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 Pre-Decisional — For Planning and Discussion Purposes Only 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. Pre-Decisional — For Planning and Discussion Purposes Only 2 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) Pre-Decisional — For Planning and Discussion Purposes Only 3 Example Mission Architecture—Launch, Cruise to Venus, deployment, and options for potential additional flight elements 4 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 Finding and Recommendations: Science 6 Pre-Decisional — For Planning and Discussion Purposes Only 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 8 to 10 kg per Potential for long-lived (60 days to a year) presence on the surface; station(s) station—5 studying superrotation, meteorology and chemistry (temperature/ stations ~50 pressure/winds/atmospheric composition) measurements in the near kg 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 Free-floating balloon Up to 150 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 Small satellite ~40 kg (Roscosmos) 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 Pre-Decisional — For Planning and Discussion Purposes Only 8 Pre-Decisional — For Planning and Discussion Purposes Only 9 Pre-Decisional — For Planning and Discussion Purposes Only 10 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 Pre-Decisional — For Planning and Discussion Purposes Only Two options of accommodating the Venera-D Lander and the VAMP Pathfinder inside the composite spacecraft: Option 1. Lander along +X axis, 2 1 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 Pre-Decisional — For Planning and Discussion Purposes Only 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 Pre-Decisional — For Planning and Discussion Purposes Only 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 Pre-Decisional — For Planning and Discussion Purposes Only 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