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At least 1,009 records · Page 56

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NASA NTRS2006

A conceptual venus rover mission using advanced radioisotope power system

The primary goal of this study is to examine the feasibility of using the novel Advanced RPS-driven Stirling thermoacoustic system to enable extended science operations in the extremely hostile surface environment of Venus. The mission concept entails landing a rover onto the Venus surface, conducting science measurements in different areas on the surface, and returning the science data to Earth. The study focused on developing a rover design to satisfy the science goals with the capability to operate for 60 days. This mission life influences several design parameters, including Earth elevation angle and the maximum communications range to Earth.

TASHE rover↗

NASA NTRS2012

Hot Flow Anomalies at Venus

We present a multi-instrument study of a hot flow anomaly (HFA) observed by the Venus Express spacecraft in the Venusian foreshock, on 22 March 2008, incorporating both Venus Express Magnetometer and Analyzer of Space Plasmas and Energetic Atoms (ASPERA) plasma observations. Centered on an interplanetary magnetic field discontinuity with inward convective motional electric fields on both sides, with a decreased core field strength, ion observations consistent with a flow deflection, and bounded by compressive heated edges, the properties of this event are consistent with those of HFAs observed at other planets within the solar system.

Venusian↗

NASA NTRS2013

Pinhole Effects on Venus Superpressure Balloon Lifetime

Experimental results are presented for a series of experiments that addressed the effect of small pinhole defects on the potential lifetime of a Venus superpressure balloon. The experiments were performed on samples of a candidate balloon envelope material through which a single small hole of 80 to 300 microns in diameter was deliberately made in each one by puncturing with a metal pin. The material was mounted horizontally in a test apparatus and then a 2-3 mm thick layer of sulfuric acid was placed on top to mimic balloon wetting at Venus. Acid penetration and damage manifested itself as a darkening of the aluminum metal and adhesive layers around the hole in the balloon material. There were no test conditions under which the acid simply fell through the pinhole due to gravity because the surface tension forces always compensated at this size. Very little acid-damaged material was observed for the smallest 80 micron pinholes while gas flowed through the hole due to balloon-like pressurization: the black spot size was approximately 0.2 mm in diameter after 6 days with 86% sulfuric acid. The damage area grew more quickly in the absence of gas flowing out of an 80 micron hole, namely at a rate of 2 mm/day. It was concluded that the flow of escaping gas out of the hole provides a substantial reduction of the rate of acid penetration and damage. Larger diameter pinholes of approximately 300 micron diameter showed larger growth rates of 0.7 mm/day with gas flow and 1.7 mm/day without. The pinhole size did not change over the duration of these experiments because the material has an outer layer of fluoropolymer film that remained intact during the process and thereby held the hole size constant. None of the damage rates measured in these experiments pose a threat to the lifetime of the balloon over the projected course of a 30 day mission because the affected area is too small to cause a structural failure either through direct damage or increased solar heating and attendant balloon pressurization leading to burst.

Venus↗

NASA NTRS2011

Navigation Support at JPL for the JAXA Akatsuki (PLANET-C) Venus Orbiter Mission

This paper details the orbit determination activities undertaken at JPL in support of the Japanese Aerospace Exploration Agency's (JAXA) Akatsuki (a.k.a. Plan-et-C and/or Venus Climate Orbiter) mission. The JPL navigation team's role was to provide independent navigation support as a point of comparison with the JAXA generated orbit determination solutions. Topics covered include a mis-sion and spacecraft overview, dynamic forces modeling, cruise and approach or-bit determination results, and the international teaming arrangement. Significant discussion is dedicated to the events surrounding recovery from the unsuccessful Venus orbit insertion maneuver.

