I fear I'm a bit light on details with this one. From what I can remember:
NASA (or its fictional equivalent) has developed its first interplanetary space program. It represents a clear breakthrough in man's progress into space. Unfortunately for the program. A sort of neo-Luddite group is continually protesting and trying to shut the program down. I recall their basic ideology being that technological progress is endangering both man and the environment, and they advocate for a return to simpler times. Something like that. I can recall two specific events in the novella highlighting this mantra.
The first occurs at a test firing of the new rocket design. The protestors have stormed into the launching area, and will not leave. They are too close to launch the rocket (the blast will kill them), and hope to stop the test launch entirely. I recall distinctly that the solution by the mission command types was to ignite the Vernier thrusters. This had the effect of making the protestors think the launch was in progress (causing them to flee), while not actually endangering anyone.
The second occurs in the spacecraft itself. The protagonist has launched, and is in space when he discovers one of the leaders of the movement has stowed away in the ship with the intent of sabotaging the flight. The leader is female, a brunette, and quite attractive. I seem to remember her being described in a rather minxy/pulp novel sense. She has a gun with her, and gets the drop on the astronaut. She does not shoot him, but makes it clear that she's either sabotaged the spacecraft somehow, or intends to do so. There is a long flight time ahead (obviously), so she has the luxury of time, IIRC. The two engage in a rather well-written discussion/debate, where each makes a strong case for their viewpoints and philosophy. There is also more than a hint of sexual tension between the two, (again IIRC).
I do not know how the story ends, as the novella was presented in several parts in a sci-fi magazine. I never got the chance to read the final part to see how the crisis was resolved.
I definitely read this in a sci-fi magazine of some sort. It was one of the mainstream ones of the day (e.g. Asimov, Analog, Sci-Fi and Fantasy, etc.) It was also an older magazine. I can't provide a specific date, but I'd guess 1970's at the latest. It could be a number of years older than that.