Request for Information_Commercial Development of Lunar Exploration Ground Sites_Communications Ground Systems_Rev2 .pdf

Request for Information (RFI) Commercial Development of Lunar Exploration Ground Sites (LEGS)

Communications Ground Systems

THIS IS NOT A REQUEST FOR PROPOSAL. NO PROPOSALS ARE TO BE SUBMITTED IN

RESPONSE TO THIS NOTICE

This notice is issued by the NASA GRC to post a Request for Information (RFI) to solicit responses from interested parties. This document is for information and planning purposes and to allow industry the opportunity to provide information on a commercial capability to develop a ground system to provide communications for vehicles transiting from the Earth to cislunar space, the Gateway in near-rectilinear halo orbit (NRHO), the Lunar surface, and Earth-Sun L1 and L2 LaGrange Points. This RFI will assist in refining the planning and execution of the Lunar Exploration Ground Sites (LEGS) Government Owned, Contractor Operated (GOCO) effort for

NASA.

This RFI is not to be construed as a commitment by the Government, nor will the Government pay for the information submitted in response. The Government may use the information to construct a future potential acquisition.

PURPOSE AND SCOPE:

For the purposes of this RFI, the LEGS communications system (hereafter referred to as “The System”) consists of three ground stations at the following locations:

LEGS-1

1. Location: NASA’s White Sands Complex in White Sands, New Mexico

LEGS-2

2. Location: Matjiesfontein, South Africa

LEGS-3

3. Preliminary Location: Western Australia, specific site to be determined.

The government seeks to understand commercial capabilities to deliver a turnkey ground station at each site, except for the antenna subsystem, which will be provided as Government Furnished Equipment (GFE). The technical requirements for the LEGS System can be found in Appendix A:

LEGS 1-3 System Requirements. A description of the GFE antenna subsystem can be found in Appendix B: GFE Antenna Description. The responsibilities of the facility and infrastructure capabilities of each of the three sites are outlined in Appendix C: LEGS 1-3 Sites Responsibility Matrix. Responders should consider that the fact that contractors must be certified to work on the White Sands Complex and that use of local labor in South Africa and Australia, to the largest extent possible, would be a requirement. All sites should be assumed to have access in place for services (i.e., water, sewer, power, etc.) as well as roadways leading to the site. Appendix D: Commercial Architecture Security Questionnaire contains guidelines on security requirements for each LEGS site.

Responses to this RFI may address any or all of the three LEGS Ground Stations. Responses should include information on capabilities and approaches to deliver an operationally ready ground station at each site for incorporation into NASA’s Near Space Network (NSN). This includes ground station development, construction, including required facilities, infrastructure, integration, and site acceptance testing. For LEGS-2 and LEGS-3 only, information on operations and maintenance (O&M) approaches and annual cost estimates are also being requested.

Responses should address the following work elements, at a minimum:

1. Project Management

2. Systems Engineering

3. Safety and Mission Assurance

4. Antenna Subsystem Integration

5. Signal Processing Subsystem

6. Monitor & Control Subsystem

7. Facilities

8. Infrastructure

9. On Site Integration & Testing

10. Ops Prep

11. Security

A draft block diagram of the System is shown below. Information on the Flight Dynamics Facility (FDF) can be found at https://fdf.gsfc.nasa.gov/.

RESPONSE INSTRUCTIONS

All comments or questions shall be submitted electronically via email to Eric Hartman, Contracting Officer, eric.t.hartman@nasa.gov. When responding reference 80GRC024Q0002RFI. Responders are asked to submit responses, in PDF format, that describes the responder’s:

1. Capability to deliver an operational ground station at all three sites:

A. Describe your recommended approach to the system design, development, integration and testing of the LEGS system.

B. Describe your relevant capabilities and experience developing, installing, testing and operating communications systems, at government owned facilities (e.g WSC), commercial, and international locations. Specifically address experience working in countries of South Africa and Australia.

C. Describe how you will conduct work on the WSC, South African and Australian sites, including information on your approach to logistics support, such as customs, import and export, and procurement, as well as infrastructure development support, such as civil engineering, excavation, construction, plumbing, electrical and electronic/internet services.

2. Rough cost estimates, broken down by work element and site, that takes into consideration the varied facility and infrastructure responsibilities. The bases of estimate for cost and schedule should include addressing the security guidelines of Appendix D.

3. Top-level schedule that includes major milestones and reviews that targets the following Operational Readiness (OR) dates, and feedback on the feasibility of those dates along with any key schedule drivers they identify:

• LEGS-1: June 2026

• LEGS-2: June 2027

• LEGS-3: September 2028

4. Approach for the annual Operations and Maintenance of LEGS-2 and LEGS-3 only, including rough annual cost estimates.

Responders are free to attach appendices that further describe their capabilities.

NASA is offering virtual one-on-one sessions to answer questions or provide clarifications to interested parties. Virtual one-on-one meetings will be for twenty (20) minutes and held during the following date and time:

Thursday, June 20, 2024, from 10:00AM – 5:00PM ET

One-on-one session times will be contingent upon the availability of timeslots at the time of the request. However, we will attempt to schedule your meeting as quickly as possible to obviate unnecessary delays. To schedule a one-on-one session, please contact the following individual:

Name: Eric Hartman Email: eric.t.hartman@nasa.gov

Responses to this RFI are due no later than COB July 15, 2024.

NASA Clause 1852.215-84, Ombudsman, is applicable. The Center Ombudsman for this acquisition can be found at: https://www.hq.nasa.gov/office/procurement/regs/Procurement- Ombuds-Comp-Advocate-Listing.pdf

If a solicitation is released, then it and any additional documents will be available on www.Sam.gov. It is the offeror's responsibility to monitor this website for the release of the solicitation and amendments (if any). Potential offerors will be responsible for downloading their own copy of the solicitation and amendments, if any.

