Continuous observations of the inner Solar System: Mapping Venus winds 4/27/2007 Continuous observations of the inner Solar System: Mapping Venus winds Mark A. Bullock Eliot F. Young Southwest Research Institute Venus nightside at 2.3 mm April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

The Atmosphere April 27, 2007 LCANS SwRI Boulder Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 The Atmosphere April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

Winds and General Circulation Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 Winds and General Circulation April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

Near-IR emission spectrum of Venus Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 Near-IR emission spectrum of Venus April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

April 27, 2007 LCANS SwRI Boulder Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 May 4, 2004 Venus 2.3 mm May 5, 2004 IRTF May 6, 2004 April 27, 2007 May 8, 2004 Eliot Young May 9, 2004 Mark Bullock LCANS SwRI Boulder LCANS SwRI Boulder

Moving through an image cube Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 Moving through an image cube 60” spectrometer slit allowed to drift over Venus disk. Acquired ‘jail bar’ spectra ~50 in 15 minutes. Reassembled into image cubes, 0.8 to 2.5 mm. April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

Venus Express VIRTIS images Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 Venus Express VIRTIS images 1.7 mm emission images Upper left: South pole at lower right, 60o S upper left. Upper right: Bottom left of image over Alpha Regio Lower left: Near south pole Lower right: Near equator in the southern hemisphere April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

Venus Observation Geometry Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 Venus Observation Geometry April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

Size of Venus at focal plane Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 Size of Venus at focal plane 5 weeks before inferior conjunction. 40” disk 26% illuminated 110 diffraction-limited elements across disk Inferior conjunction. 60” disk full nightside 160 diffraction-limited elements across disk April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

Payload Specifications Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 Payload Specifications Telescope Aperture: 1 meter Plate Scale: 0.125 arcsec Field of View: 64 arcsec Diffraction limit: 0.6 arcsec at 2.5 mm 0.2 arcsec at 0.8 mm Simultaneous imaging and spectra 0.8-2.5 mm Spectral Resolution l/dl = 4000 Pointing accuracy/stability: ±0.3 arcsec Minimum Sun angle: 10o Temperatures Structure at -40oC LN2 for IR detector array April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder

Continuous observations of the inner Solar System: mapping Venus' winds 4/27/2007 Conclusions Continuous near-IR observations of Venus cloud motion necessary to understand the general circulation. Synoptic view is highly complementary with VEX VIRTIS and VMC. Continuous cloud tracking with balloon-borne 1 m imager and spectrometer for 10 weeks will allow simultaneous atmospheric motion maps and below-cloud CO, H2O, OCS maps. These observations are key to understanding Venus’ atmospheric superotation. April 27, 2007 LCANS SwRI Boulder LCANS SwRI Boulder