I have worked on algorithms and system analysis in very similar projects and it's highly doubtful that these results are worth anything.
The radar sounder design and the numerical studies are flawed due to the used simulation methods. Numerical simulations are computationally expensive (in time and in space). Therefore many approximations are made (e.g. no real antenna pattern, no influence of the rover, thin slices of ground that is being simulated and than put together, ...)
Reading such radargrams is like reading tea leaves. I am pretty sure that most of the echos in the radargram are surface clutter from bigger rocks or hilly areas in the distance. In one of our simulation works for a very similar project we have actually shown that this has a heavy influence on the radargram and is never considered in any of the works analyzing the results from Mars (or any other space object).
These projects are extremely political even though they shouldn't be. Groups that have had instruments on previous missions will be part of the next mission, too, because they have flown instruments already. So, any study or inclination that the instrument as it is does not work is buried quickly and often unknown to many of the people in the science teams, too.
I know, it's quite cynic but it's my experience and I know that I am not the only one feeling that way. So, while the rover and the measurements themselves are impressive, the analysis is wonky at best.
This surprises me, I have seen ground penetrating radar results that have shown buried items which have then been dug up, why is this result different?
What does it matter if it's calibrated on earth? If the problem is the antenna pattern, influence of the rover itself, etc, why can't it be calibrated with the exact duplicate of the rover we have?
Radio waves propagate at different speeds through different mediums so the GPR gain and time window have to be calibrated for each soil type and other environmental factors like how wet the ground is. Once calibrated, then any deviations become interesting. Otherwise it’s just a bunch of sensor noise.
Correct. The easiest way to calibrate a GPR is to stick a metal plate in the ground and cover it with a few feet of earth dug up on location. Can’t do that with some awkward rovers and an experimental helicopter.
NASA can do some fancy signal processing to get some useful data but until its properly calibrated, any interpretation of that data especially visual should be taken with a Phobos sized grain of salt.
I still don't understand. Even if you are off about density, aren't you studying the differences in density, so that the image you generate would still be showing where those differences are located relative to each other -- even if scale might be somewhat off if you have your base density off? It doesn't seem like it would be abject failure, but more like incrementally less useful. It sounds like you are saying it is almost at abject failure on the scale of usefulness.
Yes and no. The radar isn’t only looking down into the ground. The antenna pattern has side lobes which can potentially generate large echos in the radargram, e.g. from rocks on the surface etc. you only know that there is something in some distance (or rather time delay).
The useful signal is extremely weak anyway and the clutter from the surface hides the useful signal in many cases unless you habe really strong scatterers (large and highly reflective) buried in the ground.
Plenty of commercial GPR devices operate on Earth just fine with the explicit goal to detect changes in the subsurface's dielectric properties. It doesn't matter if you're on Mars or here, GPR works in the same way and I'm pretty sure that the antenna and the signal processing has been designed for the purpose, possibly even more meticulously than the antennas of commercial GPR pushcarts. Your comment makes something simple sound highly involved and problematic.
Your understanding is correct. It's about detecting variations in dielectric properties across layer interfaces. GPR works just fine for that, whether here or on Mars. The other commenter's negativity and theorized worries about side lobes and reflectors are unwarranted.
NASA isn't doing anything here but providing the platform for the instrument.I mean, that's a lot but they are not the one in charge of running the instrument. The science teams are. GPR is a complex topic and *maybe* these signals contain the information that they think they do, but it's unlikely in my opinion.
I think the main problem of the current setup is that the science teams are not balanced enough.
The radar sounding science team is mostly geophysicists because the interpretations are geophysical in nature, but there are not enough people who are experts in radar sounding, radar system and radio frequency wave propagation in general. The reason for that is, that this is not considered science and is looked down upon as mere "engineering".
Privatized exploration would initially solve some of these problems for sure, but once a group of people and its structure has manifested I believe they would eventually suffer from the same problem.
Anyway, this is a pretty complex topic which covers many aspects such as research funding, incentives in academia, vain egos, etc.
The public sector doesn't have a monopoly on internal politics. Posturing between departments to be included in the next big initiative happens in lots of companies.
That's not guaranteed. Really it's a question of incentive structure more than public vs private.
For example there are cases I can point to of poor competition and high costs in NASA picking private companies to do big cost-plus development contracts, and cases where they did fixed-price contract bidding among a larger pool of competitors and got much better results.
While that might be true the costs of going up there are so high that there won't be 10 companies who get a crack at it.
Besides, the radar isn't the only instrument on the rover. There aren't many companies/groups in the world who have the know-how and financial means to do what NASA does here.
Apparently using the mars orbiter as a relay they can get up to 30Mbps. I couldn't find out what the transmission rate for lander -> orbiter is though. However lander direct to earth is in the Kbps on a good day.
The scale of systems to set up there for humans to stay for weeks is mind-blowing compared to the robots currently there: it's likely not before tens of years. Even doing so on the moon is years away. Sending robots with more science equipments seems more likely in our lifetime.
Would humans there be more efficient than robots to solve this question? not very likely: humans would need more tools to perform the same research.
