NASA scientists are preparing to paint the most detailed picture of Venus’ atmosphere to date when the DAVINCI mission, or Deep Atmosphere Venus Investigation of Noble Gases, Chemistry, and Imaging, launches a probe to the planet’s surface.
As the DAVINCI mission’s 0.9-meter (3-foot) wide drop sphere makes its parachute journey from Venus‘ in the early 2030s, it will carry the VASI (Venus Atmospheric Structure Investigation) instrument along with five other instruments. VASI will collect data on the temperature, pressure and winds of venus atmosphere as it makes its hellish descent and enters the crushing lower atmosphere of the planet.
“There are actually some big puzzles about the deep atmosphere of Venus,” Ralph Lorenz, lead scientist for the VASI instrument and a planetary scientist at the Johns Hopkins Applied Physics Laboratory (APL) in Maryland, said in a statement. statement. “We don’t have all the pieces to that puzzle and DAVINCI will give us those pieces by measuring composition along with pressure and temperature as we get closer to the surface.”
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Venus’ dense atmosphere hides several mysteries, including how it is structured, as well as how the planet’s many volcanoes have interacted with it over the eons. One of the key goals of scientists in plunging a probe through the atmosphere of the second planet from the sun is to determine if that world is still volcanically active. The probe could detect this through measurements of atmospheric temperature, winds and composition.
Solving these puzzles could give scientists insight into what continued volcanic activity could mean for our own planet’s atmosphere.
“The long-term habitability of our planet, as we understand it, is based on the coupling of the interior and the atmosphere,” Lorenz said. “The long-term abundance of carbon dioxide in our atmosphere, which we really rely on to keep the Earth’s surface warm enough to be habitable through geologic time, depends on volcanoes.”
A one way trip to Venus
One of the main challenges associated with investigating Venus has been the extreme conditions of the planet, which has surface pressures up to 90 times greater than those of Earth. Land and surface temperatures around 900 degrees Fahrenheit (460 degrees Celsius).
Furthermore, before any probe can reach the planet’s surface from orbit, it must first pass through clouds of sulfuric acid in Venus’s upper atmosphere. (These clouds also make Venus difficult to observe from Earth; reflective and bright, they obscure our view of the planet’s surface.)
These threats mean that DAVINCI’s descent sphere systems and sensors will be encased within a rugged submarine-like structure. But while the sphere is built to withstand intense atmospheric pressures and is insulated to protect the sensors from the intense heat near the surface of Venus, VASI’s sensors must be exposed to harsh conditions to do their job.
“Venus is tough. The conditions, especially in the lower atmosphere, make it very difficult to design the instrumentation and the systems to support the instrumentation,” Lorenz said. “All of that has to be protected from the environment or built in some way to tolerate it.”
As the sphere falls through Venus’s atmosphere, VASI will measure the temperature with a sensor inside a thin, straw-like metal tube. As the atmosphere heats the tube, the sensor measures and records the expansion and therefore the temperature without being directly exposed to the corrosive environment.
VASI will collect atmospheric pressure readings using a silicone membrane encased inside it. One side of the membrane is exposed to the vacuum while the other side faces the atmosphere of Venus. The atmosphere pushes on the membrane, stretching it, and the extent of this stretching reveals the strength of atmospheric pressure.
The instrument will measure the winds of Venus with a combination of accelerometers that check changes in speed and direction and gyroscopes that measure orientation. The mission will also track changes in wind speed and direction by monitoring changes in the frequency and wavelength of radio waves.
Named for Italian Renaissance scholar Leonardo da Vinci, DAVINCI is scheduled for launch in 2029. If it stays on schedule, the descent sphere will plunge through Venus’s thick atmosphere in 2031.
Delivery will take about an hour. The probe is not expected to survive the crash, but if it does, NASA scientists are poised to get about 17 minutes of additional science on the surface with the doomed device.
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