Venus Climate Orbiter↗

NASA NTRS2014

Evidence for Crater Ejecta on Venus Tessera Terrain from Earth-Based Radar Images

We combine Earth-based radar maps of Venus from the 1988 and 2012 inferior conjunctions, which had similar viewing geometries. Processing of both datasets with better image focusing and co-registration techniques, and summing over multiple looks, yields maps with 1-2 km spatial resolution and improved signal to noise ratio, especially in the weaker same-sense circular (SC) polarization. The SC maps are unique to Earth-based observations, and offer a different view of surface properties from orbital mapping using same-sense linear (HH or VV) polarization. Highland or tessera terrains on Venus, which may retain a record of crustal differentiation and processes occurring prior to the loss of water, are of great interest for future spacecraft landings. The Earth-based radar images reveal multiple examples of tessera mantling by impact ''parabolas'' or ''haloes'', and can extend mapping of locally thick material from Magellan data by revealing thinner deposits over much larger areas. Of particular interest is an ejecta deposit from Stuart crater that we infer to mantle much of eastern Alpha Regio. Some radar-dark tessera occurrences may indicate sediments that are trapped for longer periods than in the plains. We suggest that such radar information is important for interpretation of orbital infrared data and selection of future tessera landing sites.

surface↗

NASA NTRS2016

New Approaches to Inferences for Steep-Sided Domes on Venus

New mathematical approaches for the relaxation and emplacement of viscous lava domes are presented and applied to steep-sided domes on Venus. A similarity solution approach is applied to the governing equation for fluid flow in a cylindrical geometry for two distinct scenarios. In the first scenario, dome relaxation is explored assuming a constant volume of fluid (i.e. lava) has been rapidly emplaced onto the surface. Cooling of lava is represented by a time-variable viscosity and singularities inherent in previous models for dome relaxation have been eliminated. At the onset of relaxation, bulk dynamic viscosities lie in the range between 10(exp 10) - 10(exp 16) Pa s, consistent with basaltic-andesite to rhyolitic compositions. Plausible relaxation times range from 5 to 5000 years, depending on initial lava viscosity. The first scenario, however, is only valid during the final stages of dome relaxation and does not consider the time taken for lava to be extruded onto the surface. In the second scenario, emplacement and growth of a steep-sided dome is considered when the volume of lava on the surface increases over time (i.e. time-variable volume approach). The volumetric flow rate may depend on an arbitrary power of the dome thickness, thus embracing Newtonian as well as other rheologies for describing terrestrial and planetary mass flows. The approach can be used to distinguish between basic flow rate models for fluid emplacement. The formalism results in radial expansion of a dome proportional to t(sup 1/2), consistent with the diffusive nature of the governing equation. The flow at the front is shown to thicken as the front advances for a constant rate of lava supply. Emplacement times are intimately correlated with the bulk rheology. Comparison of the theoretical profiles with the shape of a typical dome on Venus indicates that a Newtonian bulk rheology is most appropriate, consistent with prior studies. However, results here suggest a bulk dynamic viscosity of 10(exp 12) - 10(exp 13) Pa s and emplacement times of approximately 2-16 years. Both scenarios investigated give emplacement times significantly less than prior estimates and compositions consistent with basaltic andesite.

steep-sided domes↗

NASA NTRS2017

Candidate Earth Entry Trajectories to Mimic Venus Aerocapture Using a Lifting ADEPT

A Lifting ADEPT is considered for aerocapture at Venus. Analysis concerning the heating environment leads to an initial sizing estimate. In tandem, a direct entry profile at Earth is considered to act as a facsimile for the Venus aerocapture heating environment. The bounds of this direct entry profile are determined and it is found that a trajectory from a Geostationary Transfer Orbit with a Lifting ADEPT capable of fitting on a rideshare opportunity is capable of matching certain aspects of this heating environment.

