Pushing limits: probing new gravity using a satellite constellation

Building upon earlier work, we explore the limits of using a configuration of satellites to measure the trace of the gravitational gradient tensor using intersatellite laser ranging and timing observables without relying on high-precision external observables such as deep space radio navigation or astrometry with unrealistic accuracy. A refined model, calculated with extended numerical precision, confirms that exceptional sensitivity is possible, placing within reach observational tests of certain modified gravity theories (e.g. Yukawa terms, Galileons) using heliocentric orbits in the vicinity of the Earth. The sensitivity of the experiment improves at larger heliocentric distances. A constellation placed at 30 astronomical units, still well within the domain of feasibility using available propulsion and deep space communication technologies, may approach sensitivities that are sufficient to detect not just the gravitational contribution of the interplanetary medium but perhaps even cosmological dark matter and dark energy constituents.