ATTACHMENT B

MTN OBJECTIVES AND REQUIREMENTS

04/08/2026

DRFP 80GSFC26R0011

CONTRACT TBD

MTN Objectives and Requirements

Attachment B

DRFP: 80GSFC26R0011

MTN-402-REQ-0001, Rev A

Effective Date: April 8, 2026

Check https://ipdtdms.gsfc.nasa.gov/ to verify that this is the correct version prior to use.

National Aeronautics and Space Administration

Goddard Space Flight Center Greenbelt, Maryland

MTN-402-REQ-0001, Revision A

Mars Telecommunications Network

Mars Telecommunications Network (MTN)

Objectives and Requirements Document

GSFC MTN CMO

April 8, 2026

Released https://ipdtdms.gsfc.nasa.gov/

MTN Objectives and Requirements MTN-402-REQ-0001, Rev A

Effective Date: April 8, 2026

Check https://ipdtdms.gsfc.nasa.gov/ to verify that this is the correct version prior to use.

Change History Log

Revision Effective Date Description of Changes

- 3/19/2026 Initial Release

A 4/8/2026 Added MTN-REQ-049

Revised Ground Rule and Assumption 9 and 14

Added MTN-OBJ-005

Added MTN-REQ-050

Revised MTN-REQ-019

Table of TBDs/TBRs/TBSs

Action Item

No.

Location Summary Individual/

Organization

Actionee

TBD-01 MTN-

REQ-034

Reference document for adaptive data rates currently in development.

JPL

TBD-02 MTN-

REQ-049

ICD to define scientific payload SMD

Table of Contents

1 INTRODUCTION

1.1 Purpose

1.2 Scope

1.3 Applicability

1.4 Stakeholders

2 REFERENCE AND APPLICABLE DOCUMENTS

2.1 Applicable Documents

2.2 Reference Documents

3 GOALS AND OBJECTIVES

4 GROUND RULES AND ASSUMPTIONS

5 SYSTEM OVERVIEW

6 MARS TELECOMMUNICATIONS NETWORK REQUIREMENTS

6.1 Project Requirements

6.2 Vehicle Requirements

6.3 Direct with Earth (DWE) Link Requirements

6.4 Proximity Link Requirements

APPENDIX A: ABBREVIATIONS AND ACRONYMS

APPENDIX B: LINK BUDGET TEMPLATE

List of Tables

Table 1 Ground Rules and Assumptions Table 2 Science Payload Accommodation Table 3 Legacy Proximity Link Spectrum Table 4 Advanced Proximity Link spectrum

1 INTRODUCTION

Consistent with law, the National Aeronautics and Space Administration (NASA) is working toward a high-performance Mars telecommunications orbiter(s), capable of providing assets in and around Mars with robust, continuous communications with earth.

1.1 Purpose

The purpose of this Objectives and Requirements Document is to provide objectives and requirements for the Mars Telecommunications Network Project.

The intent of these objectives and requirements is to support definition of the required “what” and to the maximum extent possible not define the “how”. However, since existing assets are already operating in and around Mars, legacy compatibility is required, and as such detailed specificity is provided in this document and associated applicable and reference documents. The longer-term vision is evolution of the existing Mars network to a higher performing system with extensibility to a 24/7 end state.

1.2 Scope

The scope of this requirements document includes orbiter(s), direct with earth (DWE), and

Proximity link related requirements. The document does not include specific launch vehicle-related requirements. This document also describes top-level objectives of the MTN orbiter(s).

1.3 Applicability

This objectives and requirements document is applicable to the Mars Telecommunications

Network Project.

1.4 Stakeholders

The following are the key stakeholders for the MTN Project:

• Exploration Systems Development Mission Directorate (ESDMD)

• Space Operations Mission Directorate (SOMD)

• Strategy and Architecture Office (SAO)

• Science Mission Directorate (SMD)

• Space Communication and Navigation (SCaN) Program

• Moon to Mars (M2M)

2 REFERENCE AND APPLICABLE DOCUMENTS

2.1 Applicable Documents

Applicable documents are those documents that form a part of this document. These documents carry the same weight as if they were stated within the body of this document.

Document Number Document Title Revision

Architecture/Mission

NASA STD-871927 Implementing Planetary Protection Requirements for

Spaceflight

Direct with Earth Links

810-007 DSN Mission Interface Design Handbook

810-005 DSN Telecommunications Link Design Handbook

503.0-B-2 CCSDS Tracking Data Message

502.0-B-2 CCSDS Orbit Data Message

Proximity Links

MRN Participation Guide

MRN Participation Guide Technical Support Package

734.20-O-1 CCSDS Bundle Protocol Specification

734.1-B-1 CCSDS Licklider Transmission Protocol (LTP)

211.0-B-6 CCSDS Prox-1 Space Link Protocol - Data Link Layer

732.0-B-4 CCSDS AOS Space Data Link Protocol

732.1-B-3 CCSDS Unified Space Data Link Protocol

211.2-B-2 CCSDS Prox-1 Space Link Protocol - Coding and

Synchronization Sublayer

211.1-B-4 CCSDS Prox-1 Space Link Protocol - Physical Layer

NASA NPR’s and Standards

NASA-STD-7009 Standard for Models and Simulations B

Lunanet Interoperability Specification 5

2.2 Reference Documents

Reference documents are those documents that, though not a part of this document, serve to clarify the intent and contents of this document.

Document Number Document Title Revision

Architecture/Mission

JPL D-106417 Mars Handbook 2022-2040 1.0

M2M Architecture Description Document C

NIST.FIPS.140-3 Federal Information Processing Standards Publication

Planetary Protection Handbook 2024

Direct with Earth Links

104-DSN 34-m BWG Stations Telecommunications Interfaces

875-0001 DSN Mission Service Interfaces, Policies, and Practices

(MSIPP)

H

820-10 Deep Space Network Services Catalog H

Proximity Links

REC 22-1 Frequency Assignment Guidelines for Communications in the Mars Region

NASA NPR’s and Standards

NPR 7123.001 NASA System Engineering Processes and Requirements D

3 GOALS AND OBJECTIVES

The top-level objectives of the MTN project are identified as:

MTN-OBJ-001

Provide communication and data exchange between assets in the Mars vicinity, the Mars surface, and Earth anticipated to operate at Mars through 2035.

