So today is April 24, and I was looking through stuff that happened on this day in U.S. history for the site. There's a bunch, but the one that stood out to me was the Hubble Space Telescope. It launched on April 24, 1990 — exactly 36 years ago today.
Here's the thing I didn't know until I looked it up: Hubble almost didn't work.
The launch
The Space Shuttle Discovery carried Hubble into orbit on April 24, 1990. The next day, the astronauts released it into space. By then the telescope had already taken 40 years and cost about $1.5 billion to build. It had been delayed for years, first because of engineering problems, then because of the Challenger disaster in 1986.
So when it finally launched, people were really excited. Astronomers had been waiting their whole careers for this.
The problem
Then Hubble started sending pictures back. And the pictures were blurry.
Not a little blurry. Blurry enough that the telescope couldn't do what it was built to do. Scientists spent a couple months trying to figure out what was wrong. In June 1990, NASA held a press conference and admitted it: Hubble's main mirror had been ground wrong.
The mirror was too flat at the edge. The error was about 2 microns — which is like 1/50th the thickness of a human hair. That's how precise space telescopes have to be. Two microns off, and a $1.5 billion telescope takes blurry pictures.
This was on the news everywhere. Late night comedians made jokes about it. Congress had hearings about whose fault it was. The most expensive science mission in NASA history was a punchline.
The fix
What I think is the coolest part is what NASA did next. They didn't give up on Hubble. They didn't bring it back to Earth. Instead, they designed a fix and sent astronauts up there to install it.
In December 1993, the Space Shuttle Endeavour flew up to Hubble, and astronauts did a bunch of spacewalks to put in new cameras and a thing called COSTAR, which was basically a set of corrective lenses. Like glasses. For a space telescope.
It worked. The first pictures after the fix were perfect. Hubble started sending back the kinds of images people had been waiting for — galaxies, nebulas, the Pillars of Creation.
Why I think this matters
Hubble is still up there, 36 years later. It was supposed to last 15 years. It has more than doubled its life expectancy and taken over 1.5 million observations. Scientists have written thousands of papers based on its data. It helped figure out the age of the universe (about 13.7 billion years, not somewhere between 10 and 20 billion like people used to think).
And it almost didn't work.
I think about this sometimes when I'm trying to fix something on this website that's broken. Like when the streak counter kept resetting and I couldn't figure out why. Obviously my problems are a lot smaller than a flawed mirror in space. But the lesson is the same one. Just because something's broken doesn't mean it's over. Sometimes you go back up there and you fix it.
Happy 36th birthday, Hubble. Thanks for the pictures.