Scientists say a future NASA probe might be able to meet a visitor from another star system while it is still in deep space.

We have already seen two interstellar objects pass through our neighborhood. Astronomers spotted ‘Oumuamua in 2017 and the comet 2I Borisov in 2019, but both were found too late for any spacecraft to reach them. The new idea argues that if we prepare in advance, the next one could be within reach.

Interstellar comets and asteroids are not born in our Solar System. They were likely ejected from other planetary systems long ago, then drifted through the galaxy until gravity guided them past our Sun.

These objects move very fast, and many arrive on steep, one-time paths, which means they are visible for only a few months. That short window is the main problem. A spacecraft must already be in a good position with enough fuel and speed to chase the target before it is gone.

Researchers suggest using a compact, ready-to-go probe that waits in a stable location, such as a solar orbit near a Lagrange point. When sky surveys announce a promising target, the craft would wake up, fire a booster, and sprint to a flyby.

New telescopes will help by finding these objects earlier. The Vera C. Rubin Observatory is designed to scan the entire visible sky every few nights, and NASA’s NEO Surveyor mission will hunt for dim objects with infrared eyes. Earlier discovery means more time to plan an intercept.

What could we learn from such a meeting? A close pass could reveal how the comet’s ices and dust compare to those in our own comets. Cameras could map the surface and jets. Spectrometers could identify molecules like water vapor, carbon monoxide, and (possibly) organics. A dust analyzer could sample tiny grains to study their size and makeup. Each of these measurements would tell us how other star systems build planets and small bodies.

It would also test ideas about why ‘Oumuamua looked so odd compared with comets we know.

There are, of course, real engineering hurdles. The relative speed will likely be tens of kilometers per second, which means the probe would get only minutes to hours near the target. Navigation must be precise, and the spacecraft must track the comet against a bright background near the Sun. Communication delays and the short encounter time mean the probe must be able to make decisions on its own during the flyby.

Even with these challenges, the plan is realistic because it builds on technology we already use. Spacecraft have executed high-speed flybys of comets and asteroids before. We know how to put a probe into a low-power state for years, then wake it when needed. The biggest change is having a mission on standby and a strategy that connects discovery alerts to quick maneuvers in space, but the ways that could be done have already been published in a paper that is being reviewed for publication in The Astrophysical Journal Letters.

If the next interstellar visitor is found with enough warning, a waiting probe could meet it on the way out and send home the first close-up data from another star system.

That single encounter would open a new chapter for planetary science and give us a direct look at building materials from worlds beyond our own.

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