VOX would produce global, high resolution topography 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, and this mission could determine if current volcanism is limited to mantle plume heads or if more widespread.
The Principal Investigator for VOX is Suzanne Smrekar at the Jet Propulsion Laboratory. Smrekar was the PI of the VERITAS 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 mission 4 to compete for funding and development, but it was not selected.
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 [surface] deformation were not fully assessed because their development was still ongoing. VOX leverages these methods and in-situ noble gases to answer [the key] New 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 isotopes. The rest of the measurements would be made from instruments on the orbiter over at least three years.
The VOX mission objectives are:
The orbiter would carry two scientific instruments and a radio:
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 isotopes.
Measurements of xenon 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.