Not to appear dumb, but why aren’t these things a problem on the Moon? Does Earth’s magnetosphere extend that far out?
How are humans going to go “further afield” than robotic landers, when the landers don’t have to carry food, water or oxygen?
Unmanned space probes just get better than better. So many striking successes that have broadened our knowledge of the solar system radically in the past couple of decades. It is really that much of advantage to put resources into sending men there?
How much did we benefit from sending men to the Moon that could not now be done by probes and rovers? Sure they came back with lots of moon rocks and some very nice images of a grey, dusty, airless landscape but probes and landers are good at that, are considerably cheaper and will always be able to withstand far more extreme environments than human beings. There are many places where man simply cannot go and Mars is certainly one of them at the moment. Our robots are are a safer bet for exploration for the foreseeable future.
It would take some dramatic developments in technology for the risks and costs for manned space exploration to become acceptable.
Is worth, even, sending a manned flight to the Moon again?
It would be far more productive to explore the depths of our oceans. Lots for science to discover in the abyss that might have some very tangible economic benefits. Lots of strange creatures down there, for sure. But we don’t seem to want to do that so much. Why?
For some reason mankind seems to be fascinated with space and putting its boots on these barren rocks, investing such heroic ventures with some noble virtue that really does not bear much under examination. It is it not simply and expensive and risky ego trip by nation states keen show the world some measure of their superiority over others. Or maybe it is the search for water and perhaps evidence of extra terrestrial life? Really what does it matter? Go all that way to discover something so primitive it barely qualifies?
If we had an earth like planet nearby, where we could clearly see evidence of intelligent life, maybe. But the candidates for that are many light years distant and we know of no way to get there within a human lifetime. The reality is that we exist at the bottom of a Relativistic Well, our lives are short and we humans are too fragile to travel far into space.
So my bet is a hundred years before it becomes cheap enough and safe enough.:dubious:
Answer to the first one is that it’s a shorter time window that you are uncovered for. Answer to the second one is your first one…basically, our moon buggy went further than any of the Mars landers have. In a few days. With 1970’s tech. With the astronauts in an open rover. So…they carried their food and air with them. A manned Mars rover will do the same…have have a range that will put any Mars lander probe envisioned or deployed thus far to shame. The real difference is…there will be a human on board, instead of a human behind a 20-30 minute time lag with a rover that is clunky and has to be really thought through for hours or days or even weeks before a course is laid in and the enter key is pressed.
It will, of course, cost a hell of a lot more. But it will get more done in one trip than we have in decades of landers, so it’s a trade off.
Your answer to the second question doesn’t make any sense. Manned Mars rovers will go farther than unmanned ones because… they have to carry supplies? What? The Opportunity rover went farther (28 miles) than any of the lunar rovers did (longest mission 16 miles).
How long did it take the Opportunity rover to go 28 miles? How long did it take the lunar rover to go 16 miles? Seriously…you need to ask this? It’s basic math. As to why, well, probably because Opportunity has limitations on it’s speed due to the fact that it’s course has to be carefully plotted and programmed in with excruciating detail. Also, it has a rather limited power budget due to it’s size and all the stuff it does. The currently in testing Mars rover is a lot faster and more responsive and has a larger power budget and larger range, even with all those supplies you were asking about because we would be spending a lot more for it and everything else than for the robotic probes. That’s the real answer. A human could walk further than Opportunity does in a day of travel…in fact, they probably will do so within a safe range from their home base. But they can certainly drive a hell of a lot further and get more accomplished both once they are there and along the way.
There are a wide range of requisite and highly desireable capabilities for interplanetary transportation and indefnite human habitation in space (which are essentially one and the same for any practical purposes) but chief among them are a solar orbiting communications/telemetry system (essentially a positioning system and satcom for interplanetary use, which is needed to support any significant expansion of any exploration ability); the ability to extract consumables and raw structural materials like water, carbonaceous compounds, and metals like iron and nickel from space reources; and power and propulsion systems (e.g. using nuclear fission or solar electric propulsion) that could allow interplanetary transits to Mars, Venus, and the asteroid belt in the periods of a few weeks instead of many months so as to reduce the hazards of exposure to space. Of these, none require fundamental developments in basic science per se, but all would require considerable development time and effort (to the tune of a couple of decades and on the order of millions of person-years) even if there were the funding and will to pursue them aggressively.
There isn’t really a range of options for a Mars mission using conventional propulsion and a low energy pseudo-Hohmann transfer orbit; they either spend 40 days in Mars orbit for an opposition-class mission, or ~17 months for a conjuction-class mission. Although it might seem desirable to maximize the return by keeping a crew on Mars for the longer period, it also entails substantial risks and the logistical challenge of keeping a crew safe and supplied for that duration, which is longer than anyone has been truly isolated in the history of humanity. Such a duration would almost require quadruple redundency in all essential systems because the failure of a air or water filtration system for an extended period of time would spell a slow and uncomfortable death for the crew.