NASA intends to publicize a listing of respondents to facilitate teaming arrangements. Should your firm desire not to be included in this listing, clearly indicate this desire in your response.

Appendix A: LEGS 1 - 3 System Requirements

Requirement Number REQ Title LEGS L3 Requirements Rationale

LEGSa.3.1000 Earth Orbiting Platform Coverage

LEGS shall provide line-of-sight service coverage to platforms between 36,000 km and 2,000,000 km.

LEGS focus is to support the "Beyond Earth Proximity" portion of the Near Space range, which addresses missions between 36,000 and 2,000,000 km. This is intended to scope the coverage area for which the LEGS solution is optimized and where LEGS is expected to meet all system requirements.

Support at other ranges would be considered on case-by-case need to support lunar transit, legacy missions, and other scenarios as documented in Service Level Agreements. Support outside the specified coverage range may have limitations based on the constraints deployed antenna system.

LEGSa.3.2010 Antenna modes of Operation LEGS shall track mission platforms in manual, ephemeris-driven, and RF-driven modes of operation for all receive signal bands suppo1ted by a given asset.

Positioning and tracking of the target User space vehicle is critical for transmission and reception command, telemet1y, radiometric information, and data.

LEGSa.3.2020 Antenna RF beam collimation

LEGS assets suppo1itng Ka- band shall have beam peaks for all supported bands collimated to within +/- 3dB of the narrowest beam peak.

Transitioning between Ka-Band and X- Band is a critical function for Operations.

To achieve MSPA, the RF beams must be co-aligned.

LEGSa.3.2030 Autotrack Handover LEGS shall support automatic autotrack handovers between supported bands of each asset.

To support continuous autotrack capabilities, the nodes must be able to transition autotrack between bands. This enables CONOPS for initially getting to Ka-band autotrack, and failback to X-band autotrack from Ka-band autotrack.

LEGSa.3.2031 Autotrack Band Selection LEGS shall be capable of allowing configurable preferences for autotrack bands for a given pass or mission configuration.

Autotrack band should be configurable based on the preferences of a given mission.

LEGSa.3.2040 Return Link Acquisition and Re- acquisition Time

LEGS shall provide signal acquisition times and signal reacquisition times defined in the Table below for ≥90% probability of acquisition at the required C/No values for the worst-case required BER (see CCSDS 130.1- G-3), measured from the time the signal is present at the Antenna to the time the following actions have occurred:

1. Carrier synchronization,

2. Symbol synchronization,

3. Viterbi decoder synchronization, if applicable,

4. Derandomizer synchronization, if applicable,

5. Block code synchronization, if applicable,

6. Frame synchronization, if applicable,

7. Data polarity ambiguity resolution, if applicable,

8. Data channel ambiguity resolution, if applicable.

Encoding Scheme Acq./Re-acq Time (Seconds)

Uncoded 1+3/Rb Conv (k=7), 1/2 1+6/Rb RS (255,223) 1+7.5/Rb RS (255,223)+Conv (k=7), 1/2 1+10.3/Rb

RS (255,239)+Conv (k=7), 1/2 1+10.3/Rb

RS (255,239)+Conv (k=7), 5/6 1+9.3/Rb

LDPC (2048,1024), 1/2 1+13.8/Rb LDPC (8192,4096), 1/2 1+20.4/Rb

LDPC (32768,16384),

1/2 1+47/Rb

LDPC (1536,1024), 2/3 1+13.2Rb LDPC (6144,4096), 2/3 1+18.4/Rb

LDPC (24576,16384),

2/3 1+38.1/Rb

LDPC (1280, 1024),

4/5 1+13/Rb

LDPC (5120, 4096),

4/5 1+17.1/Rb

LDPC (20480, 16384),

4/5 1+33.7/Rb

LDPC (8160,7136), 7/8 1+20.4/Rb Turbo (10704, 1784), 1/6 1+28.8/Rb

Turbo (21408,3568), 1/6 1+40.4/Rb

Turbo (42816,7136), 1/6

1+63.5/Rb

Supports robust signal acquisition performance, based on NASA legacy communications link operations.

Acquisition time refers to carrier synchronization and symbol/decoder synchronization acquisition time or symbol/deinterleaver/decoder synchronization acquisition time, for data rates > acquisition frame size.

LEGSa.3.2050 Return Link Frequency Uncertainty

LEGS shall, at return link acquisition, support the following carrier frequency acquisition ranges for the bands supported by a given LEGS asset:

X-Band: ± 500 kHz Ka-Band: ± 1.8 MHz

Supports signal acquisition. Based upon CCSDS 401.0-B- 32 recommendations which cover the worst case between two-way and one-way modes, with spacecraft oscillator stability included in the latter.

LEGSa.3.2070 Unpowered Flight Doppler Dynamics

LEGS shall meet its specified signal acquisition and tracking performance for the following unpowered flight dynamics:

Range Rate: ≤12 km/s Range Acceleration: ≤15 m/s² Range Jerk: ≤ 0.02 m/s³

Supports signal acquisition and tracking.

Based upon legacy flight dynamics performance values.

LEGSa.3.2080 Powered Flight Signal/Doppler Dynamics

LEGS shall meet its specified signal acquisition and tracking performance for the following powered flight dynamics:

Range Rate: ≤15.0 km/s Range Acceleration: ≤50.0 m/s² Range Jerk: ≤ 2.0 m/s³

Supports signal acquisition and tracking. Based upon legacy flight dynamics performance values.

