An icy ocean world in our solar system that could tell us more about the potential for life on other worlds is coming into focus with confirmation of the Europa Clipper mission’s next phase. The decision allows the mission to progress to completion of final design, followed by the construction and testing of the entire spacecraft and science payload.
“We are all excited about the decision that moves the Europa Clipper mission one key step closer to unlocking the mysteries of this ocean world,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “We are building upon the scientific insights received from the flagship Galileo and Cassini spacecraft and working to advance our understanding of our cosmic origin, and even life elsewhere.”
The mission will conduct an in-depth exploration of Jupiter’s moon Europa and investigate whether the icy moon could harbor conditions suitable for life, honing our insights into astrobiology. To develop this mission in the most cost-effective fashion, NASA is targeting to have the Europa Clipper spacecraft complete and ready for launch as early as 2023. The agency baseline commitment, however, supports a launch readiness date by 2025.
Nearly all of the oxygen in our universe is forged in the bellies of massive stars like our sun. As these stars contract and burn, they set off thermonuclear reactions within their cores, where nuclei of carbon and helium can collide and fuse in a rare though essential nuclear reaction that generates much of the oxygen in the universe.
The rate of this oxygen-generating reaction has been incredibly tricky to pin down. But if researchers can get a good enough estimate of what’s known as the “radiative capture reaction rate,” they can begin to work out the answers to fundamental questions, such as the ratio of carbon to oxygen in the universe. An accurate rate might also help them determine whether an exploding star will settle into the form of a black hole or a neutron star.
Now physicists at MIT’s Laboratory for Nuclear Science (LNS) have come up with an experimental design that could help to nail down the rate of this oxygen-generating reaction. The approach requires a type of particle accelerator that is still under construction, in several locations around the world. Once up and running, such “multimegawatt” linear accelerators may provide just the right conditions to run the oxgen-generating reaction in reverse, as if turning back the clock of star formation.
The researchers say such an “inverse reaction” should give them an estimate of the reaction rate that actually occurs in stars, with higher accuracy than has previously been achieved.
“The job description of a physicist is to understand the world, and right now, we don’t quite understand where the oxygen in the universe comes from, and, how oxygen and carbon are made,” says Richard Milner, professor of physics at MIT. “If we’re right, this measurement will help us answer some of these important questions in nuclear physics regarding the origin of the elements.”