Yes it is. You "just" need more backup systems as indeed, you cannot just come inside to get what you forgot, or replace what just broke or go sleep inside, if it turns out too cold outside. That is for sure and that is why I would start with the moon. To test more all of the equipment. And then test a little more. And then do some more testing.
Sure - but this was about the difficulties of a habitat on mars vs habitat in space. And for some reason, there were many, one can allmost say fanatics, who volunteered for the scam called Mars One, taking a one way ticket with the knowledge that they would die, if something goes wrong.
Energy is another increased problem. You need a lot more solar panels, and likely batteries, to supply the same energy as you get in lunar orbit. At least one order of magnitude more mass.
That is a valid point (in space there is always sun), but the Mars day is just 37 minutes longer than on earth, so it is a fixed problem that can be handled with just more needed basic material. Nothing fancy, or complicated though.
Yes, though there is way less atmosphere in the way. The result is still half of earth, so not great, but something to work with. (But personally I would go with a nuclear reactor for the main base)
I'm not sure I understand this whole contamination argument. There are so many ways to find signs of life, it could be a fossil, it could be frozen in ice deep underground it could be evidence of non-Earth compatible biology.
Sure, once humans are there we should check every alien life discovery with unprecedented rigour, but there could be evidence which can't be explained with "humans brought it with them" type of reasoning.
I guess we have different notions of what the horizon is. For me is "in my lifetime". To put it in context: I watched the first Moon landing on TV as a child, so I'm used to wait.
If you are old enough to have watched the moon landings on TV, my bet is that we will not see a manned mars mission in your lifetime. (I have my doubts it will happen in the next 40 years.)
It's funny how much things change over a decade, yet it never feels like anything is happening on a day by day, or even year by year basis. Just imagine going back 10 years in time and trying to describe to yourself what the next 10 years holds. You'd probably think yourself crazy! But to the point, in 2011 the US passed a law banning China from participating in the not-so-international ISS. The arguments given were that China had nothing to offer, and implicitly - that they'd just steal everything. Today, just slightly more than a decade later - they have one of the most advanced space programs on the planet, have built, launched, and manned their own space station, executed sample return missions from the Moon (the first since 1976!), and more.
What would you have thought the odds of that in 2011? And all of these things are the sort of stuff that is happening in just a decade. The world is changing extremely quickly (even if it often doesn't feel like it), and space tech is one of the fastest advancing industries right now. I think the best window into the future is the past. Look at the trajectory we're on, not necessarily just the US - but the whole world. It's a good one, at least as far as space goes.
> The country is now due to launch Tiangong-1, the first module of its own space station, possibly before the end of September this year. This will dock with an unmanned spaceship, Shenzhou-8, in China's first ever in-orbit docking attempt. Next year, two or three astronauts will be sent into space for the first manned docking.
> Beijing hopes to put a rover on the moon by 2013, and then a man on the moon, as well as opening its own space station by around 2020. But its ambitions could be greater still than those being publicly announced.
> "What we have seen again in reporting, as opposed to official documents, seems to be a group of Skylab-type Tiangong stations to be followed by a Chinese version of the International Space Station, which would suggest that China is aiming for a long-term human presence in [inner] Earth orbit," says Dean Cheng, an expert in China's space program at the Heritage Foundation. "Given past Chinese history — which is that their missions always last longer, weigh more, achieve more [than U.S. missions] — it is quite likely that the Chinese would try to set up some kind of longer-term presence on the moon, measured in weeks or maybe months."
You all are focusing on labeling the time to humans in Mars. But how about the time to completely discard that life exists now in Mars? How much time would it take to design, build and send a mission of this nature?
I watched the moon landings as a child. I don't expect to see humans set foot on the moon again in my lifetime. I do however expect to see opportunists suckling on the fatted pork barrel here on earth up until my expiry date. Mars is a realistically unobtainable goal but certainly a lot of people will be gainfully employed not getting there.
Why? I can understand the pessimism about bigger goals (like colonizing Mars), even I may not agree with it, but a man on the Moon? Even if one thinks the entire US Public system is dysfunctional, SpaceX is actively pursuing such a goal and advancing space tech at a rate faster than any time in our history, excepting perhaps that magical ~1959-1969 window.
And even if you have doubts about private industry, then there's China. They have all the motivation, capability, risk tolerance, funding, and more necessary. They have the stated goal of putting astronauts on the Moon by 2030, and there's no reason to think they won't succeed. They've been nailing their space goals in both terms of success and timeline. And if we look a bit more optimistically there are all sorts of third parties that would like to get back in the game, or newcomers looking to find their own place in it.
There will be people on the Moon within the next 10 years. Both Chinese and American.
Sending humans to Mars is completely doable with chemical rockets. Just a matter of investing enough money. If SpaceX is successful with further development of Starship they can very likely send people to Mars by 2040.
I don't think it's a very common understanding that on the horizon covers a span of 50+ years. It doesn't conform to any definitions I can think of, I'd hate to wait for a payrise that's "on the horizon" in your world.
There aren't any manned missions to Mars on the horizon. Returning to the Moon possibly to stay is on the horizon for the next decade or so, with concrete plans taking shape and launch capabilities either there or nearly there.
