HUMAN LAWS can be changed, waived or broken. Physical laws are less biddable. When it comes to putting humans on Mars, which he sees as the first step towards the planet’s settlement and humankind’s salvation, Elon Musk now has little to worry about from human law. Mr Musk has overseen the gutting of the FAA, America’s aviation authority and a sometime obstacle to his company SpaceX, by his so-called Department of Government Efficiency (DOGE). What is more, he stands at the side of an American president who, as well as having little regard for legal strictures, explicitly endorses Mr Musk’s Martian agenda. In his inaugural address President Donald Trump declared that it was time for Americans to “pursue our manifest destiny into the stars, launching American astronauts to plant the Stars and Stripes on the planet Mars”. This was not a one-off. He repeated the aspiration in his address to Congress six weeks later.
There are, though, physical constraints. They do not preclude reaching the orbit of Mars from that of Earth. That is, in principle, fairly simple. Put your spacecraft on an elliptical orbit around the Sun, carefully chosen so that it is tangential to Earth’s orbit upon departure, and tangential to Mars’s orbit upon arrival (see diagram). The mathematics dictate that, six to eight months later, it will arrive at a point on the orbit of Mars that lies on the opposite side of the Sun.
The only difficulty arises from the need to arrive at such a point at the same time as Mars itself does. Getting that right requires Earth to lag behind Mars by roughly 45 degrees at the time of launch, a state of affairs which comes around only every two-and-a-bit years—which is to say, only twice in any given four-year presidential term. If humans are to be launched to Mars before Mr Trump’s constitutional time is up, they will have to leave Earth’s orbit during the opportunity which opens at the end of 2028. But unless the mission is to be insanely risky, one or more uncrewed precursor landings will need to be attempted beforehand. And they would have to be launched during the opportunity which begins in late 2026.
This is what Mr Musk said he wanted to do last year. Then it seemed barely plausible. Today it looks next to impossible.
On my way to Mars
Mr Musk’s plans focus on Starship, the unprecedentedly large and, in principle, fully reusable spacecraft that SpaceX is developing at its Starbase facility on the southern tip of Texas. One of the earliest iterations of the two-stage system’s design was referred to as the Mars Colonial Transporter; its design could allow it to carry up to 100 people at a time.
Starships are supposed to weigh about 100 tonnes when empty, with crew and cargo adding as much as 150 tonnes to that. Propellant, always the biggest contributor to a launch system’s mass, would provide a further 1,500 tonnes. Even with the help of a “Super Heavy” booster to take it to 60km from the surface of Earth and a speed of around 4,400kph during the first few minutes of flight, almost all of that fuel will be needed to get a Starship to the 28,000kph which is required for a low-Earth orbit.
If all the Starship needs to do is take a pod of SpaceX’s Starlink communication satellites into orbit—the commercial-use case—then being left with only a little fuel is fine. Push out the satellites, as planned; use the last propellant to re-enter the atmosphere and land. If the intention is to send the Starship farther, though, the almost empty tanks need refilling.
This means other Starships will have to carry extra propellant to any sibling bound for Mars. How many such missions would be required depends on the tonnage each such tanker mission can lift to orbit. If Starship’s payload capacity is less than planned, the number of missions needed to fill the tanks could be 15 or 20. What the actual requirement would be, no one knows: 23 months and eight flights into the testing programme, no Starships of any sort have yet reached orbit.
Burnin’ through the sky
It is a measure of SpaceX’s reputation that when, last September, Mr Musk talked about having a number of uncrewed Starships in orbit, fuelled up and ready to head off to Mars by 2026 it seemed, if not likely, at least possible. The three or more launches a week that the company now gets from its fleet of Falcon 9s would once have seemed just as outlandish.
In October the company astonished the world by catching a returning Super Heavy booster in mid-air. The following month it brought down a Starship from its suborbital passage through space, and the fires of atmospheric re-entry, to a precisely controlled splashdown in the Indian Ocean. Estimations of the firm’s all-round wizardry increased yet further.
