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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 127 records · Page 7
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NASA NTRSDate not supplied

Assessing Huygens Probe Entry, Descent, and Landing at Titan Simulation using Dragonfly Atmosphere Model

Dragonfly is a New Frontiers Program mission that will deliver a rotorcraft to Saturn's moon, Titan. This mission follows Huygens as the previous mission that successfully landed a vehicle on Titan. A flight mechanics simulation of Dragonfly's Entry, Descent, and Landing sequence has been developed using the Program to Optimize Simulated Trajectories II. The simulation incorporates several subsystem models, including aerodynamics, gravity, and mass properties, to fully capture the multi-body six degree of freedom dynamics. Among all the subsystem models that inform the Entry, Descent, and Landing dynamics, the atmosphere model of Titan is a critical component. The atmosphere model characterizes the density, temperature, pressure, and winds that the entry vehicle experiences during the descent. This impacts several aspects of the descent such as the peak heating, aerodynamics, parachute release conditions, the dynamics of the vehicle and parachutes, and the landing ellipse. In the course of developing Dragonfly, an updated model of the Titan atmosphere has been created corresponding to Dragonfly's arrival in the mid-2030s, approximately one Titan year after the Huygens mission successfully landed a probe on Titan. This work leverages previous work done to investigate Huygens EDL sequence to assess the atmosphere model developed for Dragonfly. This is done by utilizing the updated Titan atmosphere model, the Dragonfly atmosphere model, within the Huygens POST2-based flight simulation with the goal of characterizing the differences between the atmospheric models and assessing how the Dragonfly atmosphere model impacts Huygens entry dynamics.

Huygens↗
NASA NTRSDate not supplied

Assessing Huygens Probe Entry, Descent, and Landing at Titan Simulation using Dragonfly Atmosphere Model

Dragonfly is a New Frontiers Program mission that will deliver a rotorcraft to Saturn's moon, Titan. This mission follows Huygens as the previous mission that successfully landed a vehicle on Titan. A flight mechanics simulation of Dragonfly's Entry, Descent, and Landing sequence has been developed using the Program to Optimize Simulated Trajectories II. The simulation incorporates several subsystem models, including aerodynamics, gravity, and mass properties, to fully capture the multi-body six degree of freedom dynamics. Among all the subsystem models that inform the Entry, Descent, and Landing dynamics, the atmosphere model of Titan is a critical component. The atmosphere model characterizes the density, temperature, pressure, and winds that the entry vehicle experiences during the descent. This impacts several aspects of the descent such as the peak heating, aerodynamics, parachute release conditions, the dynamics of the vehicle and parachutes, and the landing ellipse. In the course of developing Dragonfly, an updated model of the Titan atmosphere has been created corresponding to Dragonfly's arrival in the mid-2030s, approximately one Titan year after the Huygens mission successfully landed a probe on Titan. This work leverages previous work done to investigate Huygens EDL sequence to assess the atmosphere model developed for Dragonfly. This is done by utilizing the updated Titan atmosphere model, the Dragonfly atmosphere model, within the Huygens POST2-based flight simulation with the goal of characterizing the differences between the atmospheric models and assessing how the Dragonfly atmosphere model impacts Huygens entry dynamics.

Entry Descent Landing↗
NASA NTRS1972

Outer planet entry probe system study. Volume 1: Summary

General mission considerations and science prospectus, which are of a general nature that applies to several or all planetary applications, are presented. Five probe systems are defined: nominal Jupiter probe system, and Jupiter probe-dedicated alternative probe system, Jupiter spacecraft radiation-compatible alternative probe system, Saturn probe system, and Saturn probe applicability for Uranus. Parametric analysis is summarized for mission analysis of a general nature, and then for specific missions to Jupiter, Saturn, Uranus, and Neptune. The program is also discussed from the hardware availability viewpoint and the aspect of commonality.

Source record↗
NASA NTRS1972

Outer planet entry probe system study. Volume 2: Supporting technical studies

The environment, science investigations, and general mission analysis considerations are given first. These data are followed by discussions of the studies pertaining to the planets Jupiter, Saturn, Uranus, and Neptune. Except for Neptune, each planet discussion is divided into two parts: (1) parametric activities and (2) probe definition for that planet, or the application of a given probe for that planet. The Neptune discussion is limited to parametrics in the area of science and mission analysis. Each of the probe system definitions consists of system and subsystem details including telecommunications, data handling, power pyrotechnics, attitude control, structures, propulsion, thermal control, and probe to spacecraft integration. The first configuration is discussed in detail and the subsequent configuration discussions are limited to the differences. Finally, the hardware availability to support a probe system and commonality of science, missions, and subsystems for use at the various planets are considered.

Source record↗
NASA NTRS1972

Taylor instability in the shock layer on a Jovian atmosphere entry probe.

Investigation of the Taylor instability relative to the dynamical instability whose presence in the shock layer on a spacecraft entering the Jovian atmosphere is to be expected because of the difference in velocity across the shear layer. Presented calculations show that the Taylor instability at the interface between shock-heated freestream gas and ablation products is inconsequential in comparison to the shear layer instability.

Compton, D. L.↗
NASA NTRS1973

Thermal control subsystem design of a Saturn/Uranus atmospheric entry probe for descent missions to 20 bars.

