For the past decade NASA's Earth Science Technology Office has made substantial investment in technologies to enable the measurement of the complete infrared spectrum using Fourier Transform Spectrometers on orbiting satellites. These measurements, at extremely high absolute accuracy, form the basis of a climate data record that can be used to diagnose climate change. We have developed several sensors and associated technologies that enable measurement of the infrared spectrum at the Earth's surface, within the atmosphere (from aircraft), and at the top of the atmosphere (i.e., from space). We will discuss these technologies and present the roadmap for developing sensors that will ultimately be deployed as part of an operational climate observing system.