That Time NASA Tried to Make a Nuclear-Powered Rocket
Aug 10, 2023
That Time NASA Tried to Make a Nuclear-Powered Rocket
This month’s Pin of the Month is dedicated to the NERVA program. During the Space Race, NASA designed and tested a rocket engine fueled in part by nuclear fission. And it went so well (minus the funding cuts) that the prospect of a nuclear-powered rocket keeps circling back around.https://dftba.com/scishow https://www.patreon.com/scishow https://scishow-tangents.simplecast.com/ https://www.tiktok.com/@scishow http://www.twitter.com/scishow http://instagram.com/thescishowFacebook : http://www.facebook.com/scishow https://www.nasa.gov/press-release/na …https://www1.grc.nasa.gov/wp-content/ … [PDF]https://ntrs.nasa.gov/citations/19910 … https://ntrs.nasa.gov/citations/19680 … https://ntrs.nasa.gov/citations/19670 … https://ntrs.nasa.gov/citations/19910 … https://ntrs.nasa.gov/citations/19920 … https://nuke.fas.org/space/la-10062.pdf [PDF]https://www1.grc.nasa.gov/historic-fa …https://www.osti.gov/servlets/purl/46 … [PDF]https://apps.dtic.mil/sti/pdfs/AD0731 … [PDF]http://archive.gao.gov/t2pbat6/147698 … [PDF]https://sgp.fas.org/othergov/doe/lanl … [PDF]https://nuke.fas.org/space/review.pdf [PDF]https://www-pub.iaea.org/MTCD/publica … [PDF]https://history.nasa.gov/SP-4407/vol1 … [PDF]https://www.sciencedirect.com/science …https://images.nasa.gov/details/GRC-1 …https://commons.wikimedia.org/wiki/Fi …https://images.nasa.gov/details/9255078 https://www.gettyimages.com/detail/vi …https://www.gettyimages.com/detail/ph …https://images.nasa.gov/details/ksc_0 …https://images.nasa.gov/details/SLS%2 …https://www.gettyimages.com/detail/ph …https://commons.wikimedia.org/wiki/Fi …https://www.gettyimages.com/detail/ph …https://commons.wikimedia.org/wiki/Fi …https://images.nasa.gov/details/9902020 https://www.gettyimages.com/detail/vi …https://images.nasa.gov/details/S69-3 …https://www.nasa.gov/directorates/heo …https://www.nasa.gov/jpl/dawn/pia18922 https://images.nasa.gov/details/9902047
Content
0 -> This video is supported by the SciShow Space pin!
3.48 -> You can find a cool new rocket pin
every month at DFTBA.com/SciShow.
10.32 -> For all intents and purposes, a working
rocket is basically a controlled explosion.
16.02 -> So the idea of sticking a
nuclear reactor inside one
19.68 -> might seem like a…questionable idea…at best.
23.46 -> And yet, a nuclear-powered rocket was exactly
27 -> what scientists and engineers
were trying to build in the 1950s.
30.96 -> And 60s.
31.98 -> And 70s.
32.82 -> Because despite all the risk, it could literally
35.76 -> launch humanity to a new era of space exploration.
39.6 -> The NERVA program, short for Nuclear
Engine for Rocket Vehicle Application,
44.58 -> got further than you might think.
46.8 -> Before the funding got cut in the early
70s, they’d built multiple versions
51.72 -> of the engine, and had a
bunch of successful tests.
54.78 -> And while NERVA’s nuclear
engine never got off the ground,
58.38 -> the idea of one never quite disappeared, either.
61.86 -> Just this year, NASA proposed
bringing it back. Again.
66.3 -> [♪ INTRO]
69.96 -> Now, a rocket powered by splitting the atom
72.96 -> might be the most 1950s thing I can imagine.
76.44 -> It probably lived in the
suburbs and danced to Elvis too.
80.04 -> But the fifties weren’t
just one big uranium party.
82.98 -> Every rocket, no matter its appearance,
is based on the third law of motion.
87.3 -> That’s the one that says if you
push something, it pushes back.
90.78 -> Rockets push exhaust one way,
93.54 -> while the exhaust pushes back
on the rocket the other way.
97.26 -> The harder the rocket pushes the exhaust,
99.54 -> the harder the exhaust pushes the rocket.
102.42 -> That’s rocket science in a nutshell.
104.64 -> The hard part is figuring out how to give
the exhaust as big of a kick as possible.
110.28 -> The best exhaust is lightweight,
so that it doesn’t take much energy
114.18 -> to make it go super fast out
the back end of your rocket.
117.96 -> The push it provides in return gets
the best bang for your energetic buck.
121.98 -> So as the lightest known molecule in the universe,
125.28 -> hydrogen makes for great exhaust.
127.68 -> But you’ve also got to make sure you have
129.6 -> enough energy to shove that exhaust out the back.
132.3 -> In traditional rockets, that
energy comes from cracking apart
135.66 -> different molecules in your rocket
fuel and smushing them back together
139.62 -> in new ways that leaves a
bunch of leftover energy.
142.44 -> In other words, you’re both
making the exhaust and the energy
145.86 -> to move that exhaust with
the same chemical reaction.
148.98 -> Hydrogen is pretty awful
at releasing extra energy.
