X-ray Evolving Universe Spectroscopy Mission Research Articles

300 mK and 50 mK cooling systems for long-life space applications

The X-ray Evolving Universe Spectroscopy mission is a candidate for the ESA Cosmic Vision 2015–2025 plan, with two possible instruments at 300 mK and 50 mK. Astrium, under ESA contract, has worked with MSSL, RAL, and CEA-SBT, to propose a suitable payload accommodation scheme meeting ESA’s requirements. Exhaustive trade-offs were performed, according to a described methodology, leading to two designs incorporating closed-cycle active coolers maximizing well proven heritage concepts. These concepts are described, and although they have been prepared for XEUS, there are other future mission concepts which could also benefit from 50 mK cooling with a lifetime greater than 10 years.

The effect of the prompt particle environment at L2 on optical CCDs for astronomy and astrophysics

The increasing number of probes carrying large focal planes consisting of many charge-coupled devices (CCDs), planned to be sent to the L2 Lagrangian point, 1.5 million kilometres from Earth in the next 15 years, implies that a detailed study of the effects of the prompt particle environment at L2 on CCDs is required. The focus of this study will be on CCDs for optical astronomy, astrometry and photometric applications. This study will be of particular interest to GAIA the European Space Agency's (ESA) cornerstone optical astronomy mission to further explore and map sections of our galaxy in greater detail. The results will also have implications for future X-ray astronomy missions like the X-ray Evolving Universe Spectroscopy Mission (XEUS). Both the above missions will require large area focal planes incorporating many CCD detectors. The sources of the instrument background are both solar and galactic and if a probe is launched around the peak in the next solar cycle (2010), the possible false detection rate or the amount of data that could be lost during a mission must be determined. This paper presents measured data for a spacecraft in a geostationary orbit, specifically Geosynchronous Operational Environmental Satellites (GOES) data, and makes predictions of the flux and energy of the particle environment at L2. The solar and galactic cosmic ray background was determined by using the Cosmic Ray Effects on Micro-Electronics or CREME96 code. A comparison was then made between the GOES data and the output from the CREME96 code in order to make predictions about the L2 environment.

Space science applications of cryogenic detectors

The improved performance of cryogenic detectors has drastically enhanced their utilization range, allowing a number of space-based applications, with particular emphasis on astronomical observations. In this paper we provide an overview of the main applications of cryogenic detectors onboard spacecraft, together with a description of the key technologies and detection techniques used or being considered for space science missions. A summary of the cryogenic instrumentation technologies is also presented. Possible instruments for future astrophysics space missions are also discussed, using X-ray Evolving Universe Spectroscopy mission, presently proposed by ESA as a post XMM-Newton project as a reference.

Studying the evolution of the hot universe with the X-ray evolving universe spectroscopy mission – XEUS

Europe is one of the major partners building the International Space Station (ISS) and European industry, together with ESA, is responsible for many station components including the Columbus Orbital Facility, the Automated Transport Vehicle, two connecting modules and the European Robotic Arm. Together with this impressive list of contributions there is a strong desire within the ESA Member States to benefit from this investment by utilizing the unique capabilities of the ISS to perform world-class science. XEUS is one of the astronomical applications being studied by ESA to utilize the capabilities of the ISS. XEUS will be a long-term X-ray observatory with an initial mirror area of 6 m 2 at 1 keV that will be expanded to 30 m 2 following a visit to the ISS. The 1 keV spatial resolution is expected to be 2–5″ half-energy-width. XEUS will consist of separate detector and mirror spacecraft (MSC) aligned by active control to provide a focal length of 50 m. A new detector spacecraft, complete with the next generation of instruments, will also be added after visiting the ISS. The limiting 0.1–2.5 keV sensitivity will then be 4 × 10 −18 erg cm −2 s −1, around 200 times better than XMM-Newton, allowing XEUS to study the properties of the hot baryons and dark matter at high redshift.

Development of arrays of transition edge sensors for application in X-ray astronomy

The development of an array of voltage biased superconducting transition edge microcalorimeters is described. This work is directed to an application in future X-ray Astronomy missions, such as Constellation-X (USA) and the X-ray Evolving Universe Spectroscopy Mission (XEUS, Europe). After several years of very successful development of single pixel microcalorimeters (SRON showed a record energy resolution Δ E FWHM=3.9 eV for 5.9 keV photons, combined with an effective time constant of 150 μs and high X-ray absorption efficiency (94%)) work towards an array of 32×32 pixels has started. Aiming at a prototype of 5×5 pixels, several options for fabrication, using micromachining techniques are under study, both experimentally and theoretically. Measurement of thermal transport in detector support structures at sub-Kelvin temperatures indicates ballistic phonon transport. The detector development is accompanied by finite element modeling.

A New Method to Map Flares in Quasars

Recently, Chartas et al. detected a rapid X-ray flare in the gravitationally lensed, multiple-image quasar RX J0911.4+0551. Dramatic events, such as rapid X-ray flares, are useful for providing high-precision measurements of the time delays between multiple images. In this paper we argue that there is a new possibility for measuring time delays between multiple images of gravitationally lensed quasars and constraining the locations of putative flares that give rise to the intrinsic rapid variabilities of quasars. The realization of these goals, however, cannot be achieved at present because of the limited accuracy of the current measurements. We predict that timing flares with accuracies of the order of a few seconds will be needed to probe the location of the flares. The method that we are proposing will work with better instruments in near future, such as the X-Ray Evolving Universe Spectroscopy Mission.

Robotics in the service of astronomy

Robotics is an engineering discipline that has much to offer astronomy. Although its application to planetary science is broadly appreciated, its potential for astronomy is not so widely known, We present a brief outline of some of the benefits of using robots in space-based astronomy. We hope to engage the astronomy community in demonstrating the capabilities of robotics and how this type of technology can be deployed to maximize the scientific return from space-based astronomy missions. We consider in particular the role of the European Robotic Arm (ERA) mounted on the International Space Station (ISS) in the proposed XEUS (X-ray Evolving Universe Spectroscopy) mission. We also consider other potential areas in which robotics can enhance astronomical technology. We submit that robotics will become increasingly important for astronomy as an observational discipline for future generations of astronomy platforms in space.

High-Energy Astronomy From The International Space Station

The European Space Agency, ESA, is currently studying 3 high-energy astronomy missions that use the International Space Station (ISS). These are Lobster-ISS, an all-sky imaging X-ray monitor, the Extreme Universe Space Observatory (EUSO) which will study the highest energy cosmic rays by using the Earth's atmosphere as a giant detector and XEUS — the X-ray Evolving Universe Spectroscopy Mission, a potential successor to ESA's XMM-Newton X-ray observatory. These first 2 missions will he attached to the external platforms on the Columbus module, while XEUS will visit the ISS to attach additional X-ray mirrors to enlarge the original 4.5 m diameter mirrors to the 10 m diameter required to observed redshifted iron lines from massive black holes in the early Universe.