: In 2027, if all goes to plan, the ITER nuclear fusion reactor will begin burning a magnetically confined mix of deuterium and tritium. Reaching that goal entails building the machine and its associated infrastructure, a task that began in 2008 and whose cost and duration have both steadily increased. Although the US is a minor partner in the project, the US contribution constitutes a significant fraction of the country's budget for fusion research. That contribution is set to rise. According to a newly released estimate, the US bill will come to $3.9 billion—roughly four times higher than the previous estimate of three years ago. As Adrian Cho reports for Science
, the numbers are likely to intensify calls for the US to abandon the project.