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

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...

.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 land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sc ...

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 hot ...

heads or if 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 center and NASA field center in the City of La Cañada Flintridge, California, United States. Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...

. Smrekar was the PI of the

VERITAS Veritas is the name given to the Roman virtue of truthfulness, which was considered one of the main virtues any good Roman should possess. The Greek goddess of truth is Aletheia (Ancient Greek: ). The German philosopher Martin Heidegger argues ...

orbiter proposal to Venus that competed in 2015 for the Discovery Program 13 mission. VOX is a reformulation of VERITAS proposed in 2017 to NASA's

New Frontiers program The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of furthering the understanding of the Solar System. The program selects medium-class missions which can provide high science returns. ...

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 two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

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

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 A tessera (plural: tesserae, diminutive ''tessella'') is an individual tile, usually formed in the shape of a square, used in creating a mosaic. It is also known as an abaciscus or abaculus. Historical tesserae The oldest known tessera ...

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 The Ka band (pronounced as either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 26.5–40 gigahertz (GHz), i.e. wavelengths from slightly over one centime ...

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 with the 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 at Venus would be reflected in the ratio of

hydrogen isotopes Hydrogen (1H) has three naturally occurring Isotope, isotopes, sometimes denoted , , and . and are stable, while has a half-life of years. Heavier isotopes also exist, all of which are synthetic and have a half-life of less than one Orders o ...

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