MTN-OBJ-002

Provide Doppler, range, and time transfer to support positioning, navigation, and timing for assets anticipated to operate at Mars through 2035.

MTN-OBJ-003

Provide communication services to existing operational missions.

MTN-OBJ-004

Provide communications, Doppler, range, and time transfer services to the Entry, Descent, and Landing (EDL) demonstration missions anticipated to operate at Mars through 2035.

MTN-OBJ-005

Provide spacecraft bus integration, accommodation, and communication services to a science payload provided by NASA.

4 GROUND RULES AND ASSUMPTIONS

The ground rules and assumptions are identified and defined in the following table:

ID Ground Rule / Assumption

1 MTN will not require, nor does it preclude surface-to-surface relay communications for 2035 uses.

2 MTN will not require, nor does it preclude orbiter crosslink capability.

However, 24/7 end state extensibility is envisioned in the future.

3 The MTN will be compatible with the DSN communication links from deep space to Earth.

4 The MTN communication links from orbiter(s) to DSN will require ground compatibility testing with DSN, prior to launch. (Test assets such as DSN

CTT-22, MIL-71 and DTF-21 may be available subject to negotiation with

NASA)

5 The MTN contractor will deliver to NASA an MTN portable test unit for

Proximity link compatibility testing for future mission users for all Proximity links.

6 MTN will require adaptive data rates on the Proximity link, consistent with existing capability.

7 MTN will not require optical communications for DWE link, but could be considered as part of a contractor’s proposal

8 MTN will require low-rate X-band and higher rate Ka-band DWE connectivity throughout all operational phases.

9 MTN will require S-band or K/Ka-band Advanced Proximity links for higher rate missions

10 MTN will require UHF Legacy Proximity links.

11 NASA is procuring an MTN system via Fixed Price Contract (FFP), and scope includes ground and flight hardware delivery to NASA. Launch and future operations will be handled via contract options.

12 Launch vehicle interface will be proposed and managed by the contractor.

There are no specific requirements included for a particular launch vehicle.

13 MTN will require scheduling functionality and associated interfaces for both

DWE and Proximity links

14 Hosting a SMD science payload is on a do-no-harm basis, and schedule risk is critically important.

Table 1 Ground Rules and Assumptions

5 SYSTEM OVERVIEW

This document implements a nomenclature of “threshold” and “goal” requirements. The

“threshold” requirements define the minimum performance and functional requirements necessary to achieve an acceptable system. The “goal” requirements define stretch targets that are desired by project stakeholders that represent meaningful improvement over the minimum viable system.

Figure 1 Mars Telecommunications Network (MTN) Threshold Configuration

Figure 2 Mars Telecommunications Network (MTN) Goal Configuration

6 MARS TELECOMMUNICATIONS NETWORK REQUIREMENTS

6.1 Project Requirements

MTN-REQ-001 Operational Lifetime

Threshold Requirement: Mars Telecommunications Network shall provide communications and

Position, Navigation, and Timing (PNT) services for a minimum operational lifetime of 5 Earth years, beginning at operational readiness.

Goal Requirement: N/A

Rationale: A 5-year operational lifetime ensures the Mars Telecommunications Network architecture can provide stable relay services across multiple Mars missions and demonstrations beginning at operational readiness. For the purposes of this requirement, operational readiness is defined as post-commissioning and ready to provide full operational capability. (Ref: Moon-to-

Mars Architecture Description Document Rev C)

Verification Method: Analysis

Traceability: MTN-OBJ-001, MTN-OBJ-002, MTN-OBJ-003, MTN-OBJ-004

MTN-REQ-002 Proximity Link Continuity of Service

Threshold Requirement: Mars Telecommunications Network shall provide Proximity Link radiometric and communications services to current and in development Mars surface assets.

Rationale: Integrated communications and radiometric services are required to support commanding, telemetry, and precision navigation for existing and in-development Mars surface assets at UHF using the Proximity-1 Space Link Protocol (Ref. CCSDS 211.2-B-2, “Proximity-1

Space Link Protocol—Coding and Synchronization Sublayer”; CCSDS 211.1-B-4, “Proximity-1

Space Link Protocol - Physical Layer”; CCSDS 211.0-B-6, “Proximity-1 Space Link Protocol -

Data Link Layer”) Note there are slight differences between NASA and ESA assets that must be accommodated and there are also slight differences with the protocol specification from both types of assets.

Verification Method: Test

Traceability: MTN-OBJ-001, MTN-OBJ-002, MTN-OBJ-003

MTN-REQ-003 Non-Real-Time Store-and-Forward

Threshold Requirement: Mars Telecommunications Network shall provide store-and-forward capability for Direct with Earth (DWE) and Proximity communications.

Rationale: Providing non-real-time, store-and-forward enables reliable data delivery despite long delays, intermittent visibility, and periodic loss of line-of-sight between surface, orbital, and

Earth segments ensuring continuous mission communications in Mars orbital geometries without requiring real-time connectivity.

Traceability: MTN-OBJ-001, MTN-OBJ-003, MTN-OBJ-004

MTN-REQ-004 Concurrent Service Provision

Threshold Requirement: Mars Telecommunications Network shall support concurrent full duplex operation of communications relay DWE, Proximity communications, and associated services.

