A rare opportunity to send a colony ship off-Earth arose.
The target is a somewhat Earth-like planet, with the exception that it was apparently conceived by George Lucas, as it only has one climate and one terrain: Africa-like Savannah.
This poses a specific problem: not every human on Earth is equally adapted to live in Savannah like climate.
To quote from Wikipedia:
Evolution of dark skin pigmentation began around 1.2 million years ago in light-skinned early hominid species after they moved from the equatorial rainforest to the sunny savannas. In the heat of the savannas, better cooling mechanisms were required, which were achieved by the loss of body hair and development of more efficient perspiration. The loss of body hair led to the development of dark skin pigmentation, which acted as a mechanism of natural selection against folate depletion, and to a lesser extent, DNA damage. The primary factor contributing to the evolution of dark skin pigmentation was the breakdown of folate in reaction to ultraviolet radiation; the relationship between folate breakdown induced by ultraviolet radiation and reduced fitness as a failure of normal embryogenesis and spermatogenesis led to the selection of dark skin pigmentation. By the time modern Homo sapiens evolved, all humans were dark-skinned.
Humans with dark skin pigmentation have skin naturally rich in melanin (especially eumelanin), and have more melanosomes which provide a superior protection against the deleterious effects of ultraviolet radiation. This helps the body to retain its folate reserves and protects against damage to the DNA
Now, one solution would be to only recruit the colonists who are already naturally dark skinned and thus better adapted. Africans, maybe Dravidians. However, that solution is not acceptable in the reality of my story (the reason is irrelevant) - the colonist pool must include people of all skin colors and ethnic/racial/national origins. In total, we need to send ~10,000 colonists; and at least 60% would be light skinned.
Having said that, there's no major objection or problem with taking a light-skinned colonists and making them eumelanin-rich and presumably darker skinned. The colonists are guaranteed NOT to object, and whatever forces prevented African-only colony won't affect this either. So, the only problem is, how?
Thus, the question: what would be the best, easiest, least "fiction" way to achieve the goal of turning all - even light skinned - colonists as adapted to Savannah living as dark skinned ones?
"Best" is graded on how close the required science/technology is with what is state of the art in 2015 on Earth today. E.g., "nanoprobes changing someone's DNA" is a possible solution, but clearly nowhere near current state of the art capabilities.
No resupply to the colony in the next 1000 years. Whatever solution is proposed, would need to be done on Earth, in the space of, say, 5 years, and not depend on anything else anyone on Earth can/will do after that.
The colony trip is quick. Perhaps a couple of weeks. And the goal is to have the current generation of colonists adapted.
So any solutions that might involve colonists mating between themselves and having next generation more adaptable on average is NOT in scope.
No magic. Realistic science/technology only. Future ones are acceptable, but as per above, the more "futuristic" and unrealistic they are, the less suitable the answer is.
A technological solution that would simply allow a light skinned person to survive in Savannah is NOT likely to be in scope: colonists will live in lower-tech society with few spare resources for the first few hundred years. So whatever solution is proposed, it must be something that naturally persists for those hundreds of years without having access to Earth resources.