Mars: Unless you're creating pure fantasy, science fiction writing requires you spend time researching the relevant science. I don't write 'hard' science fiction, so I don't over research, but background knowledge of the field of inquiry is a minimum requirement. My forthcoming novel, Sentient, is set a hundred years into the future and colonisation of Mars has become a reality. A flash point has occurred between the two competing global powers over whether Mars should be terraformed, so I spent some time reviewing the science. It's currently a hot topic, given Elon Musk's comments about 'nuking Mars' to change the Mars climate.
Mars is a popular selection, given some of its similarities to Earth, such as size, inclination, composition and structure. Importantly, Mars has water, making it potentially a prime candidate for colonisation. However the similarities end there, with many ecological challenges to be faced, including: an unbreathable and cold atmosphere just one percent the size of Earth's and no magnetosphere, meaning high radiation levels. Hence Mars colonisation faces a myriad of daunting challenges.
Many science fiction writers have written about the process, the most detailed being Kim Stanley Robinson's Mars Trilogy, a wonderful work of imagination backed by extensive research. Sentient does not reach that level of detail, but I did take account of some of the research. There have been many studies in the last forty years. For example:
A NASA study in 1976 was one of the first serious studies of terraforming Mars, suggesting importing ammonia from the outer solar system, or coating the Mars icecaps with dark materials to increase the amount of sunlight absorption on the planet. Dark dust from Phobos and Deimos or extremophile lichens and plants were also suggested.
Technological methods were reviewed in 1997 studying the use of orbital mirrors to sublimate the poles as well as other technologies to redirect asteroids to impact the surface.
A 2014 study researched the use of bio-domes to develop colonies of oxygen producing cyanobacteria and algae to terraform domed farms for use by human missions.
So, research has shown potential methods of terraforming are possible, but the challenges of terraforming the whole planet are significant, not least being the loss of its magnetosphere. Quantities of CFC's required to trigger warming are estimated at 39 million metric tons, three times the amount produced on Earth between 1972 and 1992! Even if that could be achieved, there is a risk CFC introduction could destroy the Mars ozone, undermining efforts to shield radiation. The other possibility of introducing terrestrial organisms could be effective, but the time frames are extremely long, upwards of many million years!
Logistically , pulling resources from other planets would require large fleets of space haulers with advanced drive systems that currently don't exist. It would also need manufacturing infrastructure on Mars, requiring heavy payload rockets that would cost more than all previous space programs combined.
So is it worth it? It's clear that the Mars space program is a very ambitious long term goal that will require much more than government support, spasmodic at best given their short term electoral cycles. As science fiction writers we are afforded the luxury to speculate more idealistically as we imagine different futures. In Sentient, I imagined government willingly hand control to artificial intelligence, given the climate emergency faced in the late 21st century. Resources funded into the global industrial military complex were diverted, allowing global challenges such as climate control, space exploration and colonisation of the solar system to be addressed.