Feasibility study passive lunar marker beacon final report
Radar beacon configurations for passive lunar marker feasibility study
RADAR BEACON↗
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Investigation and study of a multi-aperture antenna system final report, 1 jan. - 1 apr. 1964
This investigation was concerned with a multiple aperture adaptive antenna system for application to receiving telemetered data from remote space vehicles or satellites. The primary criterion for determining the feasibility of such a system has been economic considerations, but of necessity many physical constraints imposed on both a single antenna and a multiple aperture system have been evaluated. These include such factors as acquisition and combining of signals, look angle, shadowing, propagation influences system spatial bandwidth, collimation, interference, doppler effects, reliability, and noise. Specific conclusions have been made for a system operating at a frequency of 2 Gc, but the system model adopted allows quick evaluation at other frequencies. At a frequency of 2Gc, the crossover point between a single antenna or a multiple aperture configuration occurs for an 85 foot reflector. However this transition region is not critical. For lunar range communications a single antenna appears to be the most economical, whereas at interplanetary ranges aperture equivalents of around 400 feet are required and achieved by arraying eight 142 foot antennas.
TELEMETRY↗
The lunar orbiter telecommunications system.
Spacecraft and ground equipment design of lunar orbiter telecommunications system
SPACECRAFT ELECTRONIC EQUIPMENT↗
Apollo unified S-band system.
Apollo unified S-band system covering station locations, uplink and downlink spectrums, spacecraft gross parameters, theory of operation, etc
SPACE COMMUNICATION↗
Preliminary design of the telemetry system for Apollo lunar surface experiments.
Design of Apollo project lunar-based telemetry system for transmitting experiment data to Earth for one year
TELEMETRY↗
Man-in-space communications subsystem.
Communications subsystem providing S-band link between LEM and Earth and VHF link between LEM AND Command Module
SPACE COMMUNICATION↗
A Hummingbird for the L sub 2 lunar libration point
Hovering lunar libration communication satellite stationary with respect to earth-moon system
Vonbun, F. O.↗
Roles of the ground and flight crew in Apollo operations.
The functions performed by ground personnel and flight crews of Apollo missions are reviewed, covering vehicle systems operation and management, Saturn launch vehicle, command-service and lunar modules, lunar rover, communication relay unit and ground-commanded TV assembly. Details of the flight path, scientific experiments, photographic equipment and crew health monitoring are also discussed in terms of these functions. The coordinated combination of large numbers of experts and data processing equipment on the ground with the crew's capabilities to operate the spacecraft and exercise on-the-spot judgements is viewed as the backbone of the successful fulfillment of Apollo missions.
Wolfer, B. M.↗
Artemis: Results of the engineering feasibility study
Information is given in viewgraph form for the Engineering Feasibility Study of the Artemis Project, a plan to establish a permanent base on the Moon. Topics covered include the Common Lunar Lander (CLL), lunar lander engineering study results, lunar lander trajectory analysis, lunar lander conceptual design and mass properties, the lunar lander communication subsystem design, and product assurance.
Source record↗
Crew-Centered Operations: What HAL 9000 Should Have Been
To date, manned space flight has maintained the locus of control for the mission on the ground. Mission control performs tasks such as activity planning, system health management, resource allocation, and astronaut health monitoring. Future exploration missions require the locus of control to shift to on-board due light speed constraints and potential loss of communication. The lunar campaign must begin to utilize a shared control approach to validate and understand the limitations of the technology allowing astronauts to oversee and direct aspects of operation that require timely decision making. Crew-centered Operations require a system-level approach that integrates multiple technologies together to allow a crew-prime concept of operations. This paper will provide an overview of the driving mission requirements, highlighting the limitations of existing approaches to mission operations and identifying the critical technologies necessary to enable a crew-centered mode of operations. The paper will focus on the requirements, trade spaces, and concepts for fulfillment of this capability. The paper will provide a broad overview of relevant technologies including: Activity Planning and Scheduling; System Monitoring; Repair and Recovery; Crew Work Practices.
