August 19, 1970

Why Frogs Were Used

The experiment used two male bullfrogs (Rana catesbeiana) because:

1. Similar Otolith System to Humans – The frog’s vestibular system closely resembles that of humans, making it a suitable model for studying balance in space.

2. Small Size – The frogs fit within the spacecraft’s limited space constraints.

3. Amphibious Nature – Frogs can survive in both air and water, which was essential for their pre-flight preparation and spaceflight environment.

How the Experiment Worked

• Surgically Implanted Electrodes – Microelectrodes were placed in the frogs’ vestibular nerves to record electrical signals from their otolith organs during weightlessness.

• Water-Filled Centrifuge – The frogs were housed in a self-contained centrifuge that periodically spun at up to 50 revolutions per minute, creating a 0.5 g acceleration to simulate gravity.

• Real-Time Data Transmission – The spacecraft collected data on how the otolith organs responded to both weightlessness and acceleration, transmitting this information back to Earth.

The experiment lasted for five days in orbit before the spacecraft was left in space without recovery.

Scientific Goals of the OFO Mission

• Study how the vestibular system adapts to weightlessness over time.

• Determine whether the otolith organs experience dysfunction or adaptation in space.

• Improve understanding of space motion sickness, which has been observed in astronauts.

NASA’s Office of Advanced Research and Technology (OART) managed the experiment as part of its vestibular research program. The Frog Otolith Experiment Package (FOEP) was developed by NASA Ames Research Center and built by the Johns Hopkins University Applied Physics Laboratory.

The Scout Rocket & Wallops Island Launch

What is the Scout Rocket?

The Scout rocket was NASA’s only all-solid-fuel launch vehicle capable of placing payloads into orbit. The OFO mission used a Scout B, a four-stage rocket designed for small satellite launches.

Key Details About the Scout Rocket:

• Height: ~73 feet

• Weight at Liftoff: ~40,000 pounds

• Stages: 4 (solid-propellant motors)

• Launch Success Rate: 93% since its re-certification in 1963

• Manufacturer: Ling-Temco-Vought (LTV), Dallas, Texas

• Managed by: NASA Langley Research Center, Hampton, Virginia

The Scout B launched from Wallops Island, Virginia, a NASA launch site used for scientific and experimental payloads. The rocket placed the OFO spacecraft into an elliptical orbit between 195 and 370 miles (313–590 km) above Earth, with an inclination of 37.7° and an orbital period of approximately 1.5 hours per revolution.

Additional Payload: The Radiation Meteoroid (RM) Experiment

Alongside OFO, the Radiation Meteoroid (RM) spacecraft was also launched. This 46-pound payload remained attached to the fourth stage of the Scout rocket and conducted two primary experiments:

1. Radiation Measurement – Used an Advanced Dosimetry System (ADS) and ionization chambers to study space radiation, which is important for astronaut safety.

2. Meteoroid Impact Study – Measured the number, speed, and direction of meteoroids to help improve spacecraft design.

Mission Timeline & Tracking

• Launch Date: August 19, 1970

• Launch Site: Wallops Flight Facility, Virginia

• Rocket Used: Scout B

• Orbital Altitude: 195–370 miles (313–590 km)

• Inclination: 37.7° to the Equator

• Mission Duration: Five days

• Primary Tracking Station: Rosman, North Carolina (which relayed data to NASA Goddard Space Flight Center)

NASA's Space Tracking and Data Acquisition Network (STADAN) stations in locations such as South Africa, Madagascar, Australia, Chile, Ecuador, Florida, and Hawaii supported the mission.

Significance & Legacy

The OFO experiment was one of the earliest biological studies in space focused on how living organisms respond to microgravity. The data collected helped scientists understand:

• The effects of space travel on the inner ear, influencing astronaut training for long-duration missions.

• Balance disorders in humans, contributing to medical research.

• Future space exploration, including adjustments needed for space habitats and extended missions.

The Wallops Flight Facility remains an important NASA site for scientific, meteorological, and commercial space launches, while the Scout rocket program helped pave the way for modern small satellite launches.

The OFO mission provided critical insights into human spaceflight adaptation and demonstrated the importance of biological experiments in space, even if the subjects were two small frogs floating in microgravity. 🐸🚀