Research and analysis

Mission Review: James Webb Space Telescope

Published 14 August 2025

1. Executive Summary

The James Webb Space Telescope (JWST) is an infrared space telescope developed by the US National Aeronautics and Space Administration (NASA) with contributions from the European Space Agency (ESA) and the Canadian Space Agency (CSA).

The UK Space Agency commissioned RAND Europe and Ipsos to produce a monitoring and evaluation (M&E) framework for future evaluations of the National Space Science Programme (NSSP) and the Science and Exploration Bilateral Programme (SEBP). As part of this, RAND Europe has conducted two mission reviews, into the James Webb Space Telescope and Solar Orbiter, to test this framework, but they do not constitute full evaluations.

Through the NSSP, the UK contributed £25m to the development and operation of JWST. UK scientists led and managed a consortium of ten European countries which developed the Mid-Infrared Instrument (MIRI), one of four instruments hosted on JWST and the only one focused on mid-infrared (mid-IR) wavelengths.

Stakeholders involved in MIRI’s development reported that the UK’s heritage in astronomy and mid-IR instrument development was key in convincing NASA and ESA of the scientific value of a mid-IR instrument, in conjunction with early financial support from UK funding agencies. Thus, MIRI represents a key example of the UK identifying a strategic priority and leveraging financial resources and the enthusiasm and expertise of its scientific community to achieve a key role in a large-scale space science mission.

UK institutions involved in the design and manufacture of MIRI made multiple technological advancements over the course of its development, including in imagery systems, insulation, cryocooling, and data-cleaning and processing tools. These technologies and skills have subsequently been deployed in other projects including GHOST, an instrument hosted on a NASA unmanned aerial vehicle delivered in 2015, and NIMCAM, an instrument in development funded by the UK’s Centre for Earth Observation Instrumentation (CEOI).

The UK’s successful development and management efforts enabled the MIRI consortium to be the first JWST instrument team to deliver. The UK’s consortium management led to ‘very strong collaborative links’ with NASA and ESA and, according to stakeholders at NASA, contributed to the UK’s reputation as a ‘partner of choice’ in space science missions. Given that every instrument is unique, based on the scientific and logistical requirements of the spacecraft, the UK’s involvement in MIRI demonstrates that entities in the UK remain capable of on-time delivery of a complex instrument to world-class specifications.

Stakeholders stressed that MIRI, and more broadly JWST, have been significant for the UK astronomy community, with some fields that were described as ‘stalling’ as researchers began to encounter the limitations of existing instrumentation being reinvigorated due to advances from MIRI and JWST. Since launch, stakeholders have unanimously described the impacts of JWST positively, with one interviewee saying that JWST ‘completely revolutionised the field’. The early preparation of scientific networks was described by researchers as essential in ensuring the UK did not fall behind other European nations.

Proximity to instrument development teams was described by stakeholders as a key factor in ensuring UK institutions and researchers were prepared to successfully capitalise on the transformational data provided by JWST. The expertise and scientific understanding developed as a result of the UK’s investments into MIRI’s development positioned the UK to understand and exploit the data derived from it. As JWST data is available to the wider scientific community, institutions and researchers who were involved in the development of the instruments had a competitive advantage in terms of early exploitation of the data.

The UK has consistently been the second-most successful nation at winning JWST telescope observing time in terms of the number of proposals submitted and approved, behind only the US. In Cycle 4, the most recent cycle awarded, 288 approved proposals featured a UK co-investigator, second only to the US (2,031) and outpacing Italy (170), France (143) and Germany (118). The UK’s average success rate across Cycles 1 through 4 (19.35%) nears the average success rate of the US (20.5%) and Germany (20.0%) and significantly outpaces Italy (15.4%) and France (15.2%).

Metric	US	UK	Italy	France	Germany
Number of proposals awarded	2,031	288	170	143	118
Success rate	20.5%	19.4%	15.4%	15.2%	20.0%

Despite these successes, concerns exist around the funding needed to exploit those successful proposals given that there is no guaranteed or simplified route to funding for UK researchers who successfully win JWST telescope time, unlike in the US.

More consideration could be given to ensuring that UK researchers have the resources and funding necessary to capitalise fully on their involvement. While data exploitation funding is the remit of UK Research & Innovation (UKRI) and the Science and Technology Facilities Council (STFC), the UK Space Agency should seek to engage with its downstream funding counterparts to ensure that the UK astronomy community to engage fully with JWST.

Large-scale multilateral space science missions play an important role in inspiring the public to engage with space, as well as addressing the STEM agenda. The public engagement campaign, jointly funded by the UK Space Agency and the Science and Technology Facilities Council, was instrumental in communicating the UK’s role in JWST to a wider audience. The WebbUK campaign directly reached over 293,000 people around the UK during its multi-year run, including many school children and teachers, with the potential to inspire the next generation of scientists, engineers and technicians.

The NSSP facilitates UK leadership in international space science missions with a relatively small level of funding, as demonstrated by the UK’s leading role in the development of MIRI and involvement in mission-level governance structures despite its relatively small contribution through the NSSP to the overall mission cost of almost US$10bn at launch. Despite these positive impacts, the UK Space Agency could take a more pro-active approach to identifying areas of existing expertise and strategic priority, using the NSSP as a lever through which to influence international space spending.

Overall, the UK’s contributions to JWST have benefited the UK, with beneficiaries including UK institutions involved in the development of the instruments, the scientific community using data produced by these instruments, and the wider UK space sector and general public. Given the expected operational longevity of JWST and the recent launch date, the scientific benefits to the UK will likely continue to develop over the course of the mission’s lifetime. Further M&E efforts should be undertaken to assess the impacts of the UK’s investment into MIRI’s development as JWST’s operational life progresses.