Venus↗

NASA NTRS2019

LEAVES: Lofted Environmental and Atmospheric Venus Sensors

LEAVES (Lofted Environmental Atmospheric Venus Sensors) is a design exercise with the goal of dramatically decreasing the cost of obtaining prioritized chemical and physical data in planetary atmospheres. Through the application of a swarm approach this concept parallelizes atmospheric exploration, with geographic coverage far exceeding what is possible with conventional monolithic platforms or sondes. Each unit in the swarm is exceptionally compact, with a powered payload mass of only a few tens of grams and a high-drag, semi-rigid structure that acts to slow each probe as it descends through the atmosphere. This structural design can collapse into a planar form to allow for efficient stowage prior to arrival at the target body. With a total per-unit mass of only 120 g, a fleet of 100 (or more) units can be very reasonably accommodated on a carrier spacecraft.Science operations, which begin when the LEAVES probes reach an altitude of 100 km, are targeted for the cloud-bearing region of Venus' atmosphere. During the roughly 9 hour, terminal velocity descent through the atmosphere, LEAVES collects data of the state and composition of the atmosphere in parallel across multiple units. These data would represent an unprecedented constraint on the distribution and concentration of targeted chemical species, and the detection of local and regional variations in both chemistry and physical properties.A novel and compelling result of this exercise was that the same optimization that produced a structure with an exceptionally low areal mass density (0.126 kg/m2) also resulted in a probe that can be deployed directly from an aerobraking orbit (~140 km at 5 km/s) without the need for aeroshell protection. This translates to a tremendous mass savings and gives LEAVES the flexibility to be carried as a secondary payload aboard either a descending surface probe or an orbital radar mapper. Because such missions are under active development or have already been proposed (but not flown), we infer that LEAVES is well positioned as a technology

Swarm↗

NASA NTRS2019

Status of Developments - Toward Long-Lived Venus Landers

Missions to the surface of Venus have had limitedlife due to the extreme environmental conditions. Theshort life has limited the science that is achievable,and there are gaps in some science, such asseismology, which is enabled by long life. This worksummarizes technical advances that are preparing usfor long-duration (weeks to months) Venus surfacemissions.

Venus↗

NASA NTRSDate not supplied

Venus Cloud Layer Investigation: Aeroshells for Entry, Descent and Deployment

Entry, Descent and Deployment (EDD) of aerial platforms at Venus follows similar operational approach as landers. •Limited only by the availability of mass efficient and robust aeroshell (heatshield/TPS) technology. •Heatshield for Extreme Entry Environment Technology (HEEET) at TRL 6 is an enabler of Venus in-situ missions.Lower ballistic coefficient, deployable concept, ADEPT, offers additional options•Low deceleration entry profile•Release of one or more payloads (balloons) from open back of the entry vehicle2

Venus↗

NASA NTRS1999

An Improved 360 Degree and Order Model of Venus Topography

We present an improved 360 degree and order spherical harmonic solution for Venus' topography. The new model uses the most recent set of Venus altimetry data with spacecraft positions derived from a recent high resolution gravity model.

Venus↗

NASA NTRS1995

Relay Satellite Orbit Selection Considerations for Future Robotics Missions to Explore Venus

Discusses orbit design trades relevant to use of a Venus orbiting relay satellite supporting a variety of potential Venus robotic mission types. The emphasis is on the impact of mission tele- communications requirements on selection of a relay satellite orbit and its characteristics that can benefit or hinder mission performance for the potential robotic missions now under consideration.

Venus↗

NASA NTRS1998

New Insights into Coronae Evolution: Mapping on Venus

Coronae are geologically and geophysically important features on Venus, since they are thought to contribute to planetary heat loss. It is thus necessary to understand their role in space and time in the evolution of Venus. We show that the formation of corona annuli can be multistaged and that the position of the annulus does not always coincide with the main topographic ridges and troughs that outline the feature. We demonstrate that coronae do not all have the same relative ages with respect to adjacent units.

coronae↗

NASA NTRSDate not supplied

Cloud Habitability From Earth To Venus: Science & Technology Considerations

Early Venus and early Earth are believed to have shared many aspects associated with the emergence of an Earth-like biochemistry: surface geochemistry, rock/water interfacing, and geothermal activity. There is significant interest in whether such life – based on water and carbon – could have persisted to the present day in Venus’s sulfuric acid cloud and haze layers, where some liquid water remains. Investigations of this possibility have been connected to understanding observations such as disequilibria in atmospheric sulfur chemistry, strong atmospheric UV absorption, and the controversial recent claim of phosphine detection.

