The XMM-Newton, also known as the X-ray Multi-Mirror Mission and the High Throughput X-ray Spectroscopy Mission, is an orbiting X-ray observatory launched by ESA in December 1999 on an Ariane 5 rocket. It is named in honor of Sir Isaac Newton. The telescope was placed in a very eccentric 48 hour elliptical orbit at 40°; at its apogee it is nearly from Earth, while the perigee is only .

The XMM-Newton, also known as the X-ray Multi-Mirror Mission and the High Throughput X-ray Spectroscopy Mission, is an orbiting X-ray observatory launched by ESA in December 1999 on an Ariane 5 rocket. It is named in honor of Sir Isaac Newton. The telescope was placed in a very eccentric 48 hour elliptical orbit at 40°; at its apogee it is nearly from Earth, while the perigee is only .