I will present the current status of hard X-ray observations of microquasars focusing more precisely on the outcome of more than 10 years of normal and monitoring programs performed with the INTEGRAL satellite. I will present a some breakthrough results which shows the major importance of the 10-1000 keV spectral range to try and understand the physics of Galactic black holes and microquasars. I will then present some of the requirements and needs to pursue these studies and improve our understanding of the mechanism at work in those still rather enigmatic objects

This talk discusses the hard X-ray window for the observation of GRBs, with a focus on two issues: the study of the prompt emission with wide-field instruments, and the follow-up of the afterglow with narrow-field X-ray telescopes. On the first question, we emphasize the crucial role of X-ray polarimetry to elucidate the nature of the prompt emision. On the second, we stress the need of a broad spectral coverage to constrain the physics of the afterglow.

CdTe is particularly well suited for hard X-ray imaging spectroscopy in space. Since IBIS/ISGRI, an ambitious R&D program has been conducted at CEA/Saclay to achieve world class performance for high energy resolution and high spatial resolution detectors, showing up ~700 eV FWHM at 60 keV on a 625 micron pitch detector, placed over a 1 cm2 unit named Caliste. The device, is buttable on its four sides, enabling the fabrication of an arbitrarily large focal plane to be installed at the focal plane of a hard X-ray mirror. Moreover, to further improve the performance and offer the possibility of imaging a PSF of a short focal length in the order of 10 meters, a new development is in course to reach a 300 micron pitch over a large surface made again of a mosaic of 4 side buttable devices: the MC2 program.

At DTU Space we have developed a high resolution three dimensional (3D) position sensitive CZT detector for high energy astronomy. The design of the 3D CZT detector is based on the CZT Drift Strip detector principle. The position determination perpendicular to the anode strips is performed using a novel interpolating technique based on the drift strip signals. The position determination in the detector depth direction, is made using the DOI technique based the detector cathode and anode signals. The position determination along the anode strips is made with the help of 10 cathode strips orthogonal to the anode strips. The proto type detector was recently investigated at ESRF and performance results will be reported for the 150-600 keV band.

Space agencies still hesitate to select astrophysics missions using deployable masts or formation flying. A previous trade off shown that, up to 50m, a deployable mast could be much cheaper to implement than formation flying for such a type of missions. The US Adam mast has already flown several times with lengths between 10m and 60m. NuSTAR mast behavior is very convincing. CNES is currently developing a deployable carbon structural mast that is expected equivalent performances to Adam mast in a passive mode and upper ones in driving mode.

The astrophysical importance of the X–ray broad band (0.1–200 keV and beyond) has been widely demonstrated by missions like BeppoSAX, XTE, and INTEGRAL. This band has been shown to be crucial to get a complete physical description of the astrophysical sources, like to establishing the geometry of the systems, the physical phenomena occurring in the emission region and the radiation production mechanisms. Furthermore, it enables us to distinguish the contribution of thermal emission phenomena from those due to the presence of high energy non thermal plasma and/or magnetic fields. The focusing telescopes in the soft gamma–ray band are nowadays taking key relevance to overcome the sensitivity limits of the current generation of gamma–ray telescopes which see the sky through mechanical telescopes or coded mask systems. In this perspective the Italian space agency have founded in 2010 a technological project devoted to the development of long focal length wide band Laue lens (up to 100 m) for hard X–/soft gamma–ray astronomy (80-600 keV). We describe the apparatus developed to assemble and test a lens petal prototype and the first results obtained. The great achievement of this project is the use of bent crystals. From measurements obtained on single crystals and from simulations, we have estimated the expected Point Spread Function and thus the sensitivity of a lens made of petals. The expected angular resolution is about 30 arcsec and the expected sensitivity in 105 s is really huge. It ranges from 10-9 to 10-8 photons cm-2 s-1 keV-1, depending on photon energy. If the petals can be unfolded in orbit, the energy band can be extended to lower energies (down to 30 keV), with a great increase in sensitivity with respect to multilayer missions. We discuss a number of open astrophysical issues inclusive of the still mysterious origin of the 511 keV from CG, that can settled with such an instrument aboard a free-flying satellite.