Report of the Venera-D Joint Science Definition Team: "Together to Venus"

Transcription

1 Report of the Venera-D Joint Science Definition Team: "Together to Venus" L. Zasova1, D. Senske2, T. Economou3, N. Eismont1, L. Esposito4, M. Gerasimov1, N. Ignatiev1, M. Ivanov5, I. Khatuntsev1, O. Korablev1, T. Kremic7, K. Lea Jessup6, S. Limaye8, I. Lomakin9, A. Martynov9, A. Ocampo10 1 Space Research Institute RAS, Moscow, Russia, 2 Jet Propulsion Laboratory, Pasadena, USA, 3 Enrico Fermi Institute, Chicago, USA, 4University of Colorado, Boulder, USA, 5 Vernadsky Inst. RAS, Moscow, Russia, 6 Southwest Research Institute, Boulder, USA, 7 Glenn Research Center, Cleveland, USA, 8 Univ. of Wisconsin, St Madison, USA, 9 Lavochkin Assoc., Moscow, Russia. 10 NASA Headquarters, Washington DC, USA, 29 November 2016 VEXAG, NASA HQ 1

2 Goals of the Venera-D SDT 1) Identify, prioritize and develop science goals, investigations, and measurements consistent with the current Venera-D concept; 2) Assess the Venera-D mission architecture including possible modular options (e.g., subsystems) for collaboration opportunities and required instrumentation capabilities. Assess technology readiness level to implement the mission concept and identify areas for which development is required; 3) Identify mission components (mission elements/subsystems/instruments) that best lend themselves to potential collaboration. Outline a general maturation schedule needed to support the Venera-D mission for launches in the post-2025 time frame; 4) Assess the precursor observations and instrumentation validation experiments needed to enable or enhance the Venera-D mission (e.g., instrument testing in a chamber that emulates the chemistry, pressures and temperatures found in the atmosphere or at the surface of Venus); 5) Evaluate how Venera-D would advance the scientific understanding of Venus and feed forward to future missions with the ultimate goal of sample return. 2

3 Venera-D Concept: Mission Elements Baseline: Orbiter : Polar 24 hour orbit with a lifetime greater than 3 years Can trade orbiter period for communication with other elements of mission for more than 24h (JSDT) Lander (VEGA-type, updated) 2+ hours on the surface (one hour to conduct baseline science and one hour of margin) Other components discussed as potential augmentations: Free flying aerial platform and balloons Sub-satellite Small long-lived stations (JSDT also considered it as an insturment on the lander) 3

4 Example Mission Architecture Launch, Cruise to Venus, deployment, and options for potential additional flight elements 4

5 Finding and Recommendations: Science priority Orbiter: Ø Study of the dynamics and nature of super-rotation, radiative balance and nature of the greenhouse effect; Ø Characterize the thermal structure of the atmosphere, winds, thermal tides and solar locked structures; Ø Measure composition of the atmosphere; study the clouds, their structure, composition, microphysics, UV-absorber and chemistry; Ø Investigate the upper atmosphere, ionosphere, electrical activity, magnetosphere, and the escape rate Lander: ü Perform chemical analysis of the surface material and study the elemental composition, including radiogenic elements; ü Study of interaction between the surface and atmosphere; ü Study the structure and chemical composition of the atmosphere down to the surface, including abundances and isotopic ratios of the trace and noble gases ü Perform direct chemical analysis of the cloud aerosols; ü Characterize the geology of local landforms at different scales; ü Search for volcanic and seismic activity; search for lightning Priorities: High, Medium, Low 5

6 Finding and Recommendations: Science 6

7 Potential contributions to Baseline Venera-D First Priority: Accommodation of Baseline Venera-D (orbiter and lander) Element Mass Description Estimate Instrument(s) Variable Raman Spectrometer; Laser Induces Breakdown Spectrometer (LIBS); X-ray Fluorescence Spectrometer (XRFS); Alpha-Proton X-ray Spectrometer (APXS) to baseline lander Venus simulation and test facilities Aerial Platform 450 kg Lifetime of 1 to 3 months; approximately 25 kg of payload to address atmospheric superrotation, chemistry, trace species, noble gases, isotopes in the middle cloud layer; mobility to different altitudes in the atmosphere Small long-lived station(s) 8 to 10 kg per station 5 stations ~50 kg Free-floating balloon Up to 150 Small satellite (Roscosmos) ~40 kg Potential for long-lived (60 days to a year) presence on the surface; studying superrotation, meteorology and chemistry (temperature/ pressure/winds/atmospheric composition) measurements in the near surface layer; limited to data taken when the relay asset is in view restricted to real time measurements. One may be included as an instrument in the payload of the lander Lifetime of up to 1 month; approximately 15 kg of payload for studying the atmosphere; moves by winds, no directed mobility; would need tracking from the Earth Magnetosphere and atmospheric science Small aerial platform ~90 kg Lifetime of 1 to 4 weeks; server as a technology demonstration for pathway to larger vehicle; very limited mass for science payload 7

