Venus& &Priori.es&for& Global&gravity& – Emissivity&(microwave/IR)& •...
Transcript of Venus& &Priori.es&for& Global&gravity& – Emissivity&(microwave/IR)& •...
Venus&Explora.on&Priori.es&for&
Understanding&Tectonic&and&
Geodynamic&Evolu.on&
Lori&S.&Glaze,&NASA&GSFC&E&VEXAG&Chair&
6&May&2015&
What’s&a&VEXAG?&• VEXAG&=&Venus&Explora.on&Analysis&Group&• CommunityEbased&forum&intended&to&provide&scien.fic&input&and&technology&development&plans&for&Venus&explora.on&over&the&next&several&decades.&&
• Supported&by&NASA&Planetary&Science&Division&• Sponsors&workshops&like&this&one&to&advance&science&• VEXAG®ularly&assesses&Venus&explora.on&goals,&scien.fic&objec.ves,&inves.ga.ons,&and&cri.cal&measurement&requirements,&and&provides&input&to&the&NRC&Decadal&Survey&&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 2&
But&first,&a&commercial&message…&• VEXAG&would&like&to&host&the&presenta.on&materials&from&this&mee.ng.&Will&get&your&permission&and&can&post&a&redacted&version&if&you&like.&
• Upcoming&Compara.ve&Climates&of&Terrestrial&PlanetsE2&Conference&
– Would&love&to&have&a&talk&summarizing&the&results&of&this&mee.ng!&
– Subtheme:&“Insights&Toward&Climate&Systems&Science&&&Climate&Evolu.on”;&encourage&others&to&submit&as&well&
– Abstract&deadline:&May&15&(next&Friday)&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 3&
• S.ll&many&unanswered&ques.ons&(Sue’s&talk)!!&&
• Deciphering&the&tectonic®ime&and&heat&dissipa.on&mechanisms&on&Venus&are&cri.cal&to&understanding&how&and&why&Venus&is&so&different&from&Earth&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 4&
Venus:&Key&to&Terrestrial&Planets&
• Planetary&Decadal&Survey&provides&a&framework&for&priori.es&
• VEXAG&builds&on&those&priori.es&to&iden.fy&more&specific&Goals,&Objec.ves,&and&Inves.ga.ons&needed&to&beker&understand&Venus&and&to&place&Venus&into&context&within&the&solar&system&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 5&
Priori.es&for&Venus&Explora.on&
Goals,&Objec.ves,&&&Inves.ga.ons&• VEXAG&“Goals,&Objec.ves,&and&Inves.ga.ons”&(GOI)&&were&compiled&based&on&broad&community&input&
• GOI&is&periodically&updated&• Significant&update&in&2014:&– Restructured&the&top&level&goals&– Assessed&priori.es&– Substan.al&community&review&and&feedback&process&
• Roadmap&and&Technology&plan&were&developed&in¶llel&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 6&
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Venus Technology Plan
May 2014
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Roadmap for Venus Exploration
May 2014 �����������������������������
Goals, Objectives, and Investigations for
Venus Exploration May 2014
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5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 7&
All&available&on&the&VEXAG&website:&
hkp://www.lpi.usra.edu/vexag/&
&
2014&GOI&• Three&top&level&Goals&are¬&priori.zed:&
I. Understand&atmospheric&forma.on,&evolu.on,&and&climate&history&of&Venus&
II. Determine&the&evolu.on&of&the&surface&and&interior&of&Venus&
III. Understand&the&nature&of&interiorEsurfaceEatmosphere&interac.ons&over&.me,&including&whether&liquid&water&was&ever&present&
• Objec.ves&are&in&priority&order&within&each&Goal&• Inves.ga.ons&are&in&priority&order&within&each&Objec.ve&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 8&
Goal&II:&Evolu.on&of&Surface&and&Interior&&Objec&ve(A( Inves&ga&on((abridged)(
• How&is&Venus&releasing&its&heat&
and&how&is&this&related&to&
resurfacing&and&outgassing&?&
• Has&the&style&of&tectonism&or&
resurfacing&varied&with&.me?&
• Did&Venus&ever&experience&a&
transi.on&in&tectonic&style&from&
mobile&lid&tectonics&to&stagnant&
lid&tectonics?&&
1.&Characterize&stra.graphy&and&deforma.on&
2.&Measure&radiogenic&4He,&40Ar,&and&Xe&isotopic&ra.os&
to&determine&interior&outgassing&over&.me&
3.&Characterize&structure,&dynamics,&and&history&of&the&
interior&
4.&Determine&contemporary&rates&of&volcanism&and&
tectonic&ac.vity&
5.&Determine&absolute&ages&for&rocks&at&loca.ons&that&
are&key&to&understanding&geologic&history&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 9&