Rationale: Concurrent, non-interfering operation of communications relay, semi-real-time delivery, DTN networking, navigation, timing, and messaging is required to support overlapping mission activities without degrading critical services. This capability ensures predictable performance under peak load, protects time-critical functions, and enables Mars

Telecommunications Network to operate as reliable, multi-mission infrastructure consistent with

SCaN architecture and NASA risk-informed systems engineering practices (CCSDS BPv7, NPR

7123.1, NPR 8705.5).

MTN-REQ-005 Hardware Delivery Date

Threshold Requirement: The contractor shall deliver completed ground and flight systems to

NASA including completion of all associated reviews and inspections by December 31, 2028.

Rationale: Consistent with Pub. L. 119-21, delivery by end of CY2028 ensures continuity of critical relay services and prevents a communications gap as existing Mars orbiters age.

Verification Method: Inspection

MTN-REQ-006 Direct with Earth (DWE) Service

Threshold Requirement: Mars Telecommunications Network shall provide Direct with Earth

(DWE) under all flight phases (i.e. launch, separation, transit, and insertion) excluding solar conjunction and occultations.

Rationale: The Mars Telecommunications Network will provide reliable, communication and radiometric services with terrestrial ground-stations.

MTN-REQ-007 Mission Environment

Threshold Requirement: Mars Telecommunications Network shall operate as specified herein when exposed to all expected environments through all expected mission phases.

Rationale: The Mars Telecommunications Network, in addition to on-orbit lifecycle, will be exposed to all relevant operational environments through deployment into orbit including but not limited to orbital insertion, time-light delays from ground command preventing timely intervention and potential intermittent loss of communication and command. [Ref. Mars

Handbook 2022-2040 Release 1.0]

MTN-REQ-008 Solar Conjunction

Threshold Requirement: The Mars Telecommunications Network Direct with Earth (DWE) connections shall operate at Sun-Earth-probe angles at 3°and greater.

Goal Requirement: The Mars Telecommunications Network Direct with Earth (DWE) connections shall operate at Sun-Earth-probe angles at 2°and greater.

Rationale: The Earth-Mars solar conjunction will prevent communications between Earth and

Mars for the duration the time of the actual line-of-sight blockage. Designing communication links to operate within 3° of the blockage will increase the availability of the links by incorporating mitigation techniques and link margin to optimize communications in the presence of solar adverse effects on the respective receivers. Operational constraints may be imposed to mitigate the potential of corrupted commands sent to the spacecraft. For this requirement, threshold values reflect expected performance of X-Band transmission.

MTN-REQ-009 Ground Commanded Prioritization

Threshold Requirement: The Mars Telecommunications Network shall provide the capability for data prioritization.

Rationale: The Mars Telecommunications Network will service multiple end users. Therefore, it is necessary to provide a means of prioritizing data to facilitate link scheduling. This prioritization scheme is controlled by ground personnel and can be specified prior to and after the network services are rendered.

MTN-REQ-010 Scheduling Functionality

Threshold Requirement: The Mars Telecommunications Network shall implement a means for user scheduling and providing associated interfaces for both Direct with Earth (DWE) and

Proximity links.

Rationale: The Mars Telecommunications Network will service multiple end users. Therefore, it is necessary to provide for scheduling ground station assets and coordinate user scheduling of proximity interfaces along with the associated interfaces for user data.

Verification Method: Demonstration

MTN-REQ-011 Link Performance

Threshold Requirement: The Mars Telecommunications Network shall meet end-to-end performance for all communication links with ≥3 dB margin.

Rationale: Meeting end-to-end performance at maximum range with at least 3 dB margin ensures reliable communications under nominal conditions. The ≥ 3 dB link margin requirement provides explicit robustness against link modeling uncertainty, hardware performance drift, pointing error, aging of RF components, and unmodeled environmental or propagation effects.

This aligns with NASA systems engineering guidance (e.g., NPR 7123.1 and NASA-STD-7009) to include appropriate performance margin for model-based predictions and long-life space assets, reducing the risk of link outages, increased retransmissions, or permanent loss of service.

Communication links to be assessed using provided link budget template (Appendix B).

MTN-REQ-012 Bit Error rate

Threshold Requirement: All Mars Telecommunications Network communication links shall have a bit error rate of 10-7 or better.

Rationale: This value is aligned with NASA best practice and ensures for accurate decryption of command link. Communication links to be assessed using provided link budget template (Appendix B).

MTN-REQ-049 Scientific Payload Considerations

Threshold Requirement: Mars Telecommunications Network shall accommodate a NASA science payload per [TBD-02] conforming to the interface and not-to-exceed envelope depicted in Table 2.

Criteria Value Units

Basic Mass 20 kg

Dimensions 55x55x45 cm x cm x cm

Nominal Power 60 W

Peak Power 60 W

Power Interface Port 28V

Communication Interface Wired

Data Comm Port RS-422, Ethernet

Max Instantaneous Data Rate 25 kbps

Daily Data Volume 200-1000 Mb

Requires Thermal Isolation No

Shock Load Limit GEVS

Table 2 Science Payload Accommodation

Rationale: MTN stakeholders anticipate the inclusion of scientific payloads. All payloads will be negotiated with the NASA team and will not impact MTN schedule requirements. While certain attributes of Table 2 imply a payload functioning as part of the MTN flight system, a deployable

CubeSat that fits within the mass and volume envelope of Table 2 is also under consideration.

Traceability: MTN-OBJ-005

6.2 Vehicle Requirements

MTN-REQ-013 Operational Readiness

Threshold Requirement: Mars Telecommunications Network shall achieve full operational readiness at Mars no later than end of calendar year 2030.

Goal Requirement: Mars Telecommunications Network shall achieve full operational readiness at Mars no later than end of calendar year 2029.

