Advances in electro-optic remote sensing technologies now enable measurements to be made in a fraction of the size once required in earlier systems. Miniaturization of critical instrument technologies including optical systems, electronics, mechanisms, cryocoolers and sensors as well as increases in the density of semiconductor electronics and detector arrays now enable instruments to be made significantly smaller while achieving the same or better performance. Additionally, spacecraft technologies including navigation, C&DH, communications, power systems, and structures can be made in a fraction of the size enabling the entire satellite and instrument to be housed in “CubeSats” (where a single “U” is 10x10x10cm), and “NanoSats” where satellites are significantly smaller than traditional but not necessarily in the “U” form factor. These technologies lead to a significant reduction in instrument, spacecraft and launch costs, building robustness into current remote sensing programs and enabling new measurements to be made through more opportunity and through constellations of satellites to improve revisit time. Numerous challenges remain, including achieving legacy performance in a small package, power and data rate limitations, and mission reliability.