This year the version of Starship used in all previous tests has been replaced by a new, larger and notionally upgraded version. It has not gone well. On January 16th the first of these “Block 2” Starships was blown up by a safety system when fires broke out in its aft section a few minutes after separating from the Super Heavy, sending a shower of debris through the skies over the Turks and Caicos Islands. Thinking it had identified the cause of the problem, SpaceX tried again on March 6th; again the engines malfunctioned; again the Starship had to be blown up; again fiery debris rained down over the Caribbean.
It looks as if a Starship that can do what is being asked of it is, at best, still some way off. The setbacks have thus sharpened the need for extra testing. But they have also slowed its pace. SpaceX always knew that, after it produced Starships capable of getting to orbit and back, it would then have to work out how to transfer ultra-cold propellants from one ship to another—something never before attempted.
It also knew that developing the capacity to launch multiple “tanker” flights in quick succession would require a lot of practice. The need to speed things up is why the company applied for a licence for 25 launches to be conducted at its Texas site over the course of this year. As it has turned out, the pace has slackened. The company may manage just four test flights in total before 2025 is half done, at which point the launch window for Mars will be only 16 months away. Mr Musk’s claim that uncrewed launches for Mars in 2026 are still on the table is very hard to believe.
Delays to Starship are not just a blow to Mr Musk’s Martian timetable. They are bad for NASA’s lunar one, too. In 2021 NASA chose a version of Starship to fulfil a crucial role in the agency’s Artemis Moon-landing programme—that of getting astronauts from the Orion capsule in which they are due to leave Earth down on to the surface of the Moon (see diagram). This Human Landing System (HLS) version of Starship, like those planned for the Drang nach Mars, would have landing legs and a life-support system as well as some space for cargo. And it, too, would need to be more or less fully refuelled in orbit.
NASA says it plans to launch the Artemis III mission, which is the one intended to return American astronauts to the surface of the Moon, and which therefore requires the services of the HLS Starship, in the middle of 2027. This would mean pulling off an uncrewed HLS dress rehearsal in 2026. If uncrewed Mars missions are not possible on that timescale, neither are uncrewed Moon missions. Artemis III, which has already been postponed a number of times, will get pushed back yet further.
Flights to the Moon are not constrained by orbital dynamics in the same way as flights to Mars. In principle, NASA could head off more or less as soon as it is ready. But it does face a political deadline. China has said that it plans to land people on the Moon in 2030. Its plans for doing so are much simpler than those on which Artemis relies, featuring no in-orbit refuelling or similar malarkey. It will be building on a record of successful recent robotic missions that America has yet to match. Daniel Dumbacher, an engineer who used to have a senior role in NASA’s human-exploration effort, recently testified to Congress that: “Any objective assessment, including my own view, concludes that [NASA’s] approach today has a very low probability to match the ‘before 2030’ milestone for landing humans on the Moon.”
On a collision course
Getting to the Moon is not, in itself, a high priority for people in Mr Trump’s orbit, despite the fact that the Artemis programme began on his watch. Mr Musk’s interest is purely instrumental; the $4bn in NASA contracts SpaceX has won for HLS will develop technologies the company needs for Mars, too. The member of the first Trump administration most closely associated with Artemis, vice-president Mike Pence, is now an unperson. The programme’s once proudly stated goal of putting the first American woman on to the Moon—and the first person of colour, too—is an initiative tainted with the sort of focus on diversity, equity and inclusion that the current administration deplores. In March that commitment was quietly removed from the administration’s website.
Being beaten to the Moon by China, though, is probably another matter. Many in Washington think that a scenario in which China reaches a Moon to which America has not yet returned is unacceptable, which argues for revamping or replacing Artemis. Blue Origin, a rocket company owned by Jeff Bezos, who founded Amazon, is developing a smaller, niftier Moon lander for later Artemis missions; perhaps it could be brought forward. Plans developed by Lockheed Martin, a defence firm, for a reusable tug to take things from Earth orbit to an orbit around the Moon might also be accelerated.
