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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.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Updating Mars-GRAM to Increase the Accuracy of Sensitivity Studies at Large Optical Depths

The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). During the Mars Science Laboratory (MSL) site selection process, it was discovered that Mars-GRAM, when used for sensitivity studies for MapYear=0 and large optical depth values such as tau=3, is less than realistic. From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). MGCM results that were used for Mars-GRAM with MapYear set to 0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. This has resulted in an imprecise atmospheric density at all altitudes. As a preliminary fix to this pressure-density problem, density factor values were determined for tau=0.3, 1 and 3 that will adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with Thermal Emission Spectrometer (TES) observations for MapYears 1 and 2 at comparable dust loading. Currently, these density factors are fixed values for all latitudes and Ls. Results will be presented from work being done to derive better multipliers by including variation with latitude and/or Ls by comparison of MapYear 0 output directly against TES limb data. The addition of these more precise density factors to Mars-GRAM 2005 Release 1.4 will improve the results of the sensitivity studies done for large optical depths.

Justh, Hiliary L.↗
NASA NTRS2023

New Retropropulsion Concept with NTAC Power for Mars Entry

Since the initial deployments of probes, orbiters, and rovers on Mars, there have been many ideas and concepts on how to perform an entry, descent, and landing (EDL) process efficiently and safely through the Martian atmosphere to place payloads onto the surface of Mars. Among the missions sent to perform EDL on Mars, only roughly sixty percent of the missions have been successful. The 5 minutes to 20 minutes of communication gap due to long-range telecommunications to Earth, described as seven minutes of terror, add to the complexity of EDL missions to Mars. As the payloads have become larger, the method of EDL has become more complex. To place an automobile-size science rover on the Martian surface requires the use of retrorockets mounted on a Sky Crane during the final subsonic stage of EDL. Larger payloads will require more propellant and more and/or larger retropropulsion engines during the earlier supersonic stage of EDL. The Sky Crane concept may not be scalable for these larger payloads and during supersonic flight; hence, new approaches are sought. A new power technology invented at NASA called Nuclear Thermionic Avalanche Cell (NTAC) may offer an additional solution. Powered by NTAC, the newly invented retropropulsion concept would ingest carbon dioxide gas, heat it up and blast it out as a new feature of the EDL process. NTAC would be reusable as a primary power source for payloads such as excavators, three-dimensional (3D) printers, or mobile equipment for mining, construction, and additive manufacturing tasks. Since NTAC would need to be landed with its host payload or as a standalone power package, assessing its ability to assist in its own EDL seems reasonable. The purpose of this Technical Memorandum (TM) is to examine the performance of NTAC in the context of EDL at Mars for motivating studies for integrating NTAC into future Mars mission architectures.

Mars entry↗
NASA NTRS2011

Multidisciplinary Tool for Systems Analysis of Planetary Entry, Descent, and Landing

Systems analysis of a planetary entry (SAPE), descent, and landing (EDL) is a multidisciplinary activity in nature. SAPE improves the performance of the systems analysis team by automating and streamlining the process, and this improvement can reduce the errors that stem from manual data transfer among discipline experts. SAPE is a multidisciplinary tool for systems analysis of planetary EDL for Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Titan. It performs EDL systems analysis for any planet, operates cross-platform (i.e., Windows, Mac, and Linux operating systems), uses existing software components and open-source software to avoid software licensing issues, performs low-fidelity systems analysis in one hour on a computer that is comparable to an average laptop, and keeps discipline experts in the analysis loop. SAPE uses Python, a platform-independent, open-source language, for integration and for the user interface. Development has relied heavily on the object-oriented programming capabilities that are available in Python. Modules are provided to interface with commercial and government off-the-shelf software components (e.g., thermal protection systems and finite-element analysis). SAPE currently includes the following analysis modules: geometry, trajectory, aerodynamics, aerothermal, thermal protection system, and interface for structural sizing.

