welcome to first galaxies
exploring the origins of galaxies in the early universe
exploring the origins of galaxies in the early universe
In October JWST passed a major milestone (or, to be more accurate, two major milestones). This is an exciting and very rewarding time for all those who have worked so hard on the JWST Observatory. The full testing is by no means done, but these accomplishments are truly major steps forward towards the launch of JWST in 2021.
The first was the completion of the integration of the optical telescope assembly and instruments (OTIS) with the sunshield and the spacecraft element (SCE). The mechanical connection was first made in September, when OTIS was lowered (extremely carefully) onto the SCE via a series of small and accurate moves in three-dimensions to ensure that all the complex hardware in the central core region came together without any bumping or scraping! This mechanical integration was a crucial step, but the integration process was only deemed to be completed when all the electrical harness connections between OTIS and the spacecraft were checked out and the alignment checks were made. This occurred in October. It all looked good. So JWST is now an Observatory! This is an enormously important step and a crucial one as JWST progresses on its way towards launch.
The second major step was to deploy and tension the sunshield. As is visually obvious, the sunshield is a large and immensely complicated structure, with multiple steps in its deployment. These included the raising of OTIS on its deployable tower (just as will be done in orbit, though here on the ground in one-g with a little assist from a precision crane with very carefully balanced forces); the roll-back of the cover that protects the sunshield during shipping and launch when the sunshield is folded up on the long arms that support it; the extension of the telescoping mid-booms that pull the cover out; and then to the separation and tensioning of the five thin layers of Kapton film with a very complex and carefully orchestrated series of cable motions. And this has to all be done in one-g with support as needed to ensure that the mechanisms are not stressed and that the deployment is faithful to the zero-g situation in space when we do the last and most important deployment! While this is going on we have to ensure that the whole observatory is supported in case of the (unlikely) event of an earthquake. The image below shows the Observatory with the fully tensioned sunshield in the large clean room at Northrop Grumman Redondo Beach from a NASA media release in late October.
To say this is a milestone is to understate the enormously complex development process and the level of cross-checking and testing that has enabled JWST to reach this point. It has taken a remarkable team of incredibly capable people spread across NASA, Northrop Grumman, the science community, and a large suite of contractors with their unique technologies, to reach this point. JWST has been at the cutting edge technologically, and has demanded the very best from those managing and working on such a complex program. It is a testament to all those involved to have JWST reach this point.
JWST has had its challenges and disappointments, with a tough period of reviews, both internally and externally, over the last couple of years when problems arose, but no mission of this complexity and technological reach will ever flow smoothly. Nor should we expect it to do so. If it is straightforward and easy, we haven’t been ambitious enough, and the science returns will not be as dramatic and far-reaching as they could have been.
We are by no means at the conclusion of the testing of JWST. The whole Observatory needs to undergo vibration and acoustic tests to demonstrate readiness for the noisy, rough ride into space. Before this series of tests can start a number of fixes need to be completed, and the delicate sunshield must be (very carefully) folded up, so that the Observatory is in its compact launch configuration. When those noise and shake tests are done, the sunshield will be deployed and the Observatory checked to ensure that everything still works OK. The sunshield is then folded up again and JWST is put into its special shipping container for transfer by boat to the Ariane launch site at Kourou in French Guiana. Further checking will be done at Kourou and the final preparations performed for launch.
There will surely be bumps in the road ahead before JWST ships to the launch site. We can be proud of the accomplishments to date, but the path forward requires continual focus on “mission success”, i.e., ensuring that JWST realizes its science capabilities at L2 following its launch and commissioning, while also being cognizant of the schedule and budget responsibilities that we have. As JWST progresses towards launch the science potential of this amazing observatory remains clear. We are on the threshold of the remarkable science discoveries that will come from a Great Observatory that is dramatically more powerful than Hubble and Spitzer. JWST will take us into a science realm beyond anything that we can now imagine.
This image is from the NASA media release in late October. There is more detailed information in that media release too. And a higher-resolution version of this image.
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