I think we'll see what amounts to McMurdo on the Moon long before we see humans on Mars, and it really makes the most sense because the Moon is only a few days away vs. months away. If something goes wrong on the Moon supplies can be sent or people can come home quickly, whereas on Mars a major failure or health problem equals almost certain death with no hope of rescue or return in time.
The Moon makes more sense economically too. It's close enough for mining and/or tourism to at least offset the cost a little.
Elon's fixation on Mars or bust is kind of irrational and monomaniacal.
I would readily bet against that. It is unclear if humans can be delivered to Mars in good enough condition to do meaningful exploration where a human presence would make a difference.
Shorter-term, it is unclear if Starship is the right rocket for any purpose due to being spec'ed for such a wide range of purposes, and incompletely spec'ed due to faith in an iterative development process that may be totally inappropriate for developing large complex systems.
It is conceivable that a Moon station could be built and manned for a relatively small multiple of the cost of the ISS. It is conceivable such a station could be evacuated in the event of a serious failure. It is conceivable that humanity will learn interesting things about the Moon and perhaps do astronomy that would be otherwise impractical.
Landing humans on Mars and not killing them would be the highest accomplishment of sending humans to Mars. Some things will have to wait for post-humans to be created, if that ever turns out to be a good idea.
You can get carried on a stretcher after a year on ISS. You're on your own when you get to Mars. The trip back won't be easier. It might be survivable. But is it ethical?
The trip to Mars doesn't take a year, even unmanned probes that take low energy trajectories make it in around 200 days. And Mars has less than half the gravity of Earth, so you wouldn't be as crippled as here.
All these objections are very reasonable, providing you accept some premises. One of them is the scale of current ships stays the same. But that isn't some fact of nature, it's just a political/economical circumstance that could change very fast, given the proper incentives.
Tangent: but in my layman understanding of all this, is it possible that we’re actually cross contaminating Mars with tiny amounts of earthly life?
I know the travel and radiation probably makes it unlikely but also seems plausible to me a few specks of mold spores or DNA fragments could survive and be preserved in the cold of space/mars. Is it possible that in billions of years, when the sun has warmed and/or pulled mars closer, this seeds another earth-like evolution of life? It all seems improbable but nothing surprises me in space.
Probes intended to land on other planets are sterilized, I believe, to try to avoid such contamination. It's a long shot that such contamination is possible, and the sterilization probably isn't perfect, but there's a general consensus that it's probably not impossible, and hey, it'd be pretty dumb to at least not like wipe down the probe before shooting it into space.
A probably dumb question: why don't these missions carry a microscope instrument and a drill? We know there is sub-surface ice or water (brine) at some locations. Bring some up and look at it.
I ask because there's a minor conspiracy theory that's made the rounds that NASA either has these things on board secretly or deliberately does not include them because they don't want to actually find evidence of life. I find that pretty unlikely and figure it's probably a lot harder to build such an instrument and get useful results than you'd think.
Using a drill on another planet where any jam or failure is permanent is staggeringly hard.
A robot can't just chuck up a bit, or wipe down dust and dirt which is stopping something from working. Or quickly regrease a bearing.
Ultimately one of the best arguments on favor of manned exploration is that despite our robotics, a human in a space suit with a shovel would get an incredible amount done in a few hours.
EDIT: drills have flown, but they are limited in capability.
Not an astrobiologist, but am a microbiologist.
IMO microscopes wouldn't be very definitive. I'd suspect they have some magnification capabilities to some extent, even for geology analysis,
For microbial life, getting chemical signatures would be much more valuable. They appear to have a mass spec. GC and laser spectrometer suite that can do some of that usefully. https://mars.nasa.gov/msl/spacecraft/instruments/sam/
IMO, the idea of NASA sandbagging on finding life is silly. It's like Pharma hiding the cure for cancer. there are real people in those organizations and that type of insanity wouldn't stay secret for long. (note to anyone replying I will not discuss/argue this stuff on this board, as it won't go anywhere productively.)
We're not even sure there's no life on the moon. There could be liquid water in deep underground lakes and there would be no sign of it on the surface.
The radar sounder design and the numerical studies are flawed due to the used simulation methods. Numerical simulations are computationally expensive (in time and in space). Therefore many approximations are made (e.g. no real antenna pattern, no influence of the rover, thin slices of ground that is being simulated and than put together, ...)
Reading such radargrams is like reading tea leaves. I am pretty sure that most of the echos in the radargram are surface clutter from bigger rocks or hilly areas in the distance. In one of our simulation works for a very similar project we have actually shown that this has a heavy influence on the radargram and is never considered in any of the works analyzing the results from Mars (or any other space object).
These projects are extremely political even though they shouldn't be. Groups that have had instruments on previous missions will be part of the next mission, too, because they have flown instruments already. So, any study or inclination that the instrument as it is does not work is buried quickly and often unknown to many of the people in the science teams, too.
I know, it's quite cynic but it's my experience and I know that I am not the only one feeling that way. So, while the rover and the measurements themselves are impressive, the analysis is wonky at best.