Is human space exploration with nuclear propulsion inevitable?

For some reason at 7:05 I said "can't be understated" instead of "shouldn't be understated". Oops. #OnlyHuman.

In the 1950's, the U.S. Air Force sponsored an R&D program to develop a nuclear powered bomber. The result was a molten salt thorium reactor that was actually operational in the 1960's.

Love these mid week technology deep dives when they come out. Please keep them coming.

Princeton Satellite Systems (mentioned at the end of the video 18:06) is in Pre-Launch on our site. They are developing the Direct Fusion Drive (DFD) propulsion system. If you are interested you should check them out!

I've been saying it for a long time. People can whine and complain about nuclear power all they want. But if we ever hope to branch out into the solar system and beyond then we NEED it. There's no way around it. nuclear power is one of the absolute essentials for space travel just as essential as water, food and air.

So excited for the possibilities with Starship. I'm like a little kid with everything related to it comes out! Cheers for the great video Marcus !

Hi Marcus, great video. I think a video on telescopes that could be fit inside Starship would be awesome.

Marcus thank you for giving a shout out to PSS at 18:06. We loved the potential of this tech so much we felt it should get shot at fundraising on our site and they're currently in pre-launch!

One of the most fascinating space-related videos i've seen. Easily commercial documentary level quality. Thank you Marcus + team!

Thanks, Marcus! Incredibly interesting for those of us who haven't studied rocket 'stuff' like you have, A great synopsis of what is going on out there in R&D.

Regarding the football field-sized radiator to manage waste heat from a 200 MW reactor, I'd love it if you do a deep dive about spacecraft thermal control, Marcus. I read a quote somewhere, adapted from the famous military one, that said "Amateurs talk powers. Professionals talk heat managements." Since space vacuum is a very good insulator, dealing with waste heat will become major headache when we start bringing up more and more powerful propulsion and power system up there. Damn you thermodynamics!

"We don't have access to an anti-gravity drive..." Excellent phrasing, Marcus.

Focussing on Isp alone led NASA to develop a severe case of the Hydrogen Religion -- and they still have not fully recovered from that. The problem is that the larger, more massive tank required for the hydrogen more than negates the Isp advantage of the hydrogen/oxygen rocket engines. CH4 comes out on top because of the smaller, lighter tank and simpler infrastructure. Similarly, what use is an Isp of 10000 if 99% of that is eaten up by having to lug around a massive nuclear reactor? For meaningful comparisons one would have to compare whole systems but that is of course very difficult and time consuming.

a space time continuum video done as efficiently as possible would take no time at all!

Great to take our eyes off Starship & SLS for a moment to see what's on the horizon... I think the Moon is the ideal place for nuclear engine development. Radiation accident? Nothing the place hasn't already seen. Making thrust? Lots of mass to hold things in place while testing...

The Krusty the Clown connection is hilarious! He was one of my favorite characters on the Simpsons and I hadn't put 2 and 2 together until this episode. Now I can't stop hearing it.

Hard to put into words how grateful I am for you and your team working so hard to create what has to be the top video to date! - for all space you tubers! I hope you get world wide attention and accolades/awards for this type of work. And to squeeze this in between your already colossal weekly productions!! You guys are phenomenal and every second is top quality content and production. @ age 76, I go back to first hand watching sputnik and everything space that has followed. I am a heavy construction project manager civil engineer and relate to this stuff big time. I helped build rocket stands, nukes, space chambers for star wars defense simulation, the NIF @ Livermore, CA - so I'm aware of this stuff, but never to the extent you just provided!! Absolutely mind expanding, even for someone who's been addicted to space, follow it intensely, yet never had it put together in such marvelous context as you and your team just did! Thanks is just the tip of our vocabulary for what I wish I could construct to pass on my gratitude, but THANKS!!

One of my favorite channels on YouTube! Especially love the weekly updates. Thanks Marcus!

On ya Marcus, appreciate the midweek vid

Hi Marcus, great mid-week deep dive as always!! A little mistake you made right there at 14:20- The interplanetary transfer station is the "Hermes" and not the "Ares 3"..