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UV Laser Development for In Situ Planetary Lander Instruments

Mass and Raman spectrometers represent progressive analytical platforms for future in situ lander missions to explore the surface chemistry of planetary bodies across the Solar System. Europa, the Moon, and Mars are some of the primary targets for future NASA missions to search for extraterrestrial life and potentially habitable environments beyond Earth, further our understanding of the timing and formation of the Solar System and identify potentially viable economic resources such as water and/or valuable metal assets. The CORALS (Characterization of Ocean Residues And Life Signatures) and CRATER (Characterization of Regolith And Trace Economic Resources) instruments are UV laser-enabled OrbitrapTM mass spectrometers currently under development for prospective lander missions to Europa and the Moon, respectively. The Raman Mass Spectrometer (RAMS) is a dual wavelength (UV and visible) laser enabled hybrid instrument that incorporates laser desorption/ ionization mass spectrometry (LDMS) and micro-Raman microspectroscopy imaging (μRS) into a compact instrument package for multiple planetary missions to the inner and outer Solar System. The Pulse Laser Ablation Sampling and Mass Analysis (PLASMA) instrument combines a multi-wavelength laser (deep-UV to near-IR), plasma source, and collision cell with a heritage quadrupole mass spectrometer (QMS) to enable high precision trace element analyses for a future Lunar lander instrument. We report on the advancement of four compact, robust, and high technology readiness level (TRL) solid state lasers operating at wavelengths 213 nm, 266 nm, 515 nm, 532 nm and 1064 nm that serve as the sampling and ionization sources, for the CRATER, CORALS, RAMS and PLASMA investigations.

Molly Fahey↗

Past US studies and developments for planetary rovers

The history of planetary rovers in the U.S. space program is outlined in the context of the goals, mission and spacecraft designs, and operations designs. The American lunar rover work has had three main stages. In the early sixties, the capacity of Surveyor lunar landers to deliver rovers with a mass of about 50 kg to the Moon was exploited. Several such machines were built and tested beginning in 1964 but none went to the Moon. A manned 400 kg short range rover was then developed. Three of these operated on the Moon in 1971 and 1972 as part of the Apollo 15, 16 and 17 missions. Following these Apollo successes, attempts were made to provide two kinds of follow on models: automated or dual mode (human carrying or not) rovers in the few hundred kg size class, and multi-ton mobile habitats that could carry humans on extended traverses. With the closing of both Soviet and American lunar exploration in the seventies, neither of these proposals succeeded. In parallel with these lunar developments, a lengthy technology program on Martian roving has gone on in the U.S., sometimes coming close to preproject status and sometimes fading away, but never quite being abandoned. As a result it is possible today to contemplate a wide range of lunar and Martian roving missions that could be made practical within a few years. However, with today's funding constraints none of the well studied, larger mission concepts appear to fit. Therefore new efforts are being made toward developing much smaller rovers taking advantage of new miniature techniques, not only in mobility systems but also in the scientific instruments that a small rover can carry. Illustrations are included.

