The James Webb Space Telescope (JWST) is expected to cost NASA $9.7 billion over 24 years. Of that amount, $8.8 billion was spent on spacecraft development between 2003 and 2021; $861 million is planned to support five years of operations. Adjusted for inflation to 2020 dollars, the lifetime cost to NASA will be approximately $10.8 billion.
That is only NASA’s portion. The European Space Agency provided the Ariane 5 launch vehicle and two of the four science instruments for an estimated cost of €700 million. The Canadian Space Agency contributed sensors and scientific instrumentation, which cost approximately CA$200 million.
NASA’s contributions to the telescope were not paid out all at once, but spread out over the course of two decades. Annual expenditures vary depending on the particular needs of the project and how many highly-trained technicians, engineers, and scientists are assigned to the program at any given time. This type of cost phasing makes it easier for NASA to shoulder the expenses of a large project year-to-year. Despite its delays and cost overruns, the project never required more than 3% of NASA's annual budget.
NASA's annual obligations for the James Webb Space Telescope (JWST) project, not adjusted for inflation. The spacecraft will begin its operational phase in FY 2022. Amounts after the current year are official projections. Source: NASA Budget Requests FYs 2005 - 2022.
You can access the raw data behind the charts in this article via this Google Spreadsheet.
The Webb telescope was not always planned to be a megaproject. It was originally estimated to cost $4.96 billion and launch in 2014. But serious mismanagement and under-resourcing during critical early planning stages caused the ambitious spacecraft to fall behind schedule. After NASA restructured the project to launch in 2018 the total cost increased to $8.8 billion. In the intervening years, the program struggled to address serious technical problems, further delaying the launch to 2021. This final delay added yet another billion dollars to the total cost.
This did not come without consequences for NASA’s Astrophysics Division, which is responsible for the agency’s space telescope missions. Since 2003, one out of every three dollars spent on astrophysics has gone toward the Webb telescope, crowding out and delaying other projects. Only a handful of small missions have launched in the last decade. The Nancy Grace Roman Space Telescope, the top recommendation of the National Academy of Sciences’ decadal survey for the 2010s, will not launch until 2027 at the earliest.
Development costs of NASA's James Webb Space Telescope (JWST) represented a significant portion of total spending on all astrophysics programs, as demonstrated by this chart comparing annual program obligations. Between 2003 and 2022, 1 out of every 3 dollars spent on astrophysics went to the JWST project. Amounts after the current year are official projections. Source: NASA Budget Requests FYs 2005 - 2022.
Most scientists believe this investment will be worth it. For comparison, the Hubble Space Telescope also suffered years of delays and billions of dollars in cost overruns, but it is arguably the most successful space science project of all time. As of 2021, the program had produced over 18,000 peer-reviewed publications that had been cited more than a million times in the scientific literature. It literally revealed new perspectives on the cosmos and is one of a handful of scientific projects to become a household name. Few (if any) people now wish that the Hubble had been canceled during its troubled development period. The James Webb Space Telescope, with its ability to peer further into space and time than the Hubble, is expected to provide similar rewards to our scientific knowledge.
It is also important to consider the cost of the James Webb Space Telescope in context. Not only are its costs spread out over more than two decades, but its total cost pales in comparison to human spaceflight projects, infrastructure spending, or even a partial border wall. Compared to the hundreds of billions of dollars the United States spends per year on defense, social, and medical safety net programs, the James Webb Space Telescope’s cost is a rounding error.
To quantify this, in the same 2003 - 2026 period that NASA will spend $9.7 billion on Webb, the United States government will spend, in total, approximately $101 trillion. The James Webb Space Telescope accounts for a mere 0.0095% of all U.S. spending during this period — the equivalent of setting aside a single penny out of a 100 dollars to answer fundamental questions about our cosmos.
The James Webb Space Telescope is expensive for a purely scientific endeavor, but perhaps that says more about our society’s limited investments in science than anything else. Should the mission succeed, the dollars and cents it took to create this technological marvel will look paltry compared to the priceless insights it provides into our cosmos.