152.34 -> So instead, rocket fuel usually
relies on bigger molecules
156.48 -> that can release more energy, but produce
exhaust that’s heavier than hydrogen,
161.34 -> and therefore less efficient
in providing that oomph.
164.88 -> Ultimately, in the choice
between lots of energy with
167.94 -> heavier exhaust or less energy with an
ideal exhaust, engineers chose the former.
173.94 -> But here’s the thing: the laws of
physics don’t say the exhaust needs to be
178.14 -> pushed out of the rocket by the
same process that makes the exhaust.
182.4 -> You just need a supply of
ready-to-go, super light hydrogen,
186.3 -> and something that can make a bunch
of energy for that hydrogen to absorb.
191.34 -> I think you know where I’m going with this.
192.96 -> According to the math, a rocket
powered by a nuclear fission engine
196.62 -> could produce twice the thrust of
a chemical rocket on its best day.
201.06 -> Plus, it would need much less
fuel for the same-sized trip.
204.78 -> The rocket would be both
lighter and more powerful,
207.48 -> getting probes or astronauts where
they were going a lot faster.
211.38 -> So in 1955, not that long after
the first nuclear power plant
215.82 -> was opened, Project Rover was born.
218.28 -> Research progressed quickly,
219.9 -> with successful reactor
prototypes starting tests in 1959.
223.98 -> NASA formed around the same time, and
soon it consolidated Project Rover
227.94 -> and other related research under the NERVA banner.
231.18 -> Over the years, NERVA scientists developed small,
234.3 -> powerful nuclear reactors that could
travel aboard a rocket and activate for
238.8 -> specific parts of the mission
whenever a big push would be needed.
242.4 -> One of the challenges they had to
overcome was those reactors creating
246.42 -> such high temperatures that some of the rockets’
249.3 -> components would have degraded and fallen apart.
252.48 -> For the record, that’s also a problem
that comes up with chemical rockets.
256.44 -> So as a fix, they designed the
engine to circulate some of the super
260.46 -> cold liquid hydrogen through a bunch
of tubes to keep everything cool.
264.42 -> So the hydrogen actually served two jobs!
267.42 -> Oh, and don’t worry, they
also knew they would need to
271.26 -> shield whatever cargo or humans were aboard.
273.78 -> They weren’t about to risk
anyone turning into the Hulk.
276.9 -> Or just, you know, getting radiation poisoning.
279.84 -> Soon, people were imagining nuclear-powered
shuttles to the Moon or even Mars.
284.94 -> The plan still involved
chemical rockets for launch,
287.64 -> since launches have a high
enough chance of going wrong.
290.76 -> And you definitely don’t want to have
to worry about the literal fallout
294.18 -> from an active nuclear reactor blowing
up a few kilometers above the ground.
298.74 -> But once outside the atmosphere,
300.42 -> the chemical piece would fall away
and the nuclear engine would start up.
304.2 -> Now, a flying container of uranium is still
not ideal, even if the reactor is turned off.
310.02 -> So in 1966, scientists blew up a
model of the reactor with explosives
314.88 -> to see how bits and pieces would spread
if the worst did happen during launch.
320.64 -> These kinds of safety and technology
tests were proceeding so well that,
324.78 -> with NASA planning for crewed
missions after the Apollo missions,
328.32 -> a full-scale NERVA rocket seemed inevitable.
331.68 -> But NASA’s budget was shrinking even
before astronauts reached the Moon.
335.46 -> Long-term, long-distance human
spaceflight wasn’t a priority.
339.78 -> By 1973, NASA had to choose between NERVA
343.2 -> and what would become the Voyager missions.
345.48 -> They chose the Voyager.
346.62 -> Which, honestly, not a bad choice.
348.6 -> Every ten years or so, though,
scientists glance back at
352.14 -> nuclear-powered propulsion, with
flurries of interest in the mid-eighties,
356.46 -> the early nineties, and the mid-2000s.
359.4 -> But even as satellites have employed all
sorts of other non-chemical thrusters
364.08 -> over the last few decades, nuclear rocket
engines still haven’t reached space.
368.7 -> At least, not yet.
369.72 -> In early 2023, NASA and the
Department of Defense announced
374.04 -> a plan to use nuclear propulsion
to take humans to Mars.
377.4 -> Which is…awesome!?
378.42 -> But NASA also proposed something
similar way back in 1969,
383.4 -> soon after NERVA’s funding was first cut.
386.04 -> … and then again in 1991.
388.44 -> So for now, nuclear-powered propulsion
remains a well-verified laboratory curiosity.
394.02 -> But soon, maybe it’ll have its day in the Sun.
397.2 -> Or, even better, its day
in the blackness of space.
400.86 -> Scientists might dream of a future
spacecraft flying through the final frontier
405.9 -> using the power of nuclear fission.
408 -> And to bring those dreams a little
closer to reality, we here at SciShow
412.44 -> have created our very own tiny
nuclear-powered rocket engine.
416.22 -> Or at least the image of one.
418.08 -> Our new pin of the month celebrates
NERVA and the wild dreams
421.8 -> scientists have had over the years
to help humans explore the universe.
425.82 -> If you’d like to celebrate
with us, head on over to
428.76 -> DFTBA.com/SciShow and pick one up.
432.84 -> Thanks for watching.
433.823 -> [♪ OUTRO]
Source: https://www.youtube.com/watch?v=9u4wtmeQB4I