Burke, James D.↗

From Paper to Production: An Update on NASA's Upper Stage Engine for Exploration

The NASA/industry team responsible for developing the J-2X Upper Stage Engine for the Constellation Program's Ares I and Ares V launch vehicles has made significant progress toward moving the design from paper to production during the past year. The J-2X exemplifies the Constellation goal of using proven technology and experience from more than 50 years of United States spaceflight experience and seeking where possible to employ common hardware in the Ares I crew launch vehicle and the Ares V cargo launch vehicle. The J-2X will power the Ares I upper stage to place the Orion crew vehicle in orbit. For the Ares V, the J-2X will place the Earth departure stage (EDS) and lunar lander in orbit and later re-start to send the Orion and lander to the Moon. Pratt & Whitney Rocketdyne (PWR) is under contract to develop and produce the engine, leveraging its flight-proven LH2/LOX, gas generator cycle J-2 and RS-68 engine capabilities, recent experience with the X-33 aerospike XRS-2200 engine, and development knowledge of the J-2S tap-off cycle engine. The J-2X employs a gas generator operating cycle designed to produce 294,000 pounds of thrust in primary operating mode for the Ares I and Ares V ascent phases. It also has a secondary mode, during which it operates at 80 percent thrust by altering its mixture ratio to perform the TLI burn for the Ares V lunar sortie and lunar cargo missions. The J-2X development philosophy is based on proven hardware, an aggressive development schedule, and early risk reduction. NASA Marshall Space Flight Center (MSFC) and PWR began development of the J-2X in June 2006. The government/industry team of more than 600 people within NASA and PWR successfully completed the Critical Design Review (CDR) in November 2008, following extensive risk mitigation testing. The team is working toward a first flight of the J-2X on the Orion 1 mission in 2014. This paper will discuss the J-2X development background and provide top-level information on design and testing to date. Details will be provided on overcoming challenges such as gas generator instability, turbine blade life, and nozzle extension selection and materials.

Kynard, Mike↗

Mission-Maps For Outbound Cislunar Transfer Trajectories

This study quantifies the robustness and sensitivity of an outbound cislunar trajectory for a lunar lander in the form of mission-maps, or topological maps that allows either a computer program or mission designer to intuitively optimize the placement of critical outbound correction burns from the derived sensitivity data. The non-linear multi-body dynamics are applied to generate an outbound cislunar reference profile used by a linear covariance analysis (LinCov) tool to compute the expected Δv and trajectory dispersions due to the initial state uncertainty, sensor errors, maneuver execution errors, and disturbance accelerations along the outbound cislunar profile. The rapid performance analysis capabilities of LinCov are complimented with parallel processing techniques to evaluate hundreds and thousands of different translational burn locations, placements, and targeting constraints to identify the combination that minimizes the total Δv usage (nominal plus 3σ Δv) and trajectory dispersions at lunar orbit insertion. This study utilizes a generalized reference targeting algorithm to quickly assess the integrated closed-loop GN&C system performance due to different targeting configurations and constraints. The resulting mission maps provide an intuitive insight to ascertain each trajectory correction maneuver’s (TCM) sensitivity to different burn times along an outbound cislunar trajectory and quickly identify desirable engineering tradeoffs when performing analysis on the number and placement of these burns that nominally zero. Multiple mission maps are generated for a variety of different performance parameters that allow engineers to visually identify optimal solutions for trajectory correction maneuver placements, the number of correction burns, and the targeting constraints for each burn.

GN&C↗

Recommended Crew Systems Capabilities for a 30 to 90 Day Four-Crew Lunar Surface Mission

For any given surface mission duration, there exists a set of surface capabilities necessary to sustain a four-person crew for the length of time the crew is on the surface. Identifying these capabilities is important to mission planners and spacecraft design engineers responsible for lunar surface habitation elements, who need to know which systems and capabilities must be prioritized for the vehicles they are designing. However, simply identifying the surface capabilities does not necessarily equal a viable surface configuration. These capabilities may or may not satisfy stakeholder expectations or even permit completion of mission objectives. Lunar lander cargo mass constraints are a powerful forcing function that requires significant efforts to reduce the mass of all surface elements, including those supporting crew habitation. The required capabilities do increase as a function of mission duration, but it is a nonlinear growth. There are key points in mission duration, beyond which certain additional capabilities are needed. This forms bands of capability between each point. Within a given band, the same functional capabilities are needed, and the only scaling is that associated with daily consumables. The next higher band requires additional capabilities. This paper will focus on those capabilities needed for missions of 30-90 days. It should be noted that there are some uncertainties interpreting NASA requirements that require capabilities after a certain number of days, as typically this refers to number of days in space, not number of days on the lunar surface. Depending on transportation architecture, the number of days between Earth launch and lunar surface landing may vary, therefore impacting when certain required capabilities are implemented. However, activities to prepare humans for missions to Mars and commercial interest in lunar development may drive progressive increases in surface duration. Missions up to 30 days are expected to follow the initial 6.5-day surface missions and there may be commercial interest in extending to even greater durations. This paper will examine the potential case of a 30-90-day surface mission duration with respect to the systems necessary to support crew living and working on the lunar surface.