LEGSa.3.2090 Forward Service Break Lock

LEGS shall provide a break-lock function which is used to break the forward service signal lock when it is suspected that the customer transponder has false locked.

A break lock command will knock the user transponder off the false lock point and enable another attempt at successful acquisition.

LEGSa.3.2100 Return Link Symbol Slippage

LEGS shall provide, for the Ground Station Symbol Synchronizer, a mean time between cycle slips in the symbol clock recovery loop of either ≥90 minutes or ≥10¹⁰ clock cycles, whichever is greater (but maximum time 6 hours if 10¹⁰ not reached for extreme low data rates), for the C/No and BER performance as follows:

Uncoded and convolutional encoding: C/No required for

10⁻⁵ BER

LDPC and Turbo encoding:

C/No required for 10⁻⁵ BER

Note: This requirement applies for transition densities of at least 40% for NRZ symbols and any transition density for bi-phase symbols

Supports robust connectivity to the customer platform, based on legacy NASA communications link operations.

LEGSa.3.2100 Return Link Carrier Cycle Slippage

LEGS shall provide Ground Station Carrier mean time between cycle slips in the carrier tracking loop of ≥90 minutes for the greater of

27.5 dB-Hz or 3 dB below the C/No that produces the worst-case required BER operating point.

To maintain robust connectivity to the customer platform, the communications carrier should remain synchronized even if the link degrades to the point where it no longer meets BER quality requirements. The mean time- to-cycle-slip is the average time that the signal can remain in the impaired state before a cycle slip occurs.

LEGSa.3.2120 C/No Variation LEGS downlink services shall accommodate an input C/No variation of 6 dB, at a rate not to exceed 10 dB/sec, without losing carrier lock or symbol lock, assuming 6 dB drop is not below the carrier slip and cycle slip C/No.

Provides support for spacecraft spins and emergencies with C/No variances.

LEGSa.3.2130 Number of Simultaneous Forward Links

LEGS shall simultaneously provide one forward link per frequency band supported by an antenna asset.

LEGS needs to simultaneously operate in all frequency bands to support the needs of user missions. For forward links, this is limited to one link in each forward band supported.

LEGSa.3.2140 Transmit Polarization LEGS shall provide independently selectable transmit Left Hand Circular Polarization (LHCP) or Right Hand Circular Polarization (RHCP) for each of the specified bands supported by a LEGS asset.

Transmit polarization must be selectable to ensure LEGS nodes can support missions using either polarization.

LEGSa.3.2150 Transmit Emissions LEGS shall meet NTIA regulations as defined in ITU Redbook Section 5.6 for transmitter in-band and out- of-band spurious and emission mask at the required EIRP for each transmit signal.

NASA complies with NTIA and ITU frequency band regulations, especially spectrum masks.

LEGSa.3.2160 Forward Link Doppler Compensation

LEGS shall provide user selectable (enable/disable) Doppler compensation to the forward link based on provided vectors.

An adjustment of the forward link frequency to compensate for Doppler shift supports signal acquisition.

LEGSa.3.2170 Transmit Inhibit Mask LEGS shall implement a configurable forward RF signal transmit inhibit mask within which transmission is automatically prohibited.

Prevents transmission of RF signals into specified areas for safety and must be configurable to allow for a changing environment around each ground station.

LEGSa.3.2180 Forward Latency LEGS shall begin to radiate a forward link data to a user mission platform within 125 ms of its receipt at the local boundary of the ground station network provided the message queue is empty at time of receipt.

Forward (command) latency refers to the time between when a command is received by the LEGS ground station from the External Interface and the time that the first bit of that command is radiated, given that there is no need to buffer that command before beginning to uplink it.

LEGSa.3.2190 Forward Link Data Rate-Metering and Buffering

LEGS shall rate-meter and buffer received forward link data.

Buffering is necessary to account for the need to support transmitting commands over a fixed rate link that arrive at the station over on a terrestrial, asynchronous network (UDP or TCP over IP), as well as the difference between network data rates and uplink data rates. The intent of this requirement is to intermittently allow the Mission Control Center to transmit forward link data at a rate higher than the forward link rate and for LEGS to meter that data to the spacecraft at the forward link rate.

This is not intended to provide a store and forward capability.

Specific details for the buffer capacity will be provided in the L4 requirements.

LEGSa.3.2200 Idle Patterns LEGS shall insert a configurable idle sequence pattern in frame data before modulation when no forward data frames are available from the external system, with configuration options that include (1) an idle sequence of alternating "ones" and "zeros", and (2) Idle Transfer Frames in accordance with CCSDS 732.0- B-3, AOS Space Data Link Protocol.

Idle Patterns are required to maintain synchronization with the spacecraft. Idle Transfer Frames, in accordance with CCSDS 732.0-B-3, AOS Space Data Link Protocol, will be needed to support Gateway requirements.

LEGSa.3.2210 Forward Link Gain Flatness (Signal Distortions)

LEGS shall meet the following transmit gain flatness constraints, as applicable for the bands supported by a given asset:

X-Band: ≤ 0.8 dB P-P over center frequency ± 10 MHz

Ka-Band: ≤ 0.8 dB P-P over center frequency ± 40 MHz

Supports robust performance and minimization of implementation losses. Based upon previous mission performance. Supports required LEGS forward data rates.

LEGSa.3.2220 Forward Link Phase Nonlinearity (Signal Distortions)

LEGS shall meet the following transmit phase nonlinearity constraints, as applicable for the bands supported by a given asset:

X-Band: ≤ 8.6 degrees P- P over center frequency ± 10 MHz

Ka-Band: ≤ 8.6 degrees P- P over center frequency ± 40

MHz

Supports robust performance and minimization of implementation losses. Based upon previous mission performance. Supports required LEGS forward data rates.

