VEXAG Presentation to PSS October 7, 2007 Orlando, Florida

Transcription

1 VEXAG Presentation to PSS October 7, 2007 Orlando, Florida by Janet Luhmann (for the VEXAG Steering Committee: CoChair Sushil Atreya, Focus Group Leads Steve Mackwell and Kevin Baines, Technology Leads Jim Cutts and Tibor Balint, NASA Program representative Tommy Thompson, Ellen Stofan, Larry Esposito)

2 VEXAG (Venus Exploration Analysis Group) VEXAG Meetings to Date: -Kickoff Meeting November 4, 2005, Pasadena -Related Venus Chapman Conference, Feb. 06 -First working meeting May 1-2, 2006, Pasadena -Second Meeting held in Crystal City, VA on Jan 11-12, Next meeting scheduled for November 4-5, 2007 in Greenbelt, MD in conjunction with the NASA Workshop on Planetary Atmospheres, And Outer Planet Analysis Group (OPAG) meetings 2

3 Current VEXAG Activities and Issues Completing our Report ( White Paper ) outlining Key Science Questions and Goals for Venus Explorationnow available Promoting developments in extreme environment technologies Organizing Venus Flagship Mission STDT kickoff Engaging the Earth Science Community in Comparative Planetology (e.g. at the upcoming VEXAG #4 meeting) Supporting Venus Express, Venus Climate Orbiter, and now EVE activities Providing support to the NRC NOSSE committee 3

4 Report Highlights: Outstanding Questions in Venus Exploration Was there ever an ocean on Venus, and if so, when did it exist and how did it disappear? Was the early Venus atmosphere like the early atmosphere of Earth, and at what point did it diverge in character so greatly and why? Why does Venus rotate so slowly and is the lack of a planetary dynamo a consequence? What was the impact on the evolution of Venus? Why does Venus atmosphere rotate 60-times faster than its solid body? How are atmospheric heat and momentum transferred from equator to poles? What caused the extensive resurfacing of Venus during the last billion years? Is Venus still an active planet? Are the resurfacing and climate change related? Was Venus ever habitable? 4

5 VEXAG Report: Venus Exploration Goals and Objectives VEXAG s Analysis translated these Questions into Three Major Goals for Venus Exploration: 1) Origin and Early Evolution of Venus: How did Venus originate and evolve, and what are the implications for the characteristic lifetimes and conditions of habitable environments on Venus and similar extrasolar systems? 2) Venus as a Terrestrial Planet: What are the processes that have shaped and still shape the planet? 3) Implications for Earth: What does Venus tell us about the fate of Earth s environment? VEXAG Web-Site -

6 The Challenge: Extreme Environments for Venus In-Situ Missions Greenhouse effect results in VERY HIGH SURFACE TEMPERATURES Average surface temperature: ~ 460 to 480 C Average pressure on the surface: ~ 92 bars Cloud layer composed of aqueous sulfuric acid droplets at ~45 to ~70 km attitude From surface to ~10 km Ref: N.Yajima, N.Izutsu, H.Honda, K.Goto and T.Imamura (ISAS) N.Tomita and K.Akazawa (Musashi Institute of Technology Univ.) Feasibility and Applicability of Planetary Balloons, Website: Sci_Bal/engplanetary.html Target region for VME Venus atmosphere is mainly CO 2 (96.5%) and N 2 (3.5%) with: small amounts of noble gases (He, Ne, Ar, Kr, Xe) small amount of reactive trace gases (SO 2, H 2 O, CO, OCS, H 2 S, HCl, SO, HF ) Zonal winds: at near surface <1 m/s; while at 60 km altitude ~ 95+ m/s Ref: E. Kolawa, Extreme Environments Technologies 6

7 NASA s 2006 Solar System Exploration Roadmap In the Solar System Roadmap team considered both the Venus In Situ Explorer (VISE) and Venus Surface Sample Return missions recommended by the NRC s Decadal Survey. The Roadmap Team also proposed a Venus Mobile Explorer (VME) mission as the next logical step after VISE, before a sample return mission. VEXAG has now played a key role in initiating an STDT to study a Flagship mission capable of long duration on the surface and extensive mobility. Ref: NASA SMD PSD SSE Roadmap Team, Solar System Exploration Solar System Exploration Roadmap for NASA's Science Mission 7 Directorate, NASA Science Missions Directorate, Planetary Science Division, Report Number: JPL-D-35618, September 15, 2006.