Rationale: Achieving Mars Telecommunications Network operational readiness by the end of

2030 ensures continuity of critical relay services and prevents a communications gap as existing

Mars orbiters age. Aligning Mars Telecommunications Network’s operational readiness with the

2028–2029 Mars launch opportunity reduces risk to dependent surface and orbital missions and supports stable programmatic planning and sustained Mars exploration. This is consistent with

Pub. L. 119-21, to deliver the MTN orbiter(s) to NASA by end of CY20208. For the purposes of this requirement, operational readiness is defined as post-commissioning and ready to provide full operational capability.

MTN-REQ-014 Non-Volatile Store-and-Forward Memory (DWE)

Threshold Requirement: Mars Telecommunications Network shall provide at least 1.0 Tbyte of non-volatile store and forward capability for the DWE link.

Rationale: Providing non-real-time data, store-and-forward capability enables reliable data delivery despite long delays, intermittent visibility, and periodic loss of line-of-sight between surface, orbital, and Earth segments ensuring reliable mission communications in Mars orbital geometries without requiring real-time connectivity. This value reflects an assumed average data-rate of 7 Mbps over an 8-hour pass per day for 2 days with a factor of 10 margin.

MTN-REQ-015 Non-Volatile Store-and-Forward Memory (Proximity)

Threshold Requirement: Mars Telecommunications Network shall provide at least 0.5 Tbyte of non-volatile store and forward capability for the Proximity link(s).

Rationale: Providing non-real-time data, store-and-forward capability enables reliable data delivery despite long delays, intermittent visibility, and periodic loss of line-of-sight between surface, orbital, and Earth segments ensuring reliable mission communications in Mars orbital geometries without requiring real-time connectivity.

MTN-REQ-016 Cybersecurity & Command Protection

Threshold Requirement: Mars Telecommunications Network shall utilize cybersecurity and command link encryption practices consistent with industry best practices.

Rationale: NASA-approved security is required to protect Mars Telecommunications Network commanding, data integrity, and authentication against unauthorized access and data compromise. It is encouraged to implement existing industry practices where appropriate.

MTN-REQ-017 Planetary Protection Guidelines

Threshold Requirement: Mars Telecommunications Network shall follow all Agency applicable

Planetary Protection guidelines (NPD 1000.3, NASA/SP-20240016475, NASA-STD-8719.27).

Rationale: As a Class 3 Mars Orbital mission per NPR 8719.27, Mars Telecommunications

Network is required to provide NASA access to the spacecraft, facilities, and documentation to accommodate planned independent verification and assurance activities, development of risk mitigation protocols, and any anomaly investigations throughout the project life cycle to achieve compliance with applicable Agency planetary protection requirements.

MTN-REQ-018 Orbital Debris

Threshold Requirement: Mars Telecommunications Network shall follow all Agency applicable

Mars Orbital Debris requirements (NASA-STD-8719.14, NPR 8715.6).

Rationale: Mars Telecommunications Network is required to demonstrate compliance with

NASA Mars Orbital debris reduction requirements NASA-STD-8719.14 and NPR 8715.6 to limit debris generation, spacecraft vulnerability, post-mission lifetime, and maximize entry safety.

MTN-REQ-019 Maximum Interlink Data Transfer Rates

Threshold Requirement: The Mars Telecommunications Network shall have the onboard capability to support continuous, minimal latency, and full rate data transfer between the Direct with Earth links and the Proximity links, and between different Proximity links.

Rationale: The Mars Telecommunications Network will be capable of supporting high-rate communications on both the DWE and Proximity links. This requirement ensures that there are no hardware bottlenecks in moving data from one interface to another or in internal processing of the MTN.

MTN-REQ-020 Deleted

MTN-REQ-040 Radio Reprogramming

Threshold Requirement: Mars Telecommunications Network shall support in-flight reprogramming of any software and firmware used either for Proximity link or DWE link protocol handling or digital signal processing.

Rationale: As a long-term relay service provider with unknown future users, it is important for

MTN to support updates to the radio software and Field Programable Gate Array (FPGA)

Hardware Description Language (HDL) used for relay services, which can address both critical compatibility issues and service improvements. This has been demonstrated to be of great value with the existing Mars relay network, with post-launch upgrades significantly improving relay performance.

Verification Method: Demonstration

MTN-REQ-042 Autonomous Navigation

Threshold Requirement: N/A

Goal Requirement: MTN shall estimate its navigation state onboard without utilization of Earth-based radiometric tracking.

Rationale: MTN is chartered to support autonomous operations and onboard processing.

Updating the navigation state onboard is key to enabling more autonomous operations at Mars, which will be critical to systems at Mars operating more independently from Earth.

Traceability: N/A

6.3 Direct with Earth (DWE) Link Requirements

MTN-REQ-021 Deleted

MTN-REQ-022 DWE Link 2-Way Coherent Ranging & Doppler

Threshold Requirement: Mars Telecommunications Network shall be able to support 2-way coherent ranging and 2-way coherent Doppler on the DWE links with a range precision 1 m and

Doppler precision of 0.1 mm/s (1-sigma) at a 60 second count time.

Rationale: Two-way coherent ranging and Doppler provide the highest-accuracy range and velocity measurements needed for precise navigation and orbit determination. These capabilities are essential for high-consequence operations and reduce mission risk by enabling stable, validated navigation solutions. Precision replicates current accuracy capability of existing systems.

Traceability: MTN-OBJ-002

MTN-REQ-023 DWE Link Communication Availability

Threshold Requirement: Mars Telecommunications Network hardware and software shall provide an average annual DWE link availability of ≥95%, exclusive of the Earth ground segment, channel propagation effects, and occultations.

Goal Requirement: Mars Telecommunications Network hardware and software shall provide an average annual DWE link availability of ≥99%, exclusive of the Earth ground segment, channel propagation effects, and occultations.

Rationale: A service availability of at least 95% ensures Mars Telecommunications Network provides reliable, predictable support for mission-critical communications and navigation. This requirement drives resilient system design and reduces operational risk for sustained Mars exploration. This is achieved through a combination of low and high rate DWE communications.

