Black Kapton Research Articles

Molecular Characterization of Polyimide Film and Silicone Adhesive Outgassing Using Mass Spectrometry

The prediction of contaminant levels is paramount to controlling and reducing their impact on space missions. In recent years, it has become clear that a real breakthrough could only be achieved through a change of paradigm, namely, by going beyond the classical characterization of total contaminant mass and instead characterizing the various emitted chemical species individually: both quantitatively and chemically. This paper first reviews the methodology proposed to achieve this objective and then its implementation on two examples of materials (Black Kapton® and NuSil CV4-2946) on the basis of existing ASTM-E-1559 outgassing data (Garrett, J. W., Glassford, P. M., and Steakley, J. M., “ASTM-E-1559 Method for Measuring Material Outgassing/Deposition Kinetics,” Journal of the IEST, Vol. 38, No. 1, 1995, pp. 19–28) including mass spectrometry (MS) data. We show that the thermogravimetric analysis performed on the contaminant deposits (heating at 1 K/min) allows a good enough time separation of chemical species to analyze and often identify them through their mass spectra. In turn, the knowledge of the fragments constituting their spectra allows an improved analysis of the MS data collected during the initial outgassing phase. The outgassing time profiles of each of these chemical species then tells a lot about their actual outgassing physical laws. On the two studied materials, outgassing physics were found to be consistent with Fickian or non-Fickian diffusion rather than with residence time desorption. After confirming these findings with more specific and more sensitive experiments, the door will be open to greatly improve assessments of the contaminant amounts and nature in flight through realistic multispecies physical models.

Photoelectron Current Measurement in Low Earth Orbit Using a Lean Satellite, HORYU-IV

This study presents the development and implementation of a photoelectron current measurement system on-board HORYU-IV satellite to take on-orbit measurements from conductive and insulator surfaces. The measurement system aims at providing critical information on photoelectron yield of materials widely used onboard spacecraft. HORYU-IV is the fourth satellites of the HORYU series developed at Kyushu Institute of Technology and it was piggy-back launched on-board H-IIA F30 rocket at an altitude of 575 km on February 17, 2016 (JST). The measurement system mainly consists of current-voltage amplifier circuits for AU, Kapton® and black Kapton® samples with gains of 1x, 3x and 1x amplification, respectively. In this article, the analysis of the on-orbit results is presented. The on-orbit results show that a photoelectron current of 2.9nA and 3.1nA was measured from black Kapton® sample at respective elevations of 70.7° and 71.1°. These results respectively correspond to a current density of 14.0μA/m2 and 18.0μA/m2 at 71.1°. This study also presents various ground-based tests results performed to verify and validate the effectiveness of the photoelectron current measurement system developed for space applications.

Recent NASA/GSFC cryogenic measurements of the total hemispheric emissivity of black surface preparations

High-emissivity (black) surfaces are commonly used on deep-space radiators and thermal radiation absorbers in test chambers. Since 2011 NASA Goddard Space Flight Center has measured the total hemispheric emissivity of such surfaces from 20 to 300 K using a test apparatus inside a small laboratory cryostat. We report the latest data from these measurements, including Aeroglaze Z307 paint, Black Kapton, and a configuration of painted aluminum honeycomb that was not previously tested. We also present the results of batch-to- batch reproducibility studies in Ball Infrared BlackTM and painted aluminum honeycomb. Finally, we describe a recently-adopted temperature control method which significantly speeds the data acquisition, and we discuss efforts to reduce the noise in future data.

