Introduction to Microgravity
Tutorial on Microgravity Research

Introduction to Microgravity

WHY Microgravity Research?

One of the most promising new areas for the commercialization of space is in the field of microgravity. Microgravity allows new materials to be developed which can not be made on Earth due to gravity. These new materials can be used to speed up future computers, reduce pollution, improve fiber optics, and enable medical breakthroughs to cure diseases.

WHAT is Microgravity?

Microgravity, also called weightlessness or zero gravity, is the absence of gravity. It is best illustrated by astronauts floating in their spacecraft. They are floating because they are in a microgravity environment. Besides astronauts, many people experience microgravity every day by riding roller coasters or jumping off diving boards. It is the "free fall" period of these activities when the microgravity occurs and of course only lasts for a short period of time.

HOW is microgravity achieved?

For research, microgravity is obtained by five methods.

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  1. Drop tower. The payload is simply dropped off the top of the tower and allowed to fall. This can provide 2 seconds of microgravity at a cost of pennies per pound.
  2. Airplane flying parabolas. The semi-famous example is the NASA Vomit Comet which is also used to train astronauts to work in a microgravity environment. This method can provide 25 seconds of microgravity at a cost in the range of a few dollars per pound.
  3. Sounding rocket. The rocket goes up and comes down in the same general vicinity, never getting into orbit. Today's sounding rockets can provide between 3 to 9 minutes of microgravity at a cost of approximately $1,000,000 per launch and payloads weighing around 1000 pounds (which equates to $1000 per pound).
  4. Space Shuttle or International Space Station. Days of microgravity can be achieved. The cost for putting a payload in orbit with the Space Shuttle is $10,000 per pound. Once available, the estimated cost for having commercial payloads on the International Space Station is $15,000 per pound (not counting the $10,000 per pound to get it there on a launch vehicle such as the Space Shuttle or the Russian Soyuz rocket).
  5. Slowly spinning an object. This is not a true microgravity environment but simulates microgravity in certain processes. Those processes must have slow reaction times such as many biological processes. The axis of rotation must be parallel to the ground and only provides benefits in certain applications.

HOW does one gain access to microgravity?

Take a coin. Toss it in the air. You have just subjected that coin to microgravity. From the time it leaves your hand until it hits the ground (or any solid object) it is experiencing microgravity. The time in microgravity might be 1 to 2 seconds depending on how high you toss the coin. For extended periods of time, one of the methods described above will be needed.

While the current costs of achieving extended periods of time microgravity are high, another major hindrance to microgravity research is getting flights. There is a substantial backlog for flights on the Vomit Comet and Space Shuttle. Researchers can wait years to get a flight. Flights on today's sounding rockets have over a 12 month lead time. Additionally, the Space Commercialization Act passed by the Unites States Congress in 1996 makes it ILLEGAL for NASA to fly commercial payloads on the Space Shuttle or the Vomit Comet! Therefore, all researchers must submit their experiments to NASA committees to determine which experiments are "good science" and eligible for a NASA flight.

A truly exciting development in the area of microgravity is a new commercial microgravity company called Zero Gravity Corporation. This company has begun offering people the chance to experience 25 seconds of microgravity via parabolic airplane flights. World famous physicist Stephen Hawking recently experienced the freedom of microgravity on one of these flights. www.GoZeroG.com has more information on the company and Prof. Hawking's flight.

Images courtesy: NASA