Habitat↗

Using Combustion Synthesis to Reinforce Berms and Other Regolith Structures

The Moonraker Excavator and other tools under development for use on the Moon, Mars, and asteroids will be employed to construct a number of civil engineering projects and to mine the soil. Mounds of loose soil will be subject to the local transport mechanisms plus artificial mechanisms such as blast effects from landers and erosion from surface vehicles. Some of these structures will require some permanence, with a minimum of maintenance and upkeep. Combustion Synthesis (CS) is a family of processes and techniques whereby chemistry is used to transform materials, often creating flame in a hard vacuum. CS can be used to stabilize civil engineering works such as berms, habitat shielding, ramps, pads, roadways, and the like. The method is to unroll thin sheets of CS fabric between layers of regolith and then fire the fabric, creating a continuous sheet of crusty material to be interposed among layers of loose regolith. The combination of low-energy processes, ISRU (in situ resource utilization) excavator, and CS fabrics, seems compelling as a general method for establishing structures of some permanence and utility, especially in the role of robotic missions as precursors to manned exploration and settlement. In robotic precursory missions, excavator/ mobility ensembles mine the Lunar surface, erect constructions of soil, and dispense sheets of CS fabrics that are covered with layers of soil, fired, and then again covered with layers of soil, iterating until the desired dimensions and forms are achieved. At the base of each berm, for example, is a shallow trench lined with CS fabric, fired and filled, mounded, and then covered and fired, iteratively to provide a footing against lateral shear. A larger trench is host to a habitat module, backfilled, covered with fabric, covered with soil, and fired. Covering the applied CS fabric with layers of soil before firing allows the resulting matrix to incorporate soil both above and below the fabric ply into the fused layer, developing a very irregular surface which, like sandpaper, can provide an anchor for loose soil. CS fabrics employ a coarse fiberglass weave that persists as reinforcement for the fired material. The fiberglass softens at a temperature that exceeds the combustion temperature by factors of two to three, and withstands the installation process. This type of structure should be more resistant to rocket blast effects from Lunar landers.

Rodriquez, Gary↗

Engineering America's Future in Space: Systems Engineering Innovations for Sustainable Exploration

The National Aeronautics and Space Administration (NASA) delivers space transportation solutions for America's complex missions, ranging from scientific payloads that expand knowledge, such as the Hubble Space Telescope, to astronauts and lunar rovers destined for voyages to the Moon. Currently, the venerable Space Shuttle, which has been in service since 1981, provides U.S. capability for both crew and cargo to low-Earth orbit to construct the International Space Station, before the Shuttle is retired in 2010, as outlined in the 2006 NASA Strategic Plan. I In the next decade, NASA will replace this system with a duo of launch vehicles: the Ares I Crew Launch Vehicle/Orion Crew Exploration Vehicle and the Ares V Cargo Launch Vehicle/Altair Lunar Lander. The goals for this new system include increased safety and reliability, coupled with lower operations costs that promote sustainable space exploration over a multi-decade schedule. This paper will provide details of the in-house systems engineering and vehicle integration work now being performed for the Ares I and planned for the Ares V. It will give an overview of the Ares I system-level test activities, such as the ground vibration testing that will be conducted in the Marshall Center's Dynamic Test Stand to verify the integrated vehicle stack's structural integrity against predictions made by modern modeling and simulation analysis. It also will give information about the work in progress for the Ares I-X developmental test flight planned in 2009 to provide key data before the Ares I Critical Design Review. Activities such as these will help prove and refine mission concepts of operation, while supporting the spectrum of design and development tasks being performed by Marshall's Engineering Directorate, ranging from launch vehicles and lunar rovers to scientific spacecraft and associated experiments. Ultimately, the work performed will lead to the fielding of a robust space transportation solution that will carry international explorers and essential payloads for sustainable scientific discovery beyond planet Earth.

