The Secrets of Space card series was issued in 1968 by the Sanitarium Health Food Company in Australia and New Zealand. The 20-card collection features illustrations of early satellites, concept vehicles, and Project Gemini objectives. One card was included with each specially marked box of Weet-Bix breakfast cereal. Secrets of Space Project Poster Series No. 5 was available by mailing a five-cent stamp to the Sanitarium Health Food Company office.

The series includes the Grumman Lunar Exploration Space Suit Mark 1 created in 1965 by JPL engineer Allyn B. "Happ" Hazard. The "marshmallow" suit design was used in 1966 for the "Major Matt Mason with Moon Suit" from Mattel's Man in Space toy series.