The Constellation-X Observatory (Con-X or HTXS) was a mission concept for an

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

space observatory to be operated by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...

; in 2008 it was merged with ESA and

JAXA The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into o ...

efforts in the same direction to produce the

International X-ray Observatory The International X-ray Observatory (IXO) is a cancelled X-ray telescope that was to be launched in 2021 as a joint effort by NASA, the European Space Agency (ESA), and the Japan Aerospace Exploration Agency (JAXA). In May 2008, ESA and NASA est ...

project, announced on 24 July 2008. The intention of the Con-X project was to provide enough X-ray collecting area to be able to feed a spectroscope of substantially higher resolution than the previous generation (

XMM-Newton ''XMM-Newton'', also known as the High Throughput X-ray Spectroscopy Mission and the X-ray Multi-Mirror Mission, is an X-ray space observatory launched by the European Space Agency in December 1999 on an Ariane 5 rocket. It is the second cornerst ...

Chandra X-ray Observatory The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources ...

and Suzaku) of space-based X-ray telescopes; this would allow the resolution of individual hot-spots at the event horizon of

black holes A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts that a sufficiently compact mass can def ...

, of warm intergalactic matter (by seeing absorption lines at various

redshifts In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in fr ...

superposed onto the spectra of background

quasars A quasar is an extremely luminous active galactic nucleus (AGN). It is pronounced , and sometimes known as a quasi-stellar object, abbreviated QSO. This emission from a galaxy nucleus is powered by a supermassive black hole with a mass rangi ...

) and of dynamics within

galaxy clusters A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second- ...

Technology for Con-X

The project intended to have separate low-energy and high-energy X-ray telescopes, to work from 100eV to 40keV spectrum. The collecting area requirements would have been achieved using a segmented-mirror technique based on slumping thin (400 µm) glass sheets onto mandrels, which avoids the handling problems of dealing with whole thin shells. Dispersive optics for the spectrometer were developed, as well as a microcalorimeter-array detector providing energy resolution per pixel of about 5eV.

The International X-ray Observatory (IXO)

In May 2008, ESA and NASA established a coordination group involving ESA,

and

, with the intent of exploring a joint mission merging the ongoing

XEUS XEUS (X-ray Evolving Universe Spectroscopy) was a space observatory plan developed by the European Space Agency (ESA) as a successor to the successful XMM-Newton X-ray satellite telescope. It was merged to the International X-ray Observatory ...

and Constellation-X efforts. The coordination group met twice, first in May 2008 at

European Space Research and Technology Centre The European Space Research and Technology Centre (ESTEC) is the European Space Agency's main technology development and test centre for spacecraft and space technology. It is situated in Noordwijk, South Holland, in the western Netherlands, al ...

(ESTEC), then in June 2008 at the Center for Astrophysics. As a result of these meetings a joint understanding was reached by the coordination group on a proposal to proceed towards the goal of developing an

(IXO). The coordination group proposed the start of a joint study of IXO. A single merged set of top level science goals and derived key science measurement requirements were established.

References

{{Space observatories Space telescopes X-ray telescopes Cancelled spacecraft