A study of scientific probes to explore the atmospheres of Saturn and Uranus to depths of between 2 and 30 bars is summarized. The study assessed configuration tradeoffs of recommended exploratory payloads, determined the types and quantities of the thermal control devices required, and evaluated thermal structural details and viable mission alternatives. These results indicated that a vented probe design with an environmental pressurization system for the first 2.5 bars of descent would satisfy the requirements for missions to either Saturn or Uranus to depths of approximately 20 bars. Parametric atmospheric descent thermal analyses are discussed and the effect of worst-case atmospheric models and navigational arrival uncertainties on mission performance are presented.

Webb, C. M.↗
NASA NTRS1973

PAET, an entry probe experiment in the earth's atmosphere.

Description of the instrumentation of a probe designed for atmospheric studies on other planets and designated PAET. The probe was launched on June 20, 1971, near Bermuda in a trial experiment for measurements of the structure and composition of the terrestrial atmosphere. The instrumentation included accelerometers, pressure and temperature sensors, a mass spectrometer, and a radiometer. The measurements, carried out during the descent of the probe from an altitude of 90 km into the sea, were a success.

Seiff, A.↗
NASA NTRS1973

Duplication in a shock tube of stagnation region conditions on a Jovian atmosphere-entry probe

Measurements are presented of the radiative emission from a shock-heated mixture of .85 H2 plus .15 He - the presumed composition of the dominant species in the Jovian atmosphere. The experiments were performed behind the incident wave in a Voitenko-compressor-driven shock tube at shock velocities of 61 and 67 km/sec. Agreement with predictions is good for both radiative emission and radiative cooling.

Compton, D. L.↗
NASA NTRS1974

Investigation of outer planet atmospheres using the pioneer entry probe radio system

The requirements for a telecommunication link which will relay information from a space probe to a carrier spacecraft during space exploration missions are examined. Specific experiments are described and the relative value of the proposed techniques are evaluated. Radio science methods as related to telecommunications systems are discussed. Operational implications of the various approaches to scientific measurement by telemetry of tracking radios are analyzed. Emphasis is placed on a conceptual description of the physics rather than the mathematical development.

Croft, T. A.↗
NASA NTRS1975

Digital simulation of a communication link for Pioneer Saturn Uranus atmospheric entry probe, part 1

A digital simulation study is presented for a candidate modulator/demodulator design in an atmospheric scintillation environment with Doppler, Doppler rate, and signal attenuation typical of the conditions of an outer planet atmospheric probe. The simulation results indicate that the mean channel error rate with and without scintillation are similar to theoretical characterizations of the link. The simulation gives information for calculating other channel statistics and generates a quantized symbol stream on magnetic tape from which error correction decoding is analyzed. Results from the magnetic tape data analyses are also included. The receiver and bit synchronizer are modeled in the simulation at the level of hardware component parameters rather than at the loop equation level and individual hardware parameters are identified. The atmospheric scintillation amplitude and phase are modeled independently. Normal and log normal amplitude processes are studied. In each case the scintillations are low pass filtered. The receiver performance is given for a range of signal to noise ratios with and without the effects of scintillation. The performance is reviewed for critical reciever parameter variations.

Hinrichs, C. A.↗
NASA NTRS1976

Heat shield characterization: Outer planet atmospheric entry probe

A full scale carbon phenolic heat shield was fabricated for the Outer Planet Probe in order to demonstrate the feasibility of molding large carbon phenolic parts with a new fabrication processing method (multistep). The sphere-cone heat shield was molded as an integral unit with the nose cap plies configured into a double inverse chevron shape to achieve the desired ply orientation. The fabrication activity was successful and the feasibility of the multistep processing technology was established. Delaminations or unbonded plies were visible on the heat shield and resulted from excessive loss of resin and lack of sufficient pressure applied on the part during the curing cycle. A comprehensive heat shield characterization test program was conducted, including: nondestructive tests with the full scale heat shield and thermal and mechanical property tests with small test specimen.

Mezines, S. A.↗
NASA NTRS1976

Preentry communication design elements for outer planets atmospheric entry probe

Four related tasks are discussed for data transmission from a probe prior to entering the atmosphere of Jupiter to an orbiting spacecraft in a trajectory past the planet: (1) link analysis and design; (2) system conceptual design; (3) Doppler measurement analysis; and (4) an electronically despun antenna. For tasks 1, 3, and 4, an analytical approach was developed and combined with computational capability available to produce quantitative results corresponding to requirements and constraints given by NASA, ARC. One constraint having a major impact on the numerical results of the link analysis was the assumption of a nonsteerable antenna on a spinning orbiter. Other constraints included the interplanetary trajectory and the approach trajectory. Because the Jupiter Orbiter Probe (JOP) program is currently in a state of evolution, all requirements and constraints applied during this study are subject to change. However, the relationships of parameters as developed will remain valid and will aid in planning Jupiter missions.

Source record↗
NASA NTRS1977

Spacecraft receiving antenna study: Outer planets atmospheric entry probe

A quadrifilar helix antenna was selected for the Pioneer spacecraft receiving antenna. A model was constructed for radiation pattern measurement at 2.2 GHz. Radiation patterns were measured with the model quadrifilar helix antenna mounted on a Pioneer spacecraft model and four different configurations were tested. The results show that the antenna location does not have a major effect on its patterns over the aft hemisphere but moving the antenna away from the spacecraft improves the antenna performance.

Kuhlman, E. A.↗