Micrometeoroid impact charge yield for common spacecraft materials

AbstractThe impact ionization charge yield is experimentally measured from four common materials used in space and specifically on the two STEREO spacecraft (germanium‐coated black Kapton, beryllium copper, multilayer insulation, and solar cells). Cosmic dust particle impacts on spacecraft have been detected by electric field and plasma and radio wave instruments. The accurate interpretation of these signals is complicated by many factors, including the details of the spacecraft antenna system, the local spacecraft plasma environment, and our understanding of the physics of the impact process. The most basic quantity, the amount of charge liberated upon impact, is generally considered poorly constrained and is suspected to depend on the target material. Here we show that for common materials used on spacecraft this variability is small for impacts around 10 km/s, and the impact charge yield can be approximated by 80 fC for a 1 pg projectile. At higher speeds (∼50 km/s), variation of up to a factor of 5 is observed. The measured yields in the 10–50 km/s range are compared to measurements and predictions from the literature and are found to be lower than predicted by at least a factor of 12 at 10 km/s and at least a factor of 1.7 at 50 km/s. Impact charge is also found to depend on angle of incidence; the data suggest a maximum at 45°.

Mitigation of lunar dust adhesion by surface modification

Dust has been recognized as one of the greatest hazards in continued lunar exploration due to its tenacious adhesion to everything with which it comes into contact. Unfortunately, there is little known about the mechanisms of adhesion on widely varying surface types: van der Waals and electrostatic forces are the dominant forces under consideration here. Surface energy, roughness, mechanical properties and electronic properties are all known to contribute to the adhesion characteristics. An optimal solution to mitigate dust adhesion would be to identify the dominant components of the adhesive force and to reduce that force by surface modification. In this study, an ion beam process was used to modify (treat) the surfaces of three dramatically different materials spanning the range of conductor (black Kapton), semiconductor (silicon), and insulator (quartz). Adhesive forces between less than 25 μ m JSC-1 lunar simulants and these virgin/treated surfaces were measured in vacuum using a centrifugal force detachment method. We found that JSC-1 particles adhered less to treated silicon and quartz surfaces, correlated with a reduction in van der Waals force due to a reduced surface energy. The large reduction in adhesion for treated black Kapton is mainly due to the large decrease in the electrostatic (image) force that results from reduced contact charging. Materials in space and on the lunar surface will be directly exposed to high-energy ultraviolet radiation prior to being covered by dust, so the UV irradiation effects on surface adhesion were also examined. Both virgin and treated quartz surfaces are most affected by the UV-irradiation, showing dramatically increased adhesion.

Preliminary Thermal Design of UNITEC-1

UNITEC-1 is a nano-spacecraft that flies to Venus. The preliminary thermal design of UNITEC-1 has been carried out. It has been clear from 1 node analysis that slow tumbling of the rotation axis is effective to reduce the temperature variations. It is difficult that both temperatures of the worst-case cold condition and the worst-case hot condition are within the allowable temperature ranges. It is desirable to conduct the survival competition as soon as possible after UNITEC-1 separates from a rocket. It is recommended from this viewpoint to use the black Kapton on the external surface except solar cells. It is clarified from the multi nodes analyses using Thermal Desktop/ SINDA/FLUINT that the temperature of the transmitter changes from 14.8 to 21.0 degree Celsius in an operational sequence under the worst-case cold condition. The temperature change of the battery can be suppressed from 15.5 to 16.6 degree Celsius in an operational sequence under the worst-case cold condition using the insulator between the battery and the internal surface. The maximum difference of temperature occurs between UOBC3 and UOBC6, and is 2.8 K. This difference is enough small to conduct the survival competition under the equal condition. The minimum period for the mission is about 114 days after UNITEC-1 separates from a rocket.

Cassini multilayer insulation blanket high-temperature exposure tests

The Saturn-bound Cassini spacecraft will be subjected to a high-temperature environment at 0.61 AU. Thermal vacuum tests demonstrated that the hybrid Kapton®-Mylar multilayer insulation lay up can withstand an outer layer temperature of 250°C without incurring any damage, and the all-Kapton layup can withstand 430°C. The latter will be applied to locales of extremely high temperatures, while the former will be applied to more than 85% of the spacecraft's blanketed surfaces. A solar simulator provided a 2.7-sun exposure to the blanket samples; outer layer temperatures of 200°C and 250°C were observed for second surface aluminized Kapton and black Kapton, respectively, which are in line with predictions. The high-temperature exposure tests established that current blanket designs will survive the Cassini mission thermal environments with margins.