Solar radiation research. Launched at 0947 local time. Reached 112.7 km.

Cruise stage tanks 1 and 4 empty. The flight continued to T+25 minutes 20 seconds over a distance of 1,315 km. Booster stage operation and separation were normal, no vibrations were detected. The cruise stage ignited but the Air Sensor System (SVD) operated abnormally. As a result there was a reduction of velocity from that planned.

Maximum Speed - 2080 kph. Maximum Altitude - 15235 m. References: 38 , 49 , 97 .

Combat Training Launch 7

Members of Langley Research Center briefed representatives of the Chance Vought Corporation of Ling- Temco-Vought, Inc., on the lunar orbit rendezvous method of accomplishing the lunar landing mission. The briefing was made in connection with the study contract on spacecraft rendezvous awarded by NASA Headquarters to Chance Vought on March 1. References: 16 .

NASA announced that a $5 million contract would be awarded to Republic Aviation Corporation for the construction of two experimental reentry spacecraft. Republic was selected from eight companies that submitted bids on March 12. The contract was part of Project Fire, to develop a spacecraft capable of withstanding reentry into the earth's atmosphere from a lunar mission. Plans called for the spacecraft to be tested during the second half of 1963. References: 16 .

Suborbital. References: 5 .

The possibility of doing more than the previously planned stand-up form of extravehicular activity (EVA) was introduced at an informal meeting in the office of Director Robert R. Gilruth at Manned Spacecraft Center (MSC). Present at the meeting, in addition to Gilruth and Deputy Director George M. Low, were Richard S. Johnston of Crew Systems Division (CSD) and Warren J. North of Flight Crew Operations Division. Johnston presented a mock-up of an EVA chestpack, as well as a prototype hand-held maneuvering unit. North expressed his division's confidence that an umbilical EVA could be successfully achieved on the Gemini-Titan 4 mission. Receiving a go-ahead from Gilruth, CSD briefed George E. Mueller, Associate Administrator for Mannned Space Flight, on April 3 in Washington. He, in turn, briefed the Headquarters Directorates. The relevant MSC divisions were given tentative approval to continue the preparations and training required for the operation. Associate Administrator of NASA, Robert C. Seamans, Jr., visited MSC for further briefing on May 14. The enthusiasm he carried back to Washington regarding flight-readiness soon prompted final Headquarters approval.

Fastest X-24 flight. Maximum Speed - 1667 kph. Maximum Altitude - 21488 m. Flight Time - 446 sec. References: 49 , 97 .

Mariner 10 flew past Mercury at 756 km altitude. Photographs taken during the pass revealed an intensely cratered, Moon-like surface and a faint atmosphere of mostly helium.

Geosynchronous ballistic missile early warning satellite. Stationed at 23 deg W. References: 1 , 2 , 5 , 6 , 67 , 107 , 274 .

Time 2 minutes. References: 81 .

Six microgravity experiments for UA)