What would cut off a Mars base from Earth's support for an extended period of time?

Consider a Mars base, circa the 2040s. A joint NASA and SpaceX mission proved successful in the 2030s, and now a real colony is starting to develop. SpaceX has brought a good number of people to the red planet, and now other companies like Relativity are starting Mars missions. Other space agencies, particularly the ESA and JAXA, are sending people to Mars. The start of a colony is doing well, working to become self sufficient.

Then disaster strikes. Some event on Earth sets the Martians adrift so to speak. They now have to fare for themselves, at least for a number of years, with no hope of resupply from Earth.

So, all that out of the way, what is the most realistic way this scenario occurs? Obviously I could do it the quick and dirty way, Earth is wiped out by an asteroid impact, but considering robust NASA tracking of such lethal asteroids, I find it hard to believe they'd miss one that big.

My current route is a war with China, in which supplying the Martian colony is rather low on the list of priorities, and all resources need to be devoted to the war effort. I do not like this solution though, as I think that a war with China at that point feels a bit like applying current events to something far down the line when it may not be realistic. I also feel like NASA would find some way to get the people on Mars assistance during the duration of the war.

Edit: Due to numerous answers depicting vast sweeping changes impossible in the next two decades, I am apt to remind you of the date in bold: circa 2040s.

• This is like asking for "how do I write the story" rather than "What could be the consequences if my story takes this turn", no? From "Talibans taking over the White House" to "Extended riots due to solar storm taking off the entire energy grid and people not able to access their Facebook accounts". Anything goes, right? Oct 18 at 9:34
• I believe that Kim Stanley Robinson, in his Mars trilogy, uses a situation where a large Antarctic shelf breaks off, causing massive flooding disasters in coastal areas, to explain why Earth stops being interested in what happens on Mars. Oct 18 at 10:02
• Just about any disaster on Earth that even slightly interferes with rocketry is going to make Mars mission support a low priority. Economic turmoil, political turmoil, a shortage of normallyeasilyobtainium. Oct 18 at 10:30
• Arguably it might more efficient to list scenarios that don't cut off Mars resupply. Oct 19 at 4:25
• You know that Mars resupply can only realistically happen every 2.1 years anyway (google "transfer window")? Miss one of those and you're already in your "number of years" scenario. Doesn't take much to ground a fleet to miss a window. Oct 19 at 5:01

My current route is a war with China, in which supplying the Martian colony is rather low on the list of priorities, and all resources need to be devoted to the war effort. I do not like this solution though, as I think that a war with China at that point feels a bit like applying current events to something far down the line when it may not be realistic. I also feel like NASA would find some way to get the people on Mars assistance during the duration of the war.

Your "War with China" (or other country) approach works - just not exclusively for the reasons you suggest. Delivering supplies to Mars involves launching a rocket, coincidentally so does delivering nuclear weapons to one's enemies. Which is why countries continue to develop rockets to destroy other rockets

Were the US and China engaged in open hostilities it's not a big reach to suggest that any rocket the US launched could be seen by China as a potential nuke and therefore be intercepted. You can't get supplies to your Martian colony if your war opponents are targeting and destroying every rocket you launch.

Earth is wiped out by an asteroid impact, but considering robust NASA tracking of such lethal asteroids, I find it hard to believe they'd miss one that big.

If you prefer a more natural disaster-type route then alternatively you could have Earth experience a large geomagnetic storm courtesy of a large solar flare and coronal mass ejection. Something similar to the Carrington Event in a heavily electronic-dependent world such as have today (or in say 20 years time) would cause massive disruption and damage to electronic kit all over the world, and in orbit too. While science is improving on predicting these solar flares there's still not a great deal of warning available and there's also nothing we can do to stop them (no matter how many times we send Bruce Willis into the sun) and given the variability in the size of such events you can almost have it be as serious or minor as suits.

• Eh, the Soviets and the US both managed a space program during a nuclear standoff. Oct 18 at 14:45
• @StarfishPrime Indeed, but during the cold war missile defense systems were in their infancy - and then development was curtailed for 30 years by the the ABM Treaty in '72 and I'm assuming when the OP mentioned "war with China" they meant the hot variety. Oct 18 at 15:26
• @Old_Fossil not necessarily, I think. It could just hit Earth and miss Mars, especially if Earth and Mars are in opposition. Oct 19 at 10:58
• Of course, if we're not talking "intercept" to mean anti-missile missiles then there are more options. Maybe by 2040 they have orbital space lasers that can shoot down anything going vaguely to space as soon as its launched, but they won't be able to accurately keep a laser on a target moving as fast as a ballistic missile once it gets up to speed, so they can't afford to wait and see if it's a missile or a space launch (or they want to kill all your space launches too because they don't want you getting your own space lasers up there).
– Ben
Oct 20 at 3:18
• @StarfishPrime yes, but that wasn't an active shooting war, and both had the common sense to notify each other of most launches. The few unannounced launches of mostly military hardware (spysats, test vehicles for ASAT and FOBS development, etc.) did cause the occasional scare. During active hostilities, ASAT and ABM systems would be engaged to intercept any launch from the enemy's homeland, announced or not. We're just lucky that never happened. Oct 20 at 9:26

