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Background: Explorer 1 was successfully launched into orbit by the US 1958-02-01 about four months after Sputnik 1 was successfully launched by the Soviet Union 1957-10-04, and Vanguard 1 wasn't successfully launched until 1958-03-17.

The Vanguard program started with Vanguard 1:

Vanguard 1 (ID: 1958-Beta 2) is an American satellite that was the fourth artificial Earth orbital satellite to be successfully launched (following Sputnik 1, Sputnik 2, and Explorer 1). Vanguard 1 was the first satellite to have solar electric power.

Eisenhower's last two sentences in the filmed message discussed below refer to scientific purpose and international arrangements.


Question What were the international space arrangements and scientific purposes Eisenhower spoke of in October 1957?


The Quote: I've transcribed the block quote below myself from the video clip at http://dbsmaint.galib.uga.edu/news/clips/wsbn33649.html found at Series WSB-TV newsflim clips of Dwight D. Eisenhower congratulating the Soviets on Sputnik and commenting on Project Vanguard and the U.S. ballistic missile program, Washington, D.C., 1957 October 9. It seems fairly accurate, but I don't have an independent official transcript for verification.

Creator:           WSB-TV (Television station : Atlanta, Ga.)
Date of Original:  1957-10-09

As to the Soviet satellite, we congratulate Soviet scientists upon putting a satellite into orbit.

The United States satellite program has been designed from its inception for maximum results in scientific research.

The rocketry employed by our Naval Research Laboratory for launching our Vanguard has been deliberately separated from our ballistic missile effort in order

  • first, to accent the scientific purposes of the satellite,
  • and second, to avoid interference with top priority missile programs.

Merging of this scientific effort with military programs could have produced an orbiting United States satellite before now, but to the detriment of scientific goals and military progress.

Vanguard, for the reasons indicated, has not had equal priority with that accorded our ballistic missile work. Speed of progress in the satellite project can not be taken as an index of our progress in ballistic missile work.

I consider our country’s satellite program to be well designed and properly scheduled to achieve the scientific purposes for which it was initiated.

We are therefore carrying the program forward in keeping with our arrangements with the international scientific community. (emphasis added)

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"International Geophysical Year" (IGY) ran from from 1 July 1957 to 31 December 1958. Eisenhower's speech in October 1957 was being made in that context.

IGY logo

Image source Wikimedia

The United States' Explorer 1 satellite was launched as one of the projects for that year.


The US intention to launch an artificial satellite during the IGY had been announced in July 1955:

"On behalf of the President, I am now announcing that the President has approved plans by this country for going ahead with the launching of small earth-circling satellites as part of the United States participation in the International Geophysical Year... This program will for the first time in history enable scientists throughout the world to make sustained observations in the regions beyond the earth's atmosphere."

  • James Hagerty, Presidential Press Secretary, July 28, 1955 (source NASA History)

These were the "arrangements with the international scientific community" the Eisenhower was talking about, and that led to the Vanguard program and the launch of Explorer 1 on 31 January 1958 (and also the later missions of the Explorer Program).

Of course, in the event the Soviet Union launched its satellite, Sputnik 1, on 4 October 1957 - before the United States could launch Explorer 1. This is why Eisenhower sounds slightly defensive when talking about the US program.


Perhaps the best-known discovery from Explorer 1 was what is now known as the Van Allen radiation belt. This was named after Dr. James Van Allen of the University of Iowa, who had designed the science package for Explorer 1. That package consisted of:

  • Anton 314 omnidirectional Geiger-Müller tube, designed by Dr. George Ludwig of Iowa's Cosmic Ray Laboratory, to detect cosmic rays. It could detect protons with E > 30 MeV and electrons with E > 3 MeV. Most of the time the instrument was saturated;
  • Five temperature sensors (one internal, three external and one on the nose cone);
  • Acoustic detector (crystal transducer and solid-state amplifier) to detect micrometeorite (cosmic dust) impacts. It responded to micrometeorite impacts on the spacecraft skin in such a way that each impact would be a function of mass and velocity. Its effective area was 0.075 m2 and the average threshold sensitivity was 2.5×10−3 g cm/s;
  • Wire grid detector, also to detect micrometeorite impacts. It consisted of 12 parallel connected cards mounted in a fiberglass supporting ring. Each card was wound with two layers of enameled nickel alloy wire with a diameter of 17 µm (21 µm with the enamel insulation included) in such way that a total area of 1 cm by 1 cm was completely covered. If a micrometeorite of about 10 µm impacted, it would fracture the wire, destroy the electrical connection, and thus record the event.

The Smithsonian National Air and Space Museum has a number of pictures of the unit (and contemporary mock-ups) on it's website.


The measurements transmitted from those instruments were the "scientific purposes" that Eisenhower was speaking about. These were expected to provide data for the scientific community about the environment that existed in Earth orbit, and was also expected to inform the design of future satellites.

All the raw data was shared and held in a series of World Data Centres maintained by the International Council of Scientific Unions (ICSU). That was all part of the arrangements agreed for the IGY.

This formed a significant part of the contribution that the US had agreed to make to scientific research in International Geophysical Year.

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    I may add that my primary school distributed information about the International Geophysical Year. That included information that as part of their participation the USA and the USSR would launch scientific satellites into orbit. Therefore, the announcement that the USSR had launched a satellite, as they had previously said they would, was not as shocking to me as it seems to have been to some other people. – MAGolding Jul 28 at 16:51

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