This view of Jupiter’s icy moon Europa was captured by the JunoCam imager aboard NASA’s Juno spacecraft during the mission’s close flyby on Sept. 29, 2022. Image data: NASA/JPL-Caltech/SwRI/MSSS Image processing: Kevin M. Gill CC BY 3.0
The ice-covered Jovian moon generates 1,000 tons of oxygen every 24 hours –
enough to keep a million humans breathing for a day.
Scientists with NASA’s Juno mission to Jupiter have calculated the rate of
oxygen being produced at the Jovian moon Europa to be substantially less than
most previous studies. Published on March 4 in Nature
Astronomy, the findings
were derived by measuring hydrogen outgassing from the icy moon’s surface using
data collected by the spacecraft’s Jovian Auroral Distributions Experiment
(JADE) instrument.
The paper’s authors estimate the
amount of oxygen produced to be around 26 pounds every second (12 kilograms per
second). Previous estimates range from a few pounds to over 2,000 pounds per
second (over 1,000 kilograms per second). Scientists believe that some of the
oxygen produced in this manner could work its way into the moon’s subsurface
ocean as a possible source of metabolic energy.
With an equatorial diameter of
1,940 miles (3,100 kilometers), Europa is the fourth largest of Jupiter’s
95 known moons and the smallest of the four Galilean satellites. Scientists believe
a vast internal ocean of salty water lurks beneath its icy crust, and they are
curious about the potential for life-supporting conditions to exist below the
surface.
This illustration shows charged particles from Jupiter impacting Europa’s surface, splitting frozen water molecules into oxygen and hydrogen molecules. Scientists believe some of these newly created oxygen gases could migrate toward the moon’s subsurface ocean, as depicted in the inset image. NASA/JPL-Caltech/SWRI/PU
It is not just the water that has astrobiologists’ attention: The Jovian
moon’s location plays an important role in biological possibilities as well.
Europa’s orbit places it right in the middle of the gas giant’s radiation
belts. Charged, or ionized, particles from Jupiter bombard the icy surface,
splitting water molecules in two to generate oxygen that might find its way
into the moon’s ocean.
Click here
for an interactive 3D visualization of Europa
“Europa is like an ice ball slowly losing its water in a flowing stream.
Except, in this case, the stream is a fluid of ionized particles swept around
Jupiter by its extraordinary magnetic field,” said JADE scientist Jamey Szalay
from Princeton University in New Jersey. “When these ionized particles impact
Europa, they break up the water-ice molecule by molecule on the surface to
produce hydrogen and oxygen. In a way, the entire ice shell is being
continuously eroded by waves of charged particles washing up upon it.”
Capturing the
Bombardment
As Juno flew within 220 miles (354
kilometers) of Europa at 2:36 p.m. PDT Sept. 29, 2022, JADE identified and
measured hydrogen and oxygen ions that had been created by the bombarding
charged particles and then “picked up” by Jupiter’s magnetic field as it swept
past the moon.
“Back when NASA’S Galileo mission flew by Europa, it opened our eyes to
the complex and dynamic interaction Europa has with its environment. Juno
brought a new capability to directly measure the composition of charged
particles shed from Europa’s atmosphere, and we couldn’t wait to further peek
behind the curtain of this exciting water world,” said Szalay. “But what we
didn’t realize is that Juno’s observations would give us such a tight
constraint on the amount of oxygen produced in Europa’s icy surface.”
Juno carries 11 state-of-the-art
science instruments designed to study the Jovian system, including nine
charged-particle and electromagnetic-wave sensors for studying Jupiter’s
magnetosphere.
“Our ability to fly close to the
Galilean satellites during our extended mission allowed us to start tackling a breadth of science, including some
unique opportunities to contribute to the investigation of Europa’s
habitability,” said Scott Bolton, Juno’s principal investigator from the
Southwest Research Institute in San Antonio. “And we’re not done yet. More moon
flybys and the first exploration of Jupiter’s close ring and polar atmosphere
are yet to come.”
Oxygen production is one of many
facets that NASA’s Europa
Clipper mission
will investigate when it arrives at Jupiter in 2030. The mission has a
sophisticated payload of nine science
instruments to determine if Europa has conditions that could be suitable for
life.
Now Bolton and the rest of the Juno
mission team are setting their sights on another Jovian world, the
volcano-festooned moon Io. On April 9, the spacecraft will come within about
10,250 miles (16,500 kilometers) of its surface. The data Juno gathers will add
to findings from past Io flybys, including two extremely close approaches of
about 932 miles (1,500 kilometers) on Dec. 30, 2023, and Feb. 3, 2024.
More About the
Mission
NASA’s Jet Propulsion Laboratory, a
division of Caltech in Pasadena, California, manages the Juno mission for the
principal investigator, Scott Bolton, of the Southwest Research Institute in
San Antonio. Juno is part of NASA’s New Frontiers Program, which is managed at
NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s
Science Mission Directorate in Washington. The Italian Space Agency (ASI)
funded the Jovian InfraRed Auroral Mapper. Lockheed Martin Space in Denver
built and operates the spacecraft.
More information about Juno is
available at:
https://www.nasa.gov/juno
Source: NASA’s Juno Mission Measures Oxygen Production at Europa - NASA
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