In a great example of cross-organisation collaboration, NASA, the ESA, and the CSA worked together on the historic James Webb Space Telescope (JWST) that launched at the end of 2021.
The JWST consists of three major components: the Optical Telescope Element (OTE), the Integrated Science Instrument Module (ISIM), and the Spacecraft Element (SCE). All three have to be in perfect working order for the telescope to launch and work properly.
Therefore, contamination control for this project covered the entire process from construction to launch, necessary due to the high sensitivity of the equipment.
Multiple companies were contracted to work on elements to help the JWST project along its journey and below discusses just two of them.
Jacobs Engineering
There were two ways that Jacobs Engineering aided the development and launch of the JWST.
Jacobs has been supporting the programme for over 14 years, modifying and upgrading “Chamber A”, the world’s largest thermal vacuum chamber used to simulate space conditions to test equipment. The JWST Optical Telescope Element & Integrated Science Instrument Module went through its more than 100-day cryo-vacuum test there in 2017.
One of the tasks was to use CFD to analyse the potential for contaminants in the cleanroom at the launch site
For this project, the Jacobs team took the 50-year-old facility and integrated several new technologies, that had never been utilised at this scale. By the end of the chamber renovation effort, Jacobs had installed three miles of new piping, a mile of vacuum jacketed tubing and more than 10 miles of wiring and optical cables.
This was all done despite challenging conditions brought on by the arrival of Hurricane Harvey in the midst of this critical test. Jacobs worked with the Johnson Space Centre to maintain stable test operations and complete this critical test on schedule, without interruption during the hurricane.
Another way in which the company aided the telescope project was through the performance of Computational Fluid Dynamics (CFD) analysis during various stages of the JWST development programme. One of the tasks was to analyse the potential for contaminants in the cleanroom at the launch site, modelling airflow with dust particles to determine particle tracks and impact points. Additional analysis was performed by TG staff to determine temperature contours and airflow ventilation needed to protect the telescope during transportation.
Jacobs’ team members on the Electrical Systems Engineering Services (ESES) III contract at NASA Goddard Space Flight Center provided logistical support to ensure that the breakdown, safe stowage and packing of support equipment used in observatory testing was completed safely, correctly and on time.
Production Automation Corporation (PAC)
There are so many phases to a huge project like this, and aside from Jacob’s team’s work on the testing and launch portion of the JWST project, cleanrooms were also needed in other construction phases.
PACs cleanroom design was for one of the final phases of the Webb telescope construction. This phase would consist of isolating the telescope for its assembly onto the rocket in preparation for launch.
A long-time supplier of PAC advised the ESA to use them for this project, following the company’s demonstrated success with other spacecraft and satellite projects.
Once chosen for the project, PAC’s cleanroom expert then determined the project requirements and sourced the necessary components of the cleanroom. At this point, the final proposal was created and presented to the teams in French Guiana, where the cleanroom would be built.
The airflow design system for this JWST cleanroom was a single pass or open-loop design
PAC chose a softwall wall system for this project. This is a “lightweight tent-like structure that isolates clean or dirty processes”. Using metal frames and clear panel walls, these enclosures are lightweight, easy to assemble, and scalable.
Space was at a premium for this project, as the area available for the telescope assembly room was restricted. This was one of the reasons that the softwall system was selected. “Our initial process involved some back and forth about design requirements and capabilities,” the company explained.
The airflow design system for this JWST cleanroom was a single pass or open-loop design designed to provide a contaminant and particulate tier-free environment.
PAC explains that “Single-pass air flow systems push air through HEPA filters mounted in a ceiling grid system. It works by pulling air from an adjacent conditioned space into the cleanroom. Then, that air exists through near-floor mounted grilles and is not recirculated.”
Lessons learned by the space agencies
Since its launch, JWST has collected some incredible images and provided data for many projects. With help from plenty of companies, the three space agencies managed this successful launch.
However, there are still some lessons learnt to be implemented in future projects for the agencies’ own operations. In an overview of the contamination control strategies of the project, a few take homes from both successful and unsuccessful aspects of the programme have been highlighted by the team.
PEOPLE: A lot of the lessons learnt surrounded the experience and management of the technical team. Whether this be directing team members towards projects catered to individual strengths or managing team shifts to prevent burnout.
An example of leaning into individual strengths was when a high-energy technician was chosen to spearhead the laundry facility upgrades in collaboration with Centre National d'Etudes Spatiales (CNES).
A way that the management prevented burnout, was with a small mid-shift team that moved the overlaps to different parts of the day than the rest of Integration and Testing (I&T). This also avoided interference between contamination control maintenance and restocking with other operations.
THE FACILITY: Looking at the facility itself, there were two contamination control innovations that proved important to the programme. One was the portable HEPA modules that allowed for creating and maintaining cleaner work areas inside and outside of cleanrooms. Though it was also noted that “future use should include stanchions or keep-out zones in front of the filter faces to prevent personnel from blocking airflow”.
Unsealed cleanroom wipe fibres were found inside the Near Infrared Spectrograph
The other innovation was sealed edge cleanroom wipes. The use of these was born out of the discovery of the shedding of unsealed cleanroom wipe fibres inside the Near Infrared Spectrograph (NIRSpec). The switch from unsealed to sealed resolved this issue for the team. Only discovered because of regular darkened room UV inspections, this discovery also emphasised the importance of this process for any fibre-sensitive mission.
Only time will tell
The infrared astronomy that JWST is conducting could last anywhere from five to 20 years. Outside of the limitations of our atmosphere, it will be providing essential data to astronomers and physicists across the globe.
How long it will last depends on how well it was designed, but also how clean it was designed as it ages. Only time will tell how clean it actually was.