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11 Venera-D Technology Assessment Summary Top risk items / Development needs for main elements : Sample processing system Ingestion system would be VEGA based but processing and manipulation would be all new and need development and testing Facility to test / qualify full-scale lander Lander instruments would need to be modified for Venus applications and tested accordingly in Venus surface conditions E.g. Enrichment and separation system for trace and noble gases isotopic analysis High impact implementations to fill science gaps/ options being evaluated: Raman or LIBS Raman Spectrometer Mobile aerial platform (winged vehicle concept or standard balloon) Small long-lived (months to year) station Sub-satellite Top risk items science gap filling options : Both aerial platforms need development and testing Small long-lived stations would need development and testing 11

12 Two options of accommodating the Venera-D Lander and the VAMP Pathfinder inside the composite spacecraft: 1 2 Option 1. Lander along +X axis, VAMP along X axis. This combination has a height of ~10 m, and the center of mass is at ~7 m height. With such height of the center of mass an additional assessment of KVTK and Angara- A5 capabilities is required Option 2. Lander along X axis, VAMP along +X axis. This combination has a height of ~10 m as well, and the center of mass is at ~3 m height. This option needs special requirements for the spacecraft design and use of a fairing with a taller cylinder part. It is recommended to reduce the height and the geometry of the VAMP in its folded form while preserving its volume. 12

13 Venera-D Top Needs for Lab Work Orbiter: Spectral line profiles under high pressures and temperatures Emissivity experiments particularly the 1 micron wavelength range Mid-IR optical fiber technology Lander: External vessel - sensor / instrument tests Optical properties of lower Venus atmosphere (Vis- IR) Evaluation of the compositional change of the trace gas components due to temperature and pressure drop during atmospheric sampling; Trace and noble gases enrichment procedure; Atmosphere (pressure / temperature) affects on remote sensing instruments (E.g. Raman) Supercritical properties of Venus like atmospheres Other platforms: UV absorption experiments to identify absorbers and identify insolation energy deposition Optical properties of cloud layers / middle Venus atmosphere Venus cloud / aerosol sampling Propagation for potential infrasound measurements 13

14 Venera-D: Mission Scenario Summary 1) The mission launch is possible in 2026, 2027 and beyond, with intervals approximately 1.5 years, using Angara-A5 rocket and KVTK or Briz upper stage 2) Initial spacecraft mass on a trajectory to Venus is 6500 kg. 3) The scientific payload mass, including subsystems and structural elements is1650 kg, plus 100 kg on the Lander. 4) The Lander-Orbiter, small long-lived stations-orbiter, aerial platform-orbiter, as well as Orbiter-Earth communication options are shown to be feasible. 5) If the aerial platform is implemented and if its folded size would be 3x6 m, it requires further development of the rocket, its upper stage and the fairing. 14

15 JSDT Findings and Recommendations: Potential Contributions, Technology, and Lab work Strategic Needs (within next 5 to 7 years): The types of instruments to achieve the Venera-D science goals require various levels of validation and maturation to ensure robust and successful operation in the Venus environment Laboratory work would be needed to characterize the chemistry of the Venus atmosphere at high temperatures and pressures Capable facilities are needed to test the mission enabling instruments and the spacecraft at the component and system level in a simulated Venus environment Need for continued development regarding all potential contributions 15

16 JSDT Findings and Recommendations: Architectural Options The Venera-D concept will evolve. The JSDT has identified a set of potential architectural options (Ambitious, Adequate, Minimal) that would achieve no less than the core science objectives Flight Elements Ambitious Mission Adequate Mission Baseline Orbiter and Lander; Baseline Orbiter and Minimal Mission Baseline Orbiter and Aerial Platform; Lander; Lander Small long-lived station Aerial Platform Science Enabled Comprehensive Atmosphere and Surface Science Core science objectives Core science objectives with enhanced atmospheric (High and Medium science priority) Challenges Potential Contribution Options --Large number of flight elements and deployments resulting in potentially high technical and scientific risk; --Integration, validation, testing, and operation of multiple flight elements DSN Support; Instrument(s); Flight Element; Test facilities Integration, validation, testing, and operation of multiple flight elements DSN support; Instrument(s); Flight Element; Test facilities Integration, validation, testing, and operation of flight system DSN support; Instrument(s); Test facilities 16

17 Near-term: Framework for Future Work Deliver final report to NASA and IKI by the end of January 2017 Longer-term: Within the development life cycle, the next steps would focus on a detailed assessment of the spacecraft based on the science requirements. Definition of a focused mission concept Definition of concept of operations for the lander including timeline of science observations, strategy for sample acquisition, handling, and analysis, data flow and downlink Refinement of instrument capability relative to the ability to achieve the science goals Refinement of mass, power, volume for a potentially contributed element Maturation of small station; instrumentation and concept for targeting and deployment if provided as a contribution Aerial Platform accommodation and deployment optimization along with science priorities and instrumentation If provided as a contribution 17

18 Together to Venus! 18