Researchers have outlined a mission concept that would send a spacecraft hurtling past the Sun at extreme proximity to build enough speed to chase down 3I/ATLAS, the third known interstellar object ever detected passing through our solar system. The proposal centers on a technique called the Solar Oberth Manoeuvre, which would require skimming within roughly 3.2 solar radii of the Sun’s surface, far closer than any probe has ventured before. With a candidate launch window stretching from 2031 to 2037 and an optimal departure around 2035, the clock is already ticking on what would be one of the most technically demanding deep-space pursuits ever attempted.
A Gravity Slingshot Closer Than Any Probe Has Gone
The core engineering challenge is blunt: 3I/ATLAS is moving too fast for any conventional spacecraft to catch. Because interstellar objects enter and leave the solar system on hyperbolic trajectories, a pursuing probe needs a velocity boost that chemical rockets alone cannot deliver. The Solar Oberth study solves this by firing engines at the lowest point of a close solar flyby, where the Sun’s gravity compresses the spacecraft’s kinetic energy into a much larger speed gain per unit of fuel. The required perihelion distance in this proposal is approximately 3.2 solar radii, or about 0.015 AU, placing the spacecraft in an environment of punishing heat and radiation that pushes thermal protection and propulsion to their limits.
For context, NASA’s Parker Solar Probe completed its 24th perihelion in June 2025, flying roughly 3.8 million miles from the solar surface. Even that record-setting pass relied on a specially engineered thermal protection system and full spacecraft autonomy during closest approach, when communication blackouts made ground control impossible. The 3I/ATLAS intercept would demand a perihelion pass several times closer, meaning engineers would need to design heat shielding and navigation systems well beyond current capabilities. No space agency has publicly committed funding or a formal feasibility study for such a mission, so the concept remains an academic blueprint rather than an approved program, illustrating how far ahead scientists must think to be ready for rare interstellar opportunities.
Why 3I/ATLAS Warrants the Risk
Only two interstellar visitors preceded 3I/ATLAS: 1I/’Oumuamua in 2017 and 2I/Borisov in 2019, both discovered too late for any realistic intercept. 3I/ATLAS, described by ESA as an object from beyond our solar system, offers a longer planning horizon but still presents severe observational limits. Near perihelion, its small solar elongation makes ground-based telescope work extremely difficult, according to a visibility analysis that catalogued the comet’s observing geometry and potential spacecraft viewing windows. That geometry means that without a nearby probe, much of the most interesting activity could unfold effectively hidden in the Sun’s glare.
The scientific payoff, however, could be enormous. Galactic dynamics modeling that draws on Gaia stellar survey data and disk chemistry frameworks suggests 3I/ATLAS has older, thick-disk-like kinematics, implying it likely formed in a stellar system billions of years ago during a period of intense star formation sometimes called “cosmic noon.” That same population modeling predicts measurable properties such as water fraction and dust-to-gas ratio, which could reveal whether volatile chemistry in distant stellar nurseries differs fundamentally from what built our own planets. A close flyby with onboard spectrometers and dust analyzers could test those predictions directly, something no Earth-based observatory can replicate for an object this small and fast, and potentially provide the first in situ sample of material formed around another star.
Early Observations Already Shaping the Science
Ground and space-based instruments have been gathering data on 3I/ATLAS since shortly after its discovery, steadily refining what a dedicated mission would need to measure. Peer-reviewed SOAR photometry captured brightness measurements on specific nights in July 2025, providing early constraints on the comet’s activity and rotation by tracking how its light output varied over time. Those data hinted at a moderately active nucleus and helped establish baseline estimates for dust production, which in turn inform thermal models used to predict how the comet will evolve as it approaches and recedes from the Sun.
Separately, researchers used non-gravitational acceleration models to estimate the nucleus diameter at roughly 0.82 to 1.05 km, though that figure carries systematic uncertainties tied to assumptions about outgassing asymmetry and bulk density, as detailed in a size-constraint analysis. Later in 2025, ESA refined the comet’s orbital path by combining Earth-based observations taken on July 2 with tracking data relayed from Mars-based assets, dramatically reducing positional uncertainty. By November, the joint NASA/ESA solar observatory SOHO had also recorded the comet as it crossed the inner solar system, adding to the growing dataset. Every refinement in orbit and physical properties narrows the design space for a potential interceptor, from required delta‑v to optimal encounter distance.
Existing Missions Could Offer Bonus Data
Even without a dedicated intercept, the science operations work identifies several active spacecraft that could gather opportunistic measurements as 3I/ATLAS passes through the planetary region. The comet’s trajectory brings it into relatively favorable geometry for NASA’s Psyche asteroid probe, various Mars orbiters, and ESA’s JUICE mission to Jupiter’s moons, raising the possibility of serendipitous imaging or dust detection if mission teams can spare pointing time. None of these craft were designed to study interstellar comets, and no agency has confirmed plans to retarget them, but even low-resolution observations from multiple vantage points could help constrain coma structure, jet morphology, or solar wind interactions that are hard to capture from Earth alone.
Such “ride-along” science would build on the heritage of previous missions that turned opportunistic flybys into major discoveries, like when New Horizons observed distant Kuiper Belt objects beyond Pluto or when Mars orbiters monitored unexpected comet encounters. In the case of 3I/ATLAS, coordinated campaigns across several spacecraft could provide a kind of sparse 3D tomography of the coma and tail, leveraging instruments such as narrow-angle cameras, ultraviolet spectrographs, and dust counters. While this would fall far short of the detailed close-up reconnaissance a purpose-built mission could achieve, it would still expand the tiny observational sample of interstellar bodies and test some of the same models that a future Solar Oberth pursuit aims to address.
From Ambitious Concept to Future Playbook
The Solar Oberth mission architecture for 3I/ATLAS also functions as a template for how the scientific community might respond to the next interstellar visitor. Because these objects arrive on unpredictable trajectories with limited warning, a fully bespoke mission for each one is unrealistic; instead, researchers are exploring modular designs, pre-qualified launch windows, and “on the shelf” technologies that could be rapidly assembled. The detailed performance estimates in the Oberth concept show that, with sufficient lead time, chemical propulsion augmented by an extreme solar flyby could in principle reach hyperbolic targets that would otherwise be out of reach, turning a one-off challenge into a repeatable strategy.
Underlying much of this planning is an ecosystem of open-access research that accelerates iteration between mission designers, dynamicists, and observers. Many of the key visibility, population, and trajectory studies on 3I/ATLAS have appeared on preprint servers whose member institutions span universities, space agencies, and research labs worldwide, allowing ideas like the Solar Oberth pursuit to be scrutinized and refined quickly. That same infrastructure depends on community support, including donor contributions that keep rapid dissemination viable for niche but time-critical topics such as interstellar intercepts. Whether or not a 3I/ATLAS chase ultimately flies, the concepts being developed now are likely to shape how humanity prepares for (and perhaps one day routinely visits) icy messengers arriving from other stars.
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*This article was researched with the help of AI, with human editors creating the final content.