This requirement is on the Mars Telecommunications Network portion of the link and not the availability of the Earth side of the link or line of sight obstructions.

MTN-REQ-024 X-band DWE Link Data Rate

Threshold Requirement: Mars Telecommunications Network shall support Deep Space X-band

DWE link data rates up to at least 0.1 Mbps Forward (DSN to MTN) and up to at least 0.5 Mbps

Return (MTN to DSN) at Mars–Earth maximum range (~400Mkm), using a single 34m BWG antenna. MTN shall support a maximum of 10 Mbps forward and return on the X-band DWE links at Earth-MTN ranges where sufficient link margin exists to meet MTN-REQ-012.

Goal Requirement: Mars Telecommunications Network shall support Deep Space X-band DWE

Link data rates up to at least 1.0 Mbps Forward (DSN to MTN) and up to at least 1.0 Mbps

Return (MTN to DSN) at Mars–Earth maximum range (~400Mkm), using a single 34m BWG antenna.

Rationale: Specifying minimum DWE data rates at Mars–Earth maximum range ensures Mars

Telecommunications Network can provide reliable commanding and high-volume data return under worst-case link conditions. Specified rates support efficient, high-throughput operations consistent with DSN services. Designing to these thresholds drives DSN compatibility and supports resilient, campaign-level Mars Telecommunications Network infrastructure in accordance with DSN interface guidance, SCaN architectural direction, and NASA systems engineering practices (DSN MIDH 810-007; DSN IRD; NPR 7123.1; Mars Telecommunications

Network Handbook). Communication links to be assessed using provided link budget template

MTN-REQ-041 Ka-band DWE Link Data Rate

Threshold Requirement: Mars Telecommunications Network shall support Deep Space Ka-band

DWE Link data rates up to at least 3.0 Mbps Return (MTN to DSN) at Mars–Earth maximum range (~400Mkm), using a single 34m BWG antenna. MTN shall support a maximum of 50

Mbps return on the Ka-band DWE links at Earth-MTN range where sufficient link margin exists to meet MTN-REQ-012.

Goal Requirement: Mars Telecommunications Network shall support Deep Space Ka-band DWE

Link data rates up to at least 2.0 Mbps Forward (DSN to MTN) and up to at least 5.0 Mbps

Return (MTN to DSN) at Mars–Earth maximum range (~400Mkm), using a single 34m BWG antenna.

Rationale: Specifying minimum DWE data rates at Mars–Earth maximum range ensures Mars

Telecommunications Network can provide reliable commanding and high-volume data return under worst-case link conditions. Specified rates support efficient, high-throughput operations consistent with DSN services. Designing to these thresholds drives DSN compatibility and supports resilient, campaign-level Mars Telecommunications Network infrastructure in accordance with DSN interface guidance, SCaN architectural direction, and NASA systems engineering practices (DSN MIDH 810-007; DSN IRD; NPR 7123.1; Mars

Telecommunications Network Handbook). Communication links to be assessed using provided link budget template (Appendix B).

MTN-REQ-025 DWE Link / Deep Space Network (DSN) Compatibility

Threshold Requirement: Mars Telecommunications Network shall be compatible with DSN per

DSN Mission Interface Design Handbook (810-007) and DSN Telecommunications Link Design

Handbook (810-005).

Goal Requirement: Mars Telecommunications Network shall be compatible with DSN per DSN

Mission Interface Design Handbook (810-007), DSN Telecommunications Link Design

Handbook (810-005) and provide functionality to support Multiple Users per Aperture (MUPA)

Rationale: Compatibility with the Deep Space Network (DSN) ensures that Mars

Telecommunications Network can use NASA’s primary interplanetary communications infrastructure without custom interfaces or redesign. The DSN Mission Interface Design

Handbook (810-007) is the authoritative source for all flight projects using the DSN and provides required interface guidance, service capabilities, and customer requirements. Designing to 810-

007 reduces technical and schedule risk, ensures interoperable communications and tracking services, and enables clear verification against an approved DSN baseline. Multiple Users per

Aperture (MUPA) is a desired functionality which will require the ability to acquire an uplink signal when multiple spacecraft are using a single aperture.

MTN-REQ-026 DWE Link / CCSDS Protocol Compatibility

Threshold Requirement: Threshold Requirement: Mars Telecommunications Network shall implement the CCSDS Bundle Protocol version 7 (BPv7) (ref. CCSDS 734.20-O-1) for data transfer in the DWE link.

Goal Requirement: Mars Telecommunications Network shall implement the CCSDS Licklider

Transmission Protocol (LTP) (ref. CCSDS 734.1-B-1), for reliable data transfer in the DWE link.

Rationale: Implementing CCSDS BPv7–compliant interfaces ensures Mars Telecommunications

Network can reliably interoperate with NASA, international, and commercial assets using standardized communications protocols.

MTN-REQ-044 DWE Return Link Selectable Data Rates

Threshold Requirement: The Mars Telecommunications Network DWE Return Link shall support a series of selectable data rates to efficiently utilize the available link margin across the variable Mars-Earth range.

Goal Requirement: N/A.

Rationale: As the distance between Mars and Earth varies from approximately 55 million to 400 million kilometers over their respective orbits, the associated change in free‑space path loss produces substantial variation in signal strength at Earth. When the planets are nearer, the reduced path loss enables higher data rates and yet still maintains required link margins.

Adapting data rates throughout the orbital cycle ensures efficient and robust communication across all DWE frequencies.

MTN-REQ-045 DWE Forward Link Selectable Data Rates

Threshold Requirement: The Mars Telecommunications Network DWE Forward Link shall support a series of selectable data rates to efficiently utilize the available link margin across the variable Mars-Earth range.

Rationale: As the distance between Mars and Earth varies from approximately 55 million to 400 million kilometers over their respective orbits, the associated change in free‑space path loss produces substantial variation in signal strength at Earth. When the planets are nearer, the reduced path loss enables higher data rates and yet still maintains required link margins.

