Star Tracker Sequence
An amazing sequence of Moon images in earthshine was taken by SMART-1 star trackers number 1 on 1 September 2006 from a height of 600 km. The images are presented as they were acquired, without additional processing.
In the final phases before impact, and as a nice add-on to the mission outcome so far, the SMART-1 scientists and the flight control team took the opportunity to test a fast tracking imaging mode with the star tracker, normally used to re-orient the spacecraft in space, and take an additional look at the Moon while the spacecraft is getting steadily closer.
The images show a beautiful dark Moon illuminated only by the light coming from Earth. SMART-1's star tracker gathered this sequence from 12:15 to 13:06 UT on 1 September, during a slew manoeuvre aimed at starting the next imaging session with the AMIE camera on board the spacecraft.
The constellations visible at the beginning of the sequence (when the star tracker started taking images) are Corona Australis and Sagittarius. Then, as the spacecraft continues its slew, the Moon's disk illuminated by earthshine starts to appear in its full beauty.
The dark highland areas correspond to flat mare basalts, about 3 thousand million years old. The bright spots on the surface correspond to relatively young craters, with fresh material brought to the surface by lunar impacts.
Approximately half-way through the sequence, it is possible to see a remarkable feature - an impact crater (a bright circle in the top right) and the elongated shapes of ejected material extending radially outward. At the end of the sequence it is possible to see highland reliefs in an oblique view.
When taking these images, SMART-1 was flying at about 600 kilometres altitude over the lunar surface.