Members of the VERITAS science team descend a slope to new rock formed from a recent flow of lava during their Iceland field campaign in early August. The team used the volcanic landscape as a Venus analog to test radar technologies and techniques. Credits: NASA/JPL-Caltech
The JPL-led international team used
the island as a stand-in for Venus to test radar technologies that will help
uncover the planet’s ground truth.
With its crushing atmospheric
pressure, clouds of sulfuric acid, and searing surface temperature, Venus is an
especially challenging place to study. But scientists know that observing its
surface can provide key insights into the habitability and evolution of rocky
planets like our own. So to get a global perspective of Venus while staying
well above its hellish atmosphere, NASA’s VERITAS (Venus Emissivity, Radio
science, InSAR, Topography, And Spectroscopy) mission is scheduled to launch
within a decade to survey the planet’s surface from orbit, uncovering clues
about the nature of its interior.
To lay the groundwork for the
mission, members of the international VERITAS science team traveled to Iceland
for a two-week campaign in August to use the volcanic island as a Venus
stand-in, or analog. Locations on our planet often are used as analogs for
other planets, especially to help prepare technologies and techniques intended
for more uninviting environments.
Members of the international VERITAS science team prepare for lidar (Light Detection and Ranging) imaging of rocks in Iceland. Lidar measurements of rocky terrain can provide information about the material, such as surface roughness that can then be compared with radar images of the same location. Credits: NASA/JPL-Caltech
“Iceland is a volcanic country that
sits atop a hot plume. Venus is a volcanic planet with plentiful geological
evidence for active plumes,” said Suzanne Smrekar, senior research scientist at
NASA’s Jet Propulsion Laboratory in Southern California and the VERITAS
principal investigator. “Its geological similarities make Iceland an excellent
place to study Venus on Earth, helping the science team prepare for Venus.”
The VERITAS mission
will rely on a state-of-the-art synthetic aperture radar to create 3D global
maps and a near-infrared spectrometer to distinguish between the major rock
types on Venus’ surface. But to better understand what the spacecraft’s radar
will “see” on the planet, the VERITAS science team would need to compare radar
observations of Iceland’s terrain from the air with measurements taken on the
ground.
From
Air to Ground
For the first half of the campaign, the
VERITAS science team studied the Askja volcanic deposits and the Holuhraun
lava field in
the Icelandic Highlands, an active region featuring young rock and recent lava
flows. For the second half, they traveled to the volcanically active Fagradalsfjall
region on the
Reykjanes Peninsula of southwestern Iceland. The barren and rocky landscapes of
both resemble Venus’ surface, which is thought to be rejuvenated by active
volcanism.
An example of the DLR airborne radar data shows elevation change of several tens of yards around the volcanically active Litli-Hrútur volcano caused by the creation of new rock. The red indicates the most change; blue, the least. Credits: DLR
Nineteen scientists from the U.S.,
Germany, Italy, and Iceland camped and worked long hours to study the surface
roughness and other properties of rocks in those regions, collecting lab
samples as well. Meanwhile, flights led by the German Aerospace Center
(Deutsches Zentrum für Luft- und Raumfahrt, or DLR) collected radar data from
above.
“The JPL-led science team was
working on the ground while our DLR partners flew overhead to gather aerial
radar images of the locations we were studying,” said Daniel Nunes, VERITAS
deputy project scientist at JPL and Iceland campaign planning lead. “The radar
brightness of the surface relates to the properties of that surface, including
texture, roughness, and water content. We collected information in the field to
ground-truth the radar data that we will use that to inform the science that
VERITAS will do at Venus.”
Flying aboard DLR’s Dornier 228-212 aircraft about 20,000 feet (6,000 meters) above the ground, the synthetic aperture radar collected S-band (radio waves with a wavelength of about 12 centimeters, or 4.7 inches) and X-band (about 3 centimeters, or 1.2 inches) data. The shorter wavelength of X-band data – the radio frequency VERITAS will employ – enables the use of a more compact antenna than S-band, which was used by NASA’s Magellan mission to map nearly the entire surface of Venus in the early 1990s.
Using a tripod-mounted lidar scanner, the science team created this image that highlighted the ropy texture of new rock formed by a recent lava flow near Iceland’s Litli-Hrútur volcano. This will be used to compare with the campaign’s airborne radar images of the same region. Credits: NASA/JPL-Caltech
By observing the surface in both
bands in Iceland, the science team will refine computer algorithms that will
help VERITAS identify surface changes on Venus that have occurred since
Magellan’s mission. Detecting changes over the last 40 years will allow them to
identify key regions of geologic activity (such as active
volcanoes) on Venus.
A key goal for the campaign was to
also create a sample library of as many volcanic surface textures in Iceland as
possible to better understand Venus’ range of eruption styles. A DLR field team
also collected compositional information with a camera that emulates the Venus
Emissivity Mapper (VEM) instrument the German Aerospace Center is building for
VERITAS. This data will support the spectral library being created at the
Planetary Spectroscopy Laboratory in Berlin.
“The different surface
characteristics and features seen on Venus relate to volcanic processes, which
relate back to the interior of Venus,” said Smrekar. “This data is going to be
valuable to VERITAS to help us better understand Venus. It will also help the
European Space Agency’s EnVision mission, which will study Venus’ surface with
S-band radar, and the community at large that wants to understand radar
observations of volcanic planetary surfaces.”
But the value of the two-week
Iceland campaign went beyond science, providing a team-building opportunity
that will resonate for years to come, said Nunes. “It was a great dynamic,” he
added. “We pushed hard and helped each other out. From borrowing gear to
driving to the study sites and buying supplies, everyone hustled to make it
happen.”
More About the Mission
VERITAS and NASA’s Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission were selected in 2021 under NASA’s Discovery Program as the agency’s next missions to Venus. VERITAS partners include Lockheed Martin Space, the Italian Space Agency, the DLR, and Centre National d’Études Spatiales in France. The Discovery Program is managed by the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the Planetary Science Division of NASA’s Science Mission Directorate in Washington.
Source: Venus on Earth: NASA’s VERITAS Science Team Studies Volcanic Iceland | NASA
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