8 VEXAG Findings Technology Investments Findings: There are credible-technical approaches, leveraging from technologies developed in industry to achieving extended operation in the Venus environment. High-temperature electronics can enable systems to operate for extended periods in the corrosive, high-pressure on Venus surface. Advanced radioisotope-power systems and active thermal-control systems could enable conventional components such as microprocessors or imaging sensors to operate for extended periods on Venus surface. While further work on mission architectures will be needed to define specific performance goals and the technology focus, technology work can and should begin now. Without NASA s direct involvement, it will not be possible to apply the results from industry to the specific needs of in-situ and near-surface exploration. Note 1 - Venus Exploration Goals, Objectives, Investigations, and Priorities: October

9 VEXAG Proposed Actions Technology Investments Proposed Action: NASA should initiate a program to develop technologies for operation in Venus extreme environment. These should include: Passive thermal-control technologies for extending operation on or near the surface from hours to days. Active thermal-control technologies and power-generation systems for extending Venus operations to many months. High-temperature electronics and other components capable of extended operation directly exposed to the Venus surface environment. Mobility systems for operation at the surface and in the lower atmosphere of Venus. A program of systems analyses to establish performance objectives and evaluate alternative approaches for mission architectures Note 1 - Venus Exploration Goals, Objectives, Investigations, and Priorities: October

10 VEXAG Findings and Proposed Actions New Frontiers Missions 1 Finding: VEXAG considers that the Venus In-Situ Explorer continues to be a vital mission to explore Venus and should be included in the FY08 New Frontiers AO. The scientific goals stipulated in the FY03 NF AO remain valid. In addition to its scientific value, the VISE mission offers a unique opportunity to validate capabilities that would be important to a future Flagship mission. Proposed Action: The Venus In-Situ Explorer should be included in the New Frontiers AO for 2008 and the general scientific goals for this mission should remain unchanged. NASA should consider implementing a technology-validation element for VISE in particular that would permit demonstration of technologies needed for a long-duration mobile mission but not necessary to the success of VISE itself. Note 1 - Venus Exploration Goals, Objectives, Investigations, and Priorities: October

11 VEXAG Findings and Proposed Actions Venus Flagship Mission Finding: The completion by VEXAG of scientific goals and priorities now makes it timely to initiate a study of a Venus Flagship mission to define a concept in more detail and identify the technologies needed to implement the mission. This study should not be delayed because a path to addressing specific-technology challenges that the resulting mission-concept raises must be embarked upon at the earliest opportunity. Proposed Action: NASA should initiate a study of a Flagship mission to Venus at the earliest opportunity. The study should assess: Key scientific questions that can be addressed by a long-duration mobile mission to the surface or near-surface of Venus. Alternative-mission architectures for addressing these scientific questions. Precursor-scientific measurements and technology validation that might be implemented with prior Discovery and New Frontiers missions. Technology investments needed to enable the Venus Flagship mission emphasizing - long-lead time technologies needing early investment. Note 1 - Venus Exploration Goals, Objectives, Investigations, and Priorities: October

12 Recent Developments Venus Flagship Architectures Mission Study The Planetary Science Division has initiated a Venus Flagship Architectures Mission study in FY08. The objectives of the study include: Provide options for an inner planet Flagship mission to be implemented in the time frame Define the enabling technologies for the mission and a technology plan to address those needs. Identify technology validation experiments that could be conducted on prior New Frontiers or Discovery missions Define a scientific and technological pathway to a Venus Surface Sample Return mission The study will be conducted under the guidance of a Science and Technology Definition Team (STDT). NASA plans to issue an invitation in the STDT in late October. VEXAG members supported the planning of the Venus Flagship Architectures Mission study and participated in two workshops held at JPL during the summer for the purpose of defining the scope and the methodology to be used in the study. The study draws on past studies including two implemented in FY07 the $1B box Titan Enceladus study and the Outer Planet Flagship studies. However, the emphasis on technology is a unique feature of this study 12

13 Other Recent Developments The STDT chairs and deputies (for science and technology) are currently awaiting confirmation of their appointments, and the solicitation for membership will appear soon. VEXAG will have a new chair shortly (in process of NAC confirmation) The EVE mission has made the short list in ESA s Cosmic Vision Program competition (next slide) 13

14 Launch Vehicle (by Roscosmos) An in-situ mission to Venus - European Venus Explorer Entry shells (by Roscosmos) (by ESA) 2 years (by Roscosmos) 1.5 hours Ref: E. Chassefiere et al., EVE, Cosmic Vision Proposal, ESA Optional Mid-cloud Balloon (by JAXA) 7 days Programmatics: ESA Cosmic Vision Class M (300M Euros) Significant collaboration with Russia Potential collaboration with JAXA & NASA Earliest Launch: 2016 (by ESA with potential contributions from CNES; Roscosmos; NASA/JPL on balloon technology) 7 days Science Objectives: Unified model of the formation and evolution of terrestrial planets Stability of the current climate Chemical / radiative processes in and below the clouds Geological history of Venus Atmospheric dynamics Electrical processes

