NASA’s Europa Clipper Aims for First Sample from Interstellar Comet

NASA’s Europa Clipper mission is positioned to potentially collect the first-ever sample from an interstellar comet, 3I/ATLAS, as it traverses the inner solar system. Researchers have determined that the probe could pass through the comet’s ion tail between October 30 and November 6, 2023, providing a unique opportunity to analyze material from beyond our solar system. This information comes from two European scientists, whose findings are currently available on the preprint server arXiv and await peer review.

The opportunity to gather data from 3I/ATLAS comes as the comet approaches perihelion, its closest point to the Sun, on October 29. The comet’s icy core is heating up, releasing gas and dust, which has led to an expanding tail. According to Samuel Gran, a postdoctoral researcher at the Finnish Meteorological Institute, “Sampling the tail in this way is the closest we can currently get to a direct sample of such an object, and thus a different part of the galaxy.”

Understanding the Potential and Challenges

The Europa Clipper is en route to Europa, one of Jupiter’s 95 moons, designed to investigate whether conditions exist beneath its icy surface that could support life. Equipped with advanced instruments, it may also analyze the ion tail of 3I/ATLAS. The ion tail consists of charged particles propelled away from the Sun by solar wind, which the Europa Clipper could intercept.

Gran and his colleague Geraint Jones, a project scientist at the European Space Agency, utilized a computer program called “Tailcatcher” to predict the likelihood of the probe crossing the comet’s ion tail. Their calculations suggest that the probe could capture “packets” of solar wind containing charged particles from 3I/ATLAS. Despite this promising scenario, several factors could impede the detection of these particles.

The instruments required for such measurements are currently inactive as the probe travels towards Jupiter. Due to a government shutdown, it remains uncertain whether NASA will be able to activate them in time. Additionally, the solar wind must blow in the right direction and at an appropriate strength for the probe to successfully collect samples from the ion tail.

Significance of the Encounter

If the Europa Clipper successfully navigates the ion tail, this event would mark “the first direct immersion in material from an interstellar object” for any spacecraft, according to Gran and Jones. Even in the absence of direct measurements of the ions, other indicators such as magnetic field draping and shock signatures could provide valuable insights into the structure and composition of the ion tail.

As the scientific community eagerly anticipates this potential encounter, the study of 3I/ATLAS could significantly enhance our understanding of interstellar comets and the star systems from which they originate. The mission emphasizes the importance of collaboration between different organizations and researchers in advancing our knowledge of the cosmos.