LEGSa.3.2230 Forward Link Phase Noise (Signal Distortions)

LEGS shall meet the following transmit phase noise constraints, as applicable for the bands supported by a given asset:

a. X-Band:

1 Hz to 10 Hz: 6 deg RMS 10 Hz to 100 Hz: 3 deg RMS 100 Hz to 1 kHz: 2.5 deg RMS 1 kHz to 10 MHz: 2.5 deg RMS

b. Ka-Band:

1 Hz to 10 Hz: 10 deg RMS 10 Hz to 100 Hz: 5 deg RMS 100 Hz to 1 kHz: 5 deg RMS 1 kHz to 40 MHz: 2 deg RMS

Supports robust performance and minimization of implementation losses. Based upon previous mission performance. Supports required LEGS forward data rates.

LEGSa.3.2231 Forward Link AM/PM (Signal Distortions)

LEGS shall meet the following transmit AM/PM constraints, as applicable for the bands supported by a given asset:

a. X-Band: ≤ 10 deg/dB

b. Ka-Band: ≤ 7 deg/dB

Supports robust performance and minimization of implementation losses. Based upon previous mission performance.

LEGSa.3.2232 Forward Link SNR (Signal Distortions)

LEGS shall provide a transmit signal to noise ratio (SNR), of ≥ 42 dB for all transmit bands supported by a given asset.

Supports robust performance and minimization of implementation losses. Based upon previous mission performance.

LEGSa.3.2240 Receive Polarization LEGS shall independently receive simultaneous Left Hand Circular Polarization (LHCP) and Right Hand Circular Polarization (RHCP) at each receive service band supported by a given LEGS asset.

Simultaneous receipt of LHCP and RHCP provides the ability for LEGS to support a wider range of future missions.

LEGSa.3.2250 Return Service BER Performance – Implementation Loss

LEGS shall provide an implementation loss within ≤2.0 dB of theoretical Eb/No [Energy per Bit (Eb) to Spectral Noise Density (No)] for a given coding scheme and BER for an input signal with AWGN, ground system distortions, and user mission distortions that are compliant with the LEGS SRD Appendix Tables A-1 (X-band), and A-2 (Ka-band).

See CCSDS 130.1-G-3 for theoretical BER performance of coding schemes.

Implementation loss is limited to theoretical BER performance values from 10⁻⁵ to 10⁻⁹, as applicable for a specific coding scheme.

Table A-1 Spacecraft Constraints for X-band Downlink Service Parameter Value Gain Imbalance

≤0.5 dB max

Phase Imbalance

≤0.5 deg max

Phase Nonlinearity

≤0.5 deg peak

Gain Flatness ≤0.4 dB peak

Gain Slope ≤0.1 dB/MHz

AM/AM ≤0.4 dB/dB AM/PM ≤12 deg/deg Bandwidth(3 dB)

2x channel symbol rate, min

The Ground System must provide a minimum error rate for user missions to receive their data successfully. The BER value may be improved by the data transmission rate, modulation schemes, and channel coding schemes. See CCSDS 130.1-G-3 for BER performance for each coding scheme.

Example Case: For Reed- Solomon coding the theoretical Eb/No for a BER 10⁻⁸ is 6.7 dB.

Therefore, LEGS delivers a BER of 10⁻⁸ at an Eb/No of

8.7 dB.

Roll-off ≥9.4 dB/MHz

Incidental AM ≤5.0 % Spurious PM ≤ 2.0 deg

Rms

Table A-2 Spacecraft Constraints for Ka-band Downlink Service Parameter Value Gain Imbalance

≤0.5 dB max

Phase Imbalance

≤3.0 deg max

Phase Nonlinearity

≤15.0 deg peak

Gain Flatness ≤2.5 dB peak

Gain Slope ≤0.1 dB/MHz

AM/AM ≤0.8 dB/dB AM/PM ≤4 deg/deg Bandwidth(3 dB)

2x channel symbol rate, min

Roll-off ≥9.4 dB/MHz

Incidental AM ≤5.0 % Spurious PM ≤ 2.0 deg

Rms I/Q Symbol Skew

≤ 3 %

LEGSa.3.2255 LEGS Packet Loss LEGS forward and return data packet loss between the modem and the LEGS system boundary shall not exceed 0.0005%.

Restricting data packet loss is necessary to ensure acceptable forward and return customer data delivery.

LEGSa.3.2260 Return Delivery Latency

LEGS shall introduce one- way latency for return data services from receipt at the antenna of the end of the input frame or block to when the end of the output of the same frame or block is made available to the local boundary of the ground station network of no greater than 1 second.

LEGS nodes provide only the demodulation, symbol/frame synchronization, decoding, and baseband data packet encapsulation functions for mission return data. The latency covers this scope of functionality and does not address latency introduced by the terrestrial network or further data processing functions that occur outside of LEGS. Coding and block size will have impacts on actual return service latency seen for a given configuration. The expected latency for a given mission configuration can be characterized as necessary.

LEGSa.3.2270 Time Tagging Accuracy

LEGS shall time tag customer downlink data for the following data rates with an error of:

< 125 kbps: ±25% of the data bit period ≥ 125 kbps: ±2 microsecond Tagging occurs upon reception of the last bit, after demodulation, decoding, and synchronization, in Earth Received Time (ERT) relative to Coordinated Universal Time (UTC) in compliance with the CCSDS standard specified in Time Code Formats (CCSDS 301.0-B-4).