Kessler Syndrome

The US/NATO military relies HEAVILY on satellites, in ways even their near-peer competitors (like China) do not. China's specific plan to combat this advantage is to blow US satellites out of the sky in the event of war between the two powers. China is also notoriously unconcerned about collateral damage in space. So it'll be messy. Therefor it's fairly obvious to people "in the know" that any sort of armed conflict between the US and China will result in china attacking US Spy/communications sats, which will leave tons of debris in orbit. That debris may trigger Kessler Syndrome, which basically results in no launches being possible due to orbital debris covering the entire planet for a given length of time. There's even a school of thought that thinks China might intentionally trigger Kessler syndrome on the grounds that it'd hurt the West (broadly speaking) more than China! (Though personally I doubt that's official CCP policy.) Depending on the details of your war this could be bad enough to effectively end terran spaceflight, or be a relatively "contained" event where everyone knows the debris will de-orbit/be cleaned up sufficiently to allow launches to resume within any convenient-to-the-plot window of time.

• This is the "right" answer, IMO. You could also skip the war with China entirely entirely and get Kessler Syndrome from too many Martian flights - like, something jettisoned by a NASA launch isn't tracked properly, and hits and ESA launch. Oct 18 at 19:02
• I find Kessler syndrome highly unlikely. Other than China, all current actors in space are making efforts to avoid generating any additional space debris (like deorbiting second stages) and new companies are seeking to do space junk cleanup. Seeing as fill reusability is an intended goal for SpaceX's Starship, I think we will not see significant space debris from Mars missions. Oct 19 at 2:47
• Kessler syndrome is a runaway chain reaction, but orbital debris could have a high chance of blocking missions without getting that far. Clearly the risk appetite for crewed missions is lower than for simple supply missions but even the latter could be clocked by a concerted attempt to take out a fleet of satellites, or perhaps the destruction of something big (ISS) in orbit Oct 19 at 9:44
• @Current There are multiple possible ways which this could come about. It certainly doesn't require a war and intentional destruction of one or more satellites. The number of planned satellites is only increasing. The number and variety of launch vehicles is also increasing. All it really takes is a single rapid unplanned disassembly (RUD) that happens to end up cascading. While the actual probability of that happening in the real world is debatable, it's certainly within the realm of possibility which, IMO, doesn't strain the suspension of disbelief which is necessary for a story. Oct 19 at 15:05
• Would Kessler Syndrome really be a serious danger for rockets which are just passing through? Even if there was a 10% chance to lose rockets headed for Mars you’d probably still try to launch instead of letting your colonists die. Oct 20 at 6:48

Last year, the COVID-19 pandemic caused severe supply disruptions for Arctic research expeditions. If I'm reading this article right, at least one team had every single resupply trip cancelled! (See the comments for more details, and a discussion of possible tension with this documentary.)

Ships from across the world that were scheduled to make journeys to the Arctic to exchange crews and drop off supplies cancelled their trips. The scientific crew in the Arctic at the time were forced to stay two months longer than originally planned.

And in the end no ship was able to make the journey north. In May, scientists finally left the Arctic on the same ship that had been their hotel and laboratory since the beginning, the Polarstern. That ship was supposed to stay in the Arctic for the entire expedition.

Even resupply trips to Canadian Arctic towns took tremendous effort to carry out safely.

COVID-19 is awful, but it's easy to imagine things much, much worse. A worldwide outbreak of the wrong disease could make crewed or even uncrewed resupply trips unacceptably dangerous to the colonists, the resupply crew, or both.

Consider, for example, an airborne fungus that can lie latent in the lungs for up to four months before erupting into an active infection, which starts with a week or more of asymptomatic transmission, and ends with death in 25% of cases. In addition to wafting from person to person, its spores can settle on surfaces indefinitely before being kicked back into the air. Various combinations of cleaning techniques seem to help reduce its spread, but no practical procedure has been shown to decontaminate air or surfaces with high confidence.

If that disease went pandemic, it would be very hard to put together supply packages that colonists could safely bring into their living areas. That would cut off delivery of food, medicine, agricultural inputs, materials for indoor construction, and air-monitoring equipment to detect the fungus.

It could even be risky to send equipment that stays outdoors. The colonists would have to touch the equipment to use or maintain it, and then they'd re-enter the living area, using procedures that weren't designed to keep out anything finer or more dangerous than Martian regolith. If the spores turned out to survive well on regolith, they could make the areas around equipment drops untrustworthy for years to come.

The colonists' tolerance for infection risk would be extremely low, because the consequences of an outbreak would be disastrous. If spores got into the living area, they could spread through many rooms before the colonists noticed them. Because of the disease's infection dynamics, an outbreak could incapacitate or kill many colonists over a short period with little warning, disrupting day-to-day survival operations. A supply cutoff would make life very hard for the colonists, but an outbreak could wipe the colony off the map, and possibly turn it into a long-term biohazardous graveyard.

