NASA is unveiling close-up pictures of the interstellar comet that’s making a quick one-and-done tour of our solar system. Discovered over the summer, the comet known as 3I/Atlas is only the third confirmed object to visit from another star. It zipped harmlessly past Mars last month. Several NASA spacecraft at and near the red planet zoomed in on the comet as it passed just 18 million miles away. The closest the comet will come to Earth is 167 million miles in mid-December. Then it will hightail it back into interstellar space, never to return.