Chandra is an x-ray space telescope. It studies x-rays from very hot areas of the Universe. These areas contain objects like supernovae, galaxy clusters, and black holes. NASA launched Chandra in 1999. 

Chandra is a satellite over 100,000 km above Earth. It makes 1 orbit of the Earth every 64 hours. X-ray observatories like Chandra must operate from space. This is because the Earth's atmosphere stops most x-rays from reaching the ground. 

Chandra has 4 curved mirrors, nested inside each other. X-rays enter the telescope and the mirrors direct the x-rays onto detectors. Chandra has increased our knowledge of x-ray astronomy.

Chandra's discoveries include:

• Observing matter around the black hole at the centre of the Milky Way.
• Showing how elements are thrown into space by supernovae.
• Finding new black holes.
• Studying what happens to dark matter when galaxies collide.

NASA expected Chandra to last for 5 years. However, Chandra is still being used to do science in 2023.