As the colonists and their support teams on Earth race to design and implement a safe resupply system, they'll both be hobbled by grave immediate threats. If the scale of the pandemic only becomes apparent in the months before a major resupply launch window, a whole wave of deliveries will have to be cancelled, and the colonists will be scrambling to prepare. Meanwhile, the people on Earth will need most of their resources to face the medical, logistical, financial, political, and emotional horrors of the pandemic, from national governments down to individual support employees. It could take a year or more just to learn enough about the fungus for meaningful risk estimation, another year for design and testing, and who knows how long to scrape together the labor, materials, and political will for construction and launch? Waiting for a good launch period will take even longer; launching from a bad window will cost even more.

• I was surprised this wasn't the first answer given what we all just went through. Oct 18 at 23:45
• @coblr, I was too! Well, write the answer you want to see in the world... Oct 18 at 23:46
• This is a good answer, but for a space mission, the kind of autoclaving that is already in common use would allow at least an unmanned supply mission to be safely launched. If the Martians chose not to use the supplies out of fear, however, they might get supplies and not use them, leading to the temptation by some to flout collective decisions and access the forbidden supplies. Great drama. Oct 19 at 0:28
• @Vectornaut The mycobacterial or anthrax spore is the gold standard of things you need to kill. Stick this stuff in foodstuffs where they are disinfected but not sterilized. Then people only find out about the contamination a couple weeks before the supply ship arrives. So now you've been waiting for months for supplies, and you are then afraid to use them. Bacteria from thermal vents may resist autoclaving, as can certain bacterial endotoxins. sciencedirect.com/topics/agricultural-and-biological-sciences/… Oct 19 at 2:54
• I'm not sure why the article linked says no resupplies were available, or that the expedition had to leave in May. maritime-executive.com/article/… At least the Kapitan Dranitsyn managed to reach the Polarstern. I actually just watched the PBS NOVA episode about the expedition yesterday. Oct 20 at 14:31

Nurdles

The world has finally cracked down on Iran's alleged dreams of being able to make nuclear missiles, and begins an all-out bombing campaign. They watch in horror as the Iranians respond by launching a rocket in defiance that they are unable to blast out of the air ... but it turns out to simply be a launch to orbit, demonstrating what might have been a perfectly valid commercial option for launching satellites.

Then their own satellites start going off line one by one. It turns out the rocket, launched on a policy of if we can't have space then you can't either, was filled with nurdles - little bits of plastic. The ones above are illustrated in the image linked from an article in the Courier (Britain), but they're Man's answer to beach sand and you can find similar articles from all over the world. In the seas of space, however, what they are is a fast-moving radar-invisible plague of countless millions of tiny bullets that make the Kessler syndrome look like a walk in the park.

I could have copied the U.S. plan West Ford more precisely, in which half a billion pieces of copper wire were shown to be capable of destroying space travel if the Soviets dominated it militarily. (They were put in low orbit that time, so this was only a brief threat) But nurdles are everywhere else ... why not here?

• Ouch, Mike. Your Kessler syndrome answer beat the other one by three hours, but it's getting the votes. I hate when that happens. +1 Oct 19 at 0:41
• Ye gads! I’m very familiar with Kessler (I work with various space launch firms), but I hadn’t heard about this particular proactive deployment. That’s really threatening! PS: good job with citations!
– SRM
Oct 19 at 15:44
• @SRM It's not like I ran the numbers on this. I'm just assuming it's possible to do about the same with them as with copper wire, "given a good design" and pieces of equal weight. Oct 19 at 18:07
• @MikeSerfas Wouldn't this just increase the "barrier to entry" (...sorry) for space? i.e. now my ships must have [nurdle-proof] armor, which makes them heavier, but other than higher fuel costs, it's possible, right? Oct 19 at 22:08
• @TCooper Low orbit around earth is around 8 km/s. Get the nurdles going across common orbits (polar launch I guess?), and their relative velocity to your space craft is around 11 km/s (if they're orbiting more equatorially but opposite direction it could be 16 km/s, but then people will probably just start launching to the west instead of the east... unless they can launch two nurdle deploying rockets in opposite directions). Anything hits pretty damn hard at 11km/s. I don't know, but I would certainly believe that it simply isn't possible to launch something with heavy enough armour.
– Ben
Oct 20 at 3:41

Massive coronal ejection unlike anything seen before

Sometimes the Sun coughs up a lot of mass and it's usually on its rotation plane. It hits us more often than we would like. Usually it just disturbs satellites for a while but scientists say a big one could knock out power stations on Earth.

If we get hit by a really large one that is bigger than the one scientists fear, it could take space stations out of commission.

A ressuply mission to Mars is too big to be sent from ground in one go. It necessarily involves some space assembly and refueling in Earth orbit. With all space ports gone this is not feasible and it should take some years to build a new one.

