On the radio the other day, my wife and I heard the head of NASA effusing about a plan to send humans to Mars by the mid-30s. These comments were in the context of the celebration of the moon landing. I interpreted it as simply a bureaucrat over-enthusing in order to maximize his budget, but my wife thought it somewhat irresponsible, because it risked getting people excited about something that was essentially impossible (and, at the least, unnecessary and VERY expensive.)
I don’t know if this lends itself to a factual answer, or will turn into an exchange of opinions, but how achievable is a human flight to Mars, compared to landing on the moon when Kennedy proposed it? What technological/human hurdles had to be overcome to reach the moon, and how do they compare with the impediments to Mars travel?
In my ignorance, I sorta view the Apollo program as a massive scaling up of technologies we already had or knew how to build. Whereas a trip to Mars involves at least a couple of “insert miracle here” or “assume technological leap there” points.
Also, I’m not expecting NASA programs to pay for themselves in terms of commercial applications, but my impression is that considerable benefits resulted from Apollo. Am I mistaken? Would it be reasonable to expect similar benefits to result from a push towards Mars?
Our resident rocket scientists will chime in soon…but I’ll start by mentioning that it’s very hard to land big things softly on Mars. Too much gravity, not enough atmosphere.
It involves way more distance, time, money, personnel, and plain old luck because a million things can go wrong during a mission spanning that distance and that amount of time in space.
It has to be part of a concrete, long term plan. You can’t justify an undertaking of that magnitude just to land, dig up some rocks and dirt, and fly back to earth as was done on the moon trips. It has to be the actual initiation of the colonization of Mars, which means it needs to be comprised of a large crew of people who can assemble the first permanent Mars station from supplemental materials flown to Mars that will be awaiting their arrival. This will necessitate a series of shuttle trips sending down and retrieving all the people necessary to do this. I could go on and on about the timing and complexities involved.
There are many ways in which a Mars mission is much harder than a Moon mission.
1: The return trip. You can launch a couple of humans and their life support system off of the Moon using a vehicle about the size of a car. And to get that vehicle to the Moon in the first place required a Saturn Freaking V. A Mars ascent vehicle wouldn’t be as difficult as one to launch from Earth, but it’d be a heck of a lot bigger than a Moon ascent vehicle. And now you’ve got to get that larger return vehicle off of Earth, and to Mars, and safely onto the surface.
2: Landing on Mars. As JKellyMap mentioned, Mars is often regarded as the most difficult to land on solid body in the entire Solar System. The atmosphere is thin enough that parachutes are almost unworkable (they’ve been used, but only for very small payloads), but you still have enough to cause turbulence and other unpredictable effects that need to be accounted for.
3: Duration of mission. The Moon mission was a few days. A Mars mission would be years. Which means that you need a lot more consumables (or ways to refresh them as you go, but that probably won’t be 100% efficient, so you’ll still need to pack extra), and you also need ways to survive the space environment for that long. So you need protection against radiation, you need either ways to tolerate zero gravity or to generate artificial gravity, and we don’t even have any idea what the effects would be of the several month-span on the surface with nonzero but low gravity. Plus the psychological angle: It’s one thing to be crammed into a tin can with a couple of other guys for a week; it’s another to do it for years. The ship would have to be larger just for the sake of the astronauts’ sanity.
4: Sunlight. A relatively minor one, but anything you’re powering using solar panels will need larger panels, because you don’t get as much sunlight at Mars’ distance.
Yeah - my wife was focusing a lot on the psychological/human aspect. (Coincidentally, I recently watched the 1st Twilight Zone ep! :D)
Does anyone know whether there are astronauts eager for this trip? Would such a willingness say something not entirely healthy about their personality?
How about a 1 way trip? Send someone off to spend the rest of their life on Mars?
I assume a bunch of supplies/materials would be sent ahead for any landers to make use of. What could be done about sending off “supply stations”? Could you launch some slow moving “barges” that could be docked with for resupply on the way out and back?
My wife was also concerned with the potential human cost. But to my mind, that ought not be an insurmountable hurdle. Sure, we should not waste lives recklessly. But if we are pushing the envelope, I have no problem with the potential loss of volunteer life factoring into the equation. I can imagine seeking ZERO risk would unnecessarily ramp up the complexity/expense.