Goal&II:&Evolu.on&of&Surface&and&Interior&Objec&ve(B( Inves&ga&on((abridged)(
• How&did&Venus&
differen.ate&and&evolve&
over&.me?&
• Is&the&crust&nearly&all&
basalt,&or&are&there&
significant&volumes&of&more&
differen.ated&(silicaErich)&
crust?&
1.Determine&the&elemental&composi.on,&mineralogy,&and&
petrography&of&surface&samples&at&key&geologic&sites&
2.&Determine&composi.onal&informa.on&for&rocks&at&large&
scales&
3.&Determine&the&structure&of&the&crust&
4.&Determine&the&size&and&state&of&the&core&
5.&Evaluate&the&radiogenic&heatEproducing&element&content&
of&the&crust&
6.&Characterize&subsurface&layering&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 10&
Roadmap&for&Explora.on&• Roadmap&iden.fies&poten.al&mission&concepts&in&three&Mission&Timeframes,&based&primarily&on&technology&readiness:&– NearEterm&(this&decade)&
– MidEterm&(next&decade)&&
– FarEterm&(beyond&2025)&
• Roadmap&does¬&preclude&competed&opportuni.es,&interna.onal&collabora.ons,&or&combina.ons&of&elements&to&form&larger&“flagship”&missions&
• Geodynamics&figures&prominently&in&the&Roadmap&for&Venus&Explora.on&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 11&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 12&
Roadmap&for&Explora.on&
• Roadmap&iden.fies&poten.al&mission&concepts&
in&four&“explora.on&domains”:&
– Atmospheric&Composi.on&
– Atmospheric&Structure&and&Circula.on&
– Surface&Composi.on&and&Morphology&
– Interior&Structure&and&Ac.vity&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 13&
Objec.ves&for&Interior&Structure&and&Ac.vity&
• Major&outstanding&ques.ons&including&understanding:&– How&Venus&formed&and&ini.ally&evolved&
– How&its&interior&dynamics&may&have&differed&in&the&past&and&whether&it&ever&had&plate&tectonics&
– The&nature&of¤t&and&past&volcanic&and&tectonic&ac.vity&and&what&roles&volcanism&tectonics,&and&vola.les&play&in¤t/past&heat&loss&and&vola.le&evolu.on&
– Whether&there&is&extensive&silicaErich&crust,&implying&substan.al&crustal&water&in&the&past&
– The&planet’s&spin&state&(rota.on&and&polar&wander)&and&how&it&correlates&to&models&of&the&interior&and&its&evolu.on&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 14&
Example&Mission&Modes&E&1&
• Orbiter&with&ac.ve/passive&remote&sensing:&
– Topography&– Radar&imaging&with&polarimetry&
– Global&gravity&– Emissivity&(microwave/IR)&
• Can&be&done&in&the&nearEterm;&instrument&and&implementa.on&technologies&are¤tly&available&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 15&
Example&Mission&Modes&E&2&• Geophysical&lander&with&~1&Venus&year&life.me&
– Seismology&over&a&large&frequency&range&to&constrain&interior&structure&
– Heat&flow&to&discriminate&between&models&of¤t&heat&loss&
– Geodesy&to&determine&core&size&and&state&
– Electromagne.c&sounding&to&constrain&gross&interior&layering&
• Technologies&for&extended&dura.on&(beyond&a&few&hours)&in&the&surface&environment&do¬¤tly&exist.&
• May&be&able&to&envision&a&longElived&lander&in&the&MidEterm,&but&investments&are&needed&now&for&that&to&happen&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 16&
Example&Mission&Modes&E&3&
• Lander&network&with&a&life.me&>&1&Venus&year&
– Same&measurements&as&to&higher&fidelity&
– Constrain&rate&of&seismicity&and®ional&crustal&thickness&varia.ons&
– Study&local&structure&of&specific&targets&(e.g.,&tesserae,&hotspots,&rits,&and&Ishtar&Terra)&
• FarEterm&objec.ve&that&requires&substan.al&investments&in&technology&development&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 17&
Surface/NearESurface&Ops&on&Venus&
• Surface&Temperature:&462&°C&
• Surface&Pressure:&92&bar&• Atmosphere&composi.on:&Highly&corrosive,&superEcri.cal&CO2&
• Ligh.ng&Condi.ons:&&– Sulfuric&acid&clouds&allow&~10%&of&the&incident&solar&radia.on&to&reach&the&surface&
– Ligh.ng&is&isotropic&(no&shadows)&5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 18&
Challenges&for&Geophysical&Lander&• Power:&&
– Bakery&approach&is&massElimited&to&a&few&hours&
– Solar&power&is¬&viable&at&the&surface&– Current&RadioEisotope&power&technology&is&too&inefficient&at&Venus&