Korsmeyer, David J.↗
The Lunar Laser OCTL Terminal (LLOT) Optical Systems
The Lunar Laser OCTL Terminal is an auxiliary ground station terminal for the Lunar Laser Communication Demonstration (LLCD). The LLOT optical systems exercise modulation and beam divergence control over six 10-watt fiber-based laser transmitters at 1568 nanometers, which act as beacons for pointing of the space-based terminal. The LLOT design transmits these beams from distinct sub-apertures of the F/76 OCTL telescope at divergences ranging from 110 microrad to 40 microrad. LLOT also uses the same telescope aperture to receive the downlink signal at 1550 nanometers from the spacecraft terminal. Characteristics and control of the beacon lasers, methods of establishing and maintaining beam alignment, beam zoom system design, co-registration of the transmitted beams and the receive field of view, transmit/receive isolation, and downlink signal manipulation and control are discussed.
laser communications↗
Potential Applications for Space Communications
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Communications↗
Design of a pressurized lunar rover
A pressurized lunar rover is necessary for future long-term habitation of the moon. The rover must be able to safely perform many tasks, ranging from transportation and reconnaissance to exploration and rescue missions. Numerous designs were considered in an effort to maintain a low overall mass and good mobility characteristics. The configuration adopted consists of two cylindrical pressure hulls passively connected by a pressurized flexible passageway. The vehicle has an overall length of 11 meters and a total mass of seven metric tons. The rover is driven by eight independently powered two meter diameter wheels. The dual-cylinder concept allows a combination of articulated frame and double Ackermann steering for executing turns. In an emergency, the individual drive motors allow the option of skid steering as well. Two wheels are connected to either side of each cylinder through a pinned bar which allows constant ground contact. Together, these systems allow the rover to easily meet its mobility requirements. A dynamic isotope power system (DIPS), in conjunction with a closed Brayton cycle, supplied the rover with a continuous supply of 8.5 kW. The occupants are all protected from the DIPS system's radiation by a shield of tantalum. The large amount of heat produced by the DIPS and other rover systems is rejected by thermal radiators. The thermal radiators and solar collectors are located on the top of the rear cylinder. The solar collectors are used to recharge batteries for peak power periods. The rover's shell is made of graphite-epoxy coated with multi-layer insulation (MLI). The graphite-epoxy provides strength while the thermally resistant MLI gives protection from the lunar environment. An elastomer separates the two materials to compensate for the thermal mismatch. The communications system allows for communication with the lunar base with an option for direct communication with earth via a lunar satellite link. The various links are combined into one signal broadcast in the S-band at 2.3 GHz. The rover is fitted with a parabolic reflector disk for S-band transmission, and an omnidirectional antenna for local extravehicular activity (EVA) communication. The rover's guidance, navigation, and control subsystem consists of an inertial guidance system, an orbiting lunar satellite, and an obstacle avoidance system. In addition, the rover is equipped with a number of external fixtures including two telerobotic arms, lights, cameras, EVA storage, manlocks, a docking fixture, solar panels, thermal radiators, and a scientific airlock. In conclusion, this rover meets all of the design requirements and clearly surpasses them in the areas of mobility and maneuverability.
Bhardwaj, Manoj↗
NASA Lunar Exploration – Gateway’s Power and Propulsion Element Communications Links
As a key part of NASA’s Artemis program to return to the moon, the Lunar Gateway will provide a platform for staging lunar missions, for gaining experience in operations beyond earth orbit, and for creating sustainable infrastructure. Of specific interest, the Lunar Gateway will provide communications support to landers, orbiters, and surface systems, including in the South Polar Region where direct line of sight (LOS) to Earth is limited or non-existent. A foundational segment of the Gateway is the Power and Propulsion Element (PPE), which will carry: solar arrays to provide power to the Gateway; electric propulsion to maintain the Gateway in its operational orbit; and communication links between the Earth and Gateway, the Moon and Gateway, and relays from the Moon to the Earth. PPE Communication Links include an X-band link to Earth for Command, Ranging, and Telemetry (CR&T), which also carries low to medium rate data; a Ka-band Direct to Earth(DTE) link for high rate data transmissions; and a Ka-band Lunar link for high data rate connections to lunar systems. This paper describes the PPE communication links from a technical perspective. Other Gateway links supported by other modules are outside the scope of this paper.
ARTEMIS↗
LunaNet Governance: Organizing and Planning for LunaNet Operations
LunaNet is proposed to be the lunar internet, providing services for communications, networking, position, navigation, and timing for missions in transit to and from the moon, in orbit around the moon, in transit to and from the surface, and on the surface. It is envisioned to be an open, international architecture with contributions from multiple organizations including international civil space agencies, commercial service providers, academic institutions, and other organizations. Using a combination of conventional and emerging technologies, LunaNet will create a lunar-centric network-of-networks that inherits some features of the terrestrial internet but has unique characteristics that will drive substantially different operations. Government acquisition efforts have already begun to procure commercial lunar communications and navigation services. A multi-stakeholder approach to developing the community-wide concepts of operation has been initiated by the Interagency Operations Advisory Group (IOAG), which is formed of international government space agencies, that includes other international organizations such as the Internet Society, Internet Engineering Task Force, International Committee on Global Navigation Satellite Systems, and Space Frequency Coordination Group as well as industry and academic participants. Products of the Interim Committee on LunaNet Governance will include the recommendation and definition of an initial international organizational governance structure; associated roles, responsibilities, and processes; and recommended steps to implement the governance approach. This paper will describe the progress made in developing these concepts and coordinating them among the participating organizations.
