Studying massive stars with the International X-ray Observatory

Chandra and XMM-Newton have deeply changed our view of the X-ray emission of massive stars. However, the majority of the massive stars being rather faint sources, the number of high-resolution X-ray spectra of massive stars remains rather limited and obtaining these spectra requires rather long exposure times. ESA, NASA and JAXA are currently designing the International X-ray Observatory (IXO) that will provide a quantum leap in collecting area compared to the current missions. In this contribution, we highlight the capabilities of IXO and its instrumentation for the study of massive stars in our Galaxy and beyond.