... An example of solar-powered flight, NASA's Helios aircraft flew almost one hundred years after the Wright brothers' historic flight on December 17, 1903. ... Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. ... Open Star Clusters M35 and NGC 2158 . ... Open clusters may contain from 100 to 10,000 stars, all of which formed at nearly the same time. Bright blue stars frequently distinguish younger open clusters. ...