Cloud↗

NASA NTRS2022

Constraining Venus and Mars Internal Structures from the Gravity Response to Atmospheric Loading

The gravity fields of celestial bodies that possess an atmosphere are periodically perturbed by the redistribution of fluid mass associated with the atmospheric dynamics. A component of this perturbation is due to the gravitational response of the body to the deformation of its surface induced by the atmospheric pressure loading. The magnitude of this effect depends on the relation between the loading and the response in terms of geopotential variations measured by the load Love numbers. In this work, we simulate and analyze the gravity field generated by the atmospheres of Venus and Mars by accounting for different models of their internal structure. By precisely characterizing the phenomena that drive the mass transportation in the atmosphere through general circulation models, we determine the effect of the interior structure on the response to the atmospheric loading. An accurate estimation of the time-varying gravity field, which measures the atmospheric contribution, may provide significant constraints on the interior structure through the measurement of the load Love numbers. A combined determination of tidal and load Love numbers would enhance our knowledge of the interior of planetary bodies, providing further geophysical constraints in the inversion of internal structure models.The gravity fields of celestial bodies that possess an atmosphere are periodically perturbed by the redistribution of fluid mass associated with the atmospheric dynamics. A component of this perturbation is due to the gravitational response of the body to the deformation of its surface induced by the atmospheric pressure loading. The magnitude of this effect depends on the relation between the loading and the response in terms of geopotential variations measured by the load Love numbers. In this work, we simulate and analyze the gravity field generated by the atmospheres of Venus and Mars by accounting for different models of their internal structure. By precisely characterizing the phenomena that drive the mass transportation in the atmosphere through general circulation models, we determine the effect of the interior structure on the response to the atmospheric loading. An accurate estimation of the time-varying gravity field, which measures the atmospheric contribution, may provide significant constraints on the interior structure through the measurement of the load Love numbers. A combined determination of tidal and load Love numbers would enhance our knowledge of the interior of planetary bodies, providing further geophysical constraints in the inversion of internal structure models.

Mars↗

NASA NTRSDate not supplied

An Overview of High Temperature Technologies for Venus Surface Applications

A brief overview is given on a range of high temperature technologies related to possible extended duration Venus surface exploration. This overview includes the Venus technology plan and Surface Platform study, and development in projects such as the Long Lived Solar System Explorer, and High Operating Temperature Technology 2016 and 2021.

Venus surface exploration high temperature technol↗

NASA NTRSDate not supplied

Performance Analysis of SmallSat Aerocapture at Venus

Aerocapture is a method of spacecraft orbital insertion that has the potential to provide mass savings as compared to aerobraking. In particular, aerocapture at Venus is desirable due to high atmospheric density and potential for science return. While promising, accurate orbital insertion by means of aerocapture requires an active guidance, navigation, and control architecture. This paper documents the initial assessment of the performance of two guidance algorithms, a generalized numerical predictor corrector and the Fully-Numeric Predictor- corrector for Aerocapture Guidance, applied to smallsat aerocapture at Venus using two different simulation environments with equivalent simulation inputs. Nominal trajectory performance is assessed. In addition, Monte Carlo analysis is performed to compare each guidance algorithm’s performance under uncertainty.

aerocapture↗

NASA NTRSDate not supplied

Performance Analysis of SmallSat Aerocapture at Venus

Aerocapture is a method of spacecraft orbital insertion that has the potential to provide mass savings as compared to aerobraking. In particular, aerocapture at Venus is desirable due to high atmospheric density and potential for science return. While promising, accurate orbital insertion by means of aerocapture requires an active guidance, navigation, and control architecture. This paper documents the initial assessment of the performance of two guidance algorithms, a generalized numerical predictor corrector and the Fully-Numeric Predictor-corrector for Aerocapture Guidance, applied to smallsat aerocapture at Venus using two different simulation environments with equivalent simulation inputs. Nominal trajectory performance is assessed. In addition, Monte Carlo analysis is performed to compare each guidance algorithm’s performance under uncertainty.

aerocapture↗