The "Nothing was typical about this innovative solution," said
Electronics on a spacecraft are usually kept warm, operating over a temperature range from 4 degrees F to 131 degrees F. Ball noted that the Webb electronics are collocated with each of the telescope's 18 hexagonal cold primary mirror segments and therefore must be operated at the same temperature as the primary mirror segments. These temperatures are as low as 405 degrees F (30K) in order to capture some of the earliest infrared light in the cosmos.
Ball, a principal subcontractor to Northrop Grumman Aerospace Systems, said it undertook the challenge to design the Webb electronics to operate in a deep-freeze cryogenic environment, recognizing that existing components had yet to be realized for such a space mission and therefore a "how-to" manual was not available.
To create the 6.5-meter Webb aperture, the mirror segments must be aligned on orbit, requiring that a set of cryogenic actuators be mounted to each segment to control individual mirror positioning and curvature radius within one ten-thousandth the width of a human hair. To do that, the Company reported that all 132 actuators required multiple wires to carry power and instrumentation signals between the actuators and control electronics.
To meet all of these complex requirements, Ball noted it located, tested and qualified off-the-shelf components for use in both a 30K cryogenic and a radiation environment to create a electronics architecture consisting of 22 cryogenic flight electronics boxes. Each box operates between 30K and room temperature to multiplex signals from the warm control electronics to one actuator at a time. The Company added that achieving this critical technological advancement for future spacecraft to explore the solar system also required:
-Determining how to create a multiplex design essential to minimize wiring and decrease the thermal heat leak from the warm control electronics to the passively cooled region of the telescope
-Reducing the mass of electronic cables by nearly 98 percent to effectively decrease overall mass of the spacecraft, and
-Developing manufacturing processes to allow the boards to survive both launch loads and multiple thermal cycles from room temperature down to 30K.
The electronic boxes drive the telescope's success because they also control the
The Company said that this advancement for the Webb was based on several earlier cryogenically cooled infrared systems supported by
"We learned through this challenge that trying to unlock the secrets of the Universe can require difficult and amazing engineering on Earth," said Strain.
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"Nothing was typical about this innovative solution," said