Published online by Cambridge University Press: 12 April 2016
The HEOS 2 satellite was launched into a highly eccentric orbit around the earth on January 31, 1972 and re-entered the earth’s atmosphere after a successful mission on August 2, 1974. Due to the orbit (apogee: 240 000 km, perigee: 300 – 5000 km) the satellite spent most of the time in the interplanetary region where the influence of the earth’s gravitation field is negligible with regard to its effect on interplanetary dust particles.