Tagging occurs on detected data frames in Earth Received Time (ERT) relative to Coordinated Universal Time (UTC) in compliance with the CCSDS standard specified in Time Code Formats (CCSDS 301.0-B-4), and as defined for Earth- Receive-Time IAW the CCSDS 911.1, 911.2, and 911.5.

Time tagging provides the user mission with the time of receipt of telemetry and mission data.

Aligns with SCaN committed time tagging accuracy. LEGS-provided Time tags may require correction for static ground system biases in accordance with LEGSa.3.2280.

LEGSa.3.2280 Return Channel Time Delay

LEGS shall make available, to each supported mission, Return Channel Time Delay (RCTD) values for each supported service configuration, with sufficient precision and accuracy to maintain the accuracy of ERT time tags specified in LEGSa.3.2270.

< 125 kbps: ±25% of the data bit period ≥ 125 kbps: ±2 microsecond

This is a calibration measurement of the time delay from the ground station antenna input to the ground station baseband output at the point of time tagging within the data transport. Accuracy aligns with data time tag accuracy requirement.

LEGSa.3.2290 Test Loops LEGS shall support short and long loop test loops, including uplink and downlink test loops, for all bands supported by a given LEGS asset.

Required to support ability to conduct tests during I&T of system, as well as during operations and maintenance activities to efficiently troubleshoot issues to meet Aₒ requirements.

Short Loop: Modem to modem with IF switch in middle.

Long Loop: Modem to Antenna and return.

LEGSa.3.2300 Forward Link Modulation Inhibit

LEGS shall provide a capability to inhibit modulation of any Uplink Service carrier through a command.

Desired capability for testing.

LEGSa.3.2310 Axial Ratio LEGS shall provide an axial ratio of less than or equal to 1 dB for each polarization (RHCP and LHCP) across the frequency ranges of all transmit and receive bands supported by the given asset.

Given the need to support simultaneous RHCP and LHCP, axial ratio values of less than or equal to 1 dB ensure sufficient performance of the overall system given the interference between polarizations.

LEGSa.3.2320 RF Performance in Spectral Environment

LEGS shall meet return service performance with all forward services operating at the defined EIRP and the RF interference signals present at the antenna received input.

LEGS assets need to perform within the RF spectral environment constraints and interferer present at the asset location.

LEGSa.3.2330 Return Link Data Buffering

LEGS shall buffer return data to account for external network latency and latency variability impacts.

Buffering of the return data is necessary to account for network latency and latency variability.

This is intended to apply to components within the return data chain (modems and

FEPs), addressing situations such as IP collisions.

LEGSa.3.2340 VCID Frame Filtering LEGS shall provide a configurable capability to filter CCSDS Virtual Channel (VC) frames from the downlink baseband data stream.

Allows for identification and removal of frames according to VCID, in order to minimize network bandwidth used for data.

LEGSa.3.3010 Network Monitoring LEGS shall monitor status and performance parameters of LEGS site equipment/systems.

LEGS must monitor the performance of the network assets to ensure operational availability in meeting user mission service requirements. It must also monitor equipment to identify network and asset anomalies to permit corrective action prior to failure.

Techniques such as predictive trending may be employed to allow for detection of network and asset anomalies prior to failure. This information is available to authorized recipients using the network asset monitoring interface.

LEGSa.3.3020 Network Control and Configuration

LEGS shall control and configure all network assets, including autonomous configuration and automatic subsystem fail over for unattended operations.

Configuration and control is critical to ensure proper operation of the network assets. Control functions are necessary to support automated operations and network control commands from operators.

LEGSa.3.3030 Schedule-driven Operations

LEGS shall perform schedule driven system configuration and execution of scheduled pass support.

Schedule-driven system configuration and execution is critical to achieving a level of automation that allows unattended operations and a minimum amount of operator interaction.

LEGSa.3.3040 Scheduling Responsiveness

LEGS shall be capable of executing a new or modified scheduled services within 5 minutes of receipt of the schedule information, assuming no other services are active.

This performance maximizes system responsiveness to mission users. Measurement begins upon complete receipt of the request from the NSN. The defined time may be clarified/adjusted when the antenna's size and slew rate are finalized.

LEGSa.3.3050 Schedule Validation LEGS shall validate schedule messages received within 3 seconds of receiving a schedule message, where schedule validation includes checks on message format and content compliance, conflicts with existing schedule, system capability, and inter-service time constraints.

Schedule validation is performed to ensure that LEGS can support the events incorporated into the schedule message. Supports address the combined LEGS and scheduling system overall need to process schedule requests within 30 minutes (per current DTE standard). Example of invalid schedule messages includes:

missing service band, missing service start and stop times, and missing schedule message ID.

LEGSa.3.3060 Acquisition Data Processing

LEGS shall process received acquisition data to support execution of signal acquisition, antenna pointing, and Doppler measurement/compensation functions.

Proper processing and interpretation of received ephemeris data is necessary to support key functions of the ground station. Acquisition and tracking data are necessary for the antenna pointing and the modem Doppler compensation (forward and return).

LEGSa.3.3070 Pre-event Service Set-up Time

LEGS shall configure operational equipment for an upcoming service within a time not to exceed:

) 5 minutes if setup includes antenna pointing ) 2 minutes if setup does not include antenna pointing.

To maximize the efficiency of operations with the LEGS services, establishing a maximum time for LEGS to set-up prior to a service enables the definition of inter-service time for schedules to adhere to. Inter-service time is defined based on the conditions of the service being ended and started. If undefined, there is potential to have services too close in time to effectively support or assume too long an interval which lowers the efficiency of communications operations.

