Currently, four teams of scientists are working on the concept of an ambitious space telescope to study four different telescope designs - HabEx, LUVOIR, Lynx and OST. So far, the team does not need to consider any cost caps to design their tasks. The cost may exceed 5 billion US dollars and may even reach nearly 20 billion US dollars. Of course, these designs are not meant to be the ultimate blueprint, but as a reference for NASA. However, NASA now wants to ensure that the new space telescope can be completed within a reasonable budget. This means that some teams will have to limit the scope of their ideas.
NASA is mainly worried that the next flagship space observatory, the James Webb Space Telescope or JWST, will be postponed and out of budget, which means that it will devour more NASA's astrophysical funds in the next few years. At the same time, the Trump administration recently proposed the cancellation of another major astrophysical task, the WFIRST telescope, and considered the design too expensive. This move shows that the government may not want to fund large-budget astrophysical missions in the future because it focuses on the return of mankind to the moon.