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Protecting the Space Elevator: Space Debris. Gabriel V. Cummings- Union Hill High School Department of Mechanical and Aerospace Engineering Rutgers University 98 Brett Road, Piscataway, NJ 08854 August 16, 2006. The space elevator faces many obstacles: Lightning strikes Atomic oxygen - PowerPoint PPT Presentation
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Protecting the Space Elevator: Space Debris
Gabriel V. Cummings- Union Hill High SchoolDepartment of Mechanical and Aerospace
EngineeringRutgers University 98 Brett Road,
Piscataway, NJ 08854August 16, 2006
Introduction
The space elevator faces many obstacles: – Lightning strikes– Atomic oxygen – Induced
oscillations – Strong winds – Meteor impacts
Most severe problem: Meteor strikes– Could destroy single
or multiple Carbon nanotube fibers
– Many larger than the 10-40 micron diameter of each fiber
– Complete elevator failure
– Loss of billions of research money
Presentation Objective • Discuss the threat of meteors hitting space
elevator• Talk about impact probability and surface
area • Propose various meteor detection systems • Present ideal design for ribbon• Discuss solutions for protecting the
structure
Surface Area
• The space elevator’s total surface area is about 210km2
• The 999 space intervals between fibers account for almost 95% of area
• Area is only 10km2 without the spaces
• Very small in comparison to Earth (509,600,000km2)
• (Surface Area space elevator/Earth)
• 1/2,500,000 at 210km2
• 1/50,000,000 at 10km2
Meteors and Mircometeors
– Nearly 300 Million meteors hit earth everyday
– About 105 Billion meteors strike Earth each year
– Almost 40 meteors a meter or larger enter the atmosphere a year
– Larger sizes are far less frequent but are more dangerous
– They are easier to detect because of size – Nearly all meteors that impact the
Earth are of a microscopic size– 1 micro gram in weight– The fastest micrometeors have as
much energy in them as a 22 caliber bullet
– Very hard to detect, because of their microscopic size and high velocity
– If they come at an angle, it could destroy more than one fiber
Artificial Satellites
• About 2,500 working and nonfunctioning satellites orbit the planet
• In total, there are over 8,000 pieces of artificial debris
• They are bound to strike the space elevator because of their orbits
• Tracking them is important• Base of elevator should
have ability to move in order to avoid a collision
Radar • Powerful radars could detect
objects as small as 1cm or less• Until recently, radar only picked
up meteors as noise• The Arecibo observatory uses a
430 megahertz detection system to record micro meteorites as a velocity
• It is one of the only systems currently available with the ability to track micro meteors
• Could detect objects of nearly every size
Satellites• Satellites can be used to
monitor space for any debris coming towards the elevator
• Provide a rough estimate on their distance and amount of time before an impact
• Better then earth based telescopes since their observations are not distorted by the atmosphere
• Increasing the number of observational satellites is a must for safeguarding the elevator
Albedo’s and Magnitude
• Albedo is the ratio of the light reflected by an object over the amount of light that is absorbed by it
• it is measured from 0-1, zero is very dull and one is very bright
• Comet’s are about 0.6 and asteroids are near 0.05-0.25
• Magnitude calculates the size range of an object
• H represents magnitude• The scale ranges from
3.0 (670-1490km) to 30 (3-6m)
• When Albedo's and Magnitude are combined to give an approximation of a projectiles size
Detection Programs• Many programs exist to
search for Near Earth Objects
• NASA’s Near and MIT’s LINEAR programs are used to protect the Earth from these deadly asteroids
• Currently, they are used to find NEO’s larger then 1km
• In order to benefit the space elevator as well, the search range would have to be decreased
• More geared for larger objects
Impact Probability
Size of Meteor
Earth Impactsper year
Space Elevator Impacts
1 micron 105 Billion 2163
1mm 1,050,000 1 every 50 yrs.
1 m 40 1 every 62,500 yrs.
Space Elevator Headquarters
• Bases would analyze accumulating detection data
• It would come from NASA, radars, satellites, and other programs
• Determines the severity of an impact
• Proposes appropriate action
• Control center at the foot of the space elevator
Ribbon Design• Ribbon is about a
meter by 100,000km• Made up of 1000’s of
Carbon nanotube fibers 10-40 microns in diameter
• To strengthen the overall design, two cross section fibers of 10-20 microns
• These would run every 100 meters
• From 500-1700km, double the width of the fibers, since this is the range where most meteors are located
• This would allow the ribbon to handle more strikes
• Also increases the critical size of a meteor hitting the space elevator
Armed Satellites
• Each of them is responsible for a certain area around the elevator
• Armed with lasers • Would destroy oncoming
meteors before they become a hazard
• Never to be pointed towards the elevator or the Earth
• Only act under the control of the space lift’s command center
Heat Energy Field
• It’s a very futuristic technology, possibly taking years to develop
• It would surround the entire structure, using a solar power energy source
• This is possible since Carbon nanotubes are good conductors of heat
• This energy would disintegrate any micro meteors before they get close to the space elevator
• Similar to the meteors burning up in the Mesosphere
Conclusion
• I discussed the threat space debris had on the space elevator
• adequate detection and protection systems• Impact Probability • Surface Area ratios• And lastly, the idea that the space elevator is a
realistic goal for the future
Works Cited• Works Cited • Baalke, Ron. "Arecibo and Micrometeors." 28 May 1997. July
2006 <www.meteorobs.org/maillist/msg04686,html>. • "Bond Albedo, Near Earth Asteroids, Radar Astronomy."
Wikipedia. 15 Aug. 2006. 15 Aug. 2006 <www.wikipedia.org>. • Briley, Mike. "Micrometeorites." University of Wisconsin. July
2006 <www.astro.wsu.edu/wortney/astro/html/meteor.html>. • Edwards, Bradley C., and Eric A. Westling. The Space Elevator: a
Revolutionary Earth-to-Space Transportation System. New York, 2002.
• Nelson, Stephen A. "Meteorites, Impacts, and Mass Extinction." 20 Apr. 2006. Tulane University. July 2006 <www.tulane.edu>.
• Yeomans, Don. "Absolute Magnitude (H)." NASA. Aug. 2006. NASA. July 2006 <www.neo.jpl.nasa.gov/glossary/h.html>.
• Yeomans, Don. "NEA Discovery Statistics." NASA. Aug. 2006. July 2006 <www.neo.jpl.nasa.gov/stats>.
Acknowledgements
• First and foremost, I would like to thank Professor Haym Benaroya for allowing me to conduct my research with him, and for showing me the importance of the space elevator
• Yuriy Gulik, for all of his help with the computer technology for my project
• Dan, Josh, Sergey, and Adaleena for keeping me entertained while I was conducting my research
• And to everyone else who helped make this presentation possible, Thank You!