Sky & Telescope - May 2022 - 19

M. PRICE AND J. SUPPE / EARTH, MOON, AND PLANETS 1995, ESA, NASA
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Plains
Coronae
Rifts
Tesserae
Ridge Belts
Wrinkle ridges
Volcanoes and flow fields
WHAT ENVISION MIGHT SEE EnVision's radar will penetrate Venus's clouds, mapping key geological features such as volcanoes and continentlike
tesserae at a resolution of about 10 km. This map shows one example of the targets the mission could study.
hope that VERITAS will last longer than its primary planned
mission, and that DAVINCI can continue performing flybys.
In fact, according to DAVINCI principal investigator Jim
Garvin (NASA Goddard Space Flight Center), DAVINCI could
go into Venus orbit on its next flyby after dropping the probe.
With VERITAS's global maps and DAVINCI's in-situ measurements
already available, EnVision will be able to reach its
full potential. If NASA had not selected its two missions for
development, EnVision would have had many more mapping
responsibilities, Ghail explains. " VERITAS is a global geophysics
mission. It's about getting topography and gravity globally,
at high resolution. And it's very good at that, better than
EnVision would be. "
EnVision's radar mapper won't get VERITAS's global coverage,
but it will see parts of the surface at higher resolution,
focusing on especially compelling geologic features to elucidate
the present and past of Venus. EnVision will therefore
be able to function like ESA's Sentinel Earth orbiters or the
HiRISE camera on NASA's Mars Reconnaissance Orbiter,
monitoring Venus's atmosphere and surface for changes over
time. EnVision's radar sounder will also draw profiles of the
subsurface structure across Venus craters, cracks, volcanoes,
and crumpled mountains, just as Mars Express and Mars
Reconnaissance Orbiter have done, helping to tell the story of
Venus's geologic history.
Finally, EnVision carries a suite of spectrometers that will
see to many levels of the atmosphere as well as to the surface.
In fact, one of EnVision's spectrometers will be a near-duplicate
of the one on VERITAS. Flying a nearly identical instrument
twice is not something that happens often in planetary
science, but it's very common on Earth orbiters, and it will
enable scientists to establish a continuous record of weather
and surface changes from VERITAS through EnVision, spanning
a decade and possibly more.
The Decade of Venus
To say that Venus scientists are thrilled about the selection of
three new missions is understating things. But there are reasons
to be happy besides the new data. " It's been a big tension
between all the [proposed] missions, " Smrekar says. " It's been
very fracturing to be so competitive all the time. It's really a
pleasure to be cooperating instead of competing. "
Grinspoon agrees. " There was this wonderful moment
after the selection when we realized, 'Oh, now we can all be
friends again,' because until then we'd been so in competition
against each other. "
Europe and the United States aren't the only ones planning
new missions to Venus. The next decade could also see
missions launched by India and even from a private company,
Rocket Lab, based in New Zealand. A spacecraft from the
United Arab Emirates will also swing by Venus en route to
the asteroid belt. Underappreciated and poorly understood for
so long, Venus will finally enjoy the kind of scientific boom
that Mars has experienced for 25 years. May that boom last at
least as long as the Age of Mars has.
¢ Contributing Editor EMILY LAKDAWALLA is a freelance
space writer and artist. Her second book, Curiosity and Its Science
Mission: A Mars Rover Goes to Work, is forthcoming from
Springer-Praxis in 2023.
sk yand tele scope .o r g * MAY 2022 19
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Sky & Telescope - May 2022

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