• This. Not just space ports, but a really big one can fry most of our electrical grids on Earth. Depending on how much time we would have to prepare (often a lot more than you think) and the damage (quite well able to mitigate enormous amounts of damage) it can take a short time before society is working. Yet it can take a lot longer before mega projects like space flight is attempted again. Depending on the damage years, if not decades. In addition, these things can be directional. Missing Mars fully. Oct 18 at 13:27
• @StarfishPrime thanks for the correction, I think that typo came from me listening to Total Eclipse of the Heart while typing :D Oct 18 at 17:07
• Was going to essentially post the same thing. Some kind of solar flare event strong enough to EMP the Earth while missing or minimally impacting Mars. Having the Martian comms knocked out briefly would add extra narrative tension, since they would have to solve that problem before realizing that Earth got hit even harder and the comms blackout is really from Earth's side. Oct 18 at 17:41
• The other impact of this is that and any ships in transit to Mars are likely to be messed up by this coronal ejection, so the impact to Mars colonies can be rather sudden. Oct 18 at 18:14
• @Anketam, anything on Mars or in transit is going to need to be hardened against solar flares. The six-month travel time is too long for a "launch and hope for the best" approach, and the thin Martian atmosphere provides far less protection than Earth's atmosphere and magnetosphere.
– Mark
Oct 18 at 22:05

MASSIVE FINANCIAL CRASH

What is "the most realistic way" such a scenario could occur is debatable, but here is a highly realistic one:

2044 experiences a sudden and massive financial breakdown as a result of speculation. Professional speculators have invested massively from the faulty belief that the value of stocks, natural resources, cryptocurrencies, housing and more would just keep rising, and small-time investors, urged by their banks, have taken large loans to cash in on these 'surefire' investments. Companies have spend their entire liquidity on stock buybacks to further boost stock prices, leaving no money for R&D or even maintenance. Then, suddenly, the bursting of one of these bubbles leads to a cascade effect where all bubbles burst. Companies, speculators, home owners and retirees all go broke.

Mass unemployment follows as the economy grinds to a halt, The public sector, strapped for funds because of an unending series of tax cuts, cannot help all the people suddenly in need of help. As the saying goes, anarchy is only three lost meals away, and people start rioting, plundering stores and farms for food (and toilet paper - never forget toilet paper). Governments try to use the military for crowd control, but soldiers aren't paid, either, and just add to the riots. The richest 0,01%, foreseeing the high likelihood of such an event, use killer robots to defend their well-stocked, fortified mansions and sit back to watch the apocalypse unfold, knowing that they will be in positions to assume control once the dust settles.

The dust, however, doesn't settle any time soon. Starvation is followed by pandemics as dead bodies litter the streets, well-armed gangs plunder what they can from people who still have a bit of food left, never mind the death toll. No-one is left to combat forest fires or handle hurricanes, drought or flooding, events that have become far more common as lackluster climate measures have proven insufficient to combat global warming. In the chaos, some nuclear weapons are also set off, for no reason anybody can guess. In this situation, the fates of a few thousand Martian colonists is very far from people's minds.

• The public sector is the one sector of the economy which literally for real cannot be "strapped for funds", unless in a country which has given up its independence and has been forced to use the imperial currency controlled by a foreign power. In an independent country the Supreme Poo-Bah of the National Bank (whatever the title is called) can always take a blank sheet of paper, write on it "This sheet of paper is worth one quadrillion monetary units" and sign it. Abracadabra hocus-pocus, the public sector has money to burn. Oct 18 at 13:25
• @AlexP The government CAN be strapped for cash, if printing money results in hyperinflation. Government spending is about faith. The Weimar republic notoriously printed money that was so devalued before it left the printer that no one had faith in the currency. If the US government got itself so far in debt funding the Mars program that people lost faith in their ability (or willingness) to pay it back, politicians might stop extending the debt ceiling. Where have I heard that story...? Oct 19 at 0:38
• @AlexP, Zimbabwe most recently, I'm sure we'll see it again somewhere before too long. The public does get money to burn, because that's the best way to keep warm if you take that path too often. Oct 19 at 7:21
• There are plenty of times when governments say that everyone has to chip in together to "balance the budget" while they make savage cuts to the public sector spending while publicly saying the public sector has to keep providing the same level of support to everyone.
– Rob
Oct 19 at 14:35
• Occasionally governments that could fiat their way out of a currency crisis are encumbered by a leader who doesn’t understand math or economics… they crash the economy by insisting on balanced budgets at a time when deficit spending would be better (“We must get our financial house in order… set example for the populace…”).
– SRM
Oct 19 at 15:48

A possible scenario is that the resupply missions are planned as minimum-energy launches every 2 years and takes about 7 months. These minimum-energy launch windows occur 780 days apart, about 2 years and 2 month. Sending spacecrafts outside of these windows would take longer time and consume more fuel. Every extra bit of fuel used eats into the payload and your spacecraft would be designed according to this.

Assuming that some kind of accident stops the planned resupply mission, it would be about 2 years before the next full supply one can be sent. It might be possible to send some smaller amounts in the meantime but to a great expense.

