Air Force Ballistic Missile Division presented briefings on the manned Military Space System Development Plan to higher Air Force and Department of Defense authorities in Washington. Also briefed were Air Research and Development Command headquarters, the Vice Chief of Staff, and R. W, Johnson, Director of the Advanced Research Projects Agency. (Chronological Space Hist, 58.)

The final flight of Squadron 20 Minuteman III missiles was turned over to SAC. This brought the strength of the 341st Strategic Missile Wing at Malmstrom AFB to 200 Minuteman missiles. The formal turnover on 3 May completed the deployment of the programmed 1,000 Minuteman missile launchers.

This was a reserve day in the L1 countdown, in case of problems in preparation. However all is on schedule for the launch. The same cannot be said for the N1. There are many delays. Mishin promised the first N1 rollout in the first half of March, but it is still in the assembly building, with no end in sight of preparations. The weather at the cosmodrome is -5 deg at night, clear pleasant days. The Hotel Kosmonavt was finished on 15 April. Although it has all of its furniture, it was not completely painted before the furniture was moved in!

The Undersecretary of Defense for Research and Engineering asked the Navy and Air Force to conduct a joint study to define a common missile which could be used in place of both Trident II and the MX. These were under separate development by the respective services. The study was also to formulate a management plan for development of the common missile and to estimate the potential savings from such a joint development.

Unmanned supply vessel to Mir. Deorbited May 11, 1987. Docked with Mir at 343 X 363 1705 23 April at rear port of Kvant. Undocked May 11 03:10. Deorbited28 May 02:59 .
Officially: Transporting sundry cargoes to the Mir orbital station. Docked with Salyut 7 on 23 Apr 1987 17:04:51 GMT. Undocked on 11 May 1987 03:10:01 GMT. Destroyed in reentry on 11 May 1987 08:28:00 GMT. Total free-flight time 2.30 days. Total docked time 17.42 days.

Preparations for the first test launch of China's first manned spacecraft were underway at the launch site, a Shanghai newspaper reported. It said the first flight would be launched in late 1999. The space cabin, telemetry system and power system had been developed in Shanghai.

Two special wind tunnels in southwest China's Sichuan Province were nearing completion. The new tunnels would be used for testing China's future space shuttle, launch vehicles, and strategic missiles. A high-frequency plasma wind tunnel and a supersonic flow wind tunnel were being built by China Aerodynamics Research and Development Center and would be the most advanced in Asia.

First launch of Russia's Dnepr launch vehicle, a converted R-36M2 ICBM. The Dnepr was launched from a silo. The third stage maneuvring bus (used on the ICBM for dispensing multiple warheads) placed UoSAT-12 into a 638 km x 652 km x 64.6 deg orbit. The third stage separated from the payload at 05:13 GMT and then made a burn into a 599 km x 1403 km x 64.6 deg orbit. UoSAT-12 was the first test of the Minibus platform, at 325 kg a larger spacecraft than earlier 50 kg Surrey UoSATs. It carried a mobile radio experiment (MERLION), a GPS receiver, and imaging cameras.

Space Shuttle Endeavour and its seven crewmembers began rendezvous preparations shortly after 3 a.m. today, which should culminate in an 8:32 a.m. docking to the International Space Station, which will be northeast of Hong Kong at an altitude of 240 miles. The shuttle is bringing an advanced robotic arm, experiments and supplies to the ever-growing science outpost. Additional Details: here....

First launch of the Antares launch vehicle, combining surplus rocket engines from the Soviet N1 moon rocket program with US-built components. The mass simulator carried instrumentation to measure the launch vehicle environment in preparation for future launches of the Cygnus spacecraft designed to carry cargo to the International Space Station. It also released four cubesats into independent orbits.