[[1] (http://legacy.gsfc.nasa.gov/Images/explorer/explorer-11_small.gif)] Explorer 11, also known as S15, was the orbital spacecraft that carried the first gamma ray telescope. This was the earliest beginnings of gamma-ray astronomy. Launched on 27 April 1961 by a Juno-2 rocket the satellite returned data until early September, when power supply problems eventually ended the mission. During the spacecraft's four month lifespan it detected twenty-two events from gamma-rays and approximately 22,000 events from cosmic radiation.
The telescope used a combination of a sandwich scintillator detector along with a cherenkov counter to measure direction of events. Since the telescope could not be aimed the spacecraft was set in an end over end tumble to give a rough scan of the celestial sphere, with emphasis on the galactic plane, the galactic center, the sun, and other known radio noise sources.
The gamma-ray events observed by Explorer 11 seemed to suggest a random distribution 'background' of gamma-rays. Later telescopes observed point sources in addition to the background noise of gamma-rays.
Explorer 32 was an aeronomy satellite that measured temperature, composition, density, and pressure in the upper atmosphere.
The Explorer VI satellite primary objective was to study trapped radiation of various energies, galactic cosmic rays, geomagnetism, radio propagation in the upper atmosphere, and the flux of micrometeorites.
The Explorer VIII satellite primary objective was to obtain measurements of the electron density, the electron temperature, the ion concentration, the ion mass, the micrometeorite distribution, and the micrometeorite mass in the ionosphere.
Explorers 2 and 5 are counted in the sequence even though they failed to achieve orbit.
The early Explorers performed a large variety of scientific missions ranging from energy particle exploration through atmospheric and ionospheric studies to investigations of micrometeroids, air density, radio astronomy, geodesy, and gamma ray astronomy-including interplanetary and solar monitoring.
The Explorer series were relatively small and uncomplicated.
Feeds |
Contact