Scientists on Reddit

Jeffrey Hoffman

NASA astronaut, first Hubble repair mission, MIT professor

We retrieved 1 post and 55 comments from u/jhoffma1, all from 2017, most often in r/IAmA.

Best moment

A redditor wrote in r/IAmA

On “IamA former NASA astronaut with 1000 hours aboard the Space Shuttle and a professor in MIT’s Department of Aeronautics and Astronautics. I'm Jeff Hoffman– Ask Me Anything!”

I imagine that lots of stuff gets loose and travels around the cabin in zero-g, so my question is what's the most surprising thing you found floating in front of your face?

u/jhoffma1 replied

The most surprising thing that anyone found floating in front of his face was, I think, his own hand! When you are weightless, you can lose track of your arms and legs if you are totally relaxed. A sleeping astronaut…

Read all of itShow less

The most surprising thing that anyone found floating in front of his face was, I think, his own hand! When you are weightless, you can lose track of your arms and legs if you are totally relaxed. A sleeping astronaut awoke to see a "mysterious hand" floating in front of his face. It took quite some time for him to realize that it was his own hand!

Personal storyStories from orbitr/IAmA · 6 points as of Nov 2026Full thread ↗

More moments

A redditor wrote in r/IAmA

On “IamA former NASA astronaut with 1000 hours aboard the Space Shuttle and a professor in MIT’s Department of Aeronautics and Astronautics. I'm Jeff Hoffman– Ask Me Anything!”

What was the greatest adversity you faced during your time in space? How did you address it?

u/jhoffma1 replied

The most critical mission was the rescue/repair of the Hubble Space Telescope. On the first day, after replacing the gyroscopes, the main door would not close, which would have doomed the telescope. It took us an hour to figure out…

Read all of itShow less

The most critical mission was the rescue/repair of the Hubble Space Telescope. On the first day, after replacing the gyroscopes, the main door would not close, which would have doomed the telescope. It took us an hour to figure out what the problem was and how to solve it, which involved using a standard tool in an unconventional way. But that's what astronauts are supposed to do - solve problems.

Personal storyStories from orbitr/IAmA · 6 points as of Nov 2026Full thread ↗
A redditor wrote in r/IAmA

On “IamA former NASA astronaut with 1000 hours aboard the Space Shuttle and a professor in MIT’s Department of Aeronautics and Astronautics. I'm Jeff Hoffman– Ask Me Anything!”

What do you do when something dusty or anything like that starts floating around? How do you stop it prom hurting people or damaging stuff? Thanks!

u/jhoffma1 replied

Dust in space is a real problem, because it doesn't fall to the ground. The air is constantly circulated through filters to remove dust and lint, but we need to be careful to minimize the amount of dust created -…

Read all of itShow less

Dust in space is a real problem, because it doesn't fall to the ground. The air is constantly circulated through filters to remove dust and lint, but we need to be careful to minimize the amount of dust created - for example no woolen clothes (lint) and no cashew nuts (too many crumbs).

Explains thingsExplaining things to strangersr/IAmA · 4 points as of Nov 2026Full thread ↗
A redditor wrote in r/IAmA

On “IamA former NASA astronaut with 1000 hours aboard the Space Shuttle and a professor in MIT’s Department of Aeronautics and Astronautics. I'm Jeff Hoffman– Ask Me Anything!”

What's the most interesting experiment that you were a part of aboard the space shuttle?

u/jhoffma1 replied

On my last flight (STS-75 in 1996) we deployed the tethered satellite, a 1.5 m diameter sphere that remained attached to the shuttle by a 20 km long wire. Looking up at the wire disappearing into space, I felt like Jack looking up at the beanstalk!

Behind the scenesStories from orbitr/IAmA · 22 points as of Nov 2026Full thread ↗