SEARCH · Search NASA

Results for “Europa”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16

All sources NASA NTRS DOE OSTI

NASA NTRS2018

Operability Engineering for the Europa Clipper Mission: Formulation Phase Results and Lessons

Operability is an important factor in both success and cost of space missions, but is difficult to quantify, and can suffer if not considered as part of early formulation and design. The Europa Clipper mission has taken a deliberate approach to infusing operability into the concepts and designs since early in the formulation phase. This paper reports on that approach to operability and the results thus far, as the Europa Clipper mission approaches its Preliminary Design Review. Definitions for operability and its various aspects are presented along with a description of the engineering and organizational approach taken to infusing operability into designs. A number of examples of operability requirements are shown, and key examples of trade studies and design decisions are described, along with influence on outcomes motivated by operability considerations. We find that support from management, empowerment of a cross-discipline Operability Working Group, consistent tracking of operability aspects over time, and broad infusion and participation in operability considerations are all significant factors in implementing operability. In particular, thoughtful and deliberate consideration of operability criteria has led to design decisions that include proper consideration of concerns related to the mission operations phase, and seem likely to provide better science results and mission outcomes.

Huh, Shin M.↗

NASA NTRS2018

Far-Field Pattern Measurement and Simulation of VHF Antenna at 60 MHz for Europa Clipper Mission

This paper presents measurements and simulations of a linearly polarized VHF folded dipole operating at 60 MHz for NASA’s upcoming Europa Clipper mission. The spacecraft contains a ground penetrating radar, consisting of an array of four VHF antennas, that will characterize the surface of Jupiter’s icy moon Europa. Measured far-field radiation patterns and reflection coefficients above a 50×80m perfect ground plane are compared to predicted results using commercial software. Normalized Far-Field radiation pattern cuts are measured utilizing a biconical antenna and receiver mounted on a flying drone. Simulations of the radiation pattern show that the number of lobes increases with the distance of the antenna from the ground due to the ground-bounce phenomenon. In addition, the measured and simulated reflection coefficients stay unchanged for height above 2 meters, which matches the predicted calculation of the reactive-near field region of this antenna. However, the antenna electrical parameters are optimized for use on the spacecraft and become detuned in the presence of a ground plane. Simulated and measured return loss discrepancy less than 0.5 dB is presented. Radiation pattern comparisons show similar agreement when taking into account the effect of far-field measurement uncertainties.

Decrossas, Emmanuel↗

NASA NTRS2018

Compact Low Power Avionics for the Europa Lander Concept and Other Missions to Ocean Worlds

This paper presents the results of NASA’s Game Changing Technology development entitled “Ultra Low Temperature Electronics” and ColdTech technology effort entitled “Cold Survivable Distributed Motor Controller”. The purpose of these back-to-back projects is to address the Command & Data Handling (CDH), Power and Motor Control needs for missions to ocean worlds such as the potential Europa Lander project. We addressed the mass reduction challenge by developing the key technologies necessary to design a next generation compact motor control avionics. The project’s goal is to allow a Europa Lander to last longer on the surface and provide more room for additional science by reducing the volume, mass and power of its avionics and the amount of energy required to keep the avionics warm.

Suh, Jong-ook↗

NASA NTRS2019

Europa Lander trajectory design: case studies for the direct-to-earth architecture

This paper presents interesting phasing problems that came up in support of design studies for a potential Europa Lander mission. Recent system trades were performed after the Mission Concept Review in fall 2017, when the NASA board recommended the Europa Lander project design a Direct-to-Earth architecture, i.e. where the Lander would communicate directly to the Earth, without data relay from the carrier vehicle.

