Ultralightweight x-ray telescope missions: ORBIS and GEO-X

Toward an era of x-ray astronomy, next-generation x-ray optics are indispensable. To meet a demand for telescopes lighter than the foil optics but with a better angular resolution <1  arcmin, we are developing micropore x-ray optics based on micromaching technologies. Using sidewalls of micropores through a thin silicon wafer, this type can be the lightest x-ray telescope ever achieved. Two Japanese missions, ORBIS and GEO-X, will carry this telescope. ORBIS is a small x-ray astronomy mission to monitor supermassive blackholes, while GEO-X is a small exploration mission of the Earth’s magnetosphere. Both missions need an ultralightweight (<1  kg) telescope with moderately good angular resolution (<10  arcmin) at an extremely short focal length (<30  cm). We plan to demonstrate this type of telescope in these two missions around 2020.