Samareh, Jamshid A.↗
NASA NTRS2013

Post-Flight EDL Entry Guidance Performance of the 2011 Mars Science Laboratory Mission

The 2011 Mars Science Laboratory was the first Mars guided entry which safely delivered the rover to a landing within a touchdown ellipse of 19.1 km x 6.9 km. The Entry Terminal Point Controller guidance algorithm is derived from the final phase Apollo Command Module guidance and, like Apollo, modulates the bank angle to control the range flown. The guided entry performed as designed without any significant exceptions. The Curiosity rover was delivered about 2.2 km from the expected touchdown. This miss distance is attributed to little time to correct the downrange drift from the final bank reversal and a suspected tailwind during heading alignment. The successful guided entry for the Mars Science Laboratory lays the foundation for future Mars missions to improve upon.

Mendeck, Gavin F.↗
NASA NTRS2013

Post-Flight EDL Entry Guidance Performance for the 2011 Mars Science Laboratory Mission

Mars Science Laboratory landed Curiosity in Gale Crater on 5 Aug 2012. Curiosity landed successfully only 2.2 km away from the expected target given the onboard navigation state. Better than the average Apollo capsule splashdown miss distance. A late bank reversal and a suspected tail wind contributed to this slight miss. Entry guidance is derived from the Apollo capsule "final phase" logic and adjusts the range flown during entry by varying the direction of the lift vector (i.e., bank angle). Refinement of the guidance gains and alternative parachute deploy triggers to reduce the ellipse size will be studied for future Mars landing missions.

Mendeck, G.↗
NASA NTRSDate not supplied

In Situ Small Spacecraft Missions Utilizing Heatshield for Extreme Entry Environments Technology

There is considerable interest in utilizing Small Spacecraft beyond low Earth orbit. In November of 2018, successful data relay operations of the MarCO CubeSats during the entry, descent, and landing (EDL) of the Mars InSight mission showed the viability of using CubeSats for interplanetary missions. Additional testament to the promise of Small Spacecraft class rideshare missions is the upcoming Artemis-1 flight test that will launch thirteen 6U CubeSats, as well as the establishment of NASA’s SIMPLEx program which will conduct stand-alone planetary science missions that launch with a primary payload. It is anticipated that continued innovations in Small Spacecraft capabilities combined with small EDL systems will expand the range of potential missions to allow for in situ investigations. Recently, NASA invested in the development of a new, efficient and capable ablative thermal protection system (TPS), utilizing 3-D Weaving. The new dual layer TPS, Heatshield for Extreme Entry Environment Technology (HEEET), is tailorable, scalable, robust, mass efficient and capable of supporting in situ missions across the solar system. Combining the HEEET entry system with innovative Small Spacecraft technology will substantially expand the range of Small Spacecraft mission applications by offering the capability for high speed entry or aerocapture at destinations with atmospheres. This paper will describe the HEEET aeroshell system and highlight various mission concepts including a dual technology demonstration mission that is under development and other concepts to deliver instruments for planetary science.

Small Spacecraft↗
NASA NTRSDate not supplied

In Situ Small Spacecraft Missions Utilizing Heatshield for Extreme Entry Environments Technology

There is considerable interest in utilizing Small Spacecraft beyond low Earth orbit. In November of 2018, successful data relay operations of the MarCO CubeSats during the entry, descent, and landing (EDL) of the Mars InSight mission showed the viability of using CubeSats for interplanetary missions. Additional testament to the promise of Small Spacecraft class rideshare missions is the upcoming Artemis-1 flight test that will launch thirteen 6U CubeSats, as well as the establishment of NASA’s SIMPLEx program which will conduct stand-alone planetary science missions that launch with a primary payload. It is anticipated that continued innovations in Small Spacecraft capabilities combined with small EDL systems will expand the range of potential missions to allow for in situ investigations. Recently, NASA invested in the development of a new, efficient and capable ablative thermal protection system (TPS), utilizing 3-D Weaving. The new dual layer TPS, Heatshield for Extreme Entry Environment Technology (HEEET), is tailorable, scalable, robust, mass efficient and capable of supporting in situ missions across the solar system. Combining the HEEET entry system with innovative Small Spacecraft technology will substantially expand the range of Small Spacecraft mission applications by offering the capability for high speed entry or aerocapture at destinations with atmospheres. This paper will describe the HEEET aeroshell system and highlight various mission concepts including a dual technology demonstration mission that is under development and other concepts to deliver instruments for planetary science.