My kid studied aero engineering. Since he was a kid, he wanted to be involved in getting greater payload to space cheaper. In his career, he was disappointed at the countless hurdles to making that happen - he now is enjoying a career in (space related) quality engineering, and pondering a career move out of space. There are a lot of neat things going on in space (and a lot of stupid costly shit), but not much is really aimed at getting large payload up cheaply.
Supply ships to the surface of Mars before the mission would be a given (and you wouldn’t even launch the humans at all until all of the supply ships made it and the ascent vehicle was ready to go). You could potentially also launch supplies for en route in advance, but they couldn’t be slow: They’d have to be going just as fast as the manned ship, or they wouldn’t be able to dock. Probably easier to just put them into transfer orbit at the same time as the manned ship.
And there’s no shortage of volunteers, even for a one-way colonization trip. But just because someone thinks they want to go, doesn’t mean they’re actually psychologically up to it. If you think you’ll be able to handle the stresses, and then find out halfway through that you can’t, there’s no backing down.
Actually, come to think of it, there might be some value in launching both most of the outbound ship, and most of the return ship, in advance and putting them into the appropriate orbits, and then just launching the humans in an Apollo-like capsule to rendezvous with each of those ships. You’d probably need some orbital mechanics black magic to get the ships into the right orbits cheaply, but NASA still has a few orbital black magicians on their payroll.
There is an older book that gives a highlevel view as to how to accomplish a Mars mission - The Case for Mars
Basically a return/supply ship is sent out first. Using a small amount of hydrogen, some basic chemistry and local CO[sub]2[/sub] you can create methan, oxygen and water for fuel and life support. The crewed ship doesn’t leave for Mars until the return ship is fueled and water/oxygen stockpiles exist. The movie “The Martian” was heavily influenced by the Mars Direct approach though I can’t remember a “passenger ship” like the Hermes.
Psychologically…well humans have been heading out into real isolation forever. Astronauts sent to Mars will be continually in contact with Earth, books, movies and everything else.
Ultimately we can question if we should try but if we did, I think we could be successful, but it requires a certain measured long term approach that US administrations and Congress have been unable to enable.
It’s not required to use the Hohmann transfer orbit, the one that takes nine months to get there, to get to Mars. It just gives you the most payload for the buck, er… for the amount of fuel. A more direct transfer orbit could probably be made in about 2 or 3 months with today’s tech. It might take 20 times as much fuel, though. So build a rocket in orbit that can take that much fuel.
So I’m thinking the best way would be to send the vast majority of the equipment and supplies by Hohmann orbit, and then once that stuff’s there, send the people by a shorter, more fuel-intensive orbit. That would minimize the problems of people being in a low g/high radiation environment for long periods of time.
I have long puzzled over this. You would need a large series of large missions. Each would have to lift hundreds of tons into Mars orbit.
A whole constellation of satellites. We cannot land without good maps and communications relays in orbit.
The return-to-earth vehicle.
Fuel for the return-to-earth vehicle.
The Mars lander and all the stuff for the base.
Then we can launch the crew to Mars orbit.
As a practical matter, it is impossible given current propulsion systems. Each ton lifted to Mars orbit would require several tons of fuel and whatnot.
There are a lot of tradeoffs like that you can make, and finding the right values for all of them is not only an engineering problem, but a political one as well. Like, an engineer can’t tell you how much risk to the crew is acceptable vs. increase in the costs or the time it takes to finish it.
We have good maps. That’s what the Mars Reconnaisance Orbiter is doing. And we shouldn’t need a large constellation of communication satellites. The ground base should be able to talk to Earth directly. At least when the Earth is above their horizon. But there’s actually no need for 24.5 hr communication.
There are no less than three very large (roughly Saturn V sized) rockets in development right now. Which is probably 2 too many, but if we ever do go to Mars, they should be adequate for launching equipment and supplies.
We can get people to Mars today. Getting them there alive (and back to Earth alive) are the hard parts
I do believe that within my lifetime we will achieve a manned mission to Mars. Colonies, on the other hand, are nothing more than the pipe dream of sci-fi geeks.
Even if you want full-time communication links, you don’t need a large constellation of comsats. 3 will do - one in a “geostationary” orbit over the landing site, and 2 others 120 degrees ahead and behind so that they form an equilateral triangle above the Mars equator. The one overhead is always available to the ground station, each sat can always see the other 2, and at least 2 of them can always see Earth.
At some latitudes you can probably do it with 2, using eccentric geosynchronous Molniya-style orbits with the satellites 180 degrees apart on the orbit.
The difficulties, cost and uncertainties of a two-way human Mars mission are vastly beyond the Apollo program.