There is, of course, the issue of illness or injury; in a year and a half, the likelihood of one out of four to six people having some serious medical emergency or experiencing a chronic problem is likely, notwithstanding that they will be operating in a hazardous environment and in non-terrestrial conditions which may well pose unexpected health complications and threats. The amount of medical supplies and expertise that could be provided to a small crew is very limited. Movies like The Martian provide an inspiring narrative for the lone astronaut braving and “sciencing the shit” out of hazards and challenges, but if we’re being honest, the reason Mark Watney survived the progressively more threatening hazards of impalation, burning, starvation, radiation, and failure to achieve intercept wasn’t because it was techincally feasible but because it would be a lousy story if he keeled over from nutritional deficiency or his rover failed on the trek to the ascent vehicle.
The assumption that a human crew could “go further afield than all the robotic lander probes thus far” is predicated on the notion that what limits rovers and probes is just ingenuity and hands-on skill, but the fact of the matter is that the real limit is the amount of weight that can be feasibly carried to the surface of Mars and the energy avaiable to vehicles once on the surface. Sending a crew doesn’t fix that problem; it compounds it as far more energy and materiel is needed to support a crew (which also has to rest for hours in between work periods and periodically return to a habitat for consumables). If we could transport 30 or more metric tons of material and people, we could also develop and send ten rovers that are three times the size and weight of Curiosity which would not have to be recovered and returned in toto at end of mission as a human crew (presumably) would. In fact, there is an entire segment of a crewed mission with virtually no scientific value in the return segment that could pay for a multitude of rovers and probes that, based upon prior experience, could continue to operate for years after the planned end of mission.
Although you state that “we don’t have a mission profile” NASA has spent considerable time and effort on a series of design reference missions (the Mars DRM 1.0 through 5.0) which have laid out specific architectures and options. It is true that interplanetary exploration is beyond current experience and so the best estimates are necessarily extrapolations from established programs, but if anything that argues that the potential error in such estimates is probably to the high side as the costs of developing technology that is not at a suitable maturity level (the Technology Readiness Level) or does not exist in any working form today tend to grow as more is learned through testing and experience. The credible estimates, e.g. those developed by people with practical experience in planning both crewed and uncrewed space exploration missions, has consisstently been at or beyond the US$500B mark. The infamous “90 Day Study” from the Bush (41) Space Exploration Initiative was US$500B in 1989 which would be almost US$1T today, so in a sense such estimates have become cheaper. No formal NASA study that I’m aware of has proposed an orbiting Mars station of any othe permanent infrastructure, and if anything the experience of the International Space Station has soured the interest in general purpose space stations.
The current Mars DRM 5.0 strongly recommends nuclear thermal rocket (NTR) propulsion for the In-Space Transportation segment for multiple reasons, including mission flexibility, the ability to carry more consumables and a heavier, possibly all-propulsive landing vehicle, having the option of avoiding an aerocapture maneuver for Mars orbital insertion, and perhaps surprisingly, a lower mission cost despite the necessity of starting up a nuclear thermal propulsion development program after decades of doing almost nothing but paper studies in the field. However, NTR has numerous challenges both technically and logistically, and even at best effort it is probably two decades or more to get a working NTR system at a TRL acceptable for mission reliabiliy. This is notwithstanding the still unsolved issue of the entry/descent/landing (EDL) problem of landing a 30 metric ton or larger crewed vehicle and separate supplies and
Setting aside discussion over what is and isn’t currently feasible from a technology standpoint, “What we can afford,” is very much a matter of balancing the completely legitimate and valuable desire to know more about our universe, virtually all of which is unaccesible to us from Earth, and the pressing needs of other areas where governance is expected to use tax revenues to the benefit of society. It is certainly fair to say that for a fraction of the cost of what is now widely viewed as an unpopular and unjust set of wars we could have afforded even a lavish single crewed Mars mission, but in reality that would still require increasing the deficit or cutting back other programs, which is unlikely for a vanity project such as sending people to Mars. For all of the complaints from space enthusiasts that the lack of human presence beyond Low Earth Orbit has somehow crippled space exploration, NASA has sent dozens of missions covering every major solid body in the Solar System, many of which are fundmantally unsuitable for human exploration, at a cost of less than the entire Apollo program or the ISS, and far less than any realistic cost for a crewed Mars mission. And it makes sense from both an exploration and anticipation of future needs to develop an intrastructure to access space resources with the ultimate expectation that technical developments will some day let us send people into space indefinitely and land up Mars and other planetary-type bodies while at the same time using developments in space to benefit society as a whole. But to do so at enormous expense today to just satisfy the expectations of enthusiats is not realistic or reasonable.