Adapting data rates throughout the orbital cycle ensures efficient and robust communication across all DWE frequencies.

MTN-REQ-047 DWE Link Channel Assignment

Threshold Requirement: The Mars Telecommunications Network DWE links shall operate on the frequency channels/bandwidths assigned by NASA.

Rationale: The MTN does not expect bandwidth for x-band to exceed 10MHz and ka-band to exceed 100MHz. Frequency authorization for each communication link is needed in accordance with NPD 2570.5E NASA RF Spectrum Management and National Telecommunications and

Information Administration (NTIA) Manual of Regulations & Procedures for Federal Radio

Frequency Management (May 2013 Edition, May 2014 Revisions) Chapter 10.

6.4 Proximity Link Requirements

MTN-REQ-027 Proximity Link Orbital Coverage

Threshold Requirement: The Mars Telecommunications Network shall provide service to surface assets and orbital assets up to an altitude of 500 km.

Rationale: This requirement serves to set the service minimum service volume for orbital users of The Mars Telecommunications Network.

MTN-REQ-028 Proximity Link Surface Coverage

Threshold Requirement: Mars Telecommunications Network shall provide services for all latitudes up to ±50° from the Martian geographical equator, and for all longitudes.

Rationale: Near-global coverage ensures the Mars Telecommunications Network system can provide reliable services for all latitudes up to +/-50 degrees from the Martian geographical equator, and for all longitudes, with only limited polar exclusions. This capability supports current NASA missions and reduces operational risk by providing consistent, predictable relay access aligned with sustained, campaign-level Mars exploration objectives. If implementing a multi-spacecraft system, this requirement applies to the network, not each unit. Coverage should optimize number of passes and pass duration to extent possible within the design constraints. For reference, current surface assets receive 2 passes per sol with current relay systems.

MTN-REQ-029 Proximity Link Time Transfer Data Correlation

Threshold Requirement: Mars Telecommunications Network shall provide radiometric time-transfer services to surface and orbital assets where the time correlation accuracy of in-situ time transfer data is traceable to Coordinated Universal Time (UTC) to within ≤ 1 millisecond error

(3-sigma) at the user interface.

Goal Requirement: The Mars Telecommunications Network shall provide radiometric time-transfer services to surface and orbital assets where the time correlation accuracy of in-situ time transfer data is traceable to Coordinated Universal Time (UTC) to within ≤ 1 microsecond error

(3-sigma) at the user interface.

Rationale: Accurate radiometric time-transfer provides timing data needed for precise positioning, navigation, and timing at Mars. This capability reduces navigation errors, supports time-critical operations, and enables reliable, interoperable PNT services for surface and orbital assets. This requirement is not intended for specifying formation of a Mars time scale (at least at this time) that is maintained to UTC or imply that Mars timing should utilize leap seconds;

however, it is intended to specify the capability of the MTN to correlate its own clocks and time relative to UTC (the civilian timescale we use and ‘tied’ to Earth Terrestrial Time (TT)) and then be able to transfer that time correlation information to user clocks so that they can relate their time to Earth-based times. Note that this will require monitoring and tracking the physical drift of MTN’s clocks and associated frequencies as well as the proper time/frequency expected in the

Mars local relativistic environment (and how it relates to terrestrial and solar system barycentric relativistic environments).

Traceability: MTN-OBJ-002, MTN-OBJ-003, MTN-OBJ-004

MTN-REQ-030 Proximity Link Communication Availability

Threshold Requirement: Mars Telecommunications Network shall provide an average annual

Proximity Link service availability ≥98% during the Proximity Communications windows.

Goal Requirement: Mars Telecommunications Network shall provide an average annual

Proximity Link service availability ≥99% during the Proximity Communications windows.

Rationale: A service availability of at least 98% ensures Mars Telecommunications Network provides reliable, predictable support for mission-critical communications and navigation. This requirement drives resilient system design and reduces operational risk for sustained Mars exploration.

MTN-REQ-031 UHF Proximity Link Data Rates

Threshold Requirement: Mars Telecommunications Network shall support UHF Proximity Link communications services for surface and orbital assets at Mars with per-user data rates up to at least 2 Mbps under nominal conditions at zenith, with the zenith distance defined to be the closest approach radial distance of MTN to the surface or orbital asset.

Goal Requirement: Mars Telecommunications Network shall support UHF Proximity Link communications services for surface and orbital assets at Mars with per-user data rates up to at least 8 Mbps under nominal proximity rate conditions at zenith, with the zenith distance defined to be the closest approach radial distance of MTN to the surface or orbital asset.

Rationale: Mars surface and orbital missions depend on Proximity relay communications to return science, engineering, and health data when direct-to-Earth links are unavailable. Existing

NASA Mars missions and relay orbiters establish a proven operational baseline for UHF

Proximity return-link throughput that the Mars Telecommunications Network seeks to build upon. Specifying minimum Proximity return-link data rates ensures continuity and interoperability with deployed Mars assets while preserving flexibility in Proximity relay architecture and implementation. Typically, the lower bound on the communications distance

(the zenith distance in the requirement) will have a lower bound equal to the minimal orbital altitude of the MRN. Communication links to be assessed using provided link budget template

MTN-REQ-032 Advanced Proximity Link Data Rates

Threshold Requirement: Mars Telecommunications Network shall support Advanced (non-UHF)

Proximity Link communications for surface and orbital assets at Mars with per-user data rates up to at least 25 Mbps under nominal Proximity rate conditions at zenith, with the zenith distance defined to be the closest approach radial distance of MTN to the surface or orbital asset.

Goal Requirement: Mars Telecommunications Network shall support Advanced (non-UHF)

Proximity Link communications for surface and orbital assets at Mars with per-user data rates up to at least 100 Mbps under nominal Proximity rate conditions at zenith, with the zenith distance defined to be the closest approach radial distance of MTN to the surface or orbital asset.

