Venus Origins Explorer (VOX) is a concept orbiter mission to

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

.Venus Origins Explorer New Frontiers Proposal
Van Kane. ''Future Planetary Exploration''. 1 October 2017. VOX would produce global, high resolution

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the landforms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...

and imaging of Venus' surface and produce the first maps of deformation and global surface composition, thermal emissivity, and gravity field to study the interior structure of the planet. Current data are suggestive of recent and active

volcanism on Venus The surface of Venus is dominated by volcanic features and has more volcanoes than any other planet in the Solar System. It has a surface that is 90% basalt, and about 65% of the planet consists of a mosaic of volcanic lava plains, indicating that ...

, and this mission could determine if current volcanism is limited to

mantle plume A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic ho ...

heads or if it is more widespread. The Principal Investigator for VOX is Suzanne Smrekar at the

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by Cali ...

. Smrekar was the PI of the

VERITAS In Roman mythology, Veritas (), meaning Truth, is the Goddess of Truth, a daughter of Saturn (mythology), Saturn (called Cronus by the Greeks, the Titan (mythology), Titan of Time, perhaps first by Plutarch) and the mother of Virtus (deity), Vi ...

orbiter proposal to Venus that competed in 2015 for the

Discovery Program The Discovery Program is a series of Solar System exploration missions funded by the U.S. National Aeronautics and Space Administration (NASA) through its Planetary Missions Program Office. The cost of each mission is capped at a lower level t ...

13 mission. VOX is a reformulation of VERITAS proposed in 2017 to NASA's New Frontiers program mission 4 to compete for funding and development, but it was not selected.

Overview

Although the Announcement of Opportunity called for a Venus lander, the VOX scientific team is proposing an orbiter with a payload capable of achieving the required objectives. The VOX proposing team explains: "At the time of the Decadal Survey the ability to map mineralogy from orbit and present-day radar techniques to detect active urfacedeformation were not fully assessed because their development was still ongoing. VOX leverages these methods and ''in-situ'' noble gases to answer he keyNew Frontiers science objectives." The VOX mission concept would have the orbiter deploy a small, simple atmospheric probe, the Atmospheric Sample Vehicle (ASV), to measure the key gases and

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

s. The rest of the measurements would be made from instruments on the orbiter over at least three years. The mission was last proposed in 2017 to NASA's New Frontiers program mission 4 to compete for funding and development, but it was not selected.NASA's New Frontier Mission Will Search For Alien Life Or Reveal The Solar System's History
Elana Glowatz, ''IB Times''. 20 December 2017.

Objectives

The VOX mission objectives are: *Investigate atmospheric physics and chemistry, including noble gases and their isotopes. *Investigate Venus' past hydrological cycles to determine the role of volatiles in crustal formation. *Investigate crustal physics and chemistry and determine the global tectonic framework and heat flow, whether catastrophic resurfacing occurred, and any type of geologic processes that may be currently active. *Investigate crustal weathering by constraining global mineralogy and surface-atmosphere weathering reactions. *Map cloud particle modes and their temporal variations, and track cloud level winds in the polar vortices. *Investigate surface-atmosphere interactions, create mineralogy maps and search for new and/or recent volcanism and outgassed water during a three-year global search.

Proposed payload

The orbiter would carry two scientific instruments and a radio: *A radar called Venus Interferometric Synthetic Aperture Radar (VISAR) would generate high-resolution imaging of the surface at 15 m to 30 m resolution, and search for minute changes in surface elevations to look for evidence of current volcanic or tectonic activity by performing repeat-passes during 3 years. *The Venus Emissivity Mapper (VEM) would employ a spectrometer using five near-infrared wavelengths where the atmosphere is transparent to map the chemical composition at the surface, and thus determine whether tesserae regions formed in the presence of water. Measurements in additional bands would study cloud structure and cloud displacement (indicating winds), and would search for water vapor in the lowermost atmosphere. *The orbiter's radio signal in the Ka-band would provide the gravity field resolution needed to estimate global elastic thickness, and map the gravity field at high resolution to study the interior structure of the planet.

Atmospheric Sample Vehicle

The VOX mission concept would have the orbiter deploy a small atmospheric probe called Atmospheric Sample Vehicle (ASV), previously named ''Cupid's Arrow''. The probe would enter the atmosphere at such speed and angle that it will bounce back into space after collecting an upper atmospheric sample. Once back in space, a miniaturized quadrupole ion trap mass spectrometer would measure the key gases and

s.Cupid's Arrow: An Innovative Nanosat Mass Spectrometer to Sample Venus' Upper Atmosphere
(PDF) Murray Darrach, C. Sotin, S. Madzunkov, E. Neidholdt. HEM's Workshop. 2015. Measurements of

xenon Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...

and its isotopes, yet to be made at Venus, would resolve key questions about the origins of the atmosphere and the cumulative volcanic activity. Similarly, a long-lost ocean on Venus would be reflected in the ratio of hydrogen isotopes.

References

External links

Why We Explore - Venus (2006, NASA)
{{Planetary Missions Program Office, New Frontiers=y Missions to Venus Extraterrestrial atmosphere entry New Frontiers program proposals Proposed NASA space probes