NASASpaceFlight.com reported Tuesday that NASA’s so-called “Road to Mars” is starting to take shape. The deep space program that would conclude with human astronauts departing for the Red Planet in 2039 would require just over 40 launches of the heavy-lift Space Launch System, including an uncrewed flight in 2018 and one flight a year to cis-lunar space starting in 2021 lasting until 2027. A flight in 2028 would launch something called the Pathfinder Entry Descent Landing Craft to Mars as a precursor for a human landing. Then the Mars program begins in earnest with a mission to Phobos in 2033 and missions to the Martian surface in 2039 and 2043.
The launch tempo for the SLS would expand from one a year to about three a year starting in 2028. The Mars campaign, including the Phobos mission and the two Mars surface missions, would take 32 launches of the heavy lift rocket, which by that time will have evolved to the Block II configuration capable of lifting 130 metric tons.
The evolving launch manifest is pretty much written in sand since it is dependent on how the next presidential administration will view deep space exploration, thus some questions occur.
First, what happens if the date of the first crewed mission slips from 2021 to 2023? Does everything else slip to the right or will some launches be eliminated?
Second, NASA is already contemplating using the SLS for planetary missions, such as Europa Clipper. That fact suggests that the actual launch tempo will be two a year during most of the 2020s and not just one a year. Space researchers have no shortage of ideas for using the heavy lift rocket for planetary missions, with targets ranging from moons like Titan and Enceladus to Uranus and Neptune. The greater the flight rate, the less each launch costs, with launch crews being in better practice.
Third, how does the recently published plan to return to the lunar surface using commercial vehicles to establish a refueling base? The plan is said to have a cost of $80 billion with $10 billion before the first moon boots hit the lunar surface. The cost could be higher. On the plus side, the ability to top off fuel created from lunar water would drastically reduce the numbers of Space Launch System launches needed for the Mars campaign, saving a considerable amount of money in the long run.
Finally, will using some kind of advanced propulsion system, say a nuclear thermal rocket similar to the 1960s era NERVA, affect the launch manifest in any way?
The bottom line is, the Road to Mars has a destination. But how one arrives there is a matter that is still unclear.