It’s time to bring back those propeller beanies that kids used to wear. Let’s do it if only to celebrate the success of NASA’s Ultima Thule mission. We still don’t have the close-up photos yet, but this little animation shows the propeller-like rotation of Ultima Thule across 9 hours between 2 p.m. and 11 p.m. on Dec. 31 (Central Time). as seen by NASA’s New Horizons spacecraft as it sped toward closest encounter with the object on Jan. 1. A full rotation takes about 15 hours.
During the shoot, the distance between the spacecraft and its target decreased from 310,000 miles (500,000 km) to just 17,100 miles (28,000 km). How amazing to see the resolution improving right before your eyes. Two sequences were created by the New Horizons team. The first shows the images at their original size, while the bottom corrects for the changing distance, so that Ultima Thule appears at constant size but becomes more detailed as the craft approaches. Watching it spin it’s clear why we didn’t see any variations in its brightness as it rotated — we only ever saw one side because its rotation was “face-on” to the spacecraft.
All the images have been sharpened using scientific techniques that enhance detail. You can see the raw photos used to create the animations on the New Horizons LORRI website. New Horizons sent the two highest-resolution images in this movie immediately after the Jan. 1 flyby, but the more distant ones were sent home on Jan. 12-14 after waiting a week for reliable communications to resume. You might remember that the probe passed close to the sun from our perspective on Earth. Radio signals from the spacecraft can be compromised by the sun’s hot corona. It’s now out in the clear and will continue to transmit images and data for nearly 40 months. Can’t wait for those close-ups. Come on, NASA, we’re on pins and needles over here.