Massive cost overruns. Key deadlines slipping out of reach. Problems of unprecedented complexity, and a generation's worth of scientific progress contingent upon solving them.

That's the current state of Mars Sample Return, the ambitious yet imperiled NASA mission whose rapidly ballooning budget has cost jobs at NASA's Jet Propulsion Laboratory in La Cañada Flintridge and drawn threats of cancellation from lawmakers.

But not all that long ago, those same dire circumstances described the James Webb Space Telescope, the pioneering infrared scope that launched on Christmas Day 2021.

The biggest space telescope ever has so far proved to be a scientific and public relations victory for NASA. The telescope's performance has surpassed all expectations, senior project scientist Jane Rigby said at a meeting recently.

Its first images were so hotly anticipated that the White House scooped NASA's announcement, releasing a dazzling view of thousands of galaxies the day before the space agency shared the first batch of pictures. Thousands of researchers have since applied for observation time.

"The world has been rooting for this telescope to succeed," Rigby told the National Academies' committee on astronomy and astrophysics.