. Large Thermal Vacuum Chamber

Case Study
Large Thermal Vacuum Chamber

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Thermal Vacuum Chamber

About

 

AEON has successfully completed the commissioning of its first Thermal Vacuum Chamber (TVC) at its CERES facility (Centre for Engineering and RESearch) located at their headquarters in Newcastle-under-Lyme, Staffordshire.

 

AEON are developing CERES to support the growing aerospace and R&D sectors across the North West and the Midlands. The TVC will play a crucial role in performing monitored ‘bakeout’ programmes for flight hardware and simulating a space environment, enabling satellite instruments and entire cubesats to be calibrated, configured, and fully flight-tested before launch.

 

AEON’s new facility will host a full complement of mechanical, optical, and thermal verification instrumentation, all of which is aimed to help technology startups, academics and instrument manufacturers access space-testing facilities which will provide a means to test and qualify the next generation of space-technologies. All the while helping the UK in increasing its share of the global space (a market that is currently estimated to be worth £400 billion).

 

AEON is able to offer:

 

  • Vacuum chamber dimensions Ø1m x 1m (extendable to 3m in length on request).
  • Vacuum down to 1×10-9
  • Monitoring of pressure/vacuum down to 1×10-9
  • Thermoelectric Quartz Crystal Microbalance (TQCM) (with thermally matched reference crystal and regeneration cycling).
  • Up to 12 temperature probes.
  • Feedthroughs for on-board power, data and signal.
  • Ultra-low loss Ø280mm optical feedthrough.
  • Temperature from -120°C to 200°C.

 

AEON_CERES BROCHURE

 

Project

 

AEON designed and manufactured Optical Ground Support Equipment (OGSE) for RAL Space’s STC-2 and STC-3 simulation chambers. All internal surfaces required a low-outgassing high absorptivity black coating to minimise the reflection of stray light during optical calibration of satellite instrumentation. Aeroglaze Z306 paint was specified as it met optical, cleanliness and outgassing requirements; and it has a proven track record of successfully being used in previous space applications.

 

Following application, it is necessary to forcefully remove most organic and inorganic condensable volatiles from the surface treatment. This type of process is known as a ‘bakeout’ and requires for the finished product to be subject to heat and vacuum, this environment forces volatile molecules to be ejected from the substrate through diffusion and desorption mechanisms; this is achieved through the application of heat and ultra-high vacuum to the Item Under Test (IUT).

 

It is important to note that materials with a high volatile mass are significant sources of contamination which can easily degrade the performance of spacecraft hardware. For components being used in high vacuum and ultra-high vacuum applications failing to outgas components before installation will not only contaminate the vacuum system with unwanted molecules, but it will also affect the pump-down profile likely leading to a much longer pump-down duration to achieve the required vacuum.

 

For this project the IUT was installed in the chamber with ancillaries (heaters and thermocouples) and was subject to a temperature of approximately 120°C (a limit set by the coating manufacturer’s maximum duty temperature) and a pressure of 1×10-6 mBar over a period of 96 hours.

 

To monitor the rate of volatile molecule outgassing, AEON’s engineers used an instrument known as a Thermoelectric Quartz Crystal Microbalance (TQCM). The TQCM is a large quartz crystal oscillator cooled to a specific temperature that promotes the condensation of ejected volatile molecules; once these molecules are adhered to the crystals surface tiny changes to the oscillators resonant frequency can be detected, therefore allowing AEON’s engineers to calculate exactly how far through the bakeout process hardware is at any given time. The TQCM can be regenerated by heating the crystal, ejecting the collected molecules then cooling back down, typically this is performed several times over the course of a bakeout campaign.

 

Chamber closeup

Results

 

AEON successfully performed the bakeout process on four OGSE windows, including protection covers and ancillary equipment. Process and environmental variables were fully monitored throughout the process and a detailed bakeout report delivered alongside hardware to empirically verify the completion of the activity to RAL Space and ECSS bakeout standards (ECSS-Q-ST-70-02C).