Dumbacher, Daniel L.↗

Lunar Node 1 and Beyond

Lunar Node 1 (LN-1) is an S-band Navigation beacon for lunar applications that was recently designed and built at MSFC. As part of NASA's Commercial Lunar Payload Services initiative, this beacon will be delivered to the moon's surface on Intuitive Machine's NOVA-C lunar lander in November 2021. During this mission, LN-1’s goal will be to demonstrate navigation technologies that can support local surface and orbital operations around the moon, enabling autonomy which would decrease dependency on heavily utilized Earth based assets like the Deep Space Network. To do this, LN-1’s design leverages Cubesat components as well as the Multi-spacecraft Autonomous Positioning System (MAPS) algorithms, which enable the autonomous spacecraft positioning through communication-integrated navigation measurements. In addition to demonstrating the MAPS payload, the radio will also be used in standard tone-based non-coherent ranging and Doppler tracking to provide an alternate approaches and comparisons for navigation performance. LN-1 will represent a single node in a potential greater MAPS network of assets. While LN-1 awaits launch to demonstrate this initial use of one-way navigation, designs are already under way for proposed subsequent missions like LN-2 to enable expanded capability. The next steps in these missions seek to include a receive capability to allow two-way ranging support with other operational spacecraft in the lunar vicinity, and to provide some component upgrades related to the radio, power, and thermal systems that will improve the longevity of the payload in the harsh lunar environment. The LN-1 design details, status, and potential forward work with mission like LN-2 will be outlined in this presentation.

Evan John Anzalone↗

Implementation of Charged Particle Behavior in Discrete Element Method (DEM) Simulations

To understand the behavior of charged lunar regolith when perturbed by lunar landers, it is important to couple the grain dynamics with mechanical and electrical particle interactions. To accomplish this, improvements have been made to a discrete element method (DEM) software package to include both short- and long-range interactions between spherical particles. Short-range interactions rely on contact between the particles, such as electrical conduction and triboelectric charge transfer driven by work functions. Long-range interactions act at a distance between every pairing of particles, such as electrostatic forces and gravitational forces. Results from simulations between a few particles are compared with theory to verify these added behaviors prior to scaling up to more complex scenarios. The radii, initial charges, electrical conductivities, work functions, and separation of the particles are varied and the resultant charges as well as the time required to reach the final state are determined.

Electrostatics↗

Addressing CFM Modeling Gaps for Application into NASA’S Future Cutting Edge Missions

NASA, the US industry, and international partners are crafting frameworks to enable sustaining lunar missions. The ongoing programs, led by the agency, and prominent industry players, encompass plans for the sustained use of cryogenic propellants in lunar landers and in-space propellant refueling depots. NASA’s proactive funding initiatives have fueled the advancement of predictive computational models tailored to enhance the storage and transfer of cryogenic propellant. This paper aims to spotlight the latest advancements in this arena and delve into the collaborative efforts surrounding predictive model development within internal NASA programs as well as current and previous collaborations with industry and international partners. The paper presents an overview of recent advancements in cryogenic fluid management model development, along with their correlation with recent microgravity and large-scale cryogenic ground tests. The tests include key experiments such as the ISS Zero-Boil-Off Tank (ZBOT) series of experiments and the (Robotic Refueling Mission 3) RRM3 test during which liquid methane was stored on-orbit for an extended period of five months. The paper also highlights the anchoring of propellant tank pressurized drain tests involving sloshing that were conducted with liquid methane propellant during the Apollo/Saturn Era. Additionally, the paper discusses model anchoring against more recent sloshing tests carried out with liquid hydrogen propellant. Notable large-scale tests, such as a liquid oxygen propellant transfer test conducted by SpaceX were also used to help correlate a two-phase propellant transfer model using the valuable data measured during the test. The paper further showcases model correlations against a substantial oxygen liquefaction test undertaken by NASA to validate In-Situ-Resource-Utilization (ISRU) technologies that will prove pivotal for a sustained lunar presence.

