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Apparently, I am a bit indecisive regarding an event that could possibly occur within the context of reality regarding nuclear thermal rockets, and I was thinking: is this space disaster scenario plausible: "The first manned Mars mission is launched under the Ares 1 rendezvous with the IMIS Endeavour. Shortly after docking with the Mission Module, the craft leaves Earth-Moon L2 for Mars. However, the mission ends in failure following a rupture in the reactor caused by micrometeorites punctures during Mars orbital insertion, rendering the crew stranded. This results in a huge national tragedy for the States as the crew is declared KIA due to extreme radiation poisoning several days later, thus delaying the launch of the Ares 2 mission by two years." I will be asking a separate question in a different site regarding the political and economic consequences. :P

If you are wondering: Integrated Manned Interplanetary Spacecraft (IMIS) was a Boeing 1968 study that was designed for a Mars mission around the 1980s - 1990s span of time, that never made it out of the drawing board. In other words, this: IMIS 1968 Encyclopedia Astronautica Article

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  • $\begingroup$ As this is stated you seem to be asking if the entire scenario is plausible, which is quite broad. Better to narrow it to consequences on a crew of a micrometeorite impact of a NTR engine sufficient to punch a hole in it (which i know from chat is what you are interested in). Also, making the title more descriptive of the question would help draw people able to answer to the question. $\endgroup$ – kim holder Apr 9 '16 at 18:28
  • $\begingroup$ What Kim said, refine the title. Fascinating study BTW. $\endgroup$ – Jerard Puckett Apr 9 '16 at 18:29
  • $\begingroup$ And available in all its six volumes on NTRS $\endgroup$ – Jerard Puckett Apr 9 '16 at 18:32
  • $\begingroup$ @JerardPuckett And 7 PDFs because Volume III is in two parts. $\endgroup$ – Future Historian Apr 9 '16 at 18:50
  • $\begingroup$ @kimholder Any bright ideas for a title, then? $\endgroup$ – Future Historian Apr 9 '16 at 18:50
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The circumstances would have to be pretty unusual for the crew to die of radiation poisoning at that point in the mission.

  • The micrometeoroid would have to be pretty big: it has to disable the NERVA engine of the Mars Capture Stage (MCS) completely. If there's any residual thrust, the spacecraft will move away from the radioactive debris cloud. Only if thrust falls to 0 will the spacecraft stay with the debris and expose the astronauts to lots of radiation.
  • The micrometeoroid would have to be big enough to break off parts of the reactor. Punching a small hole in the wall is not enough, you need reactor parts or the fuel itself to be part of the debris cloud.
  • At Mars orbit insertion, the spacecraft still contains another unused NERVA stage, the Mars depart stage (MDS). If the MCS fails, they can separate it, and fire the MDS to get on their way back to Earth.
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  • $\begingroup$ In other words: it would not be a national tragedy but rather another Apollo 13? $\endgroup$ – Future Historian Apr 10 '16 at 15:34
  • $\begingroup$ @FutureHistorian Apollo 13 had multiple problems that directly affected the crew's survival chances, including loss of oxygen, water (both for drinking and equipment cooling), electricity (fuel cells) and the SPS engine (which was in unknown condition until SM jettison, at which point it would have done them no good even if it had been in usable condition). On any reasonable mission, the Earth-Mars part would be largely coasting, so you don't need the engine as such. As long as you only lost one of your engine stages (MCS but not MDS, say), it might not even be more than a nuisance. $\endgroup$ – user May 12 '16 at 9:15

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