The life and death of a great telescope

• A study published in April used Spitzer data to reveal that the universe's earliest galaxies were brighter than expected, changing how scientists understand our early universe.
• In 2017, Spitzer confirmed that seven Earth-sized planets orbit the TRAPPIST-1 star located 40 light-years away, marking one of the most important exoplanet discoveries to date.
• When Spitzer's mission ends, scientists will lack similar NASA observational capabilities until NASA's James Webb Space Telescope (JWST) launches in 2021.

The big picture: Spitzer is still functional and could likely continue to operate for another couple of years, but NASA decided its less than $14 million annual operating budget could be better used elsewhere.

"Unfortunately, it's kind of getting to the point where the cost to keep it going is worth more than the science ... that you can get out of it. It's a horrible thing to say about a cost-benefit analysis, but scientifically, it gets that much harder to keep the spacecraft functioning."

Details: Because of the telescope's orbit around the sun, it's actually moving farther and farther from the Earth each year. Eventually, the telescope will be too far away to make meaningful communication possible.

• NASA looked to private companies to take over Spitzer operations, but none could line up funding in time.
• Originally, scientists hoped that JWST and Spitzer would be in space at the same time, gathering data in tandem to calibrate the newer telescope, but lengthy JWST delays made that impossible.

What's next: While Spitzer won't gather new data after the beginning of 2020, scientists will still be able to access the trove of information it did collect to search for new discoveries.

NASA's astrophysics future

NASA is coming off decades of science beamed back to Earth by big telescopes launched in the 1990s and 2000s.

• As those missions slowly end, the agency and scientists working with them are trying to figure out the future of NASA's astronomy and astrophysics ambitions.

NASA has a lot riding on the launch of JWST in 2021. The long-delayed infrared-focused telescope is billed as Hubble's successor, and it will mark a turning point for astronomy.

• The telescope promises to explore everything from exoplanet atmospheres to the first light emitted after the dawn of the universe.
• However, the observatory's development has been long mired in delays.
• The telescope is now estimated to cost $9.7 billion after exceeding its $8 billion cap.

On the horizon: The agency's WFIRST mission — which is designed to investigate dark energy and image exoplanets — has been on the budgetary chopping block a number of times, but its funding was reinstated by a House bill reported out of committee on May 22.

• If funding holds, WFIRST will be NASA's next big astrophysics venture in the 2020s.

The bottom line: While NASA focuses its astrophysics resources on large, expensive and highly scrutinized missions like JWST and WFIRST, the agency could be missing out on smaller, less costly telescopes that have huge scientific value.

• NASA's TESS mission, for example, was capped at $200 million, and it is already finding never-before-seen planets around nearby stars.

"I'm worried that we're not diversifying in terms of more medium-sized missions and more small missions and more nanosats. The more and more of that time and energy and budget that gets put into these mega-missions, which just keep getting bigger and bigger, it's a squeeze."