For years, NASA has talked about sending people to Mars with its gigantic new rocket, the Space Launch System (SLS), and a new spacecraft called Orion.
But NASA hasn't said how it plans to use that $US40 billion of new hardware, even after publishing a 36-page Mars exploration plan in October 2015.
Fortunately, a plan may finally be coming into place.
On March 21, President Donald Trump signed a new law that mandates NASA send people to Mars by 2033. Then, a week later, the space agency published its most detailed plan yet for reaching the red planet.
The scheme is neither for the claustrophobic nor faint of heart: it involves locking astronauts into a tube-shaped spaceship, sending them into deep space for 3 years, and giving them no form of emergency escape beyond the Moon.
What's more, astronauts would only orbit Mars in 2033; they'd never attempt a landing.
That's according to a document authored by William H. Gerstenmaier, the head of NASA's human exploration and operations directorate, which he presented during a NASA advisory council meeting on March 28.
We first learned about the presentation via a story by Eric Berger at Ars Technica.
"NASA is leading the next steps into deep space near the Moon, where astronauts will build and begin testing the systems needed for challenging missions to deep space destinations including Mars," NASA said about the new plan in a press release.
Getting to Mars in five phases
Gesternmeier's program lists five phases to reach Mars.
Phase 0 involves using the International Space Station "as a test bed to demonstrate key exploration capabilities and operations, and foster an emerging commercial space industry" with partners like SpaceX, Boeing, Orbital ATK, and others. We're currently in this phase.
Phase 1 is ambitious, involving six launches that span from 2018 through 2025.
First, NASA wants to launch its inaugural SLS rocket (a 98-metre or 321-foot-tall behemoth that's designed to rival the Saturn V rockets that blasted Apollo astronauts to the Moon). Assuming that maiden flight and tests of its new Orion spaceship go well, the space agency will launch five more SLS rockets.
Four other missions will each launch a piece of a new space station, called the Deep Space Gateway (DSG), into orbit near the Moon – a region called cislunar space – where four astronauts will help assemble and provision it.
"The gateway could move to support robotic or partner missions to the surface of the Moon, or to a high lunar orbit to support missions departing from the gateway to other destinations in the Solar System," Gerstenmaier said in the release.
Phase 2 builds on the lunar space station by launching a Deep Space Transport (DST) to it in 2027. Then, around 2028 or 2029, four lucky astronauts would spend up to 400 days inside the 41-ton tube as it orbits near the Moon.
Their mission: make sure the DST works and nothing critical stops working.
Phase 3 begins around 2030, assuming the DST and its crew experience no problems. Another SLS flight would restock the spaceship with supplies and fuel, then yet another launch would load it up with four people – the first crew to visit Mars.
Their two- to three-year-long flight "would likely involve a Venus flyby and a short stay around Mars" and "would offer no hope for an emergency return once the crew leaves cislunar space," Berger wrote at Ars Technica.
Phase 4 would happen beyond 2033, and is fairly nebulous at this point. All it calls for in Gerstenmaier's document is "development and robotic preparatory missions" to deliver habitats and supplies to the surface of Mars, plus eventual "Mars human landing missions".
Will NASA put the first boots on Mars?
It remains to be seen whether or not NASA can pull off this grand plan on the relatively flat budget Congress keeps handing it.
During the Apollo Moon missions, NASA made up more than 4 percent of the US budget. Today, its share has shrunk to about half of a per cent.
Even if NASA does manage to execute this plan, it may have competition from the private partners it hopes to get involved. The private sector may even beat NASA to Mars.
Boeing has also challenged SpaceX in beating the company to the red planet. Musk said he's okay with this because all he wants to do is colonise Mars and protect humanity from self-imposed annihilation or a rogue asteroid.
"I think it's good for there to be multiple paths to Mars ... to have multiple irons in the fire," Musk said in August 2016.
This article was originally published by Business Insider.
More from Business Insider: