page_title: Orbiting Frog Otolith
section_title: The OFO spacecraft
hierarchical_section_title: Orbiting Frog Otolith / The OFO spacecraft
context_page_description: The Orbiting Frog Otolith was a NASA space program which sent two bullfrogs into orbit on 9 November 1970 for the study of weightlessness. The name, derived through common use, was a functional description of the biological experiment carried by the satellite. Otolith referred to the frog's inner ear balance mechanism.
  The Orbiting Frog Otolith Program was a part of the research program of NASA's Office of Advanced Research and Technology. One of the goals of the OART was to study the vestibular system function in space and on Earth. The experiment was designed to study the adaptability of the otolith to sustained weightlessness, to provide information for human spaceflight. The otolith is a structure in the inner ear that is associated with equilibrium control: acceleration with respect to gravity as its primary sensory input.
  The Frog Otolith Experiment was developed by Torquato Gualtierotti of the University of Milan, Italy, when he was assigned to the Ames Research Center as a resident Research Associate sponsored by the National Academy of Sciences.
context_section_description: The OFO experiment was originally designed for flight within the Apollo Applications Program, which was established to make optimum use of hardware used in Apollo lunar missions. However, because the low acceleration levels needed for the experiment could not easily be maintained in a manned Apollo spacecraft, an unmanned satellite was later chosen as a more suitable vehicle. The satellite's design eliminated exposures to acceleration levels above 10⁻³g (10 mm/s²). This meant that the experimental specimens could experience an almost weightless state.
  The spacecraft had a diameter of approximately 30 in (760 mm) and a length of 47 in (1,190 mm). The octagonal lower section of the spacecraft housed the electronic apparatus. The upper section, which contained the experiment package, was shaped like a truncated cone. A heat shield covering this upper section protected the experiment during re-entry into the Earth's atmosphere. A yo-yo de-spin assembly was located around the girth of the spacecraft. Four booms, folded against the side of the spacecraft, were located radially around the satellite. After the spacecraft separated from the launch vehicle, the yo-yo despin subsystem slowed spacecraft rotation. The four booms were then released to extend from the side of the spacecraft. The extension of the booms increased the moment of inertia of the spacecraft, permitting the acceleration level to remain below 10⁻³g.
caption: Launch of the Orbiting Frog Otolith (OFO) capsule
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