Events that require prior service to complete or the antenna to move prior to beginning a new event will adhere to an inter-service time of the Post-event idle time plus the Pre-event set-up time. Events that do not require ending of other services or antenna movement (i.e., MSPA) only must adhere to an inter-service time based on pre- event service set-up.

LEGSa.3.3080 Post-event Return to Idle State Time

LEGS shall return operational equipment to defined idle state configuration within:

) 5 minutes of the end of a scheduled event if returning to the idle state includes antenna stow, ) 2 minutes of the end of a scheduled event if returning to the idle state does not include antenna stow.

To maximize the efficiency of operations with the LEGS services, establishing a maximum time for LEGS to return to an idle state following an event and stow the antenna enables the definition of inter- service time for schedules to adhere to. Inter-service time is defined based on the conditions of the service being ended and started. If undefined, there is potential to have services too close in time to effectively support or assume too long an interval which lowers the efficiency of communications operations. Events that require prior service to complete or the antenna to move prior to beginning a new event will adhere to an inter-service time of the Post-event idle time plus the Pre-event set-up time.

LEGSa.3.3090 Real-Time System Reconfiguration

LEGS shall begin reconfiguration of an ongoing service for a predefined set of service parameters within 30 seconds of receiving a validated reconfiguration request.

Real-time system reconfiguration is required to support network and user mission anomalies and unscheduled modifications to ongoing services. Detailed performance for each type of reconfiguration will be addressed in the associated ICD.

LEGSa.3.3100 Station Logging LEGS shall provide logging of all operator, system, and automated data entries, data modifications, and faults.

Robust logging data provides a method of activity auditing, fault detection, and scenario reconstruction.

LEGSa.3.3110 Scheduled Services Anomaly Notification

LEGS shall provide notifications to defined external systems of anomalies affecting LEGS scheduled services.

Notification of scheduled services anomalies provide the means to coordinate any changes resulting from a condition that affects user mission operations. The condition may necessitate a change in user mission support and priority.

LEGSa.3.3120 Status/Performance Data Time Tagging

LEGS shall time stamp collected status and performance data with UTC (USNO) with an accuracy ≤10ms and a resolution of ≤1ms.

LEGS status and performance data needs to have a ground time stamp to support activities such as trending and analysis, and anomaly investigation. This represents the minimum accuracy across all equipment, as equipment using 10MHz or 1-PPS reference can generally have significantly better accuracy.

LEGSa.3.3130 Operator Schedule View

LEGS shall provide an interface that gives LEGS operators the ability to query and view LEGS operational schedules.

LEGS ground station operations will be driven by the LEGS operational schedule.

The ability to view schedules is necessary to provide situational awareness for operators, particularly when operator activities are necessary in contingency operations.

LEGSa.3.3140 Operator Interface LEGS shall provide an interface to operators that provides situational awareness, allows monitoring of equipment status, and permits control of equipment configurations.

Monitoring and control information must be conveyed to an operator, and an operator needs the ability to control equipment configurations when necessary.

LEGSa.3.3150 Operator Remote Access

LEGS shall provide access to the remote operator interface commensurate with all applicable standards in NPR 2810.1F governing remote access and user authentication.

LEGS operational concept minimizes staffing requirements.

Enabling remote operations allows additional options for future operations.

LEGSa.3.3160 Operator Manual Scheduling

LEGS shall provide operators with the appropriate credentials the capability to manually enter schedule requests.

The capability for manual scheduling will be important to ensure necessary spacecraft communications and safety of astronauts. Manual capabilities can also support maintenance and test efforts.

LEGSa.3.3170 Operator Support for Human Spaceflight

LEGS shall provide active, dedicated operator support for all scheduled events involving human spaceflight for the duration of the event.

Human spaceflight support missions require dedicated operator support for events.

Therefore, LEGS will have to plan to have a dedicated operator monitoring human spaceflight events.

LEGSa.3.3180 Automation For Staffing Approach

LEGS shall include automation to support being staffed 8 hours per day, Mon- Fri, to support routine uncrewed mission operations.

The expected staffing approach for LEGS is a 8 hours per day from Monday to Friday.

Therefore, LEGS needs sufficient automation to support routine uncrewed missions without significant operator engagement.

LEGSa.3.3190 LEGS Automated Alarm Notifications

LEGS shall provide automated alarms and notifications to designated operators to support and enable operator response to anomalies.

To enable effective operator response to anomalies, LEGS will provide notifications to the designated operators.

LEGSa.3.3200 Ground Station data and information analysis and reporting

LEGS shall provide the ability for operators to retrieve, analyze and trend system functionality and performance using logged ground data.

The system must provide the ability for operators to conduct analysis of system function and performance over time to perform analysis, trending, and anomaly investigation related to ground station operations.

Without these capabilities, performing this operations analysis is not reasonably possible. Additionally, these capabilities are needed to assess if the system is meeting performance, proficiency and availability requirements over time.

LEGSa.3.3210 Service Accounting Reports - Generation

LEGS shall provide the ability for operators to generate offline Service Accounting Reports to document the performance of the system that occurred during provisioning of customer support.

Service Accounting Reports are needed so that the information and metrics on ground system performance can be documented.

LEGSa.3.3220 Service Accounting Reports - Retention

LEGS shall retain logged service accounting input data online for a minimum of one year.

The ground station must retain the service accounting data and information online for a duration that is sufficient to ensure that access to it is possible when it is predicted to typically be needed.

LEGSa.3.4010 Schedule External Interface

LEGS shall receive schedule messages from the external Schedule System.

The LEGS concept assumes an external scheduling entity provides conflict-free requests, and only limited validation occurs within the LEGS system. This is necessary to ensure that LEGS properly receives event information and is able to execute schedule driven operations.