Heatshield↗
NASA NTRSDate not supplied

Mars 2020 – Landing a 1-ton rover and helicopter in an ancient Martian Lake

The Mars 2020 spacecraft launched in July 2020 and landed the Perseverance rover and Ingenuity helicopter successfully in Jezero crater on Feb. 18, 2021. Mars 2020 is the first stage of the Mars Sample Return campaign that will bring back the first samples from another planet to Earth. The entry, descent, and landing (EDL) sequence of the Mars 2020 spacecraft largely leveraged the previous Mars Science Laboratory (MSL) mission from 2012. Mars 2020 retained most of the EDL sequences of MSL, including active maneuvering during hypersonic flight to accurately target the landing site and use of the Skycrane descent stage that slowly lowered the rover while hovering above the ground. But Mars 2020 also added Terrain Relative Navigation, a machine vision-based system that allowed the spacecraft to navigate using an on-board camera that mapped ground landmarks to an on-board map, allowing the spacecraft to safely land in locations that were too hazardous for any previous Martian mission. Come hear about the “Seven Minutes of Terror” and the eight years of effort that went into the engineering behind the spacecraft.

Soumyo Dutta↗
NASA NTRS2017

Mars Molniya Orbit Atmospheric Resource Mining

This NASA Innovative Advanced Concepts (NIAC) Phase I study examined the revolutionary concept of performing resource collection and utilization during Mars orbital operations in order to enable the landing of large payloads. An exploration architecture was developed, out of which several mission alternatives were developed. Concepts of operations were then developed for each mission alternative, followed by concepts for spacecraft systems, which were traded to assess their feasibility. A novel architecture using Mars Molniya Orbit Atmospheric Resource Mining is feasible to enable an Earth-independent and pioneering, permanent human presence on Mars by providing a reusable, single-stage-to-orbit transportation system. This will allow cargo and crew to be routinely delivered to and from Mars without transporting propellants from Earth.In Phase I, our study explored how electrical energy could be harnessed from the kinetic energy of the incoming spacecraft and then be used to produce the oxygen necessary for landing. This concept of operations is revolutionary in that its focus is on using in situ resources in complementary and varied forms: the upper atmosphere of Mars is used for aerocapture, which is followed by aerobraking, the kinetic energy of the spacecraft is transformed into usable electrical energy during aerobraking, and the atmospheric composition is the source of oxidizer for a landing under supersonic retropropulsion. This NASA Innovative Advanced Concepts (NIAC) Phase I study explores a novel mission architecture to establish routine, Earth-independent transfer of large mass payloads between Earth and the Mars surface and back to Mars orbit. The first stage of routine mission operations involves an atmospheric resource mining aerobraking campaign following aerocapture into a highly elliptical Mars orbit. During each pass through the atmosphere, the vehicle ingests the atmospheric oxidizer and stores it onboard, using solid oxide electrolysis to convert the primarily CO2 atmosphere into usable O2 for propellant. Power is made available through the use of magnetohydrodynamic energy generation, which converts the motion of the plasma in the shock later into usable electrical energy. Upon termination of the aerobraking sequence, the descent vehicle detaches from the orbit stack, deorbits, and executes the entry, descent, and landing sequence. Hypersonic deceleration is achieved via a deployable heat shield to lower the vehicle ballistic coefficient, and supersonic and subsonic deceleration are achieved via retropropulsion. Mars surface operations involve resource mining of the Martian regolith to produce CH4 and O2 propellant to be used for the subsequent MDAV ascent back to high Mars orbit (HMO) providing an apoapsis raise maneuver to initialize the aerobraking sequence, in addition to providing fuel from the Mars surface for EDL propulsive descent. The Resource Collector Vehicle (RCV), which is used for the orbital mining operations, is raised back to HMO via onboard deployable augmented solar electric propulsion. Concepts of operations were developed for each mission alternative, to evaluate between them and assess feasibility.

