XMM-Newton

XMM-Newton [ESA]

XMM-Newton (X-Ray Multi Mirror Observatory) carries three very advanced X-ray telescopes. They each contain 58 high-precision concentric mirrors, delicately nested to offer the largest collecting area possible to catch the elusive X-rays. These Mirror Modules allow XMM-Newton to detect millions of sources, far greater than any previous X-ray mission.

The spacecraft consists of main sections:

• a seven meter long black telescope tube;
• a squarish service module also carrying three 'mirrors modules' at its forward broader end;
• the focal plane assembly housing the X-ray cameras and detectors at its other extremity.

This 'tri-clops', with its golden eyes is more than 10 meters long, just fitting under the Ariane-5 fairing for its launch. Its pair of solar panels have a 16 meter span.

The spacecraft's design features extremely high mechanical stability. Its position and control systems allow it to point at targets in the sky over long periods with a remarkable pointing accuracy of 0.25 arcsec over a ten second interval.

X-rays can only be focused by changing their course accomplished by bouncing them off a surface at a shallow angle. XMM-Newton uses barrel-shaped mirrors angled along their length to focus them on the detectors. The three 'mirror modules' each have 58 wafer-thin nickel mirrors, which are gold-plated and nested in each other just a few millimeters apart. The total mirror surface area exceeds 120 m², larger than a tennis court. Constructing the mirror modules to such a level of perfection is one of the programme's greatest achievements.

XMM-Newton also carries an 'Optical Monitor' which will observe in the visible and ultraviolet the same region of the sky as the targeted X-ray sources.

The science instruments are:

• 3 European Photon Imaging Cameras (EPIC)
  new type of CCD (PN) developed by the Max Planck Institute of extraterrestrial Physics in Garching, Germany.
• 2 Reflection Grating Spectrometers (RGS)
• Optical Monitor (OM), co-aligned with the main X-ray telescope, will give the XMM mission a multi-wavelength capacity. 30-cm aperture Ritchey-Chretien telescope (with a 170-600 nm spectral range).
• EPIC Radiation Monitor System (ERMS)

In March 2023 ESA extended to operations until December 2026, and indicatively until end of 2029.