Profiles & Overviews | Flight Hardware

Key Research Questions

• Are single cells capable of sensing and responding to changes in gravity, or are only multicellular systems capable? Do single cells sense gravity directly (intracellularly) or indirectly (environmentally-mediated effect)?
• If single cells sense changes in gravity directly, what are the intracellular structural/functional mechanisms that are sensitive to gravity perturbation?
• How do the following modifying factors affect gravity sensing at the cell level: cell size, cellular dynamics; changes in cell shape; prokaryotic versus eukaryotic cells, adaptive versus non-adaptive cells; circadian rhythms?
• If multicellular systems are necessary for gravity sensing, how is this effected? What cellular structures and processes that extend across several cells might be involved? What aspects of cell-cell communication are affected? Would the requirements for cellular interaction/assembly increase sensitivity to indirect or environmentally mediated effects?
• What are the mechanisms involved in the transduction of the stimulus of altered gravitational force to a cellular response? By what pathways is the perception of altered gravity relayed intracellular and/or extracellularly?
• How is the expression and regulation of genetic information, cell division, cell differentation, signal transduction, membrane dynamics, intracellular transport, secretion, alternate pathway regulation, and cell-to-cell communication influenced by gravity and/or microgravity?

Profiles & Overviews

A Critical Period for Vestibular Development

Source: Spaceline   Format: PDF
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Description: This article profiles an experiment that determined there is a critical period in the development of zebrafish, in which normal gravity must be experienced in order for the vestibular system to develop properly. (Posted on 11/03)

Genetic Factors in Gravity Sensing in Plants

Source: Spaceline   Format: PDF
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Description: This article profiles research that so far has identified two genes associated with gravity sensing and signal transduction. (Posted on 7/00)

Gravity Detection in Plants

Source: Spaceline   Format: PDF
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Description: This article profiles research into how plants perceive and respond to gravity. (Posted on 7/00)

How the Brain Distinguishes Gravity

Source: Spaceline   Format: PDF
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Description: This article profiles research that suggests that the brain senses and processes gravity by integrating signals from two different sets of organs in the vestibular system. (Posted on 11/03)

Mechanical Stimuli Factsheet

Source: ASGSB   Format: HTML
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Description: This factsheet offers a brief overview of current NASA research into the perception and response of biological organisms to mechanical stimuli. (Posted on 7/00)

Plant Perception and Response to Gravity

Source: Spaceline   Format: PDF
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Description: This article profiles research into how plants sense and respond to gravity, in particular the biochemical and molecular events involving calcium, which is thought to play an important role in plants' processing of gravitational signals. (Posted on 11/03)

Role of Balance Organs in Posture Control

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Description: This article profiles a study of astronauts that revealed information about the role of the otolith organs in posture control. (Posted on 11/03)

Role of Gravity in Mammalian Development

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Description: This article chronicles research that found that exposure to gravity is important for normal vestibular system development in rat fetuses. (Posted on 11/03)

Flight Hardware

Frog Otolith Experiment Package

Source: NASA
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Description: The Frog Otolith Experiment Package, designed to study the effect of microgravity on the vestibular system, flew on Orbiting Frog Otolith-A. (Excerpt from Life into Space 1965-1990) (Posted on 12/00)