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 .