These uncertainties include long-duration human exposure to microgravity. A key purpose of the ISS was to study this, $150 billion was spent and lots of research was done. However it is still unknown how well humans could survive and function given the typical exposure lengths of a two-way Mars mission.
You could hypothetically design a rotating “centrifugal gravity” ship, but a purpose of all the ISS research was determine a pathway to enable long-duration human Mars missions using a “zero gravity” spacecraft design. Maybe some of that money could have been better spent on the relatively straightforward engineering problems of a rotating artificial gravity vehicle.
Another major difference between human moon vs Mars missions is the surface dust. Photos inside the Lunar Module show the Apollo astronauts covered in lunar dust, looking like coal miners. This was despite having vacuum cleaners, special brushes and training in dust hygiene.
By contrast it has recently become known that even tiny human exposure to Mars surface dust could be fatal since it is coated with toxic calcium perchlorates. It has yet to be explained how such antiseptic clean room conditions could be realistically maintained during a human Mars mission.
Kennedy gave the “we choose to go to the Moon” speech in 1962. The leap from there to Apollo 11 was more than just “scaling up.”
In 1962, the Gemini program had just started. They used the Titan II GLV, which could put 3.6 tons into low earth orbit. The Apollo program needed a rocket that could put 140 tons into orbit. Each of the 5 engines on the Saturn-V was 10 times more powerful than the one on the Titan II.
As you may have seen in the movie Hidden Figures, orbital calculations were done by hand until around 1960. NASA started using IBM computers around that time, but a computer was still something that took up an entire room and operated using punch cards. But for Apollo, they had to build a computer that could fit inside the spacecraft. The Apollo Guidance Computer was one of the earliest computers to use integrated circuits (what we now think of as “computer chips”). Of course, that also meant there were no established processes for developing safety-critical software.
Nobody had done an EVA (spacewalk) until 1965. Think about that - nobody had ever used a spacesuit in space until 1965. (That link is to the first American EVA, the first Russian one was earlier that year.)
No successful docking of two spacecraft was done until 1966. Not even a successful rendezvous of two spacecraft until 1965.
The Saturn V F-1 engine long predated Apollo. Test firings of F-1 components were done in 1957 (the year of Sputnik 1). The first static firing of a full-stage developmental F-1 was performed in March 1959. A long-duration full-thrust test of the F-1 was done in May 1962, before John Kennedy’s “We choose to go to the Moon” speech in September 1962: This Week in NASA History: 1st Full-Thrust, Long-Duration F-1 Engine Test - May 26, 1962 - NASA
A successful Apollo program was possible because long-lead-time items like the F-1 engine started development long before Apollo itself.
This is a very key point. In fact James Webb, NASA administrator during the Kennedy years, argued the same about the lunar missions, and basically he was right. He felt that instead of a rush to the moon, the program should be part of a long-term space strategy. I don’t claim that Kennedy was necessarily wrong considering the cold war priorities and that the Russians were trying to get there first, but it nevertheless resulted in a situation where after the Apollo landings, NASA’s position basically became “so now what?”. There wasn’t any logical followon. Many other great things happened, sure, and in one way or another they all leveraged learnings from the lunar program, but none were directly related. They all could have happened on their own, and probably sooner.
For Mars missions, a coherent long-term strategy becomes an order of magnitude more important. And I really don’t know if colonization is a viable strategy. The Antarctic is a welcoming tropical paradise compared to Mars, where the atmosphere is both toxic and almost non-existent. (Besides being mostly CO2, there is almost twice as much carbon monoxide in the Martian atmosphere on a percentage basis as CO2 on earth.) At most, we might have very limited research outposts on Mars analogous to those in Antarctica, but the costs would be absolutely staggering. We would likely learn as much at a very small fraction of the cost with more robotic missions, which I suspect is the foreseeable future of space exploration. For the cost of manned Mars missions, both in terms of money and time, we could send many different robotic missions to Mars, Europa, Titan, and many other interesting moons and other places, and build tremendously sophisticated spaceborne instruments to observe the universe.
It arguably could be. But it would be monstrously more expensive than the already mind-numbing cost of “land, plant a flag, leave some footprints, and head home.”
This is a huge problem for potential manned missions: how much you can accomplish for a small fraction of the cost with robotic probes. This technology has advanced tremendously in the past 50 years - vastly more than tech associated with putting humans in space.
Mars looks like a good place for sentient silicon, not sentient meat.
