Moon exploration is emerging as the next global strategic priority in space exploration. Several dozens of commercial and institutional missions to the Moon are planned for the coming decades, with a major contribution also expected from ESA (e.g. Orion service module, ESA participation in Gateway lunar station and contribution to multiple lunar robotic missions). In spite of the wide variety of missions planned for the Moon, a lunar navigation (and communication) infrastructure is not yet available.

In light of this, and in close coordination with the HRE Directorate, the Executive has defined a reference Roadmap for Lunar PNT service provision (ref. ESA/PB-NAV(2020)9), consisting of three phases:

• Phase 1: based on the use of the signals from existing Earth GNSS constellations received thanks to high-sensitive receivers and directional antennas;
• Phase 2: complementing the use of the Earth GNSS signals with dedicated lunar orbiting ranging satellites, integrated as part of an ESA proposed Lunar Communication and Navigation Service (LCNS); and
• Phase 3: further enhancing the LCNS system with additional lunar orbiting and surface infrastructure, providing a full Lunar PNT autonomous service and full moon navigation surface coverage.
• This vision is also shared with NASA, closely cooperating with ESA in this field.

In line with this roadmap and preliminary system studies being carried out in NAVISP-El1-023, a Lunar Communications and Navigation Services (LCNS) Phase A/B1 system study has then been agreed to be launched as a joint initiative by the Telecommunications and Integrated Applications (TIA), Human and Robotic Exploration (HRE), and the Navigation (NAV) Directorates. The NAV Directorate is in charge of supporting all the PNT related aspects of this study.

In complement to the LCNS Phase A/B1 study, as explained in ESA/PB-NAV(2020)9, there is technical consensus on the importance to implement a pre-development of the most critical associated navigation technologies.

The main objectives of the Navigation Payload demonstrator for future LCNS satellite therefore aim to: 

• Provide an in-depth understanding of the critical potential functionalities of Navigation Payload and its sub-System, Units/elements as part of the future LCNS system; 
• Perform a preliminary design of a complete flight model of Navigation Payload; ∙ Implement critical functions and critical technology of elements of the Navigation Payload for Lunar through an EBB and assess relevant performances; 
• Reduce the implementation risk of the future models (EQM/FM) equipment by assessing the associated critical technologies in due-time and proposing an implementation roadmap for the Navigation Payload of the LCNS system and potential hosted TASIs.