Low-gravity fluid modeling↗

Fuel-Efficient Descent and Landing Guidance Logic for a Safe Lunar Touchdown

The landing of a crewed lunar lander on the surface of the Moon will be the climax of any Moon mission. At touchdown, the landing mechanism must absorb the load imparted on the lander due to the vertical component of the lander's touchdown velocity. Also, a large horizontal velocity must be avoided because it could cause the lander to tip over, risking the life of the crew. To be conservative, the worst-case lander's touchdown velocity is always assumed in designing the landing mechanism, making it very heavy. Fuel-optimal guidance algorithms for soft planetary landing have been studied extensively. In most of these studies, the lander is constrained to touchdown with zero velocity. With bounds imposed on the magnitude of the engine thrust, the optimal control solutions typically have a "bang-bang" thrust profile: the thrust magnitude "bangs" instantaneously between its maximum and minimum magnitudes. But the descent engine might not be able to throttle between its extremes instantaneously. There is also a concern about the acceptability of "bang-bang" control to the crew. In our study, the optimal control of a lander is formulated with a cost function that penalizes both the touchdown velocity and the fuel cost of the descent engine. In this formulation, there is not a requirement to achieve a zero touchdown velocity. Only a touchdown velocity that is consistent with the capability of the landing gear design is required. Also, since the nominal throttle level for the terminal descent sub-phase is well below the peak engine thrust, no bound on the engine thrust is used in our formulated problem. Instead of bangbang type solution, the optimal thrust generated is a continuous function of time. With this formulation, we can easily derive analytical expressions for the optimal thrust vector, touchdown velocity components, and other system variables. These expressions provide insights into the "physics" of the optimal landing and terminal descent maneuver. These insights could help engineers to achieve a better "balance" between the conflicting needs of achieving a safe touchdown velocity, a low-weight landing mechanism, low engine fuel cost, and other design goals. In comparing the computed optimal control results with the preflight landing trajectory design of the Apollo-11 mission, we noted interesting similarities between the two missions.

guidance logic↗

Lunar Surface Crater Thermal Effects on Lander Radiator Performance

Lunar surface craters smaller than the spatial resolution of surface meshes used in typical Lunar surface thermal models (10 to 60 meters per pixel) may impact the accuracy of thermal model extrema predictions. The goal of this study is to investigate the thermal sensitivity of representative lander systems with realistic thermal surface orientations in bare and cratered terrain environments at relevant Artemis mission locations. This thermal analysis task investigates the impact of lunar surface craters on lander radiator performance by comparing heat rejection capability results between bare and cratered terrain environments. This study examines external body-mounted lander radiator thermal performance across varying lander heights (5.5m, 20m, 50m) and radiator orientations (horizontal, 45º tilted, and vertical) at two representative Artemis mission latitudes (-89.5ºS and -82.5ºS), spanning from the Shackleton Connecting Ridge to Mons Mouton Plateau.

