Tweel (A Martian Odyssey) Tweel (A Martian Odyssey) Tweel (also referred to as a "Tweerl", the exact pronunciation of the word is said to be impossible for humans) is a fictional extraterrestrial from the planet Mars, featured in two short stories by Stanley G. Weinbaum. The alien was featured in "A Martian Odyssey", first published in 1934, and "Valley of Dreams" four months later. Weinbaum died of lung cancer soon after, and a third installment in the series never saw fruition. Tweel remains one of the most recognised aliens in early science fiction, and is said to be an inspiration for aliens in the
Colonization of Mars protect astronauts and spacecraft from radiation. In September 2017, NASA reported radiation levels on the surface of the planet Mars were temporarily doubled, and were associated with an aurora 25-times brighter than any observed earlier, due to a massive, and unexpected, solar storm in the middle of the month. Mars requires less energy per unit mass (delta V) to reach from Earth than any planet except Venus. Using a Hohmann transfer orbit, a trip to Mars requires approximately nine months in space. Modified transfer trajectories that cut the travel time down to four to seven months in space are possible