15 Take Home Messages There is a lot of exciting and important science to do above and on Venus, our closest neighbor in the solar system. Venus proximity to earth makes it a highly accessible target Important science can be accomplished with existing technologies to address Venus science objectives including missions under the New Frontiers program However, investments in new technologies are required for next major steps forward in exploration following the scientific exploration pathway established for Mars Technology demonstrations in early missions will retire risk for later missions and should be considered as desirable and acceptable parts of a New Frontiers mission to Venus 15

16 Venera Surface Perspectives (Venera data post-processed by Don P. Mitchell) Robots have been there. We can do it again with more/better capabilities. 16

17 Upcoming Meeting(s): VEXAG NASA Planetary Atmospheres Workshop OPAG November 4-9, 2007 Greenbelt Marriott Hotel Greenbelt. Maryland Sunday - Nov. 4 (half-day) and Monday - Nov. 5 - VEXAG Meeting #4, Tuesday and Wednesday - Nov NASA Workshop on Planetary Atmospheres, Thursday and Friday Nov Outer Planet Analysis Group (OPAG)

18 VEXAG Meeting #4 - Sunday November 4, Afternoon 12:30 PM - Sign-In / Pick-up Handouts / Coffee and Pastries 1:00 PM - VEXAG Meeting #3 Overview and Objectives - Sushil Atreya and Janet Luhmann 1:15 PM - VEXAG Goals and Objectives Document Steve Mackwell 1:45 PM - Venus Mission Architectures and Technology Developments Jim Cutts and Tibor Balint 2:00 PM Recap of International Planetary Probes Workshop Jim Cutts 2:15 PM - European Venus Explorer Proposal and ESA's Cosmic Vision Program Eric Chassefiere 2:30 PM - Coffee Break 2:45 PM - Education and Public Outreach Rosalyn Pertzborn 3:00 PM - Preview of OPAG Meeting Sushil Atreya for Fran Bagenal 3:15 PM - Special Science Briefing Venus Express VIRTIS Science Results - Pierre Drossart / Giuseppe Piccioni 3:45 PM - Open Mike Presentations (1-2 slides, up to 10 minutes each) 4:30 PM - Planetary Science Summer School Venus Mission Study 4:50 PM Preview of Monday s Activities Sushil Atreya and Janet Luhmann 5:00 PM - ADJOURN

19 VEXAG Meeting #4 Monday November 5, :30 AM - Sign-In / Pick-up Handouts / Coffee and Pastries 9:00 AM - NASA Headquarters Perspective on Venus Exploration - Jim Green and Andy Cheng 9:30 AM - Status Report: ESA's Venus Express - Hakan Svedhem 9:50 AM - JAXA's Venus Climate Orbiter - Masato Nakamura and Takeshi Imamura 10:10 AM - NASA S Discovery Candidate VESPER Gordon Chin 10:30 AM Coffee Break 10:45 AM - MESSENGER Flybys Sean Solomon, Hakan Svedhem 11:15 PM Evidence for Past Oceans on Venus Mark Bullock 12:00 LUNCH 1:15 PM Preview of NASA Workshop on Planetary Atmospheres - Phil Crane 1:30 PM - Venus-Earth Climate Connections Special Session 4:45 PM - Wrap-up - Next Meeting - Recommendations - Action Items - Sushil Atreya and Janet Luhmann 5:15 PM ADJOURN

20 VEXAG Meeting #4 Monday Afternoon November 5, :30 PM - Venus-Earth Climate Connections (25-minutes each) o Greenhouse Effect and Radiative Balance on Earth and Venus - Dave Crisp o Climate Sensitivity and History of Venus and Earth - Mark Bullock o Aerosols on Earth and Venus - Brian Toon 2:45 Coffee Break (15 Minutes) o Atmospheric Dynamics of Venus and Earth - Jerry Schubert o Solar History Effects on Venus and Earth Climate Janet Luhmann for David Brain o Sulfur Isotope Ratios and Constraints on Climate - Alex Pavlov 4:15 General discussion - Venus-Earth Climate Connections (all) 4:45 PM - Wrap-up - Next Meeting - Recommendations - Action Items - Sushil Atreya and Janet Luhmann 5:15 PM ADJOURN

21 VEXAG wishes to thank Elizabeth Kolawa, Tibor Balint and their technology development team members at JPL for their ongoing support and inputs to this presentation Further thanks to the Planetary Program supporters of VEXAG: Adriana Ocampo at NASA HQ, and Tommy Thompson, Venus Program Lead at JPL. This content results from the collective efforts of the members of the Venus Exploration Analysis Group 21

22 Back Up Charts Mission Descriptions 22

23 Key Extreme Environment Technologies Technology needs could be categorized into three general areas: 1) Environmental protection technologies providing isolation from extreme environments; 2) Environmental tolerance for exposed components or systems; 3) Operations in extreme environments. Protection systems: Hypervelocity Entry Pressure Mitigation Temperature Mitigation High-Temperature Electronics Power Storage Power Generation Mobility Technologies Balloon and Parachute Materials Sample Acquisition & Mechanism Telecommunication Issues Testing for Extreme Environments 23

