A development of X-ray sensitive microcalorimeter arrays is presently being undertaken to provide a spectroimager of high-energy resolution which could fit the focal plane of the X-ray astronomy spatial missions of the new generation (ESLAB 1999/093/SA). The infrared-sensitive arrays which have been realized at LETI in collaboration with the SAp, for the PACS experiment on board the Herschel satellite (Proceedings of the SPIE Conference of Orlando, 5-9 April 1999, 3698-38), are taken as the basis of this development which will rely conservatively on standard technology. (C) 2003 Elsevier Science B.V. All rights reserved.