So the mars people last got supply about 1.5 years ago, expecting it to arrive in about 7 months when they find out that they will have to wait almost three years instead.

And now, somehow, the next resupply again is canceled. Two more years of awaiting.

--- added below to answer --- The problem with a resupply mission does not have to be any world-disaster level stuff. Rockets use risky technology and contains millions of parts, and just perhaps some small thing breaks and disables the mission. You might read up on the Apollo 13 disaster where a small oversight almost killed the astronauts. The base problem was a design change in an electrical circuit, which created a latent problem that occured in Apollo 13. It could have happened in earlier flights. Perhaps the resupply rocket was hit by some stuff dropped in earth orbit, say a screw driver dropped a few years earlier from the space station.

• and the increased energy demands and time requirements for the less optimal launches could mean the missions can't be undertaken with existing technology. That's pretty much the answer that makes most sense to me as it is effectively the current state of technology and doesn't require some semi-mystical event from happening that'll need to be explained away Oct 20 at 9:29

Earth goes silent.

Some ideas why were put forth in this question.

The weird case of the unresponsive Earth - why does the Earth stop communicating with Mars?

But I like the idea of not knowing. Earth just stops answering. My favorite part of the movie Night of the Comet was before all the zombie stuff, when the heroes hear one radio station is still playing and they go there, only to find it is a robot radio station - still new stuff in 1984.

Earth is still transmitting but only automatic things. The Martians do not have big enough telescopes to see down there and so do not know what is happening on the surface.

At the end of the story, Mars gets a radio transmission. "Hey. What's up, Mars?" Then a chuckle, and nothing more.

• With like 8 billion people on the planet, and radios being pretty trivial to build out of all the junk we have lying around, it is hard to imagine something that would leave Mars totally ignorant no matter what happens as long as a few million people survive whatever it was. Oct 20 at 14:56
• @MikeWise - OP can use your comment as dialogue for some Mike Wise equivalent on Mars. Good stuff. The answer from his solemn Martian comrade after she finishes her smoke. "Yeah. Hard to imagine." Oct 20 at 16:03
• I like it :) ... Oct 20 at 16:48

A change in president

New president comes in decides the whole landing on Mars thing is a scam as clearly humans can't breath in a vacuum and thus the whole landing must be filmed on a sound stage somewhere. So he cuts funding to NASA, to give his buddies a tax break so they can own another golf course, and orders continuous and never ending government inquires to find out where this fake Mars base is, tying up NASA for years.

Of course people are protesting this and trying to point out the evidence, but he shrugs it off as "people are always protesting about something, first they wanted clean water and clean air and now they want to waste more money sending that clean water and air to Mars instead?"

Doesn't help that it turned out all the Mars colonists voted for the other guy in the election. Or that the Mars mission was the cornerstone achievement of the previous president.

• I'm gonna be honest.... this is a really unrealistic scenario. Yes there is a growing trend of misinformation and conspiracy theory, even among those who should know better, but the President also isn't the only one who decides these things. NASA gets their annual budget, and chooses as they will what to do with it. The President can make decisions on spaceflight, but doing something as drastic as defunding NASA would require congress to also be in support - and NASA stays alive because of NASA jobs in many states - ie, NASA isn't getting defunded. Oct 19 at 16:58
• Because congress never changes to the same side as the president elections? Or if the president want to wrap an agency up in so much red tape, new environmental reviews, or not nominating the senior leadership to congress leaving dupties in charge you don't have the authority to make decisions? Yeah a president could never screw an agency up if they wanted.
– Rob
Oct 19 at 17:49
• the thing is, you're characterizing this as something the Republicans would do. Historically however, at least in recent decades, Republican administrations have put more effort into space policy, seeing it as an opportunity to stoke patriotism, generate jobs, etc. Even if you took it the route of the democrats stopping it... there are so, so so many NASA jobs in many states that just eliminating NASA's funding would never get through. Oct 19 at 18:26
• @Current It doesn't have to be an existing party. There's 20 years to build an explicit Anti-Science party in, starting from the Anti-Vax and conspiracy sentiment stirred up by Covid there's plenty of room to grow into. Who even believes there really are people on Mars? Oct 20 at 8:50
• Unfortunately, that sounds quite believable scenario to me (and not just in worldbuilding, but IRL too). See for example Fallen Angels by Larry Niven / Jerry Pournell for related idea of science deniers becoming popular enough to vote new government in power, whose actions force Earth to new ice age (with unexpected twist about which political party was responsible for that!) Oct 20 at 11:46

Reaching Mars with resupply-levels of material (not just a crate of potatoes) is on the absolute vanguard of current tech, and given the laws of physics and economics not experiencing a giant upheaval, will stay there pretty much indefinitely.

A lot of specific materials, parts, people and facilities are absolutely neccessary to make a resupply run to Mars viable - there is not that many spaceports, rocket factories, hardened chips, ... that it would be inconceivable, or even unlikely, to see the accidental death of a few people, an unrelated crisis pinching some distant supply line, or a mild catasrophe wrecking some important infrastructure set back a space programme for years.

