Nuclear Powered Spacecraft

[southwestforests]

A recent book on nuclear spacecraft
Amazon.com

A copy of that arrived here yesterday.
Have only skimmed through it at this point.
Looks good.
Was published April 16, 2023; is print on demand and this copy was printed January 23 in the little burg of Monee, Illinois, just south of Chicago.

Just for fun, here's a 2009 NASA interview with the author,

Manfred H. "Dutch" von Ehrenfried Oral History

Here's the beginning of it,

Wright: Today is March 25th, 2009. This oral history interview with Manfred “Dutch” von Ehrenfried is being conducted for the Johnson Space Center Oral History Project in Lago Vista, Texas. The interviewer is Rebecca Wright, assisted by Sandra Johnson. We thank you so much for taking time this afternoon to sit down and visit with us for this project.

von Ehrenfried: Well, this ought to be fun.

Wright: We’re looking forward to it. We would like to start today by you sharing with us how you first became involved with NASA.

von Ehrenfried: Okay. I was going down to Langley [Air Force Base], [Hampton] Virginia to join the Air Force, and I was teaching school, and I was applying for jobs at the national laboratories, having just gotten a degree in physics. I thought I would be a physicist. But they would send me back little terse letters like, “Well, when you get your PhD, give us a call.” In the meantime I realized that I wasn’t going to go to a national lab. But I was interested in flying. So I went down to Langley, took my physical, flunked it—because I checked item 12, had asthma as a child, or something like that. Flunked me on the spot. I walked out the door with my head between my tail and just was really depressed. I saw a sign that said NASA [Langley Research Center]. I said, “Well, I’ve heard of them.” Knocked on the door, so to speak, interviewed with Chris [C.] Critzos, who showed me around, and met Gene [Eugene F.] Kranz and John [D.] Hodge and a few others. Sort of hired me on the spot, like, “You’re just what we needed.”

 

[southwestforests]

Relevant to the realm of nuclear-electric propulsion,

Electric spacecraft propulsion may soon take a leap, thanks to new supercomputer
News
By Keith Cooper
published 25 January 2025

Electric propulsion is being increasingly used on space missions and could ultimately replace thrusters using chemical rockets.

Electric spacecraft propulsion may soon take a leap, thanks to new supercomputer

Electric propulsion is being increasingly used on space missions and could ultimately replace thrusters using chemical rockets.

www.space.com

"For missions that could last years, [electric propulsion] thrusters must operate smoothly and consistently over long periods of time," Chen Cui of the University of Virginia School of Engineering and Applied Science said in a statement.

Before solutions can be put in place to protect a spacecraft from these backscattered electrons, their behavior in an ion-engine plume must first be understood, which is where Cui and Joseph Wang of the University of Southern California come in. They've performed supercomputer simulations of an ion engine's exhaust, modeling the thermodynamic behavior of the electrons and how they affect the overall characteristics of the plume.

"These particles may be small, but their movement and energy play an important role in determining the macroscopic dynamics of the plume emitted from the electric propulsion thruster," said Cui.

What Cui and Wang found was that the electrons in the plume behave differently depending upon their temperature and their velocity.

"The electrons are a lot like marbles packed into a tube," said Cui. "Inside the beam, the electrons are hot and move fast. Their temperature doesn't change much if you go along the beam direction. However, if the 'marbles' roll out from the middle of the tube, they start to cool down. This cooling happens more in a certain direction, the direction perpendicular to the beam's direction."

In other words, the electrons in the core of the beam that are moving fastest have a more or less constant temperature, but those on the outside cool off faster, slow down and move out of the beam, potentially being back-scattered and impacting the spacecraft.

Now that scientists better understand the behavior of the electrons in the ion plume, they can incorporate this into designs for future electric propulsion engines, looking for ways to limit the back-scatter, or perhaps confine the electrons more to the core of the beam. Ultimately, this could help missions powered by electric propulsion to fly farther and for longer, pushed by the gentle blue breeze of its ion plume.