NASA's SLS Rocket
An artist's interpretation of NASA's SLS rocket, which the agency hopes will launch humans on a flight to Mars in the coming decades.

NASA has announced that it will launch a rocket designed to carry humans to Mars in 2018, allowing amateur astronomers and science fiction buffs across the world to bask in the idea that humans could walk across the red planet sooner rather than later.

The space agency announced late Wednesday that engineers have formally approved the development of the Space Launch System, a heavy-lift rocket with the most powerful booster ever. The machinery, which is expected to cost $7 billion to develop, is a key part of NASA’s long-term plans to helps humans visit Mars and, if all goes according to plan, walk on asteroids.

“Our nation is embarked on an ambitious space exploration program, and we owe it to the American taxpayers to get it right,” added Associate Administrator Robert Lightfoot, who oversaw the SLS review. “After rigorous review, we’re committing today to a funding level and readiness date that will keep us on track to sending humans to Mars in the 2030s – and we’re going to stand behind that commitment.”

The SLS moving from the formulation phase to the development phase is an important step, but scientists have stressed that’s all it is: A single step toward a greater goal. It will have an unprecedented lift capability of 130 metric tons and almost certainly hit delays along the way, but NASA maintained that a test flight will take off in four years.

The simple notion that humans could actually travel to Mars would have been unimaginable only decades ago, when scientists believe the planet’s red hue was proof it was home to some kind of vegetation and when science fiction fans devoured books like Ray Bradbury’s “The Martian Chronicles” in 1950.

It’s also a reflection of the Obama administration’s policies regarding space travel, in which the president promised the redesign of a new heavy-lift launch vehicle by 2015. With the SLS approval, NASA can cross that goal off its list one year early and focus its efforts on carrying out an asteroid mission by 2025, then a U.S.-crewed orbital Mars mission within the decade after that.

The plan was criticized at the time by NASA astronauts Neil Armstrong, Jim Lovell and Eugene Cernan, who lambasted the president for choosing to invest in Mars and asteroid missions over NASA’s Constellation moon program. Questions were also raised in 2013, when the administration requested a NASA budget of $17.7 billion for 2013, a steep cut from the $59 billion it received in 2012.

NASA administrator Charles Bolden sought to calm nervous observers at the time when he said NASA would simply adjust to the constraints, as many government departments did last year. His comments Wednesday, though, were evidence that the outlook is again bright.

“We are on a journey of scientific and human exploration that leads to Mars,” Bolden said in the announcement. “And we’re firmly committed to building the launch vehicle and other supporting systems that will take us on that journey.”

A NASA-produced video explanation of the SLS rocket initiative is included here: