Advancements in sensors/detectors are needed to support future NASA mission concepts including polarimetry, large format imaging arrays, and high-sensitivity spectroscopy. The corresponding data acquisition systems must employ high-speed, extra low power, linear analog-to-digital converters (ADCs) featuring a wide input bandwidth and reasonable effective number of bits, followed by a digital signal processor usually implemented inside a field-programmable gate array with a relatively low-speed data interface. In addition, radiation tolerance represents one of the main requirements for the space-oriented electronics. Commercially available ADCs feature high power consumption, high latency, poor linearity, and low radiation tolerance at high input bandwidths above 1GHz. To address the described needs, we propose a novel, low-power, high input bandwidth, radiation-tolerant, under sampling ADC with an output digital demultiplexer that enables direct data loading into a standard FPGA. Wide input bandwidth, low input return loss, 6-bit accuracy, low distortion and power consumption will be achieved through utilization of a proprietary adaptive matching filter and dual-output sample-and-hold amplifier followed by two reduced-rate ADCs. The digitized signals are delivered to the proprietary low-power LVDS output buffers after rate adjustment and realignment to the selected clock signal. Advanced technology featuring heterojunction bipolar transistors will provide the required radiation tolerance.