Deep Sky Black Properties

NOTE: Deep Sky Black properties below represent both as tested information as well as expected performances based on testing conducted on earlier variations of "similar" products, including the product which was known as Martin Black (MB). All testing by Equinox Interscience to date indicate that where we specify an expected result, that the expectations are quite reasonable. Testing to date has shown Deep Sky Black to meet or exceed expectations for performance.

Electrostatic Charge Deep Sky Black surface does not support electrical potential higher than approximately 200 volts. Above this level, the charge leaks off through the coating with no change to the surface properties. This is typical of anodized surfaces of this type.

Vibration It is expected that the Deep Sky Black surface could release some particles in "extreme" vibration environments. Again, this is typical of anodized surfaces of this type and these extreme environments are typically harsher than the typical launch vehicle spectrum. The particles in this case can be removed from the surface by a cleaning process. Test results indicate that the cleaning process eliminates particles to the background level of particles collected at random with a sample tape. MB surface had been subjected to vibration tests, both mechanical and acoustical, early in its development. The mechanical vibration was 10 g sinusoidal, with a sweep rate of 2 minutes per octave; 20 g root mean square (RMS) Shuttle spectrum for 18 minutes.

There was no mechanical or optical deterioration. An 18 minute acoustic vibration test at 145-dB Shuttle Spectrum was also conducted with no mechanical or optical deterioration.

Temperature and Vacuum It is expected that Deep Sky Black surface will show no deterioration or degradation after exposure to the following environments:

  • Temperatures up to 450 deg C at 10 to the minus 5 Torr
  • Simulated sunlight (including ultraviolet) exposure for 500 hours at 10 to the minus 5 torr

Cryogenic Test - Test were conducted on MB back in July of 1970 at the Electronics Laboratory, San Diego, Ca. Hemispherical emittance (absorbance) tests were conducted at 4 and 77 K. In the far-infrared region (7 to 120 m m), emittance was 0.985 or better.

Handling Abrasion by touching, wiping, or dropping articles on the surface modifies the surface structure and may reduce the absorptivity or Lambertian character of the surface. The surface is also subject to contamination from dust, airborne particles, and outgassed organic molecules or clusters, and this contamination will change the optical properties of the surface. It is important, therefore, to handle parts with Deep Sky Black surfaces with the care afforded "all" optical surfaces.

Outgassing It is expected that Deep Sky Black passes NASA SP-R-0022A specifications (General Specification, Vacuum Stability Requirements of Polymeric Material for Spacecraft Applications, 9 September 74). It is found that most anodize surfaces of this type do well in testing for this characteristic. Early studies from the literature on the outgassing of MB are available. Oak Ridge National Laboratory (C.M. Egert and J.A. Basford: "Vacuum Outgassing from Diffuse-Absorptive Baffle Materials." Proceedings of the SPIE, Vol 1330, 1990, pp 178-185) and Goddard Space Flight Center (T. Heslin, and R. Hunkeler: "Outgassing Rates of Various Aluminum Anodizes." Materials Technology Report, MTR No. 755-011, Goddard Space Flight Center. April 1975). Studies indicate that water is the primary component, followed by two other elements of air nitrogen and oxygen. Between 240 C and 800 C carbon dioxide, sulfur dioxide, sulfur monoxide, and two unidentified species (34 and 78 atomic mass units) had been detected.

Baffle Edge Application In the optical design of most sunshades, baffles are used to prevent stray light reflected by the interior surfaces of the shade from reaching the optical system entrance pupil directly. However, it is impossible to eliminate all light reflected by the edges of the baffles themselves; thus these edges must be designed to reflect the minimum light possible. Equinox Interscience works with your design team to optimize the baffle engineering approach.

Deep Sky Spaceship Black Deep Sky Spaceship Black provides a more durable surface. Deep Sky Spaceship Black also has been shown to be less susceptible to reaction with atomic oxygen. The Spaceship Black variation in the process has also shown a somewhat improved optical performance in the near- and middle- IR. Reflectances from about 37% at 2,3 m to about 25% and from about 15% at 5.5 m to about 3.5% has been demonstrated and verified in recent characterizations at Raytheon Santa Barbera Research Center. The performance in the visible region of the spectrum is maintained. From historical information, we know that the so-called "enhanced" version of MB was subjected to atomic oxygen testing. The results were documented in the Proceedings of the SPIE, Vol 511, 1984, pp 24-30.

Process and Material Spec Numbers for Deep Sky Black:
Process: EIP10021A-2 Rev C (October 31, 2000)
Material: EIM10021A-2 Rev A (August 1, 1997)
Equipment: EIE10021A 2 Rev A (August 1, 1997)

Process and Material Spec Numbers for Deep Sky Spaceship Black:

Process: EIP10022A-2 Rev C (October 31, 2000)
Material: EIM10022A-2 Rev A (August 1, 1997)
Equipment: EIE10022A-2 Rev A (August 1, 1997)

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