Landau, Damon↗

NASA NTRS2019

All-metal dual frequency RHCP high gain antenna for the extreme environments of a potential Europa Lander

A new all-metal dual-frequency RHCP high gain antenna is under development at NASA’s Jet Propulsion Laboratory for a potential Europa Lander. The antenna is mainly made of metal so it could survive the harsh environment conditions of Europa (i.e. very low temperature and high radiation and ESD levels). The antenna is flat to meet drastic volume constraints and has efficiencies higher than 80% at both the uplink and downlink X-band Deep Space frequency bands. This antenna is a key component for the potential mission enabling Direct Link to Earth (DTE) without any relying on an Orbiter to relay the data.

Chahat, Nacer↗

NASA NTRS2019

Numerical study of lander engine plume impingement on the surface off Europa

Plume exhaust from lander engines would be of concern when landing on the surface of Europa since it could have detrimental effects on both the landing surface and powered descent vehicle. The plume could also entrain particles and redirect them up toward the landing vehicle, as well as erode and contaminate the surface where science would be conducted. In this work, a numerical methodology is developed and validated to conduct a first-order assessment of individual engine plumes of a potential Europa Lander vehicle. Computational Fluid Dynamics (CFD) is used to solve the flow field inside and immediately downstream of the nozzle, while the Direct Simulation Monte Carlo (DSMC) method is applied further downstream where the flow becomes rarefied. An interface between the two domains is defined where macroscopic flow data is passed from the CFD domain to the DSMC domain, establishing a one-way coupling. Plume pressure and velocity fields, as well as ground heating, pressure and density flux profiles, are obtained at altitudes from 25 m down to 10 m, spanning the final stages of landing. The codes and methodologies used in this study are successfully validated with simulations conducted by Morris et al. [1-3] of the Apollo Lunar Module Descent Engine (LMDE) exhaust plume impinging onto the lunar surface.

Hoey, William↗

NASA NTRS2020

Europa Clipper Passive Thermal Control Valve Test and Analysis

Europa Clipper spacecraft utilizes passive thermal control valves (TCV) in an active thermal control system to maintain spacecraft component temperatures within their allowable limits. The single-phase mechanically pumped fluid loop recovers heat from the electronics and uses it to maintain propulsion system warm. When excess heat is dissipated the mixing valves direct the fluid to the radiator to reject this additional heat. The loop uses two mixing TCVs placed in series to modulate fluid flow and heat rejection rate from the radiator. This paper describes the thermal and hydraulic test results for Europa Clipper engineering model (EM) mixing valves. For the first time two heritage mixing valves previously developed for the Mars Science Laboratory (MSL) were placed in series to modulate flow to the radiator from 0.1% to 95% of full flow between temperature range of 4 oC to 24 oC. Individually, each mixing valve was able to modulate the flow from 2% to 96% of full flow between the temperatures of 4 oC and 24 oC. Pressure drop was measured between 1.5 to 3 psid depending on the temperature of the mixed fluid and the opening fraction of the valves. A methodology was developed, tested, and validated to adjust the setpoints with an accuracy of 0.1 oC. The measured flow splits were corrected for the effects of impedance due to the flow meters used to measure the flow rates. Finally, flow rate to the radiator increased linearly as a function of mixed temperature for individual valves, while it increased parabolically with temperature when two mixing valves were placed in series.

Mastropietro, AJ↗

NASA NTRS2021

Navigating Low-Energy Trajectories to Land on the Surface of Europa

The current interest in sending a probe to the surface of Europa in search of life demands not only efficient strategies in mission design, but also requires the capability of knowing the navigability of such types of trajectories. An initial search to find low-energy approach trajectories with a variety of topologies that are challenging to navigate is initially performed in the circular restricted three-body problem. These trajectories are subsequently converted to the ephemeris model and used for detailed navigation analysis. We explore several maneuver strategies and assess spacecraft state uncertainties at Europa arrival as well as fuel consumption.

