IGY Bulletin, Number 9, March 1958 - First US-IGY satellite

On to the IGY Bulletin issue #9 from March, 1958. The download of this 16-page issue from the AGU website can be found here. The articles in this issue are:

1. First US-IGY satellite
2. Phototrack
3. Life sciences in the IGY
4. Cruise of the Brown Bear

Here I will summarize the first article. In an earlier post, I wrote about the successful launch into orbit of Explorer 1 on the anniversary of that historic event. This Bulletin article starts by summarizing rocket and satellite characteristics. The payload instrumentation was for measuring the cosmic ray intensity, the density of meteoric matter, and temperatures inside and on the skin of the satellite. A geiger counter was used to measure cosmic rays. Impact of solid meteoric particles was measured by a microphone and also by erosion gages based on changes in electrical characteristics. Thermal probes measured temperatures.

A schematic of the 80" long satellite, scanned from the article, is shown below:

Two radio transmitters allowed tracking by the Minitrack system. A telescopic sighting was reported from the Moonwatch team in Alamogordo, NM, and a naked-eye sighting reported from a Moonwatch team in Manhattan, KS. The latter reported the brightness to be that of a fifth-magnitude star, about 15 times dimmer than Polaris (the North Star).

In my post from a month ago, I showed the stamp that was finally issued at the turn of the 20th century to commemorate this launch, somewhat ignored until then because the U.S. was second into space. I have now acquired covers with cachets postmarked on the 15th (1973), 20th (1978), and 25th (1983) anniversaries of the launch, shown below.

One of 100 covers from the Smithsonian Milestones of Flight series, Stamp is the IGY president Eisenhower 8¢ (Scott #1393, 1970).

The 20th anniversary cover is franked with the 13¢ Kennedy definitive (Scott #1287, an older stamp from 1967).

This cover was not postmarked, but has a cancellation honoring the launch of Explorer 1. The cachet showing the rocket, satellite, and Wernher von Braun actually seems to commemorate the 25th anniversary of the founding of NASA, later in the year on 1 Oct. 1958. The 20¢ stamp shows the U.S. flag (Scott #1894, 1981).

The 15th anniversary cover included a small leaflet from the National Air and Space Museum. 

It stated that Explorer 1's cosmic ray measurements showed a lower than anticipated cosmic ray count. James Van Allen (who signed another Explorer 1 cover shown earlier) suggested the reading was spurious because the instrument had been saturated by a strong belt of radiation trapped in the Earth's magnetic field. This was to be verified by the Explorer 3 satellite, launched on 26 March 1958, one of the most significant findings of the IGY.