Space Based Instrumentation

The most prevalent space based scientific instruments are passive optical. That is they sense radiation at optical wavelengths, ultraviolet through infrared. Filters and coatings are invariably required. In some instruments the filters are the primary wavelength discriminator.

Barr has been providing filters to the space science community for over 30 years. Our customers represent institutions, agencies and commercial firms worldwide. Well over 100 flight instruments carry Barr filters and coatings.

Key Applications:

Instrument Payloads

Barr filters are key components of a wide range of optical instrument payloads. These filters function in the same roles as ground based instrumentation however they must be highly reliable, surviving and functioning after launch and sometimes hostile space environments, often operating at cryogenic temperatures. This functionality may be required over very long periods while unattended. Usually several years elapse between the manufacture and test of our filters and the mission launch. Some science mission phases do not commence for years after launch due to an extended cruise phase. The science mission may last several years. Elapsed time from manufacture to mission end is often ten years and can easily be 20 years. Our filters must and do retain full functionality over those periods.

Filter and Coating types include

Wheel-mounted image quality bandpass filters
Multispectral filter assemblies and patterned filter arrays
Dichroic beamsplitters
Variable filters and coatings
Low reflectivity black mask ‘dark mirrors’
Enhanced mirrors

Ultra Narrow Bandpass Filters

Barr is well known for its specialized ultra-narrow bandpass filters. For space applications these are used in the receiver optics of LIDAR systems including world’s first NASA LIDAR in space. Another emerging application is in the detection of lightning and sprites from space. Barr is the principal world wide supplier of these filters.

System Utilities and Station-keeping

Some filters and coating are used in applications not directly associated with the primary science mission. Satellite positioning and pointing are often monitored with an optical system. The internal sensor systems must be protected from environmental stress during integration, launch and operation. Very robust coatings on outer window surfaces are required for example. Some of these non-payload applications include:

Protective antireflection coatings on external surfaces
Solar rejection filters
Sun sensor filters
Limb sensor filters

Space Qualification

The key differentiator for filters used in space is rigorous space qualification. Barr has qualified all filters used in space applications. The qualification program is developed for each application based on customer requirements and heritage qualification activities. All qualification testing is managed by Barr including in-house testing activities in all categories except ionizing radiation tests. This testing is performed in local institutional facilities with which we maintain close, long-trem relationships.

Space qualification may include the following environmental testing

Humidity (for survival prior to launch)
Thermal / cryo cycling
Vacuum cycling
Adherence
Radiation exposure
- Solar, including solar UV
- Total dose gamma
- Protons

Products & Services

Optical Filter and Coating Products:

UV through LWIR Bandpass and edge Filters
Multispectral filters
Beamsplitters
High Efficiency Mirrors
Single and multi notch filter
Rugate Filter
Filter Arrays

Thin Film Products:

Custom metallization schemes