LEGSa.3.4020 Schedule Validation External Interface

LEGS shall provide a schedule validation response to the external Schedule System for each schedule message received.

To enable effective operations and mission support, LEGS will acknowledge the result of validating the schedule message received. Supports combined Schedule System and LEGS's ability to process schedule requests within 30 minutes.

LEGSa.3.4030 Unused Time External Interface

LEGS shall provide unused time messages to the external Schedule System.

LEGS ground stations are expected to provide unused time messages to a schedule system to support effective scheduling processes and minimize conflicts.

LEGSa.3.4040 In-service Reconfiguration Request External Interface

LEGS shall receive in-service reconfiguration requests.

Standard interfaces for reconfiguration requests and service status reduces complexity in communicating this information between LEGS stations and all stakeholders, including user missions.

LEGSa.3.4050 In-service Reconfiguration Validation Interface

LEGS shall provide a validation response for each in-service reconfiguration request received.

LEGS must provide feedback to external systems of whether the in-service configuration request was validated and accepted, or if there are any issues. This prevents situations of the mission assuming the configuration change was accepted when the station is not acting on the change because it was not valid.

LEGSa.3.4060 Event Status and Performance Data Interface

LEGS shall provide a defined set of event status and performance data to external systems.

During a given service, LEGS stations must provide a set of station status and performance data to external entities.

LEGSa.3.4070 Ground Station Health and Status Interface

LEGS shall provide ground station health and status information, to include notifications of any resource changes that impact the ability to deliver any services that are scheduled, to external systems.

To ensure that situational awareness of node health and status for relevant external systems/organizations, LEGS will provide station health and status information, to include notifications regarding resource changes that will impact scheduling of services.

LEGSa.3.4080 Site Weather Data LEGS shall provide site weather data to external users and LEGS operators for each antenna asset under LEGS MCS control.

Mission operations personnel, have a need to understand the weather conditions at the ground station for the purposes of correlating it with communications systems performance and configuration.

LEGSa.3.4110 Acquisition Data External Interface

LEGS shall interface with the Acquisition/Tracking Data System to receive acquisition data.

The LEGS must interface with the Acquisition/Tracking Data System to enable acquisition and tracking. Acquisition and tracking data is necessary for the antenna pointing and the modem Doppler compensation (forward and return).

LEGSa.3.4120 Tracking Data Message Interface

LEGS shall interface with the Acquisition/Tracking Data System to send radiometric data.

To support delivery of ranging and services, LEGS needs to provide ranging data in a common format.

LEGSa.3.4130 Offline Access to Tracking Data

LEGS shall provide archived tracking data to FDF upon request.

The Flight Dynamics Facility (FDF) nominally receives tracking data in real-time as a stream service during ground station contacts with the spacecraft. If FDF experiences any problems in saving any or all of this data and needs that lost data for processing, LEGS needs to provide a method for FDF to access the archived data outside of the contact periods to fill those gaps.

LEGSa.3.4140 Externally Accessible Browser Portal

LEGS shall provide an externally accessible secure browser-based portal to view information related to the ground station, to include:

Schedule timeline with associated activities.

Station Status.

In-service status.

Weather data.

LEGS will add the ability for customers to use a browser- based client for Mission scheduling activities and status.

LEGSa.3.4150 Externally Accessible Browser Portal – User Actions

The externally accessible secured browser-based portal shall be able to initiate actions authorized for external users, to include the ability to:

Manage schedule activities.

Export schedule to a standard format.

Submit in-service reconfiguration requests.

LEGS will take on the ability to create a browser-based client capable of a, b, and c in the requirement text above.

LEGSa.3.4210 Return Service Data External Interface

LEGS shall interface with the External Mission Data Systems to send return data.

Standard service execution interfaces across all network assets are fundamental to the LEGS network. This interface consists of both science (high rate and low rate where applicable) and telemetry.

LEGSa.3.4220 Forward Service Data External Interface

LEGS shall interface with the External Mission Data Systems to receive forward data.

Standard service execution interfaces across all network assets are fundamental to the operations of LEGS assets.

LEGSa.3.4230 Schedule Data External Interface

LEGS shall make validated scheduled Activities available to external users.

The Flight Dynamics Facility (FDF) nominally receives tracking data in real-time as a stream service during ground station contacts with the spacecraft. LEGS is expected to provide an endpoint for FDF to retrieve validated schedule Activities in order to coordinate intake of tracking data in real time. The Missions will also require validated schedule parameters for mission planning.

LEGSa.3.4310 CP External Interface LEGS shall follow the requirements in the SCaN-CP IRD when using NASA Communications Program (CP) Network services.

The requirements in the SCaN- CP IRD describe the ways in which the SCaN Network interfaces with CP network services. Using the existing IRD ensures common interfaces between SCaN and CP systems.

LEGSa.3.4320 ICAM External Interface

LEGS shall follow the requirements in the SCaN- ICAM IRD in using NASA ICAM services.

The IRD describes the ways in which the SCaN Network and ICAM interface and enforces commonality across SCaN- ICAM interfaces.

LEGSa.3.4340 Timing and Frequency Reference Interface

LEGS shall interface with an external time and frequency reference system.

High accuracy time and frequency reference is necessary to meet tracking requirements. LEGS is expected to utilize an external reference and therefore, must maintain an interface to this external reference.

LEGSa.3.4350 Mission Voice Interface

LEGS shall interface to the enterprise mission voice system.

LEGS provides a mission voice capability for all LEGS sites.

To integrate with the broader institutional mission voice enterprise, the capability provided at LEGS must integrate with the larger enterprise capability.

