t h e e x p lo ra t io n o f V e n u s c u rre n t u nde rs t a ndi n g , o p e n q u est i o n s , a n d n e x t s t e p s c o l i n wi l s o n | p a u l b y r n e | r i c h a r d g h a i l | m a r t h a g ilm o r e | s u z a nne s m r e k a r | a l l a n t r e i m a n | s e a n s o l o m o n Slides credit: Paul Byrne (NCSU) L P SC 2019 | 50 Yea rs of P laneta ry S c ien ce introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext steps the exploration of Venus Moon 1950s 13 Venus 1960s 18 1960s 63 1970s 10 1970s 22 1980s 7 1980s 0 1990s 0 1990s 4 2000s 1 2000s 11 2010s 1 2010s 13 im a g e cre dit: Éder Ivá n L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s an Earth -size world in the hab itable zone 82% Earth mass 95% Earth radius 0 .72 A U Goldstone (1962) retrograde rotation Mariner 2 (1962) h igh temperatures in lower atm osp h ere n o resolvable m a g n etic field L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |3 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s a sky by turns hospitable and lethal 96.5% C O 2 high D/H ratio super- rotating atmosphere g lobal cloud layer Vega balloons (1985) highly variable atmospheric co nditions H 2SO4 clouds Earth- like co nditions ~50–65 km L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |4 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s hell made real Venera 13 and 14 (1982) photos of the surface sedimentary- like rocks first recording of sound on another planet 740 K, 93 bar basaltic lithology g round im a g e cre dit: M attia s M alm er L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |5 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s a world without mod ern plate tectonics differentiated interior Magellan (1990 ) near- g lobal image and topographic co verage thicker crust for some high - standing terrain some volcanic regions co rrespond to upw elling deeply co mpensated lowlands suggest downw elling im a g e cre dit: N a tion a l Geog raphic L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |6 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s a relatively young surface? distribution indistinguishable from random Magellan (1990 ) no C aloris/SPA/H ellas ~900 identified craters none few er than ~3 km in diameter L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |7 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s a relatively a ctive surface? Venus Express (2006) detection of transient hotsp ots high emissivity may d enote recent lavas active volcanism? temporally variable S O 2 im a g e cre dit: hd-wallpapersdown load.com L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |8 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s a relatively mobile su rface? evid ence for lateral motion Magellan (1990 ) w idesp read tectonic deformation more deformation than Mercury, Mars, or the Moon L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |9 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s what did early Venus look like? Mariner 5 (1967) P ioneer Venus (1978) p ossib le loss of atmospheric w ater formerly present o ceans? im a g e cre dit: N ASA/G SFC L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |10 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s is there continental cru st? highly deformed terrain stratigraphically oldest material Venera 8 (1972) elevated radiogenic element abundances L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |11 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s two Earth -like worlds? do these planets have a shared history? if not, why not? when did their paths diverge? im a g e cre dit: N ASA/G SFC L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |12 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s so where do we go from here? co mposition of surface materials co mposition, evolution structure (and activity) of the atmosphere of the interior L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |13 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s we n eed to und erstand V en u s in its own right… L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |14 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s …but also in terms of how it compares with other worlds, b ecause : L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |15 introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s Venus w ill help us understand the rules that govern Earth -like worlds L P SC 20 19 | 50 Ye a rs of P laneta ry S c ience byrne et al. |2019.03.20 |16 Venus exploration vehicles: a range of platforms for different science goals introduction | Venus from afar | the atmosp h ere | the surface | the interior | surp risin g find ing s | op en q uestions | n ext step s thriving in the clouds European Venus Explorer (EVE): a balloon mission in the heart of the habitable layer • Helium superpressure balloon, 53-57 km float altitude. • Follows heritage of French/Soviet Vega balloons (1984) • Benefit from benign climate: 10 – 50 °C, atmospheric densities like those found at 0 to 5 km altitude on Earth. • Ideal platform for trace gas mass spectrometry (thermally stable) • Explore clouds of liquid water (albeit mixed with sulphuric acid). • Use high winds of 200-250 km/h to circumnavigate the planet in 5-8 days. T. Balint a pathway to surface operations 1. Short-duration (~ 1 hr) Venera-style landers 2. High-temperature ambient-temperature landers 3. Mobile robotics EnVision Venus orbiter Finallist in ESA’s M5 Space Science mission competition Strong NASA participation (being defined) Currently entering phase A study (2019-2021) Selection expected summer 2021. Launch in 2032 Aerobraking 2033 - 2035 Nominal science mission 2035-2038 Three science themes Activity – How geologically active is Venus today? History – How have Venus’ surface and interior evolved? Climate – How did Venus’ atmosphere become so hostile? EnVision radar: the value of spatial resolution • Radar has come a long way since the 1980s when Magellan radar was developed. • Magellan radar spatial resolution was 100 m at best. • Modern radar could enable spatial resolution approaching 1 – 5 m. • Modern radar has lower noise, better radiometric resolution, clearer imagery.