# Hubble's Second Chance: Fixing Our Favorite Space Telescope

# This is your Astronomy Tonight podcast.

Good evening, stargazers! Today we're celebrating December 18th—a date that marks one of the most dramatic moments in space exploration history.

On December 18th, 1999, the Space Shuttle Discovery thundered into orbit carrying a crucial cargo: the Space Telescope Imaging Spectrograph (STIS) and a corrective optics package for the Hubble Space Telescope. But here's where it gets really interesting—this was actually the *second* servicing mission to fix Hubble's infamous spherical aberration problem!

You see, when Hubble first launched in 1990, scientists discovered a heartbreaking flaw: the primary mirror had been ground to the wrong specifications by just 2.2 micrometers—about 1/50th the width of a human hair. This tiny imperfection meant the most expensive telescope in history was essentially nearsighted! The space community was *devastated*.

But then came the heroes of STS-61 in December 1993, who installed corrective optics—essentially prescription glasses for a telescope! And on this day in 1999, the crew returned to give Hubble a technological upgrade, installing STIS and a new camera. It was like giving humanity's favorite observatory a complete makeover while it orbited 375 miles above our heads!

This is the stuff that reminds us why we explore the cosmos—sometimes with a wrench in hand!

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