On January 9, 2024, at 3:03 in the afternoon China time, a spacecraft called the Einstein Probe took off into space on a rocket named Long March 2C. This happened at a place in China called the Xichang Satellite Launch Centre. The Einstein Probe’s job is to look at the sky and search for flashes of X-ray light that come from space, like neutron stars and black holes.
The Einstein Probe is a big project where the Chinese Academy of Sciences (CAS) works with the European Space Agency (ESA) and a group in Germany called the Max Planck Institute for Extraterrestrial Physics (MPE).
Carole Mundell, who is in charge of science at ESA, said, “I want to say well done to our friends at CAS for starting this cool mission that will help us learn a lot about X-ray space stuff. At ESA, we think working with others around the world is a great way to learn more about space. I hope the Einstein Probe does a really good job.”
The Einstein Probe has two special tools to help it watch the whole sky and find new X-ray lights. These tools are called the Wide-field X-ray Telescope (WXT) and the Follow-up X-ray Telescope (FXT). The WXT is designed to work like lobster eyes. It uses lots of tiny square tubes to move light to the parts that detect it. This lets the Einstein Probe look at almost one-tenth of the sky at once. When the WXT sees new X-ray lights, the FXT, which can see less of the sky but in more detail, will take a closer look right away.
ESA helped test and set up the X-ray parts and the WXT’s mirror. They also worked with MPE and a company in Italy to make the mirror for one of the FXT’s two telescopes. MPE made the mirror for the other telescope and the parts that detect things for both FXTs. ESA also made a system to keep unwanted electrons away from the detectors. During the mission, ESA’s places on the ground that talk to space will help get the data from the spacecraft. Because ESA helped so much, they get to use 10% of the data the Einstein Probe collects.
The mission is really important because it helps us understand the most powerful things that can happen in space. Big bursts of X-rays happen when neutron stars crash into each other, stars explode, or things get pulled into black holes or pushed away by their strong magnetic fields.
Erik Kuulkers, who studies the Einstein Probe for ESA, said, “I can’t wait to see what the Einstein Probe will find. Because it can see so much of the sky, it will catch X-rays from neutron stars bumping into each other and help us figure out what makes the waves of gravity we can feel on Earth. Sometimes we feel these waves but don’t know where they come from. By quickly finding the X-ray flashes, we can figure out where many of these gravity wave events started.”
After it left Earth, the Einstein Probe went into an orbit about 600 kilometers up. It goes around the Earth every 96 minutes, tilted at an angle of 29 degrees. This lets it watch almost all of the night sky in just three times around the Earth.
For the next half a year, the team working on the mission will check and set up the tools. After they make sure everything is ready, the Einstein Probe will spend at least three years keeping a close eye on the whole X-ray sky.