And maybe SpaceX could contribute something other than the Starships it would have been working on anyway. Robert Zubrin, an aerospace engineer whose ideas about reaching and settling Mars were a great influence on Mr Musk, argues that SpaceX should develop a new expendable second stage for the Super Heavy, allowing it to launch things other than Starship. Doing so could provide a way to transport large payloads to places beyond low-Earth orbit, including the Moon.
Mr Musk has shown no interest at all in such deviations from his defining goal; at its heart the Starship is still the Mars Colonial Transporter. Neither he nor the administration will be keen on spending a lot on new hardware from his competitors. But if no action is taken, Mr Trump will not only be denied the glory of sending American astronauts off to Mars before his second term comes to an end; he runs a real risk of seeing Chinese astronauts in pole position in the race for the Moon, too.
Having a good time
The end of Mr Trump’s term, though, will in no way represent the end of Mr Musk’s ambitions. This gives him an interest in future-proofing SpaceX, which can expect no favours under a Democratic administration. He will want to see Starlink built into the government’s operations to the greatest extent possible and to make SpaceX’s launch services and satellites ever more central to the operations of America’s Space Force, at the expense of its various rivals. But the best way to extend his political launch window, from his point of view, will be to use his energy, his money and any technological leverage over government systems he might achieve through DOGE to ensure that Mr Trump’s successors are pro-Musk, if possible, and, if not, at least Mars-curious.
Such a follow-on administration does not have to be committed to paying for Martian high jinks; just to stay out of their way. Indeed, though government money would doubtless be welcome, extramural Mars missions would have their own advantages, allowing for a degree of flexibility that government-funded missions could scarcely contemplate.
No mere boosterism
One big question concerns any return journey. Starships refuelled in orbit could definitely get to Mars if they perform as specified. But they will not be able to get there with enough fuel to come back. The way SpaceX intends to deal with this problem is by borrowing an idea of Dr Zubrin’s: make the methane needed to refill the tanks out of Mars’s carbon-dioxide atmosphere and subsurface ice.
Dr Zubrin imagined landing a propellant-production facility on Mars before the astronauts arrived, so they would know when they got there that there would be a means of returning. But to do this for a spacecraft as big as Starship would mean a plant with either a great many solar panels or a small nuclear facility of as yet unspecified and untested design. Having to transport such payloads one or two orbital opportunities before the first crewed missions would push back those missions well into the 2030s. Even Mr Musk might not be able to keep his political launch window open that long, try as he might.
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The alternative would be to send the first pioneers to a place with no existing fuel cache. That would increase the risks of an already perilous mission. Mars-bound astronauts will face the possibility of radiation exposure and muscle-wasting during the prolonged weightlessness of their transit; the Martian environment is far less hospitable than anywhere on Earth. An attempt to remain on a foreign planet for as long as six years, even with resupplies every two-and-a-bit years, would be utterly gruelling. No worse, perhaps, than what was endured during some 18th- and 19th-century voyages of exploration. Yet no more assured of success, either.
This is not the way a government would do things. When President John F. Kennedy set America the goal of landing a man on the Moon before the end of the 1960s, he specified it should also bring him safely home. Mr Musk is not interested in doing things the government way, however, nor in overseeing something like the Apollo programme. Kennedy wanted Moon missions not because he was interested in the Moon (he wasn’t) but because he wanted to demonstrate that America’s will, innovative capacity and industrial might could be harnessed to achieve an extraordinary feat—one beyond the Soviet Union.
Mr Musk wants Mars missions because he wants to see Mars settled. His rhetorical commitment to the idea is tightly aligned with the preferences revealed by his actions and investments. There is little doubt that he would be able to find kindred spirits, quite possibly well fitted to the task, who would spearhead that destiny without a guaranteed route home. And if they would take the risks, so would he.
Don’t want to stop at all
Indeed, all indications suggest that he would go further. There is no doubt that part of Mr Musk’s alliance with Mr Trump comes down to opportunism: the president’s authority hugely assists the goal of making travel to Mars first possible and then routine. In his megalomania, Mr Musk is using the American polity as a booster stage from which to launch the multiplanetary human destiny in which he believes himself to play a crucial role.
His incentives to catch and refurbish that first stage when he believes its job to be done are much less clear. ■
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