I certainly hope not! I have some experience in this area, having worked on adjunct studies for DRM 3.0 and 4.0 as well as proposals for interplanetary communications and telemetry (among other ill-fated efforts) but my opinion is hardly the last word. There are people with more experience than me who believe that a crewed Mars mission is feasible and worthwhile. But they also acknowledge that it will not be done for US$40B, or by a rag-tag group of improvising geniuses, or that we have to discover life on Mars tomorrow else we might lose our chance to be first, or whatever. It may seem discouraging to some that going to Mars is far more difficult than science fiction movies make it seem as if it ought to be—I know I went from enthusiastic advocate to cautious optimist to pragmatic critic as I learned more about what such a mission would actually take at a detail level—but it also illustrates that doing “hard things” like space exploration is really more about long, steady effort and development of technology and infrastructure than it is about grandstanding speeches and “Eureka!” moments, which is important. The real lesson of the Apollo program is not to predicate support of your program to one particular goal or event, but make it sufficiently and consistently worthwhile that there is a continuity of enthusiasm regardless of the winds of public opinion and the vagaries of politics.
Stranger
I opened this thread because I was interested in what Stranger’s response would be. And, of course I agree with him.
We will never go to Mars.
Certainly. But we won’t send that sort of tonnage to Mars sans humans. That’s the reality. We certainly could send a robotic probe with a larger power budget, though we’d have to have vastly improved AI or we’d still have similar issues to the current probes wrt the time lag and detailed course input and very slow movement rate due to the fact that if it gets stuck there isn’t some guy on board with a shovel to dig it out or otherwise work to free it other than programmers trying to spin the wheels one way, seeing what happens, then another, seeing what happens, etc etc.
Yes, the crewed mission would pay for many robotic missions (at $4 billion or so a pop I make that out at something like 50 missions, give or take)…especially if we want to wait a century or so at the current rate for the data and missions to trickle in. And we aren’t going to spend the money, even collectively, for 50 unmanned missions.
Anyway, this is exactly the debate I wasn’t looking for since it’s the same old thing with folks digressing into should we could we, where I’m asking if we will or won’t in a certain time frame. You gave your answer to the OP, I gave mine. We sort of agree that it won’t (probably) happen, even if our reasons are not completely aligned.
I think that there are two key stages to a timeline: First we have to commit to the goal, and then we have to follow through on that commitment. The second part is fairly predictable: We know what the engineering challenges are, we know what engineering challenges we have overcome in the past, and so we can extrapolate how long it will take to solve those challenges. But the first part is completely unpredictable. The political will does not currently exist for a Mars mission. Oh, sure, a lot of politicians say that they want it, but they don’t say it like they mean it, and they’re not backed up by enough people. And it’s impossible to tell when the political will will shift.
Of course, technology will also influence the political will: If the mission gets cheaper, a lot more people will support it. The most plausible sequence I can see is the following:
1: People will research further into improvements in carbon-based materials technology, because incremental advances in that will provide direct, Earthly benefits that companies will be able to directly monetize.
2: Eventually, fishing lines, golf clubs, skyscrapers, and suspension bridges will be made using carbon nanofiber, and infrastructure will be established for producing it in large quantities.
3: Once the large-scale infrastructure is in place, some Elon Musk type (I say “type”, because Musk himself might be dead or otherwise out of the game by this point) will lead an effort to use that infrastructure to build a space elevator, providing cheap access to space.
4: Once that cheap access to space exists, it will be relatively simple to build another elevator designed for Martian conditions, and send it to Mars.
5: With elevators on both ends enabling missions measured in tonnage rather than grammage, most of the other engineering challenges to a manned Mars mission (or to anywhere else in the Solar System) become much simpler.
I’m optimistic that all of this might happen in my lifetime. But I’ll probably be a very old man.
There is a realistic alternative to the Hohmann transfer thatis much more flexible in terms of launch windows and uses a lot less fuel (a major consideration when moving thousands of tons of meat-support hardware). It is, as you probably know, called Ballistic Capture, where the vehicle is sent out beyond the target and drops down to it, greatly reducing the braking requirement. Of course, it also significantly increases transit time, which would be fine for the separate freight vessels but might be too costly for the crew.
Which is one issue, but another, huge, problem has constantly been glossed over by advocates and given almost no attention by others: psychology. If you have a crew of 10 (a lot, but the mission should pad for likely losses), you certainly cannot hope to guarantee the mental/emotional stability of all of them. Nobody has a really handle on how a very long mission millions of miles into the dark, with no abort option, would affect the crews’ minds, and one person going crazy could realistically imperil the entire mission. The only way to find out is to do it, which would be quite the expensive gamble.