McElrath, Tim↗

NASA NTRS2020

Characterization Testing of Space-Flight Lockheed Martin Micro1-2 Cryocooler for the Mapping Imaging Spectrometer for Europa (MISE)

The Mapping Imaging Spectrometer for Europa (MISE) instrument on the Europa Clipper mission uses a Lockheed Martin “high-power” Micro1-2 pulse tube cryocooler with a heat rejection temperature around 220 K to provide cooling at 80 K. This paper describes the thermal performance and exported forces characterization testing and results of the space-flight Lockheed Martin Micro1-2 cooler optimized for these conditions. Prior to these characterization tests, the cooler passed random vibration and thermal vacuum cycling at Lockheed Martin.

Rodriguez, Jose↗

NASA NTRSDate not supplied

Solid-state Laser Development for the in Situ Spectroscopic Europa Explorer Instrument

The in Situ Spectroscopic Europa Explorer (iSEE) instrument is an ultra-compact laser-enabled Raman spectrometer instrument that meets the top-level science requirements for multiple future planetary in situ missions to explore the surface and atmospheric chemistry of planetary bodies across the Solar System. Enceladus, Europa, the Moon, Mars, and Venus 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. We report on the advancement and space flight qualification of a compact, robust, solid-state laser operating at 515 nm that serves as the excitation source for the iSEE investigation. The iSEE instrument is being developed under a NASA Maturation of Instruments for Solar System Exploration (MatISSE) program. The iSEE laser is a diode pumped 1030 nm Yb:YAG microchip laser with a second harmonic generator to achieve an output wavelength of 515 nm and coupled to a multi-mode fiber for delivery to the Raman spectrometer probe. The fundamental 1030 nm laser operates at a pulse repetition frequency (PRF) of 1-10 kHz with pulse energy of 95 μJ and ~800 ps pulse width. A 15 mm long Type II KTP crystal is used for second harmonic generation from 1030 nm to 515 nm. The residual fundamental 1030 nm is separated from the 515 nm beam using a pair of dichroic filters. A focusing lens couples the 515 nm beam to the optical fiber to produce an output laser pulse energy of 20 μJ. A custom vacuum fiber feedthrough assembly was designed with two 105 μm core fibers, and two 200 μm core fibers. One fiber is needed for coupling the laser to the iSEE instrument, and the additionally fibers provide redundancy and design flexibility. The laser enclosure is pressurized with >1 atm of clean dry air. The laser has been designed to minimize the size, weight, and power (SWaP) for a lander instrument with minimal resources. The laser will go through environmental testing including vibration and thermal vacuum testing for space flight qualification. Here we discuss the design, trade studies, performance, and environmental qualificationtesting of the iSEE laser.

Solid state laser, Raman spectrometer, visible las↗

NASA NTRSDate not supplied

Solid-State Laser Development for the in Situ Spectroscopic Europa Explorer Instrument

Solid state laser, Raman spectrometer, visible las↗

NASA NTRS2021

Sailing Towards an Expressive Scheduling Language for Europa Clipper

The mission planners for NASA's Europa Clipper deep-space mission use automated scheduling software to generate activity plans and command sequences for multiple instruments and subsystems before sending the sequences for execution on board. Both science and engineering planners must translate their intents into expressions of mission constraints, goals, and preferences that the scheduling engine understands. This paper describes the ongoing development of a dedicated domain-specific java-embedded language that can efficiently and accurately capture such concerns for the Europa Clipper mission, along with a user-interface companion for the language.

Schaffer, Steve↗

NASA NTRS2021

Nonlinear Navigation Analysis for a Europa Lander Mission Concept

Navigation strategies typically use linearized techniques to predict maneuver statistics. This method has been successfully employed on numerous high-energy trajectories, but may not be valid for low-energy ones due to the highly non-linear environment. We explore nonlinear navigational techniques applied to a Europa Lander concept by assessing trajectory sensitivity. The linearity assumption is tested at different phases of the endgame trajectory. Maneuver strategies and placement are considered to improve the delivery to Europa. Several cases of non-linear statistical maneuver Monte Carlo simulations are conducted to optimize maneuvers and compare ∆V statistics against conventional linear simulations.

