System Requirements Document - Lunar Exploration Ground Sites SAM

National Aeronautics and
Space Administration

GRC-LEGS-REQ-001

Revision: NISS-0
Effective Date: 09/21/26

Research and Technology Mission Directorate (RTMD) / Space Communications and Navigation (SCaN)
NASA John H. Glenn Research Center
Cage Code No.: 1QFP5
21000 Brookpark Road, Cleveland, Ohio 44135

Lunar Exploration Ground Sites
(LEGS) Public Private Partnership
(PPP)
System Requirements Document (SRD)

Document History Log

Document
Revision

Effective Date

NISS-0

09/14/2026

Description
Notice of Intent to Sole Source

List of Figures

List of Tables

Introduction

Project Overview
As National Aeronautics and Space Administration’s (NASA) advances its initiatives in support of the Moon-to-Mars architecture, the demand for increased ground station capabilities continues to expand. Lunar Exploration Ground Sites (LEGS) are space communication ground stations built primarily for lunar services to support this communications demand. LEGS ground stations are designed to be extensible to support NASA’s future space communication needs for the Lunar campaign and coverage within the Near-Space Beyond-Earth Proximity range of 36,000 km to 2,000,000 km from the Earth.
LEGS is a network capability within NASA’s Space Communications and Navigation (SCaN) Program’s portfolio. NASA procures these network services from a commercial Contractor. The LEGS subnet is planned to contain a minimum of six Direct to Earth (DTE) space communication ground stations built primarily for lunar services in support of the National Aeronautics and Space Administration’s (NASA) Moon to Mars (M2M) architecture. Two LEGS antennas are being built and will be provided to a commercial Contractor as Government Furnished Equipment (GFE) for integration into their network infrastructure using a Public Private Partnership (PPP) agreement. The dual-band antennas provide coverage to cis-lunar orbital missions and lunar surface missions while line of sight is available. Services include command and telemetry communications in both X-band and Ka-band frequencies, along with ranging and one- and two-way Doppler services in the X-band. The antennas provide communications services to both Human Spaceflight (HSF) and non-HSF missions.
The following number of operational DTE sites are expected to be in place in three phases during the execution of the PPP contract:
x Initial configuration of three (3) lunar DTE sites by October 2027 to support NASA missions
x Full redundancy configuration of six (6) antennas by October 2028 (minimum size of the