The lifecycle of space telescopesby Jeff Foust
|
| “Hubble remains a scientific powerhouse despite flat budgets,” said Lotz. “Over the past 10 years, Hubble has produced 30% more science with effectively 30% less spending power.” |
During a town hall session at last month’s American Astronomical Society (AAS) meeting outside Washington, officials with the Space Telescope Science Institute (STScI), which handles Hubble science operations, outlined the potential impact of those cuts. They said NASA had asked them, as part of an ongoing “senior review” of astrophysics spacecraft that had already completed their prime missions, to plan for a 20% cut in its budget for fiscal years 2026 through 2028.
STScI prepared what is known as an “in-guide” response to fit operations into that budget, which would result in cuts to telescope operations. “There’s no in-guide scenario in which we can continue operating Hubble as we have in the past,” said Julia Roman-Duval, interim head of the Hubble Space Telescope Mission Office at STScI, including maintaining capabilities, grant funding and “mission risk posture.”
The proposed cuts would range from reduced support for observing modes on Hubble to cutting grants from astronomers using Hubble. The institute has budgets $30 million annually for those grants in recent years but the proposal would cut that to $10 million.
There would also be fewer staff available to deal with problems with the telescope, which marks 35 years in orbit this year. “Those are the folks who are able to work around those ‘unknown unknowns’ and anomalies, and so not having them around would mean that the mission risk would increase,” she said.
STScI has already been tightening its belt to accommodate a smaller reduction planned in 2025. That includes a smaller reduction in grant funding and cuts to its outreach efforts that include shutting down social media accounts last fall and hubblesite.org, a repository of Hubble images and press releases, in March. The contents of that site will be moved to a NASA website.
“With this approach,” Roman-Duval said of those near-term cuts, “we delay any irreversible changes until we have more certainty on where the budget scenarios are headed.”
The cuts come despite the facts that Hubble continues to work well, even in a single-gyro mode it entered last summer. Demand for telescope time from astronomers outpaced what was available by a factor of six to one, a measure known as the oversubscription rate.
“Hubble remains a scientific powerhouse despite flat budgets,” said Jennifer Lotz, director of STScI, at the town hall meeting. “Over the past 10 years, Hubble has produced 30% more science with effectively 30% less spending power.”
Congress has yet to pass an appropriations bill for fiscal year 2025, with the federal government operating on a continuing resolution that funds programs at 2024 levels until March. There’s hope, Lotz said, that a final spending bill could override at least the near-term cuts. “We’re hoping for the best but preparing for the worst,” she said.
JWST own budget pressures
STScI also handles the science operations of JWST, a telescope still coming into its prime after its launch a little more than three years ago. JWST has a formal prime mission of five years, and as of the AAS meeting last month it was just past the halfway mark of that prime mission.
At a separate town hall session at the AAS meeting, institute officials said the interest in using JWST continues to grow. “JWST is not even close to hitting its peak science or demand,” Lotz said. “It’s performing better than expected.”
| “It’s extremely worrisome that, while we’re in the middle of the prime mission, we’re also maybe looking at significant budget cuts,” Brown said. |
In the most recent cycle of proposals for observing time on JWST, called Cycle 4, the oversubscription rate was more than nine, higher than Hubble. Project officials credit that to astronomers better understanding what JWST is capable of doing as they see the scientific results of early observations. NASA and STScI say the telescope is performing better than expected and could continue to operate for more than two decades.
However, even JWST is facing budget pressures. NASA requested $127 million for telescope operations and $60 million for science grants in its 2025 budget proposal, a funding level it projected to remain flat through 2029.
Tom Brown, head of the JWST mission office at STScI, said at the town hall that mission costs were set “somewhat idealistically low” during planning for the mission a decade before launch. In addition, inflation has been higher than projected in recent years, eroding buying power.
He said STScI was being asked to conder a “significant” cut, which he defined as 20%, to the JWST operating budget. That could start as soon as October, when fiscal year 2026 begins.
Much like the case for Hubble, the prosed JWST cuts would affect much of the telescope’s operations, from support for astronomers using the telescope to the ability to promptly resolve any anomalies.
“It’s extremely worrisome that, while we’re in the middle of the prime mission, we’re also maybe looking at significant budget cuts,” Brown said. “The impacts are quite significant when you’re talking about a 20% cut to operations.”
Astronomers at the town hall session were alarmed, but project officials at STScI and NASA noted that there are sharp budget pressures across all of NASA’s astrophysics programs, and more broadly for its science portfolio. Jane Rigby, senior project scientist for JWST at NASA, offered a more optimistic long-term view, given the confidence that, technically, JWST could be able to operate for many more years. “We don’t actually know what that ultimate lifetime for Webb is going to be, but we want it to be several decades.”
