SOLRAD (SOLar RADiation) 1 is the public designation for SOLRAD/GRAB 1, a combination science and surveillance satellite launched into orbit on 22 June 1960.

The GRAB mission was also successful, operating until 22 September 1960, and revealing that the Soviet air defense radar network was more extensive than had been expected.

The United States Air Force began a program of cataloging the rough location and individual operating frequencies of these radars, using electronic reconnaissance aircraft flying off the borders of the Soviet Union.

Some experiments were carried out using radio telescopes looking for serendipitous Soviet radar reflections off the Moon, but this proved an inadequate solution to the problem.

The project was restarted under the name "Walnut" (the satellite component given the name "DYNO"[2]: 140, 151 ) after heightened security had been implemented, including greater oversight and restriction of access to "need-to-know" personnel.

The Navy had wanted to determine the role of solar flares in radio communications disruptions [8]: 300  and the level of hazard to satellites and astronauts posed by ultraviolet and X-ray radiation.

[13] On 5 May 1960, just four days after the downing of Gary Powers' U-2 flight over the Soviet Union highlighted the vulnerability of aircraft-based surveillance, President Eisenhower approved the launch of an operational SOLRAD satellite.

[14]: 32 The satellite's SOLRAD scientific package included two Lyman-alpha photometers (nitric oxide ion chambers) for the study of ultraviolet light in the 1050–1350 Å wavelength range and one X-ray photometer (an argon ion chamber) in the 2–8 Å wavelength range, all mounted around the equator of the satellite.

[16] The satellite's GRAB surveillance equipment was designed to detect Soviet air defense radars broadcasting on the S-band (1550–3900 MHz).

As it traveled over the Soviet Union, the satellite would detect the pulses from the missile radars and immediately re-broadcast them to American ground stations within range, which would record the signals and send them to the NRL for analysis.

[18] Like most early automatic spacecraft, SOLRAD/GRAB 1, though spin stabilized,[8]: 300  lacked attitude control systems and thus scanned the whole sky without focusing on a particular source.

[10]: 13  So that scientists could properly interpret the source of the X-rays detected by SOLRAD/GRAB 1, the spacecraft carried a vacuum photocell to determine when the Sun was striking its photometers and the angle at which sunlight hit them.

[19] SOLRAD/GRAB 1, the world's first orbital solar observatory, transmitted more than 500 batches of scientific data between June and November 1960,[10]: 64–65  after which it became impossible to determine the angle at which the Sun hit the SOLRAD experiments.

[23]: 28 It had been hoped during design and development that SOLRAD/GRAB 1 would be able to identify above-ground atomic tests, which produced strong emissions of X-rays in the bands that the satellite could detect.

[25] Thus, though the satellite's surveillance equipment functioned for the 92 days from launch until their failure on 22 September 1960, GRAB 1 only returned 22 batches of data, its first delivered on 5 July 1960 [21] to the station at Wahiawa, Hawaii, well out of the range of Soviet detection.

[5]: 3  Even this first limited surveillance endeavor saturated the ground teams' ability to analyze and process the data [5]: 39  and yielded valuable information, including the revelation that Soviet air defense activity was more extensive than expected.