surface&temperatures&
• Thermal:&– Passive&cooling&solu.ons&(e.g.,&phase&change&materials)&limited&to&a&
few&hours&
– Ac.ve&cooling&requires&power&• Instrumenta.on/Electronics:&
– Some&progress&has&been&made&in&highEtemperature&electronics&–&Possible&upcoming&“Extreme&Environments&Centennial&Challenge”&
– Technologies&for&high&temperature&seismometer&have&been&demonstrated&&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 19&
Recent&Technology&Workshop&• Instrumenta.on&and&Lab&Measurements&Workshop&held&at&Langley&April&7E8&
• Heard&about&lots&of&clever&ideas:&– HighEtemperature&capableµelectronics&based&on&arrays&of&carbon&nanotubes&
– Unspooling&power&generator&(tethered&balloon&in&wind&field)&
– Thermoacous.c&S.rling&Heat&Engine&for&cooling&and&power&
– Al.tude&cycling&balloons&– Gliders&that&can&“dip&down”&to&low&al.tudes&&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 20&
• ESA’s&Venus&Express&ended&its&almost&9&year&mission&in&January&2015&
• JAXA’s&Akatsuki&2nd&akempt&to&go&into&orbit&in&December&2015&
• Focus&on&atmospheric&dynamics&
• Nothing&else&“on&the&books”&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 21&
Current&Status&
• Russia&and&India&thinking&about&Venus&
• Both&ESA&and&NASA&offer&periodic&compe..ve&opportuni.es&to&propose&innova.ve&missions.&
• ESA’s&Cosmic&Vision&– MEclass&(medium&size)&
– LEclass&(larger&size)&• NASA&
– Discovery&(medium&size;&every&~3&yrs)&
– New&Fron.ers&(larger&size,&prescribed&science&objec.ves)&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 22&
What’s&Next&in&Venus&Explora.on?&
• Medium&(M)Eclass&concept:&EnVision&orbiter&
• Study&past&and¤t&rates&and&styles&of&geologic&ac.vity&(radar&imaging,&topography,&and&surface&change,&IR&imaging,&ground&penetra.ng&radar)&
• Spa.al&and&temporal&varia.on&of&trace&gases;&signs&of&ac.ve&volcanism&
• Unfortunately¬&selected&in&most&recent&round&–&Next&.me!&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 23&
ESA’s&Cosmic&Vision&
R.&Ghail&–&this&session&
NASA&Discovery&Program&• 28&proposals&to&des.na.ons&throughout&the&solar&system&are¤tly&under&review&
• 4&Venus&mission&concepts&&– 3&orbi.ng&radar&missions&focused&on&answering&major&geophysical&ques.ons&
– 1&in&situ&atmospheric&mission&focused&on&answering&fundamental&ques.ons&of&atmospheric&origin&&&evolu.on&and&history&of&water&
• Step&1&selec.ons&of&3E5&concepts&expected&in&September&2015&–&stay&tuned!!&
• Step&2&selec.on&of&ONE&mission&in&&~September&2016&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 24&
NASA’s&New&Fron.ers&• Venus&In&Situ&Explorer&is&one&of&5&recommended&
missions;&primary&objec.ve&defined&by&NASA&
Planetary&Decadal&Survey&is&to&characterize&the&
physics&and&chemistry&of&the&crust.&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 25&
Surface&and&Atmosphere&
Geochemical&Explorer&(SAGE)&
(Larry&Esposito,&PI)&
&
New&Fron.ers&Mission&
proposed&in&2009&
&
Next&Call&September&2016&
&
• NASA&Venus&Flagship&–&two&op.ons&have&been&examined:&
– Venus&Flagship&study&(2009):&orbiter&with&surface&and&
atmosphere&science,&2&balloons&
and&2&landers&
– Venus&Climate&Mission:&low(er)&
cost&Flagship&op.on&to&
characterize¤t&climate&with&
orbiter,&balloon&and&drop&sonde)&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 26&
NASA&Flagship&
Conclusions&• Importance&of&understanding&the&interior&and&surface&evolu.on&of&
the&terrestrial&planets&is&recognized&by&the&decadal&survey&
• Venus&community&has&iden.fied&several&high&priority&inves.ga.ons&for&addressing&key&ques.ons&about&how&Venus&loses&its&heat&and&to&place&constraints&on¤t&levels&of&ac.vity&
• Current&technology&is&more&than&adequate&to&support&an&orbital&geophysics&mission&to&Venus&–&orbital&radar&mission&could&go&a&long&way&to&answering&many&ques.ons&
• Major&challenges&for&longElived&landed&geophysical&missions&
• No&Venus&missions¤tly&“in&the&works”&by&NASA&or&other&space&agency&&
• Compe..ve&opportuni.es&exist&within&NASA&(Discovery&and&New&Fron.ers)&and&ESA&(ME5)&–&Stay&tuned!!&
5/6/2015& Compara.ve&Tectonics&and&Geodynamics& 27&