LEGSa.3.5010 LEGS Node Inherent Availability

LEGS shall provide an inherent availability of 0.99 measured over any 10,000 hour period for a given service.

Inherent availability (Aᵢ) is the probability that a system, when used under stated conditions in an ideal support environment (i.e., using available tools, spares, and personnel), will operate within specifications at all times. Aᵢ is one non- redundant path and includes all systems/subsystems necessary to maintain a specified service (e.g., uplink, downlink, and tracking) within performance specifications. Aᵢ excludes preventive maintenance actions, logistics supply time, and administrative downtime but includes corrective maintenance downtime.

A service is defined as forward, or return, or tracking for each frequency band.

LEGSa.3.5020 LEGS Node Operational Availability

LEGS shall provide an operational availability of

0.99 measured over any 10,000 hour period for each service.

Operational availability (Aₒ) is defined as the probability that a system will operate satisfactorily at a given point in time when used in an actual or realistic operating and support environment. Aₒ includes any system/subsystem redundancy that is included in the implemented architecture. Aₒ includes logistics delay time, ready time, and waiting or administrative downtime, and both preventive and corrective maintenance downtime. For this requirement, a service is defined as forward, or return or tracking for each frequency band.

Loss of availability due to facility services such as power or air conditioning, or loss of system capability resulting from unusual weather conditions, such as icing or severe rainstorms, are not counted. Operational Availability (Aₒ) value will be based on the SCaN Service

Availability value for “critical services”.

LEGSa.3.5030 Environmental LEGS shall meet the operational performance and survivability characteristics necessary for the defined environmental conditions of each site.

Environmental conditions differ between ground site locations.

The LEGS system at each location must be able to meet performance requirements given the specific environmental conditions of the site. Exact conditions/values under which the antenna must maintain performance (or survive under) will be defined for each location.

Environmental conditions to relevant to each site are defined below for WSC, will be modified for other locations .

WSC Environmental Conditions

Parameter Value Wind Per

LEGSa.5031, LEGSa.5033 and

LEGS.5010.

Ambient Temp (Exposed equipment)

Operate in range of -26 C to 54 C (-15° Fahrenheit (F) to +130° F).

Withstand continuous exposure in non-operational state to temperatures between -30 C to 70 C (-22°F to +158° F)

Rain Withstand rain rates of up to 10 centimeters (cm)/hr (4 in/hr) without structural damage.

Relative Humidity (Exposed equipment)

Meet all performance requirements for up to 100% relative humidity with condensation

Hail Survive 1-inch diameter hail in winds of 48 km/hr (30 mph) without damage

Snow Withstand a ground snow load of 30 pounds per square foot (psf) without structural damage

Ice Withstand 19mm (0.75 in) of ice in winds of 64 km/hr (40 mph) without damage

Seismic Activity

Not be damaged by Earth movement consistent with International Building Code

(IBC)

Indoor Conditions

Operate at interior ambient temperature range of 15° C to 32° C (59°F to 90°F) and relative humidity ranging between 20% and 90% non-condensing

LEGSa.3.5031 Operational Wind Conditions

LEGS shall meet all operational performance during sustained winds of up to 48 km/hr (30 miles/hr) with gusts of 72 km/hr (45 miles/hr)

Within typical wind conditions for a given site, LEGS must be able to meet all operational performance parameters.

LEGSa.3.5033 Wind Survivability LEGS shall survive winds of 130 km/h (81 miles per hour [mph]) winds in any position and 193 Km/h (120 mph) in stow without structural damage.

Antenna structure needs to be survivable through rare significant wind conditions to ensure performance over the system lifetime.

LEGSa.3.5040 Service Life - Electrical and Mechanical

LEGS shall have electro-mechanical, electronic, and electrical components that are sustainable for > 15 years from the ORR date for that site, where sustainment includes all activities to service, repair, or upgrade station equipment without diminishing available functionality or increasing power, space, and cooling needs.

The ability to sustain the electrical and electro- mechanical equipment composing LEGS is required to ensure performance over the expected lifespan of the system. Given that obsolescence for commodity items can be as little as 5 years, supporting the expected lifespan of a ground station necessitates a broader approach that considers upgrades for obsolete commodity parts and does not solely rely on keeping obsolescent parts in service.

LEGSa.3.5050 Service Life - Antenna and Facility

LEGS shall have a serviceable life expectancy of > 30 years from the ORR date for that site for the antenna, structures, and facilities.

Facilities and antenna structures are key to meeting system operations longevity expectations.

High serviceable life expectancy contributes to the overall ability to maintain LEGS assets and support long- term performance.

LEGSa.3.5060 Logistics and Sparing Support

LEGS shall provide on-site sparing and logistics support to meet the required Aₒ and Service Restoration.

Maintenance of hardware and software is required to meet the required operational availability for the system.

LEGSa.3.5070 Asset Maintenance LEGS shall allow authorized physical and logical access necessary to perform preventative and corrective maintenance activities.

Maintenance of hardware and software is required to ensure high performance of the LEGS system.

LEGSa.3.5080 Restoration of Service LEGS shall restore service within one hour for 95% of all service outages when averaged over a period of one year.

Each user mission must be able to depend on the continuation of LEGS services. Restoring service within an hour allows LEGS to limit the impact of outages on missions.

LEGSa.3.5090 Failover Performance LEGS shall automatically detect a failure and execute a failover to recover redundant service capabilities within 10 seconds.

This excludes antenna failures, and other failures where redundancy does not exist.

Automated failover limits the set of failures which can cause lengthy outages. It also maximizes the probability of recovering services being executed when a failure occurs.

Failover time starts when a failure occurs and ends when the redundant component(s) is switched into service.