https://skyandtelescope.org/astronomy-news/interstellar-comet-3i-atlas-what-we-know-now/#:~:text=The Trajectory,through the inner solar system.&text=As Comet 3I/ATLAS continues,spacecraft might fill the gap.
Capturing the Comet at Perihelion
Marshall Eubanks (Space Initiatives Inc.) has calculated that several interplanetary spacecraft as well as Mars orbiters or rovers could have a clear view of 3I/ATLAS while it’s out of Earth’s view. He has been communicating with members of the teams managing these missions.
Artist’s concept of the Jupiter Icy Moons Explorer (JUICE), currently on its way to the giant planet. It could potentially turn around to gaze at the interstellar comet, but such a change to the mission plan isn't trivial.
ESA / AOES
The two best candidates, Eubanks tells
Sky & Telescope, are the Jupiter Icy Moons Explorer (JUICE), and Psyche, which is on its way to the asteroid of the same name. JUICE, he says, “will have a wonderful view of 3I,” from less than a third of an astronomical unit (au) away (about 10 times closer than the comet’s distance from Earth at that time), and has some instruments that could do useful observations. But making a sudden change in such an expensive mission, which has been many years in planning and development, is far from trivial. Any changes would have to be developed carefully to avoid endangering the primary mission, and no decision has been made yet by that team.
Psyche will be similarly well placed, about 0.4 au away from 3I/ATLAS. But it’s under steady propulsion from its ion drive, which might make observing the comet tricky. Robotic observers at or around Mars might have an easier time making the adjustments needed to make useful observations, Eubanks says.
One way or another, it would be useful to have observational coverage of the comet’s entire journey through the solar system. Astronomers still regret that there were such limited observations of the two previous interstellar objects, because their discoveries occurred relatively late in their solar system passes.
This time, continuous coverage could capture unusual activity takes place such as fragmentaion. As Eubanks says, “it would be very nice to be able to observe that in real time, as opposed to just trying to guess what happened afterwards.”
