Effects of outgassed products from spacecraft materials on the insulating strength of the space vacuum

Phillips, Robert G.; Alexander, Georgia; Merryman, S.A.; Gordon, L.B.

doi:10.1109/ceidp.1988.26306

“…The necessity to reduce weight in order to decrease launch costs is a considerable factor for the large use of honeycomb-structured panels of aluminum alloy [17,26]. Although proven and reliable, remarkable efforts have been taken to search for a lighter, tougher, and more conductive item.…”

Section: Current Spaceborne Systemsmentioning

confidence: 99%

“…In Advanced composite materials (ACM) can be best characterized as materials that are governed primarily by the properties of the reinforcing fibers, which have high 6 strength and high stiffness characteristics and occupy a high volume fraction of the composite. Due to their low density, unusually high axial or longitudinal specific strength and stiffness values are obtained [17,1]. Examples of fibers used are carbon, aramid, and glass and they typically have widths in the order of microns.…”

Section: Evolution Of Compositesmentioning

confidence: 99%

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electromagnetic interference

Weik

2000

Computer Science and Communications Dictionary

0

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Space vehicles encounter an unpleasant environment in space with dangers such as extreme temperatures, solar radiation, out-gassing, debris, and micrometeoroids. The cost of launching systems into space is extremely high and stands between $10,000/lb -$12,000/lb. As a result, there is an emergent requirement of weight/cost reduction for future space systems that still comply with the rigorous specifications to properly function in space. This study focuses on the potential utilization of nanocomposite materials for satellite structures as a solution to reduce system weight while retaining the desired survivability against electromagnetic interference (EMI).Four, eight-ply nanocomposite panels were fabricated from Cycom 5575-2 glass with multi-walled carbon nanotube (MWNT) plies. The control panel had eight plies of glass fabric reinforced composite only and will be referred to as 8G. This enabled the comparison of all properties with and without carbon nanotubes (CNTs). The other three panels had differences in the placement of layers containing CNTs: the first one had four CNT plies on one half with four plies of glass on the opposite half and will be referred to as 4G/4CNT, the second one had two plies of CNT on the exterior of each side with four plies of glass in the middle and will be referred to as 2CNT/4G/2CNT, and the third one had alternating CNT/glass fabric plies across the thickness and will be referred to asThese four configurations were measured for their respective EMI shielding properties after experiencing monotonic tension load, thermal cycling, and a combination v of thermal cycling followed by monotonic tension load. EMI measurements were taken in terms of decibels (dB) before and after each thermal cycle or monotonic tension test.Tension tests involved increasing the load incrementally until ultimate failure. Thermal cycling was conducted with a cycle having a total soak time of 20 seconds. The first 10 seconds were at +60 °C and the last 10 seconds were at -60 °C. The total number of thermal cycles was 17,500. Multiple EMI shielding effectiveness (SE) values were measured on metallic materials for comparison. The average EMI SE of type 2024 aluminum and type 7075 aluminum for the frequency range of 2 GHz -18 GHz were 112.6 dB and 113.46 dB, respectively. In a previous study, EMI SE values for four distinct nanocomposites containing nickel nanostrands (NS) were measured and their averaged attenuation prior to testing are as follows: Control 1 -58 dB, Exterior 1 -73 dB, Exterior 2 -66 dB, Interlaminar 1 -64 dB, and Midplane 1 -55 dB. The stacking sequence of the 8-ply, NS nanocomposites was a quasi-isotropic lay-up of [0/90/±45/] s . The Control specimen contained no NS plies, the Exterior specimens had one NS ply on the exterior of the 0° ply for a total of two NS plies, Interlaminar had one NS ply between the 0° and 90 plies and one NS ply between the 45° and -45° plies for a total of four NS plies, and the Midplane specimen had one NS ply directly in the midplane between the -45° and -45° p...

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“…reveals an 8-ply stacking sequence with varying fiber orientation. The matrix resin is the continuous phase in which the reinforcing fiber is contained, provides uniform load distribution to the fiber, and safeguards the composite surface against abrasion or environmental corrosion[17,9].…”

mentioning

confidence: 99%

Electromagnetic Interference

1982

Pacing Clinical Electrophis

8

0

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Space vehicles encounter an unpleasant environment in space with dangers such as extreme temperatures, solar radiation, out-gassing, debris, and micrometeoroids. The cost of launching systems into space is extremely high and stands between $10,000/lb-$12,000/lb. As a result, there is an emergent requirement of weight/cost reduction for future space systems that still comply with the rigorous specifications to properly function in space. This study focuses on the potential utilization of nanocomposite materials for satellite structures as a solution to reduce system weight while retaining the desired survivability against electromagnetic interference (EMI). Four, eight-ply nanocomposite panels were fabricated from Cycom 5575-2 glass with multi-walled carbon nanotube (MWNT) plies. The control panel had eight plies of glass fabric reinforced composite only and will be referred to as 8G. This enabled the comparison of all properties with and without carbon nanotubes (CNTs). The other three panels had differences in the placement of layers containing CNTs: the first one had four CNT plies on one half with four plies of glass on the opposite half and will be referred to as 4G/4CNT, the second one had two plies of CNT on the exterior of each side with four plies of glass in the middle and will be referred to as 2CNT/4G/2CNT, and the third one had alternating CNT/glass fabric plies across the thickness and will be referred to as (G/CNT) 4. These four configurations were measured for their respective EMI shielding properties after experiencing monotonic tension load, thermal cycling, and a combination Institute of Technology laboratory technicians, Dr. Volodymyr Sabelkin, and Air Force Research Lab personnel who continuously afforded me with the assistance and expertise needed in the laboratories. My beloved wife for having lovingly endured and sacrificed much in order to grant me the time required to complete my thesis. Lastly, to the one who breathes life into me and gives every good gift, Jesus Christ.

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