mounted. A jettisonable propulsion module with an Altair 2 solid-propellant motor provided the thrust for final orbital insertion. The OV1/Atlas combination was economical for the time, costing just $1.25 million per launch ($4545 per of payload). The standardized format also afforded a quick experiment proposal-to-launch period of just fifteen months. The program was managed by Lt. Col. Clyde Northcott, Jr. Significant results Data from OV1-4's Tissue Equivalent Ionization Chamber, compared to a similar instrument orbited on Gemini 4, determined the radiation dose Gemini astronauts traveling at OV1-4's altitude (~) would receive: 4 rads per day at a 30° inclination orbit or 1.5 rads per day at a 90° (polar) inclination orbit. In late May 1967, during a period of high solar and magnetic activity, OV1-9 returned the first evidence of Earth's long theorized but never measured electric field. The satellite detected a stream of protons flowing out of the atmosphere into space moving at more than per second. OV1-9 also studied the variation of proton fluxes in the outer Van Allen Belt during that same period, determining that fluxes were ten times greater four days after May's maximum solar activity than they had been before the flare; it took ten days for the fluxes to return to normal levels. The X-ray spectrometer on the co-launched OV1-10 returned the most comprehensive set of solar X-ray observations to date. These data enabled scientists to determine the relative density of neon to magnesium in the solar corona through direct observation rather than using complicated mathematical models. The ratio of neon to magnesium was found to be 1.47 to 1 (+/- .38). OV1 Missions OV2 Background The OV2 series of satellites was originally designed as part of the ARENTS (Advanced Research Environmental Test Satellite) program, intended to obtain supporting data for the Vela satellites, which monitored the Earth for violations of the 1963 Partial Test Ban Treaty. Upon the cancellation of ARENTS due to delays in the Centaur rocket stage, the program's hardware (developed by General Dynamics) was repurposed to fly on the Titan III (initially the A, ultimately the C) booster test launches. The USAF contracted Northrop to produce these satellites, with William C. Armstrong of Northrop Space Laboratories serving as the program manager. Spacecraft The OV2 satellites were all designed on the same plan, roughly cubical structures of aluminum honeycomb, in height, and wide, with four paddle-like solar panels mounted at the