Final answer:
The notion that 'Reds' were sent to Mars 50 years ago is part of an attractive narrative of space colonization but is not based on fact. No human mission to Mars has occurred as of early 2023, and astronauts have not traveled beyond low Earth orbit since Apollo 17 in 1972.
Step-by-step explanation:
The question about how long ago 'Reds' were sent to Mars is likely referring to the hypothetical event or the scientific ambition of sending humans to Mars. Based on the context provided in your question, the correct answer choice is (a) 50 years ago. However, it is important to note that in reality, as of my knowledge cutoff in early 2023, no human mission to Mars has yet occurred. The last human mission beyond Earth's low Earth orbit (LEO) was Apollo 17 in 1972, which was to the moon, not Mars.
In regard to how much astronauts would have aged on a trip to and from Earth at near the speed of light, time dilation would occur. This means that astronauts would age less than people who remain on Earth due to the effects explained by Einstein's theory of special relativity. The problems related to travel to stars that are 20 or 30 light-years away include the vast distances requiring incredibly long travel times at speeds we currently cannot achieve and the immense energy requirements. The speeds required for these trips approach the speed of light, which brings about the effects of time dilation that would make the astronauts experience time more slowly relative to Earth.
There are attractive narratives about colonizing Mars within 50 years, but these have not come to fruition primarily due to the technological, financial, and physiological challenges associated with deep space travel. Therefore, no 'Reds' have been sent to Mars 50 years ago or at any time in the past.