Roman approaches launch
While there was doom and gloom to some degree about Hubble and JWST at the AAS meeting, the mood about Roman Space Telescope was much more upbeat. A standing-room-only crowd filled the mission’s town hall session to hear about how that space telescope, the top priority of the 2010 astrophysics decadal survey, was coming together. (Free drinks and appetizers also helped attendance, no doubt.)
The telescope is taking shape at the Goddard Space Flight Center, with all its major component and instruments now there. “We really are at a very major milestone right now,” said Julie McEnery, senior project scientist for Roman. She showed off images of the integrated telescope, with technicians now connecting cables and performing tests.
Roman is scheduled to launch no later than May 2027, but could launch as soon as the fall of 2026 if upcoming integrating and testing activities go well. “What makes me really excited is that, now that we’re in January 2025, I can say that we're working towards a launch next year, which is simultaneously incredibly exciting and utterly terrifying,” she said.
| “Now that we’re in January 2025, I can say that we're working towards a launch next year, which is simultaneously incredibly exciting and utterly terrifying,” McEnery said. |
Roman’s main instrument is the Wide Field Instrument, capable of imaging and spectroscopy in visible and near-infrared wavelengths. The instrument will be used for a series of three “community surveys” intended to collect data needed to address key science goals in cosmology and exoplanet demographics.
Roman also carries a coronagraph instrument, designed to precisely block light from an individual star to enable direct imaging of exoplanets orbiting it. The instrument is officially a technology demonstration with 90 days of observing time guaranteed in the mission’s first 18 months. That will be used to verify the performance of the instrument but, as McEnery noted in the town hall, that is expected to take only 15–30% of that time, freeing up the rest for additional demonstrations that will include science.
“The best way to demonstrate the technical capabilities of an instrument is to try and do challenging science,” she noted.
As a sign of the progress on Roman, a telescope that was repeatedly threatened with cancellation just five years ago, the town hall focused primarily on the science the telescope will enable, from the various surveys planned to development of a cloud-based platform for accessing and analyzing the large volumes of data that Roman will produce. “You can’t survey the sky 1,000 times faster than Hubble without having 1,000 times data volume,” McEnery said.
Habitable Worlds gets started
As Roman gets closer to the launch pad, the Habitable Worlds Observatory is taking its first steps. NASA formally established a project office for the mission last year at the direction of Congress, hoping to build on the lessons learned from past missions to enable development of a large space telescope that will be used to look for potentially habitable exoplanets as well as general astrophysics.
“Roman is actually on cost and on schedule, so we’ve demonstrated that when you architect something you can meet cost and schedule,” said Lee Feinberg, principal architect for the observatory, during an AAS session. “Our job is to architect this so that when the team does go through Phase A and begins, they can deliver on a schedule.”
| “Think of Habitable Worlds Observatory as a super-Hubble that will be capable of performing transformative astrophysics,” said Arney, “as well as being the first observatory ever designed to search for signs of life on planets outside of our solar system.” |
That means an early focus on the overall design of the observatory and maturation of critical technologies for it, an issue that caused problems for JWST. “Design problems are baked into the cake at the start and not uncovered until you’ve eaten half the cake,” he said, reading a quote from one agency report on lessons from large missions. “Our goal here is to find the right recipe so that when we build that cake, we can have that cake and eat it all the way through.”
The office is following guidance previously outlined by NASA for HWO that included several key characteristics for the observatory, such as designing to cost and schedule as well as the use of next-generation of launch vehicles and in-space servicing.
Feinberg said the office has developed three “exploratory analytic cases” (EACs) for the design of HWO, general concepts that allow scientists and engineers to examine the tradeoffs of certain design choices. EAC1 could fit inside the seven-meter payload fairing of Blue Origin’s New Glenn, while EAC2 and EAC3 would require SpaceX’s Starship and its nine-meter payload bay. EAC2 would have a mirror that would not need to fold up, as JWST’s segmented mirror did, while the other two designs include foldable mirrors.
Scientists are also refining the instrument requirements and the science cases for the telescope. “Think of Habitable Worlds Observatory as a super-Hubble that will be capable of performing transformative astrophysics,” said Giada Arney, the observatory’s interim project scientist, “as well as being the first observatory ever designed to search for signs of life on planets outside of our solar system.”
At this early stage, optimism about that future, still potentially two decades away, was the theme of the meeting, with many of the hard decisions and potential problems still well in the future. The hope among those present is that HWO’s team will learn the lessons from past large space telescopes and, at least, not repeat them.
“I have to tell you,” said Feinberg, who previously worked on JWST, “I have never been more excited to work on a space telescope because of what this one can do.”
Note: we are now moderating comments. There will be a delay in posting comments and no guarantee that all submitted comments will be posted.