The supply rocket fails spectacularly, with no readily apparent cause - a billion dollars down the drain. (Emergency-) Supplies on Mars will last another three years, so the consensus is to thoroughly investigate the failure, revise protocols, and launch at the next window in 2 1/2 years.

Turns out the failure was due a Y2K-like thing in the communications module. Redoing the QA for another module will take too long - Solution: switch to another launch vehicle, will launch from Baikonur (they have the only comms that fit to that size and type of vehicle). T minus one year: Oops, Baikonur has to trash their main dish, because it needs some crystals that were only manufactured during the Soviet Union, and stores are running out. No problem, manufacture is being revved up again, will only take two years...

Solution (with sweat forming on forehead): Launch two smaller vehicles from Guiana, couple loads in orbit, go to Mars. We did that ten years ago, worked like a charm, didn't it? T minus five months: Oops, that maneuver was on an orbit we cannot currently use due to debris, and the research group that figured out the nitty-gritty ten years ago, and could easily redo their work for another orbit (well, after rewriting most of their code, because that one package turned out to be buggy as hell, and has since been deprecated, and the cloud-platform it ran on has switched gears since) - yeah, those gals all drowned on that boating accident three years ago, remember? No problem, other people are just as smart, and will be easily able to reproduce and test their solution in, say, 6 months?

Solution (with medication-enhanced calmness): Launch with emergency-QA'ed comms on original vehicle. T minus one week: Ah, chucks, that incoming weather from Cuba is a little too gusty to already put our rocket on the pad, no worries, the windows stays open for like 14 days, we'll just wait it out. One week later: T minus one week: People, do we really only have that one effing crawler to take the rocket out to pad? And you are telling me a vital hydraulics-line broke? What diameter? Are you kidding me? Ok have one hand-knit from unicorn hair, if needs be - there's a one-billion dollar mission waiting on that line - what? two weeks? ...Etc...

Point being that most space mission have one payload, five approximately applicable vehicle-types, one launch facility per type, .... the redundancy is really small because of cost. Everything is super specific, super expensive, super rare, so it pains to keep more than a few of it in stock. There is less than ten chip factories on earth, that could produce certain chips ubiquitous in all the space-equipment, and only two or three are, at any point in time.

For cinematic reasons, i would have the container with the needed goods be stuck on a bottom-rung container on a ship grounded in the Suez Canal...

• Should "it would be inconceivable" read "it would not be inconceivable"? Oct 21 at 18:36
• I am not absolutely sure, @Vectornaut , but rather confident in my grammar there : The sentence runs: " there is not that many spaceports [...] that it would be inconceivable [...] to see [...] a catastrophe [...] set back a space programme for years" Oct 22 at 19:43
• Ahh—I see the intended parsing now, but it took me some effort even after reading the folded version. Splitting up and reorganizing this sentence would make the answer much more readable for me. Oct 24 at 10:58

Obviously I could do it the quick and dirty way, Earth is wiped out by an asteroid impact, but considering robust NASA tracking of such lethal asteroids, I find it hard to believe they'd miss one that big.

The way NASA and other agencies detect space rocks is with a couple of things:

• Radar; the object 'close-in' on every orbit around the sun and they can predict its future orbits (how most are caught)
• Visibility; the objects transfer in front of a visible object and cast a 'shadow'.

But as was shown with the Oumuamua asteroid, its tough to spot objects coming into our solar system quickly.

When it was first observed, it was about 33 million km (21 million mi; 0.22 AU) from Earth (about 85 times as far away as the Moon), and already heading away from the Sun.

So theoretically it's possible to not detect an inbound asteroid from outside our solar system until it's too late.

Example of why we cant detect it: https://www.sciencenatures.com/2021/10/a-huge-asteroid-almost-hit-earth-but.html

How we wouldnt be able to do anything to prevent it: https://www.sciencealert.com/nasa-s-emergency-simulation-reveals-why-we-may-not-be-able-to-stop-an-asteroid-impact

It takes 21 minutes for light to travel from Earth to Mars. It would take humans about a year to travel to Mars. Frankly, the proper question should be what events would establish earths support for a mars base?

The first Mars colonists are unlikely to ever return to Earth. If they sent an urgent message, it would take almost an hour just to get a response. If they needed supplies from Earth, that would take about a year to get. Those guys should plan on being pretty self-sufficient and not needing a lot of stuff from Earth.