Lunar Surface↗

Measuring the Wear and Abrasive Resistance of Air Plasma Sprayed Aluminum Oxide for Lunar Exploration

Lunar regolith, especially finer dust particles traveling at high velocities, can cause significant wear and abrasive damage to structural components that ensure a prolongated presence on the surface of the Moon. With the absence of an atmosphere and lower gravity than on Earth, regolith particles maintain high velocities at large distances from where they were generated, for example next to lunar landers. Wear-resistant ceramic and ceramic composite materials can improve the durability of spacecraft components during long missions on the Moon’s surface. Aluminum oxide coatings are lightweight, have multifunctional properties, and have high strength including high hardness and wear resistance. These properties can help improve the durability of structures used in space exploration. Air plasma sprayed (APS) aluminum oxide coatings have demonstrated the potential to protect critical structures. This study investigated the abrasive wear resistance of APS aluminum oxide coatings via Taber abrasion experiments. Taber abrasion offers the advantage of quantifying the abrasive wear behavior of particles with different shapes on a surface. In this work, an abrasive wheel made of silicon carbide was utilized to evaluate wear properties of specimens progressively over 5000 cycles. This experiment focused on testing two series of specimens to determine whether a bond coat composed of nickel, chromium, aluminum, and yttrium (NiCrAlY) improved the protective behavior of the APS aluminum oxide coating. The specimens varied in topcoat thickness and were made with and without an approximately 100 µm bond coat layer. The mass of the specimens was measured at 400 cycles, 800 cycles, 3800 cycles, and 5000 cycles. Increasing thickness was found to result in higher wear for samples with and without a bond coat. Increased mass loss in samples with a bond coat was observed indicating a need for further studies on the overall impact of the use of a bond coat on the protective behavior of the coatings. To continue designing wear resistant coatings for structural protection in space missions, the multifunctional properties of the APS aluminum oxide coating will be studied. Future experiments will determine whether the APS aluminum oxide coating can protect the structures from other aspects of the harsh space environment, such as extreme temperature variations and ionizing radiation.

aluminum oxide↗

NASA Announces Spacecraft Decontamination Procedures

The National Aeronautics and Space Administration has announced procedures for the sterilization of planetary spacecraft and revised the procedures for the decontamination of unmanned lunar landers.

DECONTAMINATION↗

An innovative technique for static and dynamic V/STOL testing

Initial hover testing of the Navy's XFV-12A V/STOL technology prototype aircraft is being conducted in the former Lunar Lander Research Facility at the NASA Langley Research Center. The aircraft incorporates a unique lift/control concept for V/STOL flight. A key element in the development of this aircraft has been the application of existing hardware and facilities to conserve program funds. Adaptation of the NASA Gantry has created a V/STOL aircraft test facility with unique capability and flexibility. Static lift and control measurements can be obtained and dynamic hover flight can be conducted over a wide range of realistic test conditions.

Lewis, E. L.↗

Comparison of solar photovoltaic and nuclear reactor power systems for a human-tended lunar observatory

Photovoltaic and nuclear surface power systems were examined at the 20 to 100 kW power level range for use at a human-tended lunar astronomical observatory, and estimates of the power system masses were made. One system, consisting of an SP-100 thermoelectric nuclear power supply integrated with a lunar lander, is recommended for further study due to its low system mass, potential for modular growth, and applicability to other surface power missions, particularly in the Martian system.

Hickman, J. M.↗

Comparison of solar photovoltaic and nuclear reactor power systems for a human-tended lunar observatory

Photovoltaic and nuclear surface power systems were examined at the 20 to 100 kW power level range for use at a human-tended lunar astronomical observatory, andestimates of the power system masses were made. One system, consisting of an SP-100 thermoelectric nuclear power supply integrated with a lunar lander, is recommended for further study due to its low system mass, potential for modular growth, and applicability to other surface power missions, particularly in the Martian system.

Hickman, J. M.↗

Reusable Manned Lunar Vehicle

Report presents concept for reusable manned spacecraft to fly to and from Moon. Concept calls for lunar lander based in low orbit around Moon and transfer stage that shuttles between orbiting lander and Earth. Lander would deliver 30 tons of cargo to surface of Moon robotically and return to low orbit around Moon. Alternatively, lands eight crew-members and supplies for 165 days and return them to orbit. Transfer stage carries propellant for lander from Earth. Upon return to atmosphere of Earth slows itself by aerobraking.

Sherwood, Brent↗