ScienceIamA former NASA astronaut with 1000 hours aboard the Space Shuttle and a professor in MITâs Department of Aeronautics and Astronautics. I'm Jeff Hoffmanâ Ask Me Anything!
Sep 20th 2017 by jhoffma1 • 20 Questions • 210 Points
THAT'S IT FOR TODAY. THANKS FOR ALL OF YOUR GOOD QUESTIONS. SORRY I COULDN'T ANSWER ALL OF THEM, BUT I HOPE THIS HAS BEEN INTERESTING FOR YOU.
PLEASE JOIN US FOR 16.00X - INTRODUCTION TO AEROSPACE ENGINEERING AND HUMAN SPACE FLIGHT, STARTING NEXT TUESDAY (26 SEPTEMBER).
AND REMEMBER THAT MITX WILL OFFER A NEW SPACE COURSE IN THE FALL OF 2018 - 16.885X - SPACE SHUTTLE SYSTEMS ENGINEERING.
I'm Jeff Hoffman - former NASA astronaut and current MIT Professor. In my spare time, I'm the director of the Massachusetts Space Grant Consortium and Deputy Principal Investigator of an experiment on NASA’s Mars 2020 mission.
I've logged 1000 hours of flight time aboard the Space Shuttle, spent four years as NASA’s European Representative, and joined the MIT faculty in August 2001.
My free Introduction to Aerospace Engineering course on edX begins September 26th.
I'd love to answer any questions you have about outer space!
Dr Hoffman, I watched your MIT Space Shuttle class (twice) and am very interested in space history (propulsion engineer!). Listening to you, Aaron Cohen and others, I've always wanted to ask this question: The Shuttle was a marvel that achieved all of its "technical" requirements, but failed to meet its flight rate and ease-of-reusability goals. At what point during the development of the system did the engineering team realize the shuttle wouldn't "work" in the sense of flight rate/reusability? What was the reaction of the program management? Was a decision ever conscientiously made to simply get the current design flying and try better the next time around?
This is too complex a question to deal with simply. The Space Shuttle course is now being prepared as a MITx course which will be given in the fall of 2018. We will discuss this more fully at that time.
Would you fly to space again (for example to the ISS) if you were offered to do so?
I'd go in an instant (but please don't tell my wife, who is happy that I am not flying anymore!)
Dr Hoffman, what kind of material was used for the Space Shuttle thermal protection system? It was only ceramic materials or ceramics matrix composite with silica fibers?
The tiles were ceramic. There were also thermal blankets on cooler parts of the shuttle and there was carbon-carbon on the hottest parts like the nosecone and wing leading edges. This will be covered in the fall 2018 MITx course on Space Shuttle Engineering
Dr. Hoffman, how long will be the travel from Earth to Mars?
With current propulsion technology, about 8 months each way.
It's a lot like backpacking food. Mostly dehydrated or MREs. The Russians use a lot of canned food. It's pretty gooey. Your sense of smell is decreased in space, probably because of all the extra fluid in your head. NASA gave us lots of hot sauce to spice things up. When I got back from my flights, the first thing I wanted was a nice salad that was cruchy and I could chew on.
Do you think there is a future for Aerospace engineers, specifically propulsion engineers?
Aerospace is a vibrant field, with lots of new technologies being developed. We desperately need better propulsion, but currently nobody seems to know how to do this.