After World War II, the U.S. Naval Research Laboratory (NRL) gained access to captured German V-2 rockets to install scientific instruments on suborbital flights from White Sands. Herbert Friedman, a physicist in the electron optics division led by Edward O. Hulburt, had for years studied the theoretical possibility that the Sun emits X-rays capable of ionizing the upper layers of Earth's atmosphere — particularly the ionosphere's E layer, key to long-range radio communications — but had no means to test it until the arrival of the V-2 rockets. On September 29, 1949, Friedman, together with S. W. Lichtman and E. T. Byram, launched a V-2 rocket equipped with Geiger counters that reached 150 km altitude. The data telemetered during the flight clearly showed the presence of solar X-rays of about 8 Å above 87 km altitude, along with ultraviolet radiation at higher altitude. It was the first time a scientific instrument carried beyond Earth's atmosphere detected high-energy radiation from the Sun, confirming that the solar corona emits X-rays and establishing the physical mechanism sustaining the upper atmosphere's ionized structure. The result made Friedman, already a recognized specialist in laboratory X-ray detection, a pioneer of astronomical observation from space via rockets, a field he himself continued developing over the following three decades (Bragg spectrometer, first dedicated solar satellite SOLRAD, X-ray images of the Sun).