24 Scientific Objectives: Composition and isotopic measurements of surface and atmosphere Near IR descent images Acquire and characterize a core sample. Demonstrate key technologies for VSSR Mission & LV Class: New Frontiers Class Launch Vehicle Class: TBD Roadmap Strawman New Frontiers Mission: Venus In Situ Explorer VISE Science Payload: Neutral mass spectrometer with enrichment cell. Instruments to measure elements and mineralogy of surface materials. Imaging microscope Technology & Heritage:. Sample acquisition and handling in Venus environment Passive insulation and survival at Venus Mission Technology Studies: Decadal Survey 2002 of Surface & Atmospheric In Situ Explorer (SAIVE) JPL proposal in response to New Frontier Mission solicitation. Technology studies in In Space Propulsion, Low temperature materials and autonomy. 24 POC: Tibor.Balint@jpl.nasa.gov

25 NASA s Solar System Roadmap Team Recommendations for the first Venus Flagship Mission Venus Mobile Explorer (VME) is the next logical step in the exploration of Venus after the New Frontiers VISE mission. VME would: Operate on the surface of Venus for >90 days Sample the surface at local and possibly regional scales. Search for granitic and sedimentary rocks indicative of an ancient ocean Lay the scientific and technological ground work for a subsequent Venus Surface Sample Return VME is a technologically challenging mission requiring an investment in technologies for Surviving and operating in the severe environment of Venus (high temperature, pressure, sulfuric acid) Power RPS combined with active cooling is likely only option for long duration surface operations Mobility on the surface or in the lower atmosphere Measurement techniques suited to the Venus environment. VME would benefit from technologies demonstrated on VISE 25

26 Proposed Roadmap Mission: Flagship Class Venus Mobile Explorer (VME) Measurement Objectives: Survey imaging at a variety of spatial scales Acquire & characterize surface samples at multiple sites Other physical and chemical measurements TBD Exploration Metrics: Operate in Venus surface environment for 90 days+ Mobility attributes TBD Technology Heritage from Prior Missions: Sample acquisition and handling in Venus environment Thermal control technology Aerial Platform (recommended by the Roadmap Team) OR New Technology Capabilities: Surface Rover (Maybe a Long Duration Static Lander as descope) Mobility on surface or through the atmosphere Long duration operation at or near the surface 26 POC Tibor.Balint@jpl.nasa.gov

27 Proposed Roadmap Mission: Flagship Class Venus Surface Sample Return VSSR Science objectives: Measure isotopic composition of oxygen in surface rocks Measure isotopic composition of trace elements to characterize core and mantle formation. Determine the age of returned rocks. Exploration Metrics: Return samples of Venus rock soil and atmosphere for analysis on Earth TBD year turnaround mission TBD weeks on the surface Mission & LV Class: Flagship Class LV- TBD Science Payload: As needed for sample identification. Sampling arm and in situ instrumentation Technology & Heritage: Rendezvous and Sample Return Systems from Mars Sample Return missions Balloon technology demonstrated in VISE mission to deliver sample to ascent vehicle launch altitude Ascent vehicle capable of surviving on the surface of Venus and launched from 65 km altitude to orbit Mission Technology Studies: Decadal Survey, POC:

28 Telecom (not shown) -Pointing DTE vs. Relay -Power requirements VME Example Summary of Enabling Technologies Mobility Technologies - Metallic bellows ( balloon ) - Buoyancy control - Lifetime / leak rate / corrosion - Materials (bellows; parachute) - Surface mobility (not shown) Pressure Control - Materials (e.g., titanium, honeycomb, composite shell; beryllium shelf) - Material creep - Mass reduction with developments - Volume (component miniaturization) Thermal Management & Control - Passive control: aerogel; PCM; MLI - Active control: see RPS RPS & Active Cooler - Heat rejection at high T - Active cooling to payload Energy Storage (not shown) - High temperature batteries inside pressure vessel Technologies must mitigate the extreme environments - High temperature (~460 C) - High pressure (~92 bars) - Corrosion (supercritical CO 2 ) Long-lived in-situ exploration of Venus requires significant technology development, that is common to all mission architectures VME aerial mobility / rover / static lander Component Hardening - Inside pressure vessel - High temperature electronics - Electronic packaging - Science instruments - External components / sensors - Imagers / Optics (at interface) Electro-Mechanical Systems - Exposed to external environment - Actuators, arms, moving parts - Sample acquisition and transfer - External valves - Antenna gimbals Testing for Extreme Environments - At relevant pressure, temperature, atmospheric composition Hypervelocity Entry (not shown) 28 - TPS; aeroshell Venus Mobile Explorer - VME: artist s concept