Rationale: Mars surface and orbital missions depend on Proximity relay communications to return science, engineering, and health data when direct-to-Earth links are unavailable. Advanced

Proximity link data rates are derived from stakeholder input and anticipated needs within the

MNT operational lifetime. Typically, the lower bound on the communications distance (the zenith distance in the requirement) will have a lower bound equal to the minimal orbital altitude of the MRN. Communication links to be assessed using provided link budget template (Appendix B).

MTN-REQ-033 Simultaneous Proximity Links

Threshold Requirement: Mars Telecommunications Network shall simultaneously support ≥ 2 simultaneous concurrent full-duplex legacy links and ≥ 1 advanced Proximity links within the

Mars Telecommunications Network Proximity antenna fields of view.

Rationale: Supporting at least two concurrent full-duplex legacy links and at least one advanced proximity link (for a total of at least 3 links) enables Mars Telecommunications Network to provide simultaneous two-way communications for multiple surface and orbital users, reducing scheduling conflicts and supporting time-critical operations. This capability ensures Mars

Telecommunications Network can function as shared, resilient campaign infrastructure with acceptable operational risk (NASA-HDBK-1002).

MTN-REQ-034 Adaptive Data Rates

Threshold Requirement: The Mars Telecommunications Network Proximity link system shall support adaptive data rates from surface and orbital assets.

Rationale: Adaptive Proximity links will achieve significant improvement in throughput capacity by using available link margin. Requires basic changes to the transmitter and/or receiver parameters including modulation, symbol rates, frequency channels, symbol coding, and others that affect the throughput and performance of the communications channels when conditions change. (ref. CCSDS 211.0-B-6, TBD-01)

Traceability: MTN-OBJ-003, MTN-OBJ-004

MTN-REQ-035 Proximity Link 1-Way Doppler

Threshold Requirement: The Mars Telecommunications Network shall provide in situ 1-way

Doppler tracking services to users with a precision of 0.5mm/s (1-sigma) at a 60 second count time.

Goal Requirement: The Mars Telecommunications Network shall provide in situ 1-way Doppler

& Ranging services to users with a precision of 0.5mm/s (1-sigma) at a 60 second count time and ranging precision of 1 meter.

Rationale: Pseudo-range and one-way forward Doppler reference signals support navigation when two-way tracking is unavailable or impractical. These services support high-dynamics mission phases, reduce onboard complexity for users, and improve navigation continuity, autonomy, and overall mission resilience.

MTN-REQ-036 Proximity Link 2-Way Doppler

Threshold Requirement: The Mars Telecommunications Network shall provide for in situ 2-Way coherent Doppler tracking services to users with a precision of 0.5mm/s (1-sigma) at a 60 second count time with a latency of less than 10 seconds.

Goal Requirement: The Mars Telecommunications Network shall provide for in situ 2-way coherent Doppler & Ranging services to users with a precision of 0.5mm/s (1-sigma) at a 60 second count time and ranging precision of 1 meter with a latency of less than 10 seconds.

Rationale: Two-way coherent ranging and Doppler provide higher accuracy measurements

(relative to one way measurements) needed for precise navigation and orbit determination. These capabilities are essential for high-consequence operations and reduce mission risk by enabling stable, validated navigation solutions. Precision replicates current accuracy capability of existing systems.

MTN-REQ-037 Position, Navigation, and Timing (Service Reference Signals)

Threshold Requirement: The Mars Telecommunications Network shall provide pseudorange

(PR) and 1-way forward Doppler reference signals with a signal-in-space-errors (SISE) contributions of root sum square (RSS) position and velocity errors, respectively, of ≤100 meters and 5 cm/sec (3-sigma).

Goal Requirement: The Mars Telecommunications Network shall provide pseudorange (PR) and

1-way forward Doppler reference signals with a signal-in-space-errors (SISE) contributions of root sum square (RSS) position and velocity errors, respectively, of ≤50 meters and 3 cm/sec (3-sigma).

Rationale: The Mars Telecommunications Network shall be capable of providing reference signals that can be used by all assets at any time to calculate their own position and time. SISE includes errors from: spacecraft on-board state knowledge (position, velocity and time), signal integrity and on-board path delays, predicted spacecraft states conveyed to users, and states and time representation. SISE does not include delays and phase noise introduced by the user system.

The threshold value reflects what is achievable utilizing procurable USO clocks. The Goal value assumes use of atomic clock system.

MTN-REQ-038 Advanced Proximity Link Protocol Standard

Threshold Requirement: Mars Telecommunications network Advanced S-band or K/Ka-band proximity links shall comply with Section 4.2 LNSP-User Proximity Interfaces and Section 4.4

LNSP-User Contingency Interfaces in the Lunanet interoperability Specification, Rev 5, and all

Advanced Proximity Links band shall implement a comparable interoperable (i.e. not proprietary) interface compliant with appropriate CCSDS protocol standards.

Rationale: The Mars Telecommunications Network will implement a non-proprietary standard for Proximity link protocol.

MTN-REQ-039 Open-Loop Recording

Threshold Requirement: The Mars Telecommunications Network shall provide open-loop recording for critical events (of 10 minutes in duration or less) at a selectable sampling rate ≤ 2

MHz with ≥ 8 bits per each component of a complex sample including recording at least 8 bits of

AGC information and a 32-bit time tag at a rate ≥ 1 Hz.

Rationale: The Mars Telecommunications Network shall support the needed functionality currently available to legacy users during critical events (e.g. EDL, Mars Ascent, etc) for all operational proximity bands.

Traceability: MTN-OBJ-003, MTN-OBJ-004

MTN-REQ-043 Service Provision to Surface Assets

Threshold Requirement: The Mars Telecommunications Network shall support communications and navigation with any surface asset in view of the Mars Telecommunications Network, when above 10 degrees elevation angle, measured from the surface asset to Mars Telecommunications

Network.

