In its place, at a cost of about $200 million each, two smaller satellites of the new intermediate class are now planned, one to study the earth's magnetosphere and one to study solar X-rays.

The first solar X-rays were recorded by T. Burnight.

As solar X-rays strike the surface, they cause the elements to fluoresce X-rays with well defined energies.

Some solar system bodies emit X-rays, the most notable being the Moon, although most of the X-ray brightness of the Moon arises from reflected solar X-rays.

Similar solar cycle-related variations are observed in the flux of solar X-ray and UV or EUV radiation.

Scattered solar X-rays provide an additional component.

The missile reached an apogee of 108.7 km and carried aeronomy (winds, pressure, temperature), solar X-ray and radiation, and biology experiments.

NRL Ionosphere 1 solar X-ray, ionosphere, meteorite mission launched a V-2 on September 29, 1949 from White Sands at 16:58 GMT and reached 151.1 km.

It was an Aerobee RTV-N-10 configuration reaching an apogee of 127 km with NRL experiments for solar X-ray and ultraviolet detection.

Despite not attaining the intended lunar orbit, the mission met many of its original goals in exploring solar wind, interplanetary plasma, and solar X-rays.