Theoretically, a million or so candidates would have to be trained from age two or three in the sciences, nav/aeronautics, astronomy (might as well use the trip for some high-quality space study) and in ways to avoid killing each other while cooped up in the Mars bus/RV for months on end. Perhaps they could also learn some kind of arcane meditation technique for lowering their metabolism during slack hours/days. Whatever the case, a mission simply could not leave until we have nearly absolute certainty that the humans will be assets more than liabilities.
I expect to stick around until about mid-century.
I don’t expect to see humans go to Mars and return to Earth in my lifetime.
it mostly comes down to politics.
if trump offers to go, dems will fund the mission privately and build the missile-- i mean the “spacecraft.” its 2019 so… sometime in the next 300 days or so.
im kidding, obviously. they would just raise taxes about 300% to fund it.
Having studied this problem as a PhD candidate, let me offer an engineering perspective*. I believe there are numerous technological hurdles that need to be crossed over before anyone (Chinese, USA, EU) could contemplate a manned mission to Mars. I will keep this list short.
*Inspiration: There was an episode in “From the Earth to the Moon” where a manager (Chris Kraft, in the show but probably not Real Life) who explained to the audience the various technologies that were planned to be demonstrated, step by step, in future missions to pave the way to the moon. My list here is similar.
-
Demonstrate the ability to land a vehicle on Mars that has the ability to take off and fly to Martian orbit. Never been done. The current Mars sample return mission architecture involves such a capability. (The mission is in three parts, part 1 is gathering scientifically valuable samples, which will be collected by the 2020 lander / rover, currently called Perseverance, IIRC.)
-
Demonstrate the ability to process the Martian atmosphere into fuel, i.e. In-situ resource utilization (ISRU) on Mars. This has been done on Earth but not yet where it’s needed, to refuel a human-capable ship. These ideas were nicely summarized by Dr. Zubrin in “The case for Mars” 25 years ago, and used in the fictional book and movie “The Martian.”
-
Human spaceflight problems:
a. Demonstrate ability to keep astronauts safe from the higher levels of radiation encountered during the trips to and from Mars, and on Mars.
b. Demonstrate ability for humans to live together without going nuts, cooped up inside a small spacecraft and Martian habitat for months. The best case for flying to and from mars involves a 6-month journey one-way, and a long minimum stay on Mars (18 mo. IIRC) -
Demonstrate the ability to land a large vehicle, capable of carrying astronauts, on Mars. This has long been a problem. However, SpaceX’s experiences with propulsive landing of large boosters (and current successes with their “Starship”) may successfully solve this problem. Trouble is, after landing they will be out of fuel. So they will need functioning ISRU system to refuel so they can come home (see point 2).
-
Demonstrate a very large number of deep-space planetary habitat and spacesuit (PLSS etc.) technologies. There is a lot of research that has to happen. Trying out such research on the moon may be a great way to go, so I support returning to the moon as a precursor to going to Mars.
I can’t say we’ll go or not go to Mars eventually. Who knows, humanity might become inspired one way or the other. Please watch the above list; to the extent that these are being checked off, you’ll be able to rate humanity’s readiness to actually go should the need or desire arise.
There has been no significant technological change since this thread was started. Chronos very clearly described the process in two parts in a post above. The first part is nowhere close to fruition and because of mundane considerations is less likely to occur now than a year and half ago.
Hi TriPolar,
Seeing that many people seem to have made up their minds based on the posts above (esp. Stranger’s), I wanted to put forth a simple list of obvious hurdles that we could all use to gauge progress. The list is intended to be politically and technologically agnostic (i.e. no discussion of what kind of rocket engines are required or their costs).
And, it seems to me that we are actually making progress on a couple of the points. Mars sample return? Yeah, step 1 has been committed to. I actually lost my academic advisor who went back to JPL to manage the Perseverance rover mission. Then, look at SpaceX’s Starship tests. So the progress continues.
I am not sure about others but Elon Musk will definitely reach Mars and if not for colonization purposes, at least to implement his desire to be buried on Mars.
Does he want to be:
Buried in the Martian soil?
Fireball in re-entry? (Is Mars’ atmosphere thick enough for that?)
Ashes scattered in orbit?
Something else?
NASA is on it (well, for 45 days, anyway):
Nice, thanks Elendil!
Turns out we have all had to participate in this isolation simulation ourselves this past year thanks to Covid. My family has survived, sane and reasonably well adjusted, but my productivity has dropped to minimum levels. With the recent trend of sub-freezing ice, snow and other “deep space” conditions limiting our EVA opportunities, it isn’t getting any better. 
Houston, we all have a problem.