Rationale: The Mars Telecommunications Network shall provide service to all surface users within view of the system. For the purposes link assessment, field of view below 10 degrees of elevation will not be supported.

Traceability: MTN-OBJ-001, MTN-OBJ-003

MTN-REQ-046 Legacy Proximity Link Spectrum

Threshold Requirement: The Mars Telecommunications Network Legacy Proximity Links shall operate at UHF frequency from Table 3.

Label Link Direction Frequency

Proximity Forward Orbit-to-User: 435-450 MHz

Proximity Return User-to-Orbit 390-405 MHz

Table 3 Legacy Proximity Link Spectrum

Rationale: The proximity link frequency selection supports interoperability from different service providers for legacy and future user spacecraft, meet internationally coordinated spectrum, and where applicable, enables leveraging hardware and standards’ developments for the moon that may be used for Mars (e.g. LNIS, CLPS/CMPS, human class landers, rovers, habitats, payloads).

These values are aligned with the SFCG Recommendation, SFCG 22-1R4 and International

Table of Frequency Allocations for Mars. Note that these frequencies are currently SFCG recommendations only and do not guarantee allocation for Mars Proximity applications.

MTN-REQ-048 Advanced Proximity Link Spectrum

Threshold Requirement: The Mars Telecommunications Network Advanced Proximity links shall operate at a minimum of either S-band or K/Ka-band frequency from Table 4 for User to

Orbit and Orbit to User links.

Label Link Direction Frequency

Proximity Forward Orbit-to-User: 2025-2110 MHz

22.55-23.55 GHz

Proximity Return User-to-orbit 2200-2300 MHz

25.5-27.5 GHz

Table 4 Advanced Proximity Link spectrum

Goal Requirement: The Mars Telecommunications Network Advanced proximity links shall operate at a minimum of K/Ka-band frequency from Table 4 for User to Orbit and Orbit to User links.

Rationale: The proximity link frequency selection supports interoperability from different service providers for legacy and future user spacecraft, meet internationally coordinated spectrum, and where applicable, enables leveraging hardware and standards’ developments for the moon that may be used for Mars (e.g. LNIS, CLPS/CMPS, human class landers, rovers, habitats, payloads).

These values are aligned with the SFCG Recommendation, SFCG 22-1R4 and International

Table of Frequency Allocations for Mars. Note that these frequencies are currently SFCG recommendations only and do not guarantee allocation for Mars Proximity applications.

Bandwidth use is expected to be spectrum-efficient within the specified bands and coordinated with NASA.

MTN-REQ-050 Raw Data Mode

Threshold Requirement: The Mars Telecommunications Network shall provide the ability to receive, store, and forward demodulated and decoded bits directly as received without any protocol applied for all proximity links.

Rationale: This mode is called “raw data mode” and is helpful during EDL events to capture and quickly return data transmitted from these incoming Mars missions without requiring post-processing by ground operators, which is typical of open-loop recordings (see MTN-REQ-039).

This mode is not specified in the Proximity-1 specification and is distinct from Proximity-1’s

“expedited mode”, which requires that received data be structured as Prox-1 frames and rejects frames with bad CRCs. The use of this mode does not preclude the use of the open-loop recording of the same received signal.

Traceability: MTN-OBJ-001, MTN-OBJ-003

Appendix A: Abbreviations and Acronyms

AGC Automatic Gain Control

BER Bit Error Rate

BP Bundle Protocol

BWG Beam Wave Guide

CCSDS Consultative Committee for Space Data Systems

CLTU Communications Link Transmission Unit

CY Calendar Year dB Decibel

DSN Deep Space Network

DWE Direct with Earth EDL Entry, Descent, and Landing

EIRP Effective Isotropic Radiated Power

ESDMD Exploration Systems Development Mission

FPGA Field Programable Gate Array

FWD Forward

GEVS General Environmental Verification Standard

HDL Hardware Description Language

IRD Interface Requirements Document kHz Kilohertz km Kilometer

LDPC Low-Density Parity-Check m meter

M2M Moon to Mars

Mbps Megabits per Second mm Millimeter

MTN Mars Telecommunications Network MUPA Multiple Users Per Aperture

NASA National Aeronautics and Space Administration

NPR NASA Procedural Requirements

PNT Position, Navigation, and Timing

RTN Return s Second

SAO Strategy and Architecture Office

SCaN Space Communication and Navigation

SISE Signal-in-Space-Error

SMD Science Mission Directorate

SOMD Space Operations Mission Directorate

Tbyte Terabyte

UHF Ultra-High Frequency

USO Ultra Stable Oscillator

UTC Coordinated Universal Time

Appendix B: Link Budget Template

The following link budget templates are provided for the vendor to fill out as part of their proposal. List all gains and margins as positive and all losses as negative in the link budgets provided. These templates provide initial insight into a representative approach and are not constraints on the links the vendor can propose or implement. Include link budgets for all links at all frequencies for a proposed configuration.

Direct With Earth (DWE) Links

Table B-1: DWE Return Link

1List out all losses that are covered within these rows.

2Provide link budgets for both the minimum and maximum distances between Mars and Earth, as listed in MTN-REQ-044. Use 55,000,000 km for the minimum Mars-Earth Distance and

400,000,000 km for the maximum Mars-Earth Distance.

3The modulations compatible with DSN are documented in the DSN Link Design Handbook, 810-005 Module 206. If using GMSK at rates higher than 10 Msps, assume an extra 1 dB implementation loss at the DSN receiver.

4Select a DSN-compatible coding scheme and list the rate in this row.

5List corresponding Required Eb/N0 values for the coding scheme from Table B-2 in this row.

Node Parameter Value Units Equation Comments

1 MTN Transmit Power…