LunaNet↗
Comparing Performance of Coded Communications over Fading Channels between the Lunar South Pole & Earth
In this paper we design and analyze an end-to-endcommunication system between a lander/rover on the surface ofthe lunar South Pole and an Earth station. Various communicationsystems on the lander or rover could be used for the Earthto-Moon communication in both the uplink and downlink direction.To communicate to and from the lander/rover on the lunarSouth Pole, low and/or medium directional antennas onboardthe lander/rover will have to be pointed at low elevation anglesbetween 2 to 10 degrees, thus causing multipath fading effectsdue to reflection of a portion of the transmitted electromagneticwaves from the surface of the Moon. These are not commonlyencountered in traditional deep space communications betweena spacecraft and a ground station.We investigate various design methods and analyze such communicationsystems, in the presence of multipath fading. Wemodel the fading channel based on existing and simulated data.For coherent reception, the acquisition and tracking loop shouldacquire and track incoming carrier phase in presence of Ricianmultipath fading. For this communication system in additionto estimating the received carrier phase, the amplitude of thefading signal should also be estimated, in particular to be used inthe decoder. We consider simple modulation and coding schemesin particular those specified in the CCSDS standards for spaceapplications.After designing various components of the communication system,we use Simulink models to obtain the end-to-end performanceof the communication link under investigation. Basedon the available data, the fading channel can be accuratelymodeled as a Rician fading channel with various Rician parametersdepending on the Earth elevation angle, which alsoaffects the Doppler spread. Therefore, the challenge is todesign a communication system robust in the presence of themultipath fading where the channel conditions change in timeand thus produce fading. In summary, this paper comparespossible communication system designs, performance analysis,and simulations for coded system with/without interleaving withhard/soft decision and with/without channel state information(CSI), over a communication link between a lander/rover at theLunar south pole and a Deep Space Network station in presenceof Rician fading.
Cheung, Kar-Ming↗
Science Hybrid Orbiter and Lunar Relay (SCHOLR) Architecture and Design
Considered both a stepping-stone to deep space and a key to unlocking the mysteries of planetary formation, the Moon offers a unique opportunity for scientific study. Robotic precursor missions are being developed to improve technology and enable new approaches to exploration. Robots, lunar landers, and satellites play significant roles in advancing science and technologies, offering close range and in-situ observations. Science and exploration data gathered from these nodes and a lunar science satellite is intended to support future human expeditions and facilitate future utilization of lunar resources. To attain a global view of lunar science, the nodes will be distributed over the lunar surface, including locations on the far side of the Moon. Given that nodes on the lunar far side do not have direct line-of-sight for Earth communications, the planned presence of such nodes creates the need for a lunar communications relay satellite. Since the communications relay capability would only be required for a small portion of the satellite s orbit, it may be possible to include communication relay components on a science spacecraft. Furthermore, an integrated satellite has the potential to reduce lunar surface mission costs. A SCience Hybrid Orbiter and Lunar Relay (SCHOLR) is proposed to accomplish scientific goals while also supporting the communications needs of landers on the far side of the Moon. User needs and design drivers for the system were derived from the anticipated needs of future robotic and lander missions. Based on these drivers and user requirements, accommodations for communications payload aboard a science spacecraft were developed. A team of interns identified and compared possible SCHOLR architectures. The final SCHOLR architecture was analyzed in terms of orbiter lifetime, lunar surface coverage, size, mass, power, and communications data rates. This paper presents the driving requirements, operational concept, and architecture views for SCHOLR within a lunar surface nodal network. Orbital and bidirectional link analysis, between lunar nodes, orbiter, and Earth, as well as a conceptual design for the spacecraft are also presented
Trase, Kathryn K.↗
Trajectory Design for MoonRise: A Proposed Lunar South Pole-Aitken Basin Sample Return Mission
This paper presents the mission design for the proposed MoonRise New Frontiers mission: a lunar far side lander and return vehicle, with an accompanying communication satellite. Both vehicles are launched together, but fly separate low-energy transfers to the Moon. The communication satellite enters lunar orbit immediately upon arrival at the Moon, whereas the lander enters a staging orbit about the lunar Lagrange points. The lander descends and touches down on the surface 17 days after the communication satellite enters orbit. The lander remains on the surface for nearly two weeks before lifting off and returning to Earth via a low-energy return.
NASA's New Frontie↗