Mining↗
NASA NTRS2003

Control in Unmanned NASA Missions

This viewgraph presentation reviews several general aspects of control for NASA space missions. Included in the review are the Entry, Descent and Landing (EDL) for both Mars Exploration Rover (MER), and Mars Science Laboratory (MSL); and the control of the MER Rover. Also included is discussion about control issues in relation to formation flying, adaptive optics and precision wavefront control, sensors for environmental control- ENose. Essential developments in the areas of control are important for increase in Autonomy/Automation is essential for deep space manned missions. Other areas of concern are robustness and the need to address life support system control issues.

wavefront control↗
NASA NTRS2005

MER EDL: Overview and Reconstruction Status

An overview and reconstruction of the Mars Exploration Rover (MER) Entry Descent and Landing (EDL) is shown. The topics include: 1) Background; 2) MER Candidate Landing Sites; 3) MER Entry Heritage w/Viking & Mars Pathfinder; 4) MER EDL Animation; 5) MER Entry, Descent, and Landing (EDL) Sequence; 6) Pre-Entry Spirit Entry Atmosphere Models; 7) Spirit Landing Ellipse at Final OD, & Updated Estimate Differenced 1-way Doppler; 8) Spirit Landing Ellipse at Final OD and Final Location Estimates; 9) Monte Carlo Results for Spirit ; 10) Reconstructed and refined Spirit Entry Density Profile; 11) Mars Pathfinder Attitude Reconstruction; 12) Spirit Attitude Reconstruction; 13) Spirit Entry Ground Track; 14) Reconstructed Spirit Terminal Descent Dynamics (Side View); 15) Opportunity Landing Ellipse at Final OD, & Updated Estimate Differenced 1-way Doppler; 16) Spirit Landing Ellipse at Final OD and Final Location Estimates; 17) Monte Carlo Results for Opportunity; 18) Reconstructed Opportunity Entry Density Profile; and 19) Opportunity Attitude Reconstruction.

Desai, Prasun N.↗
NASA NTRS2017

Terahertz Instruments for CubeSats

We have been developing terahertz high resolution spectrometers and radiometers on CubeSat platforms for astrophysics, planetary science, and Earth science applications. We are also developing millimeter-wave communications systems on CubeSat platforms to provide communication links during the entry-descent-landing (EDL) phase of Mars and other planetary missions. In this paper, we present an overview of the state of the millimeter-wave and terahertz instrumentation development for CubeSat platforms. We discuss the design and implementation challenges for these instrument developments. We also look into innovative packaging solutions, antenna technology, and low-power backend options for these instruments. We show that CubeSats and SmallSats will play a key role in future scientific space missions and also they will find increasing applications in commercial communication and other endeavors.

SmallSat↗
NASA NTRS2004

Radio science receiver support of the Mars Exploration Rover Landings

The low power levels of the communication signals during the Entry Descent and Landing (EDL) sequences of the Mars rovers prevented the transmission of telemetry at X-band signal to inform the mission operations center of the health and progress of the spacecraft. As an altemative, a series of tones were sent to indicate basic spacecraft conditions and execution of critical events. An open-loop receiver designed for Radio Science experiments was used to acquire the signal during this time. The receiver recorded over a 100 Khz bandwidth to identify the presence of the carrier and tones. The data were fed in real-time to a processing unit which detected the carrier and the frequency separation of the tones from the carrier, in order to determine which event has occurred. Up to 256 different tones were possible. During the actual events, all tones were identified, and the carrier was tracked down to the surface, and for the second rover, through the bouncing which followed, and finally, while stopped on the surface, found the carrier and tones which indicated the spacecraft was alive. In order to identify the tones, the ground receivers had to be able to respond to the bevy of events occurring in the relatively short timespan of EDL.