Hernandez, Sonia↗

NASA NTRS2022

Design and Development of High-Performance Imaging Lidars for Extreme Radiation Environments of Europa

To enable safe landing on unknown terrain, such as Europa, JPL has been developing two next-generation dual-mode lidars that can provide long range altimetry as well as dense 3D mapping in real-time during landing. In this paper, we discuss the overall concept, development strategy and report on the detailed progress of the lidar development. Besides, the use for Europa, the flexible design and reconfigurability of lidars allow for a wide range of operation on other planetary bodies.

Machan, Roman↗

NASA NTRS2022

A Model-Based Approach for Europa Lander Mission Concept Exploration

This study investigates the usage of a system model as a means to capture concept formulation for a potentialmission. Efforts are underway at JPL to explore thearchitectural and system concepts for a lander on Europa.Executing a mission on the surface of Europa poses uniquechallenges that will require the lander to operate with onboardautonomy that is more sophisticated than systems previouslyoperated by JPL. Current tasks to explore surface missionconcepts intend to identify concepts that enable a high degree ofonboard autonomy as well as identify the issues and technicallimitations that restrict autonomy. The Europa lander missionconcept team is developing a system model to support thisexploration.The results of this study highlight how executable systemmodeling and the associated engineering environment may beapplied to pre-project conceptual exploration. The applicationof system modeling has resulted in a central system model thatprecisely describes the concepts formulated by the EuropaLander Mission Concept Team. Documentation in the form ofdiagrams and narrative has been directly generated from thesystem model and accessible by team members in a webapplication. The executability of the system model enablesvarious analyses such as simulation of interactions betweencomponents and evaluating system behavior againstrequirements. Execution of the system model has produced statetimelines, plots of system variables, and simulation traces basedon input scenarios. The executable system model enables therapid and repeatable production of these artifacts.

Reeves, Glenn↗

NASA NTRS2002

Europa orbiter mission concept

The challenges of the Europa Orbiter mission are the substantial energy required for a direct trajectory, the long duration of the mission, the high total-radiation dose, and the need for radioisotope thermoelectric generators.

Europa orbiter Europa↗

DOE OSTI2023

Non-Synchronous Rotation on Europa Driven by Ocean Currents

It has been suggested that the ice shell of Jupiter's moon Europa may drift non-synchronously due to tidal torques. Here we argue that torques applied by the underlying ocean are also important and can result in non-synchronous rotation. The resulting spin rate can be slightly slower than the synchronous angular rate that would have kept the same point of the ice shell facing Jupiter. We develop an ice shell rotation model, driven by ocean stress calculated using a high-resolution state-of-the-art ocean general circulation model, and take into account the viscoelastic deformation of the ice shell. We use the ice shell model results together with observed limits on the ice shell drift speed to constrain ice shell parameters such as effective viscosity, which is currently uncertain by at least four orders of magnitude. Our results suggest, at best, sluggish ice shell convection. Depending on the relaxation time scale of the ice shell and on the ocean currents, the ice shell may exhibit negligible drift, constant drift, or oscillatory drift superimposed on random fluctuations. The expected rotation rate exceeds ~30 m/yr; future spacecraft observations can be used to test these predictions and yield insight into the properties of the ice shell and underlying ocean.

15 GEOTHERMAL ENERGY↗

NASA NTRS2002

Continued evolution of Europa subsurface exploration technologies

The Galileo results convincingly indicate that Europa has a deep salty ocean covered by a shell of water ice a few tens of kilometers thick; this physical description gives rise to a host of thoughtful speculation as to the nature of the ocean, its seafloor, and the likelihood of microbial life within it. We argue that this situation points to the high desirability of a series of in-situ missions to examine the ice and, ultimately, the ocean.

subglacial Europa↗