Centimeter-Accurate One-Way Laser Ranging Anywhere in the Solar System — Case Studies of Lunar and Martian Landings

We proposed the ACES ELT laser receiver (launched onboard ISS on 21.4.2025) with 1-cm-diameter receiving optics for cm-accurate one-way laser ranging to Mars orbiter and Mars lander as well as laser ranging from Mars orbiter to rovers onboard Mars (Perseverance, Rosalind Franklin). The two-way on the orbiter is just used to observe time-drift once a day or over a shorter period of time, of the small Rb clock  (2.5 L) that is used for one-way laser ranging. We have also officially proposed a similar setup for the Moon landing, based solely on the one-way laser ranging from Earth. In this concept, onboard corner-cube reflectors are used to estimate the time drift of the clock connected to a laser receiver and to enable one-way laser ranging. With or without the full transponder option, the proposed setup allows centimeter-level accuracy one-way laser ranging anywhere in the Solar System, relying entirely on an onboard stable clock in combination with a laser receiver that time-tags the laser pulses received from ILRS stations on Earth. This setup enables highly accurate scientific missions on Mars and the Moon—such as for gravity and altimetry mapping—and supports the realization of precise reference frames for both Mars and Moon, considering the recent deployment of multiple small laser retro-reflectors on their surfaces that cannot be observed from the Earth.