Abstract: An example apparatus includes a pointing structure, a magnetic-contrast bearing, and drive circuitry. The magnetic-contrast bearing is coupled to the pointing structure, and includes a magnetic array and a substrate that is arranged with the magnetic array. The drive circuitry generates a magnetic field that interacts with the magnetic array and causes control of a pointing position of the pointing structure.

Abstract: A sensor comprising a vapor cell including a vapor of alkali atoms is disclosed. The sensor further comprises a first photonic integrated circuit (PIC) configured to direct light of a first wavelength into the vapor cell and incident on the vapor of alkali atoms, wherein the light of the first wavelength is configured to excite the alkali atoms to a first excited state from a ground state. The sensor further comprises a detector configured to detect a response of the alkali atoms, after the alkali atoms are excited from the first excited state to a Rydberg state, to incident electromagnetic radiation.

Abstract: Systems and methods for clock synchronization are disclosed. A client synchronization system (CSS) may transmit RF pulses to a server CSS over micrometeorite ionization trail (MMIT) channels, and may receive RF pulses from the server CSS over MMIT channels, each received RF pulse following transmitted RF pulse. The client CSS may receive from the server CSS over MMIT channels measurement data including pulse arrival times at the server CSS. The measurement and transmission data may be correlated to identify RF-pulse pairs, each pairing a transmitted RF pulse received by the server CSS with a received RF pulse received from the server CSS, both over the same MMIT. TWTT analysis may be applied to timing data the pairs to compute time offsets between a client clock and a server clock. An analytical model of clock drift may be applied to the offsets to synchronize the client clock to the server clock.

Abstract: An example apparatus includes a pointing structure, a magnetic-contrast bearing, and drive circuitry. The magnetic-contrast bearing is coupled to the pointing structure, and includes a magnetic array and a substrate that is arranged with the magnetic array. The drive circuitry generates a magnetic field that interacts with the magnetic array and causes control of a pointing position of the pointing structure.

Abstract: Example gravity gradiometers are described that utilize high precision resonant optical cavities to measure changes in gravitational forces at high sensitivities. In one example, a sensing system includes a gravity gradiometer and a controller. The gravity gradiometer includes a first mirror and a second mirror arranged to form an optical cavity having an optical axis. The controller is configured to detect, responsive to displacement of at least one of the first mirror and the second mirror along the optical axis, a change in gravity gradient.

Abstract: Example gravity gradiometers are described that utilize high precision resonant optical cavities to measure changes in gravitational forces at high sensitivities. In one example, a sensing system includes a gravity gradiometer and a controller. The gravity gradiometer includes a first mirror and a second mirror arranged to form an optical cavity having an optical axis. The controller is configured to detect, responsive to displacement of at least one of the first mirror and the second mirror along the optical axis, a change in gravity gradient.