Microgravity Science Overview

Welcome to NASA's newest science!! Astronomy is thousands of years old, and began when the first human stared out into space. Chemistry is centuries old, with many of its origins in "alchemy," the attempt to turn lead into gold. Unlike these two science areas, microgravity science is in its infancy. Born of the space age, the first space experiments in microgravity science were carried out only 30 years ago. Our 16 years of research in microgravity science on the space shuttle is therefore just a first step in growing a vibrant and exciting science to generate new knowledge.

What is the purpose of Microgravity research?

NASA has a mission to advance and communicate scientific knowledge and understanding about:

• the universe and the solar system
• the earth, and
• the use of the space environment for cutting-edge scientific research.

This third part of our mission at NASA is microgravity science. We use the unique environment of space, with its near-absence of the effects of gravity, to perform science research that cannot be done anywhere else.

What does "Microgravity" mean anyway?

Microgravity is a term used by scientists to mean "very little gravity." The effects of gravity aboard an orbiting spacecraft like the space shuttle are reduced significantly compared to what one experiences on the ground. Here is a little tutorial with some animations that demonstrate gravity effects while in orbit. The "gravity" part of the word "microgravity" is fairly obvious. The "micro" part comes from Greek, and is a common prefix used in science to mean "one millionth." Since the effects of gravity aboard the shuttle are reduced by nearly a factor of 1,000,000 over what we feel on Earth, the name "Micro gravity" is given to describe the million-fold reduction in gravity that we have in our orbiting laboratories.

By the way, the symbol "µ" is the Greek letter for "m". This symbol is used frequently to refer to the science of microgravity, or "µG ", as in the logo pictured with the above paragraph.

What's so special about Microgravity?

Things in space simply do not behave the way we observe them on the ground. Consider the following simple examples from your kitchen at home:

• When you want to put Italian dressing on your salad, you have to shake it up, because the oil and vinegar are separated. What would the salad dressing do in in microgravity?
• When you boil a pot of water, the water bubbles, overturns, and mixes as it boils. What happens in microgravity?
• It's simple enough watch liquid being "soaked up" by a paper towel after a spill in the kitchen. How might similar liquid move in microgravity?

The answers to these three questions are related to the scientific concepts of density, convection, and surface tension. Gravity's presence in each of these three examples produces the familiar behaviors we observe on the ground. In space, where the effects of gravity are minimized aboard an orbiting spacecraft, these three simple examples reveal themselves to behave very differently .

These physical properties, along with many others, have influences on materials and systems that are often masked by the presence of gravity. If one wants to have a detailed scientific understanding of how these masked properties actually work, the only way to study them is to remove the effects of gravity by putting your laboratory in orbit.

Our MSL-1 Mission Scientist Dr. Mike Robinson likens experiments in microgravity to a trip to the symphony. "When you go to the symphony, you normally hear all the instruments folded together into a common sound. It's often tough to hear what exactly each player in the orchestra is doing. Lifting the veil of gravity, by placing our laboratory in orbit, is like being able to separate out each of the individual orchestra members and study "player-by-player" what they are playing in great detail. Of course NASA doesn't study music, but instead we study each of the important physical processes that occur in order to gain fundamental scientific knowledge about how things work."

What kinds of things can we learn about?

The answer to this question is LARGE, and much too detailed for an "overview." However, on MSL-1, research is generally aligned in three major scientific areas:

• Materials Science in Metals and Alloys

Many unique properties of metals and alloys can best be studied in microgravity. On MSL-1, we have the Large Isothermal Furnace and TEMPUS facilities dedicated to carrying out a variety of experiments to learn more about the fundamental science of these materials. WHY we do Materials Science in Space HOW we do Materials Science in Space WHAT WE'VE LEARNED in Materials Science Research

• Biotechnology / Protein Crystal Growth

The microgravity environment is exceptionally well-suited for growing large, well-ordered, complex crystals. In particular, we're interested in crystallizing many different biological proteins that can be found in the human body, for example. When we use the microgravity environment to grow a better crystal, we can then study that crystal on the ground to better understand the structure of the protein, and acquire knowledge about how it works in the human body. WHY we do Protein Crystal Growth HOW we do Protein Crystal Growth WHAT WE'VE LEARNED in Protein Crystal Research

• Combustion Research (The science of burning)

It may seem strange because combustion is so common, but there are a large number of fundamental scientific questions that are not well answered in the field of how things burn. Much of this is due to the fact that gravity plays a very large role in determining the external characteristics of fire and burning, and shields us from much of the internal physics. The Droplet Combustion Experiment, an experiment called SOFBALL, and the Fiber Supported Droplet Combustion Experiment (FSDC) are three of the experiments on MSL-1 dedicated to the science of burning. WHY we do Combustion Research HOW we do Combustion Research WHAT WE'VE LEARNED in Combustion Research

June 19, 1997

Author: Dr. John Horack
Curator:Bryan Walls
NASA Official: John M. Horack