A new mission to reach the 3i/Atlas comet, NASA scientists are studying the possibilities

When it was around 4.3 astronomical units (AU) of the sun, it was calculated a eccentricity of 1.004, sufficient for a hyperbolic trajectory. In addition, its entry speed of 38 km/s would confirm its interstellar nature.

An astronomical unit corresponds to the average distance between the earth and the sun. It has around 150 million kilometers.

During his approach, it was estimated that his perihelion – the point closest to the sun – would occur on September 30, 2025, at only 0.34 AU. It would also increase to only 0.18 AUs in March, Offering an unusual opportunity to try to reach it from this planet.

A new study, conducted by researchers from the State University of Michigan, assessed whether a spacecraft already in orbit around Mars or the Earth could have reached the comet before it escapes. The result was surprising: since March, the mission would have been achievable with existing technology.

From the earth, the launch was already impossible at the time of the discovery, because to reach the comet, it would have taken a speed greater than 24 km/s. On the other hand, since March, the calculations show that the necessary impulse would have been much lower, in the capacities of probes currently in service.

The best time for a launch would have been on July 1, ironically the same day of its discovery. By taking advantage of this window, The meeting could have taken place on October 3, Precisely when the comet would have reached its minimum distance from March.

What we could have learned closely

3i/Atlas is probably a comet from the Oort cloud of another star. An overview would therefore have made it possible to analyze the proportion of isotopes in its ice cream, to measure its cometary activity and to verify whether its nucleus presented characteristics similar to those of known comets or exotic properties.

A mission equipped with spectrometers and cameras would have allowed us to directly study the nucleus structure, the gases released by sublimation and their interaction with solar radiation, as well as to determine if it contains organic compounds such as those observed in local comets, while looking for possible rare molecular signatures.

In the coming months, She will reach a maximum magnitude of 10, Too low to be observed with domestic telescopes, but also visible with professional instrumentation. This confirms that this is a small object, With a nucleus of 1 to 2 kilometers in diameter, probably covered with thin hair (coma).

The detailed study of interstellar objects allows to reconstitute their dynamic and chemical history, And to learn more about planetary training processes around other stars. 3i/Atlas offered us this possibility and leaves us a clear lesson: we must be ready before the next visitor crosses our doors.

Since March yes, from the earth no

Depending on the calculations, A mission launched from Earth after discovery was no longer possible. It would have required a Delta-V superior to more than double the capacity of any current launcher. On the other hand, since March, an orbit vessel could have reached the comet without resorting to revolutionary technologies.

The Delta-V (ΔV) corresponds to the capacity of a spacecraft to accelerate and decelerate. It is a measure of the total impulse necessary to modify your speed during orbital maneuvers and trajectory changes.

The Delta-V necessary since March was only 3.5 km/s in the best scenario. Even with a delayed launch of a few weeks, the required impetus remained reasonable. Several probes in Martian orbit would have had enough fuel to make the maneuver, provided you act quickly.

The overview would have taken place in October, When 3i/Atlas would have increased to 27 million kilometers from March, A low distance at the astronomical scale, ideal for making close observations and obtaining detailed images of the moving nucleus – an extraordinary occasion with minimal additional cost.

However, this did not materialize, the time having been insufficient to redirect a mission. This shows that having operational vessels on other planets can offer strategic advantages, and that Mars could become an advanced platform to explore the solar system … and beyond.

The future: waiting interceptors

The key lies in anticipation: if an interstellar object is detected and probes are ready, an overview becomes possible. But for that, you need a spatial architecture allowing a rapid reaction. We cannot design a mission since zero each time a visitor appears.

A concrete proposal consists in having prepositioned interceptors, That is to say, vessels placed strategically in orbit around Mars, From the land or to Lagrange points (like the JWST), which would remain inactive until the reception of an alert. With enough fuel and suitable sensors, they could be launched in a few days or weeks to their target.

The concept is already underway: ESA will launch the probe in 2029 Comet Interceptor, which will wait at point L2 and will be activated when a new virgin or interstellar comet will appear – a strategy that could radically transform

With 3i/Atlas, we were close, but we did not reach the goal. However, if we hear the lesson and prepare our probes with a long-term vision, perhaps we will succeed, next time, to achieve something that we have never done: to study face to face a fragment of another stellar system- Who, no, is not an extraterrestrial vessel.