerts back and forth, asking who’s in the best place on the planet to spot something in space.
Six weeks after first seeing the booster, Peter Birtwistle, 63, was observing the sky for asteroids from his garden in Newbury, southern England. His telescope picked up a tiny point of light tracking the sky. He told BBC News that calculations indicated it was part of a missile. Space junk falls out of sight, often unexpectedly. For seven years, the rocket hardly saw a part – even in January, it appeared again.
‘I took some pictures when it passed close to the ground,’ he explained. He sent his images to astronomer and data scientist Bill Gray, on the East Coast of the United States. It’s the expert who has gone on to identify it as a SpaceX booster bound for the moon. Gray explains that tracking space junk is often “investigative work.” The rocket’s insignia cannot be seen – astronomers have to piece together its identity by tracing its path backwards through space. They then match its orbit to the dates, launch locations, and trajectories of the rockets. However, some space missions, including China, do not advertise their routes. ‘For a Chinese mission, we know the launch date because it’s on TV. So I think it’s going to get to the moon – usually in four or five days. Then I calculate a rough orbit,’ Gray explains. And sometimes it makes mistakes. Weeks after SpaceX was identified, another observer sent Mr. Gray new data, revealing that his identification was impossible. Run the numbers back and conclude that this was the third stage of a rocket from China’s Change 5-T1 moon mission, which was launched in October 2014. This garbage may have emerge from a rocket like this one built by SpaceX.
China denied this, saying that the upper layer re-entered Earth’s atmosphere and burned. Mr. Gray sticks to his expectations. It is believed that China confused the tracking of two parts of missiles. ‘I’m 99.9% sure it’s China 5-T1,’ he says. In fact, we’ll never be sure. Professor Hugh Lewis, from the University of Southampton, says the scientific value of tracking waste in deep space is limited. But he says it’s important to “keep an eye on what’s out there,” especially as human settlement in space is becoming increasingly likely. ‘It’s the chaos we’ve created,’ he says. ‘Those things we think are safe can actually come back to Earth unexpectedly.’ Wherever it comes from, no one will witness the last moments of the booster. Evidence of what happened won’t come until two lunar orbiting satellites pass over the expected impact site and photograph the resulting crater feature. And with the augmented being broken into thousands of pieces, a lot of physical evidence of its true origins would also be lost. Our best estimates are given by Mr. Gray and the volunteer astronomers observing the sky.