• This is just plain inaccurate. Predictions on a crewed Mars mission transit time vary, but they never are more than 7 months, and usually around 6 or a bit lower - definitely not an entire year. You are also inconsistent in your statement that it would take an hour to get a response back - when you mentioned earlier that it takes 21 minutes one way. Further, you assert that "the first Mars colonists are unlikely to ever return to Earth." This is just plain untrue, and is a falsehood I see many in the general public espouse. Perhaps it is due to the pipe dream Mars One project. (1/2) Oct 19 at 17:12
• Mars trips would take a long time - a two year mission, with a year or so spent on Mars - but as nuclear propulsion is developed it would reduce the travel time greatly. Self sufficiency would be very difficult early on, because of the myriad of tech needed to keep astronauts alive. Several supply craft at least, with redundant systems and material, would be delivered to the planet prior to astronauts even arriving. By the time of the 2040s, multiple countries and companies may have set up on the red planet, and a rotation of supply craft would be coming in. (2/2) Oct 19 at 17:15
• @Current if it takes 21 minutes one way, then it is a minimum 42 minutes round trip - rounds up to an hour. I think rounding up is fair b/c if it is an important ask maybe someone on Earth will need 20 minutes to think about it. I also rounded up the trip time - which I think is also fair b/c do you really believe that Earth can send a ship to Mars on less than one week notice? I believe that the first Mars colonists will never return to Earth, but I don't really know. Oct 19 at 20:04
• Okay, I think the justification about communicating is fair - but the trip time is still overshooting, especially for the 2040s. Every trend in the space industry is moving towards faster, reusable, convenient launching. NASA isn't ignorant. They've seen movies like the Martian, and they are obsessed with redundancy. Especially with Starship and other new space vehicles, supplies could, quite literally be loaded up in a week. I also want to know why you believe that the first Mars explorers will not return. That would be a dramatic failure on NASA's part. Oct 19 at 20:22
• @Current I believe after multiple months in zero gravity, one's muscles would deteriorate to such an extent that re-entry to Earth (and its gravity) would be by itself fatal. We could combat this by making the trip shorter and/or including a gym in the spaceship. Vegetative patients in nursing homes get more exercise every day than our space travelers. Oct 19 at 23:16

Yellowstone Eruption.

Yellowstone is a big vulcano, if errupt then we will have crisis. Dust in atmosphere prevent starts, then will be hunger and breaks in many countries. You can use it to give small or big gap in flights, if want then that can be 5 yeras, if want then can use this as civilisation collapse for 1000 years or more.

• Given that there are people monitoring the yellowstone supervolcano, and would certainly notice anomalies, it is reasonable that we would be able to tap off the pressure if an eruption seemed likely. However, even then, predictions for an eruption range from any time, to thousands of years from now. I do not think such a disaster would occur any time soon. Oct 19 at 7:17
• We do not have technical solution to prevent eruption. We can make it little smaller only. Maybe some nukes can help but when eruption starts then only nature apply. And as You say predictions are from tommorow to 20 000 years in future. Thats our universe. in His one can be a little diffrent. Oct 20 at 6:36
• .....nuking the yellowstone Volcano sounds like the worst possible idea ever. An already awful eruption would be made worse by radioactive dust. Nukes don't usually improve situations. Oct 20 at 7:39

Nobody likes the martians anyway!

They're always up there on their red planet, feeling smugly superior, looking down their noses at us earthlings on our polluted and overpopulated planet. They're a drain on taxpayer money, and we've had enough of it. Let the martians fend for themselves!

All sorts of things could turn the people of earth away from those on mars:

• They waste a lot of money. Perhaps due to something like overpopulation or automation/AI taking over jobs, there's mass homelessness or unemployment. People feel that the money should be spent on earth, rather than sent to mars.
• The martians dislike people back home. Maybe after a few years or decades of freedom, they publically rebuke the countries or corporations that sent them there, discouraging them from continuing to fund the project.
• Broken promises. The mars crew was supposed to do research, but for some reason, they're unable to. Maybe they just get lazy. Maybe they end up fighting, split into factions, and divide up the equipment. Someone goes rogue and hits the centrifuge with a baseball bat. That sort of thing.

None of these would typically be likely to cause a government/company to leave them stranded on mars alone, but perhaps there are other factors back on planet earth that make it worse. Maybe a group overthrows a major government due to widespread corruption or something, and they take the opportunity to relieve the taxpayers of the burden (or the martians are just forgotten about, necessary supply chains are destroyed, etc.).

