As the eccentricity continues to increase, the question shifts from “What is the shape of its trajectory?” to “how much does the Sun change its path in the Solar System?” For 3I/Atlas with an eccentricity greater than six, the answer is “not very much at all.” The object approached the inner Solar System in a roughly straight line, experienced a gentle curve around the Sun near the orbit of Mars, and will now fly out of the Solar System again.
So, the object clearly did not originate here, which means getting a better look at it is the first priority. Unfortunately, 3I/ATLAS's closest approach to Earth's orbit occurred while it was on the far side of the Sun from Earth. We've been getting closer since then, but all the equipment that provided the best views was in orbit around Mars and was designed primarily to point downwards. NASA's Nicky Fox, associate administrator for science, praised the camera crews for pushing NASA's hardware “beyond its design capabilities” to image the object.
This includes using MAVEN mission (designed to study the atmosphere of Mars) to obtain spectral information, as well as the HiRISE camera that captured the image below. Other images taken from solar observatory and two separate missions heading to asteroids. Other equipment that can typically image such objects, such as Hubble and JWST, have also switched to 3I/ATLAS imaging.
What do we know now
Hubble got the best view from 3I/ATLAS; his data shows that the comet has a diameter of no more than a couple of kilometers. It doesn't show much change over time, suggesting that if it rotates, it does so very slowly. As it warmed up, it showed some differences: it first produced a jet of material on its side facing the Sun, and then radiation pressure pushed it behind it, forming a tail. There are some indications that, as we saw during the Rosetta mission's visit to one of our solar system's comets, much of the material may be ejected from individual “hot spots” on the comet's surface.
