This is the official NASA seal, originally designed in 1958 by illustrators at the NASA Lewis (now Glenn) Research Center and put forward by James Modarelli, the head of NASA Lewis' Research Reports Division. The seal was officially adopted by executive order in November 1959. The yellow and white spheres represent a planet and an orbiting body; the blue starfield represents space; the red chevron represents aeronautics (based on an advanced supersonic wing model being tested at Langley); and the white orbital curve emerging from the yellow planet represents space travel. An overview of the development of the design, along with references to more detailed and precise sources, can be found in Chapter 6 of Emblems of Exploration.
Great Images in NASA Description

Source: NASA Official website, [1], page 65 and [2]. Transferred from en.wikipedia to Commons by NativeForeigner using CommonsHelper.
The original uploader was Vargklo at English Wikipedia.