• I find this to be very, very unrealistic. This story takes place circa 2040s, and even amidst climate change problems, Earth will still be a far easier place to live than Mars. For at least the first few decades, if not the first half century, living on Mars would be difficult. The obnoxious notion from the general public that space is too expensive, though I feel I could mention these ignorant opinions, don't usually have bearing on what actually happens in space (and that goodness for that). I find it hard to believe further, that the Martian colonists would somehow become.... (1/3) Oct 19 at 17:02
• .... at odds with their home nations. Remember, this is the 2040s. Mars exploration only began in the early 2030s, and so they rely heavily on Earth for survival. And.... just why is Mars so much more free than Earth? Yes, they would likely do things as a direct democracy, but that doesn't mean that they're going to purposefully sever ties with the people keeping them alive. And then..... the Mars crew gets lazy. This I find just... a really odd scenario. NASA astronauts work unbelievably hard, and they would be the core part of such a colony. Even private astronauts or tourists.... (2/3) Oct 19 at 17:06
• .... understand the monumentality of being the first settlers of Mars. Further, NASA and its partners would vet colony applicants greatly. They vet not only for people with appropriate skills and expertise, but also people who are emotionally stable and such. Being all cooped up together in a Mars habitat, this is very important. As for "they take the opportunity to relieve the taxpayers of the burden" - American taxpayers pay like $35 a year, or less, to fund NASA. I apologize if I've been overly harsh. I just don't feel like you have the expertise to speak on this topic. (3/3) Oct 19 at 17:09 • @Current I was mostly just listing possible reasons, since which ones work for a particular scenario would vary. I didn't think too much about the 2040 aspect of it, but I still think they could work. The "gets lazy" part was less of a serious suggestion, but researchers splitting into factions and refusing to work with each other has been documented to have occured before, such as with Biosphere 2.0. As for people's "ignorant opinions" not usually having an impact, I wasn't saying they would on their own. In fact, (cont.) Oct 19 at 17:10 • @Current in my answer I even state "None of these would typically be likely to cause a government/company to leave them stranded on mars alone". Some other event which greatly exagerates this would be needed, like the mentioned mass homelessness/unemployment or unstable government. My goal with this answer was to provide slightly less dramatic reasons this could happen, than something like a global war or huge natural disaster/CME. I'm sure these would be unlikely, sure, but I don't know what's going on in your story, and this could be perfectly fine depending on the surrounding world. Oct 19 at 17:13 unspecified calamity In my story idea, Mars bases simply stopped hearing from Earth. It happened generations ago now, so is referred to in vague terms. It's just a trope to explain why the colonies are barely self-sufficient and don't get any outside help. They can look at Earth and its Moon through their telescopes and remark about how the continents were blackened in Grandfather's day but are looking healthy green with seasonal changes now; how patches are artificial lighting can be seen but nothing like how it reportedly looked during the Space Age. Really, the only specific thing is how it starts. Once things get bad, it will snowball and there will be wars, famine, and pestilence. Even the people in the Bronze Age knew that. Whatever the specific "spark" that started it, though, it can be credited ultimately to overpopulation. A much simple answer is changing political priorities and changing corporate priorities. Just look what with the ISS- the US retired the Space Shuttle fleet and didn't anything ready to go so they paid the Russians to resupply them. If the Russians had not been accept a reasonable resupply contract and ISS being close (and didn't have their own astronauts onboard- there was change the Russians could have totally killed their own ) there is good chance supply on the ISS might have cut to barebones. Mars so much further away people won't be strongly reminded that there are Martians to support- the US and corporate interests decide let's farm asteroids or set space stations- Mars has to be somewhat sufficient anyway. • This is an oversimplification of things. Firstly, if political support for the ISS had simply dried up, NASA and Roscosmos would not leave astronauts and cosmonauts on the station. NASA's around$20 billion budget can completely pay the few hundred million to get astronauts home from the ISS, even if they need Russia to do so - which they do not need anymore with Crew Dragon. In the case of a Mars program, such a program would not be cancelled if there were still people on Mars. It would be a very easy thing to villainize politicians as astronauts dying on Mars would be extremely.... (1/2) Oct 21 at 17:02
• ...high profile. A colony also would take many decades to be self sufficient. It would not be there by the 2040s. I also find it quite hard to believe that a market like operations on Mars, especially with the growing space industry, would just be ignored by the private sector. When NASA transitions their more official contracts with SpaceX to go to Mars (and let's be realistic, that is the only way this is happening) they will hand out additional contracts to other companies, making NASA just a customer, and building commercial incentives on Mars. Oct 21 at 17:04

Earth goes the Empire way [1], losing its capability to build rockets. This can be explained with a war that destroys industries supplying space or with a move away from science by humanity as a whole, going back to the medieval way.

With time, the old rockets crash and burn and the space capability shrinks, until it becomes non-existent.

• [1] Empire is a reference to the Empire playing a part in Asimov's book series Foundation. The Empire in the book loses the capability to build reactors, with the union decaying over time.
• How on earth does all of Earth become an empire by the 2040s, and then further lose the ability to build rockets? Oct 21 at 17:39
• @WasatchWind Well, Empire is actually a reference to Asimovs' Foundation, where the Empire lost the capability to build reactors, similarly complex to the space industry. I mentioned two ways to see this happen. Do you think all are implausible? Thanks for the comment btw, added a note to reflect this. I'm kinda new in Worldbuilding and thought most should know Foundation here :) Oct 21 at 18:43
• Okay, I was not aware you were talking about Foundation. The thing I'll say is - the question was answered. You don't need to provide more when an answer has already been accepted. Oct 21 at 20:45
• @WasatchWind ohh I didn't know this was a rule. Would be nice if you can point me to the rulebook so I can learn. Anyway thanks for taking the - back, was kinda flustered because I thought my answer is not THAT bad. Maybe was just in my head^^ Oct 21 at 20:51
• @WasatchWind Dang, didn't know thats the case around here, makes sense how you reacted. Sounds a lot like diehard Worldbuilding fans, hmm. anyway have a great day and good luck with your book :) Oct 21 at 21:05