Description: Precision Navigation and Timing (PNT) is a critical resource for government and commercial aerospace. Given the high launch cost and shift toward smaller payloads, reducing the size, weight, and power (SWaP) of space-based navigation systems is a critical need. Atom-interferometric inertial sensors have demonstrated superior performance over conventional inertial devices owing to the intrinsic stability of atomic systems. Central to making cold atom sensors practical is their ability to reliably operate for extended periods without user intervention. Current laser diodes, which are at the heart of atomic sensors, suffer from power degradation and mode hops on timescales incompatible with long term deployment. Because these properties are inherent to the diodes, it is prudent to circumvent these problems with diagnostic protocols aimed at early detection and action. Diodes close to mode hopping can be temporarily taken offline to tune away the mode hop via current and temperature. Diodes with degraded power can be taken offline entirely in favor of a healthy diode. This approach will provide a robust, wavelength-agnostic technique to deliver reliable, long-lived laser sources at atom sensor-relevant wavelengths. AOSense proposes to develop a cold atom laser module (CALM) capable of supporting a broad range of atomic sensors. Development of the CALM laser module will result in a ruggedized and reliable laser source capable of autonomously driving an atom-based sensor within the space environment. Such an effort would enable space-based applications for atomic sensors such as IMUs, clocks, and magnetometers, opening up significant market opportunities in the defense and commercial sectors.

Benefits: Frequency stabilized lasers are at the heart of atomic sensors and their robust operation will be required for any future NASA mission that relies upon an atomic sensor. Atom interferometric sensors can be configured as accelerometers, gyroscopes, gravity sensors, magnetometers or precision time keeping devices. In each case they are best-in-class sensors and have the potential to enable new missions and applications of interest to NASA. Atom interferometers configured for gravity sensing can be used to map the earth's gravity gradient from orbit or to characterize the mass distribution of an asteroid for redirect missions. Atomic magnetometers offer the potential for improved remote sensing of magnetic fields and magnetic field gradients and could be used for precise characterization and monitoring of magnetic fields from orbit. Gyroscopes and accelerometers based on atom interferometry can provide orders of magnitude increases in inertial sensitivity which could lead to dramatic improvements in navigation and guidance systems. Ultra-precise atomic based gravity sensors and optical clocks could provide new methods for detection of gravity waves and tests of general relativity. Finally, robust frequency stabilized lasers are useful for non-atomic applications such as LiDAR and coherent laser communications.

Robust frequency stabilized lasers will also benefit the development of atomic sensors for non-NASA applications. Atom interferometric sensors can be configured as accelerometers, gyroscopes, gravity sensors, magnetometers or precision time keeping devices and therefore can be applied to a wide range of military platforms in addition to commercial applications. Precision navigation systems based on atom interferometric inertial sensors have the potential to provide precision positioning in environments where GPS signals are not available. Atomic gravimeters and gravity gradient sensors can be used for geophysical exploration and homeland security applications. Cold atom based frequency standards will ultimately replace the current generation of commercial cesium beam clocks that are widely used for timekeeping in a variety of systems.