Despite the fact that the closest meeting of the NASA spacecraft was only a few hours with Pluto, the probe was still able to track the image of the planet and its satellite, Charon, for a full day.
Both Pluto and Charon are tidal blocked systems. This means that the same hemisphere of Charon always collides with the same hemisphere of Pluto, because a full rotation around its axis takes the same amount of time. One revolution of Pluto and Charon lasts about 6, 4 Earth days. Thus, the New Horizon, having just begun its approach, already had the opportunity to take photographs.
With the passage, each side of the cosmic bodies gradually came to light, but, as shown in these successive images, the probe began taking pictures long before it approached the point of “closest approach”, which allows us to look (albeit a bit blurry) deep into a distant planet.
The spacecraft New Horizons used its tools Ralph and LORRI to make an image of an object at a distance of 8 million km or 5 million miles. These figures are far from those recorded on July 7, 2015, namely only 645, 000 km or 400, 000 miles. The most minimal distance was noted already on July 14th. It is equal to 12,500 km or 7,800 miles. The most striking for scientists were peculiar craters on the “other side” of Pluto (photos taken at 10:00 from two different positions). These features were almost instantly discovered as soon as the device began to plunge into the atmosphere of Pluto. All mission scientists knew that there would be the best perspective for photos here.
The remaining images of the mission show only extensive plains and dynamically (quickly) frozen mountain ranges, which are already well known to all after the passage several months earlier. Observation of a duration of 6 hours shows exactly how the hemispheres “collide”, forming the famous “heart” of Pluto, which was unofficially called “Tombaugh Regio”.
As for Charon, its surface contrasts strongly with the changes occurring on the surface of Pluto. In this sequence of images, the encounter with Charon's hemispheres is shown at the 12 o'clock position.
