What is Microgravity?
The Microgravity technique in the context of civil engineering consists of measuring minute variations in the gravitational pull of the Earth and interpreting the presence of voids and cavities from these readings. Gravity anomalies arising from voids and cavities are superimposed upon much larger variations due to height, latitude and regional geological variations and are virtually undetectable by conventional gravity investigations. Microgravity surveying has developed considerably over the last ten years however, and with the development of modern high-resolution equipment, careful field acquisition techniques and sophisticated reduction and analysis, these anomalies can be detected and interpreted. Not only do the isolated anomalies reveal the location of caverns and voids, but they also provide information on their depths and shapes. The ‘missing mass’ associated with the void can also be calculated and by implementing a post-remediation survey the remediation can be verified. Th
The weightlessness that is experienced in freefall or in orbit around the earth is actually microgravity. These situations create a sense of floating, but gravity is still acting on the person or object, so the term microgravity is used. If you have ever ridden a roller coaster that took you quickly up and down a hill, or that stopped at the very top of a quick rise, you’ve experienced microgravity. When you fall at the same speed as your surroundings, you experience microgravity, a feeling that you are floating in space. Astronauts orbiting the earth experience long periods of microgravity as they orbit. The astronauts and their space shuttle or space station are both falling at the same speed, so the microgravity makes it seem that they are floating inside it. A vehicle, like the space shuttle, that is orbiting the earth is actually constantly falling toward it. The space shuttle is moving at a very high speed in just the right direction, so even thought it’s falling toward the earth
Many people mistakenly think that gravity does not exist in space. However, typical orbital altitudes for human spaceflight vary between 120 – 360 miles above Earth’s surface. The gravitational field is still quite strong in these regions, since this is only about 1.8 percent the distance to the moon. Earth’s gravitational field at about 250 miles above the surface is 88.8 percent of its strength at the surface. Therefore, orbiting spacecraft, like the space shuttle or space station, are kept in orbit around Earth by gravity. The nature of gravity was first described by Sir Isaac Newton, more than 300 years ago. Gravity is the attraction between any two masses, most apparent when one mass is very large (like Earth). The acceleration of an object toward the ground caused by gravity alone, near the surface of Earth, is called “normal gravity,” or 1g. This acceleration is equal to 32.2 ft/sec2 (9.8 m/sec2). If you drop an apple on Earth, it falls at 1g. If an astronaut on the space statio
Gravity is a force that governs motion throughout the universe. It holds us to the ground and keeps the Earth in orbit around the Sun. Microgravity describes the environment in orbital space flight, which has very weak gravitational effects (one-millionth of what is felt on Earth) and which is sometimes referred to as a state of ‘weightlessness.’ The condition of microgravity occurs when an object is in ‘free fall.’ In free fall, an object falls faster and faster, accelerating with exactly the speed of attraction caused by gravity. Objects traveling around the Earth in a state of continuous free fall, or orbit, are essentially weightless even though their mass remains the same. Conducting research in a microgravity environment gives researchers a unique opportunity to study the true nature of processes and materials without having to consider the effects of Earth’s gravity. Thus, physics theories can be tested at levels of accuracy that are impossible on Earth. Microgravity experiments
Gravity cannot simply be switched off, but its effects can be compensated with the help of an appropriate acceleration force. The acceleration force must have exactly the same absolute value as the gravity force and it must point into the opposite direction of the local gravity vector. The resulting equilibrium of forces is called in the normal language: “weightlessness”. In practice, however, an exact equilibrium state is difficult to obtain and a very small gravity force is always remaining. Specialists therefore speak of “microgravity” rather than “weightlessness”. Under microgravity conditions, various fundamental physical phenomena are significantly altered or even fully removed, in particular convection, buoyancy, hydrostatic pressure and sedimentation. Compensating the force of gravity by creating a microgravity environment can help to better observe and control physical, chemical and biological processes and phenomena that are normally overshadowed or dominated by the effects o
