TL;DR
- When chemistry just doesn't cut it
- Santa Claus in a flying saucer
Current events / Today I learned
I’m combining these two today because they intertwine perfectly :)
I was pleasantly surprised to see this USA Today opinion article on a topic I’m really interested in. NASA’s latest budget contains a $100mm research allocation for nuclear thermal rockets, with a demonstration set for 2024. Let me give some background on this; don't let the word nuclear intimidate you!
Most rockets today use chemical propulsion, meaning fuel is combusted to produce exhaust that propels the rocket forward. This produces the high thrust needed to escape Earth’s gravity, but it’s not that efficient, and the technology has mostly been the same since the dawn of the Space Age. Newer alternatives like ion drives are the opposite – high efficiency but low thrust – so they’re good for deep space maneuvers but utterly useless for launching from Earth. The ultimate solution would be nuclear thermal propulsion, which would use a nuclear reactor in the rocket to heat liquid hydrogen to super high temperatures, then expel the hot gas out the nozzle. Nuclear rockets should be able to launch from Earth at twice the efficiency of the best chemical rockets
Most rockets today use chemical propulsion, meaning fuel is combusted to produce exhaust that propels the rocket forward. This produces the high thrust needed to escape Earth’s gravity, but it’s not that efficient, and the technology has mostly been the same since the dawn of the Space Age. Newer alternatives like ion drives are the opposite – high efficiency but low thrust – so they’re good for deep space maneuvers but utterly useless for launching from Earth. The ultimate solution would be nuclear thermal propulsion, which would use a nuclear reactor in the rocket to heat liquid hydrogen to super high temperatures, then expel the hot gas out the nozzle. Nuclear rockets should be able to launch from Earth at twice the efficiency of the best chemical rockets
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| Artist's impression of a nuclear thermal rocket over Mars. Credit: Infinity's Edge |
So if nuclear rockets are so great, why don’t we use them? Actually, we tried – in the 1960s at the height of the Apollo program, NASA successfully tested several experimental nuclear prototypes through their Rover and NERVA projects. Engineers hoped to use this technology to take humans to Mars by 1980. But after the Moon landings when NASA’s budget got slashed, the entire project was mothballed, and the technology has been lost and ignored for the past 5 decades.
I’m interested in this topic because I’m so frustrated by it. Human technological advancement has been so rapid the last 100 years, it’s rare to find instances of stagnation. An operational nuclear rocket could drastically reduce the time to get to Mars, saving future astronauts from the detriments of prolonged space travel in zero-G. To see it go undeveloped due to lack of funding or political will would be quite a shame. I hope to see nuclear rockets launching to Mars within my lifetime.
This day in space history
On March 12, 1923, astronaut Wally Schirra was born. Schirra was one of the members of NASA’s first class of astronauts, the legendary Mercury 7, and is in fact the only astronaut to have flown in all 3 of NASA’s first human spaceflight programs – Mercury, Gemini, and Apollo. His Gemini 6A mission in 1965 is the most interesting to me, launching in conjunction with Gemini 7 and performing the first manned orbital rendezvous.
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| Gemini 6A and 7 approached to within 1 feet of each other and could have docked had they been so equipped |
Gemini 6A is also memorable because Schirra played a Christmas practical joke on Mission Control, reporting a UFO sighting piloted by a man in a red suit (i.e. Santa Claus), then playing Jingle Bells over the radio with a harmonica he had smuggled onboard. What’s the point of being an astronaut if you can’t have any fun?
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