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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 desi

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.

okokwhatever 3y ago
Interesting. Do you think private exploration solves this problems?
- Shinmon 3y ago
  Not sure to be honest. 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.
- stetrain 3y ago
  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.
  - BurningFrog 3y ago
    The point of competition is that if 10 deeply flawed organizations take a crack at a problem, they won't all produce garbage.
    - sdenton4 3y ago
      Or! They all produce garbage as they chip away at costs, and make bank telling people what they want to hear. The incentives are all wrong.
    - Shinmon 3y ago
      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.
    - stetrain 3y ago
      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.
sgt101 3y ago
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?
- throwup238 3y ago
  They’ve been calibrated on Earth for use on Earth.
  - czbond 3y ago
    Oh interesting - so Earth calibrated systems expect... a specific density for display of signals?
    - throwup238 3y ago
      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.
      - neom 3y ago
        Are you insinuating that NASA sent an incorrectly calibrated device? I know NASA has its flaws but this seems like a stretch no?
        koheripbal 3y ago
        I think he means it would need to be calibrated on Mars as the exact ground density and composition isnt known from earth
        throwup238 3y ago
        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.

okokwhatever 3y ago

Interesting. Do you think private exploration solves this problems?

Shinmon 3y ago
Not sure to be honest. 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.
stetrain 3y ago
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.
- BurningFrog 3y ago
  The point of competition is that if 10 deeply flawed organizations take a crack at a problem, they won't all produce garbage.
  - sdenton4 3y ago
    Or! They all produce garbage as they chip away at costs, and make bank telling people what they want to hear. The incentives are all wrong.
  - Shinmon 3y ago
    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.
  - stetrain 3y ago
    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.

sgt101 3y ago

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?

throwup238 3y ago
They’ve been calibrated on Earth for use on Earth.
- czbond 3y ago
  Oh interesting - so Earth calibrated systems expect... a specific density for display of signals?
  - throwup238 3y ago
    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.
    - neom 3y ago
      Are you insinuating that NASA sent an incorrectly calibrated device? I know NASA has its flaws but this seems like a stretch no?
      - koheripbal 3y ago
        I think he means it would need to be calibrated on Mars as the exact ground density and composition isnt known from earth
        throwup238 3y ago
        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.