With plans underway for NASA’s massive new Space Launch System, the possibility of sending a manned mission to Mars may be closer than ever. But will the competition get there first?

The dream of someday sending astronauts to Mars is swiftly moving away from the realm of science fiction and toward science fact. Shortly following the unveiling of its new Mars rover Curiosity, NASA recently revealed its plans for the Space Launch System (SLS), the most powerful launcher in history that could one day carry explorers to asteroids or even the red planet itself.

The SLS heavy-lift rocket is expected to be the largest and most powerful of its kind, capable of lifting five to eight times the payload weight of today’s strongest rockets. In its full configuration, it will be considerably taller than the unmanned moonshot rockets and provide 20 percent more thrust. The system will also incorporate and expand upon previous space exploration technologies.

“Remember the shuttles we shelved just a few months ago? Well various parts of the new shuttle will be reminiscent of those — only bigger and badder,” science and sci-fi blog io9 explains. “Numerous components on the SLS, ranging from its fuel tanks to its rocket boosters, will be based on up-scaled and upgraded versions of technologies featured on retired NASA tech.”

While the previously scrapped Constellation shuttle program had the specific goal of completing a mission to the moon by 2020, deadlines and destinations haven’t definitively been set for the SLS yet.

“We’ve talked conceptually about multiple destinations. We talk about an asteroid in 2025. We talk about Mars being the ultimate destination,” William H. Gerstenmaier, NASA’s associate administrator for human exploration, told the New York Times. “We can do pretty exciting missions with the capability that we’ve got.”

Overall costs for the project are expected to be significant, and while the U.S. space agency has received a mandate from Congress for developing a heavy-lift, deep space rocket, budget constraints may hinder some of the long-term objectives.

“NASA calculates it will have spent about $18 billion on the project by the time the inaugural (unmanned) test launch occurs in late 2017,” BBC News reports. “This figure includes not just the work on the rocket, but its Orion astronaut capsule and the ground work needed at Kennedy to get the spaceport ready for a new type of launch vehicle.”

There hasn’t yet been a successful manned trip to Mars, and mounting such a mission would likely add a considerable amount to the already sizable SLS expense. Given these financial considerations, some experts have advocated for a “one-way visit” to Mars — in other words, establishing a permanent presence on the planet in order to avoid the challenges involved in bringing a team back to Earth.

“[F]ollowing several robotic missions to deliver equipment and supplies, the initial astronauts would set up an embryonic colony — a basic habitat with greenhouses, water supplies, power systems. Every two years — the launch window for trips to Mars — more astronauts would arrive to join and resupply them,” NOVA explains. “Permanent colony or not, what advantages does one-way have over round-trip, according to supporters? Above all, it’s not nearly as pricey as two-way.”

While colonizing Mars may seem a bit extreme, just getting there in the first place poses numerous problems, even with a rocket as powerful as the SLS. For one, the physical demands made on astronauts may be severe.

“A newly discovered eye condition — found to erode the vision of some astronauts who’ve spent months aboard the International Space Station — has doctors worried that future explorers could go blind by the end of long missions, such as a multi-year trip to Mars,” the Orlando Sentinel reports. “While blindness is the worst-case scenario, the threat of blurred vision is enough that NASA has asked scores of researchers to study the issue and has put special eyeglasses on the space station to help those affected see what they’re doing.”

Other physical concerns involved in a long-term space voyage, such as the expected three-year mission to Mars, include the effects of exposure to cosmic radiation and the loss of bone mass in microgravity conditions.

NASA and the scientific community may need to work quickly if they hope to make the U.S. the first country to land humans on Mars. The European Space Agency (ESA) announced last month that it is partnering with Russia’s Roscosmos space agency for a joint mission to Mars. According to SmartPlanet, ESA head Jean-Jacques Dordain said the two groups will “carry out the first flight to Mars together.”

A major factor in the partnership is Russia’s ongoing success in the Mars500 project, which is a long-term isolation experiment designed to simulate the conditions of a voyage to Mars and back with a six-member crew.

“Dordain stopped short of declaring a timetable for such a mission, or on whose spacecraft the joint mission will ride. But he did set the stage for another epic, decades-long scientific struggle between two great world powers,” Popular Science notes. “So who will set foot on Mars first, the U.S. or Russia and its European partners?”

Earlier: Inside Curiosity, NASA’s Next Mars Rover

Resources

NASA Announces Design for New Deep Space Exploration System
NASA, Sept. 14, 2011

NASA Has Unveiled the Rocket that Will Take Us to Mars
by Robert Gonzalez
io9, Sept. 14, 2011

NASA Unveils New Rocket Design
by Kenneth Chang
The New York Times, Sept. 14, 2011

SLS: The Rocket in Need of a Destination
by Jonathan Amos
BBC News, Sept. 14, 2011

A One-Way Trip to Mars?
by Peter Tyson
NOVA, Nov. 4, 2010

Blurred Vision Plagues Astronauts Who Spend Months in Space
by Mark K. Matthews
The Orlando Sentinel, Sept. 19, 2011

Europe, Russia: We’re Going to Mars
by Andrew Nusca
SmartPlanet, Aug. 19, 2011

European Space Agency Plans to Team up with Russia for the First Manned Mission to Mars
by Clay Dillow
Popular Science, Aug. 18, 2011