Deep Space Network (DSN)↗
NASA NTRSDate not supplied

Application of A Dual-Quaternion Six Degree-of-Freedom Guidance to Human-Scale Mars Entry, Descent, and Landing

Landing humans on Mars comes with many challenges, including the execution of a safe and precise entry, descent, and landing (EDL) sequence. Various NASA studies have shown that there are a variety of EDL guidance methods that potentially offer solutions to the human-scale EDL precision landing problem and work is ongoing to assess new and novel methods. As part of these ongoing studies, a dual-quaternion-based six degree-of-freedom guidance algorithm was implemented in the Program to Optimize Simulated Trajectories II (POST2), a NASA-and industry-standard spacecraft trajectory and vehicle design tool. This algorithm considers both translational and rotational dynamics and casts the trajectory optimization problem as a quadratically constrained quadratic program (QCQP) with various constraints at discrete nodes throughout the trajectory. The QCQP problem is solved via an alternating direction method of multipliers (ADMM) approach, and the output is a discretized optimal trajectory. The guidance is applied to a NASA reference human-scale Mars EDL system, and results are compared and discussed.

Optimization↗
NASA NTRSDate not supplied

Application of A Dual-Quaternion Six Degree-of-Freedom Guidance to Human-Scale Mars Entry, Descent, and Landing

Landing humans on Mars comes with many challenges, including the execution of a safe and precise entry, descent, and landing (EDL) sequence. Various NASA studies have shown that there are a variety of EDL guidance methods that potentially offer solutions to the human-scale EDL precision landing problem and work is ongoing to assess new and novel methods. As part of these ongoing studies, a dual-quaternion-based six degree-of-freedom guidance algorithm was implemented in the Program to Optimize Simulated Trajectories II (POST2), a NASA-and industry-standard spacecraft trajectory and vehicle design tool. This algorithm considers both translational and rotational dynamics and casts the trajectory optimization problem as a quadratically constrained quadratic program (QCQP) with various constraints at discrete nodes throughout the trajectory. The QCQP problem is solved via an alternating direction method of multipliers (ADMM) approach, and the output is a discretized optimal trajectory. The guidance is applied to a NASA reference human-scale Mars EDL system, and results are compared and discussed.

Optimization↗
NASA NTRS2002

Critical Spacecraft-to-Earth Communications for Mars Exploration Rover (MER) entry, descent and landing

For planetary lander missions, the most challenging phase of the spacecraft to ground communications is during the entry, descent, and landing (EDL). As each 2003 Mars Exploration Rover (MER) enters the Martian atmosphere, it slows dramatically. The extreme acceleration and jerk cause extreme Doppler dynamics on the X-band signal received on Earth. When the vehicle slows sufficiently, the parachute is deployed, causing almost a step in deceleration. After parachute deployment, the lander is lowered beneath the parachute on a bridle. The swinging motion of the lander imparts high Doppler dynamics on the signal and causes the received signal strength to vary widely, due to changing antenna pointing angles. All this time, the vehicle transmits important health and status information that is especially critical if the landing is not successful. Even using the largest Deep Space Network antennas, the weak signal and high dynamics render it impossible to conduct reliable phase coherent communications. Therefore, a specialized form of frequency-shift-keying will be used. This paper describes the EDL scenario, the signal conditions, the methods used to detect and frequency-track the carrier and to detect the data modulation, and the resulting performance estimates.

entry, descent, and landing communications↗