NASA Mars Perseverance Rover: Digging Into Drill Data:
You probably think that the drill being employed on Perseverance Rover is bound to be special, but do you know just how clever it is? The problem that the drill has to balance is getting maximum life from the drill bit itself while achieving the job of collecting samples of rock and sediment.
One of the first things we look at is how difficult it was for the drill to make progress through the rock. The rover has a rotary percussive drill, which means the drill bit pushes against the rock while spinning and hammering. When we are coring or abrading, an algorithm controls the amount of force and percussion. We call this algorithm "prodapt," short for proprioceptive adaptive, because the drill adjusts its settings by sensing and assessing its own performance in real-time. The goal is to try and maintain a certain rate of progress into the rock that isn't too slow or too fast. The rate we aim for keeps our drill bits healthy and creates high-quality cores and abrasions for the scientists.
The prodapt algorithm can range from level 0 to level 20. Levels 0 through 2 have no percussion at all, which we call rotary only drilling. (We never do rotary only abrading, so these low levels are only used while coring.) Level 3 has light percussion, and the percussion and force increase all the way up to the most force and the most percussion at level 20.
If the drill senses that it is not making fast enough progress through a rock, it will increase the prodapt level. If it senses that it is making progress too quickly, it will decrease the level. One note: although hard rocks often require higher levels, the interaction between the drill and the rock is complex, so prodapt level doesn't always match up with rock strength. A rock might require high drill levels but break easily if a different type of tool was used.
(Score: 0) by Anonymous Coward on Tuesday April 19 2022, @04:18AM
It is an interesting controls problem. I wonder how they calibrated and tested it.
(Score: 0) by Anonymous Coward on Tuesday April 19 2022, @06:30AM (5 children)
Automated equipment sent instead of persons multiplies, and I underline multiplies, the risk of failures.
Yes they keep telling sending men to mars is difficult. You know what is more difficult? the first russian lunar mission with automated equipment. in 1970.
Are we going to believe that russians and chinese care that much for the life of one astronaut to substitute them with robots, increasing the costs and the risk of failure? Lunokhod 1, rather successful, yet failed for undisclosed and possibly trivial reasons. Oh, little rock in wrong place on a wheel? your multibillion mission is over. Better luck next time.
There is no need to believe in a flat earth (what?) or in "we never went to the moon". Decades into the space program and man doesn't go past the van allen belt. Except for the 69 lunar mission of which we have a lot of photos of astronauts on the moon, like it was meant to prove astronauts have gone there rather then to actually explore the fucking moon. Interesting.
The easiest interpretation, we cannot go past van allen belt so we send probes.
The other possible interpretation, we don't want to show too much of what happens in space so we made an excuse, an impenetrable barrier and crafted all disinformation to pretend we cover up such barrier.
There is no way we spend resources sending robots instead of trained astronauts which risk life but solve all the little problems that even advanced robots can fall prey of.
(Score: 0) by Anonymous Coward on Tuesday April 19 2022, @11:55AM (4 children)
Going to Mars is a minimum 2.5 year round trip, including about 2 years on surface. The only difference between that and a permanent Mars base is crew rotation. That is a much harder problem than sending robots. We don't even know what the long term effects of partial gravity are, so we don't know for sure whether Mars is even survivable for two years or would cripple the crew. We have lots of data for 1g and 0g but nothing in between.
The idiotic part of the Mars Sample Return project is that they are dropping the samples along the way instead of keeping them with the rover for easy retrieval.
The reason the US hasn't gone beyond LEO since Apollo is entirely due to politics and greed. There is a bipartisan contingent in Congress that is violently opposed to non-pork spending and they have been actively sabotaging crewed spaceflight for fifty years. That's how disasters like SLS continue to happen.
Russia is out of the running because they are broke. Even before the war it was an open question if Roscosmos would last until 2024 when the current ISS agreement ends. After Rogozin's recent tantrums I don't expect them to survive the year.
China isn't sending crew to the Moon or Mars because they can't do it yet, but they are learning fast. Truth be told they are far more careful about their people's lives than the Russians ever were so they actually have a decent chance at succeeding. I fully expect them to militarize space in the name of 'protecting it from pirates' (aka Western private exploration and colonization efforts) as soon as they have a permanent presence. They've already started with the rhetoric.
(Score: 0) by Anonymous Coward on Tuesday April 19 2022, @03:25PM (3 children)
You're not the first to say this (but since you are AC, maybe you are the only one saying this and I can't tell), but where do you get this idea? The samples are being stored in a storage tray inside the rover. What happens after that depends upon the health of the rover. The rover will hold on to them until the TBD return mission comes for them, unless there is some other reason to drop them off early (rover issues), and then the sample tray would be deposited somewhere as a unit.
(Score: 0) by Anonymous Coward on Wednesday April 20 2022, @12:33AM (2 children)
I have posted this before, with links to NASA's own statements on the subject. Here's two.
https://mars.nasa.gov/resources/25005/mars-2020-perseverance-rover-sample-caching-system/ [nasa.gov]
https://www.jpl.nasa.gov/images/pia24497-perseverance-sample-caching-system-doors [nasa.gov]
Emphasis mine on both quotes.
Maybe I'm misreading. Believe me, I'd love to be wrong.
(Score: 0) by Anonymous Coward on Wednesday April 20 2022, @01:57AM (1 child)
They're not leaving them individually where they dug them, they are being stored in a tray in the rover. The part that is still TBD is where they are going to drop them. The Mars retrieval mission will fly a lander to pick them up, but they haven't figured out how they're going to do the handoff. I believe they want to keep them in the rover and have the rover deliver it, but if they think they might have some issue before the retrieval mission can come, then they'll drop the sample tray somewhere "safe." As far as I know, they're still working on the mission details for the retrieval mission, but regardless we're probably seven to ten years off from that taking place.
It's all just pretty concept web pages [nasa.gov] at this point.
(Score: 0) by Anonymous Coward on Wednesday April 20 2022, @04:01AM
I had understood that there would be multiple caches made as they went along, but I'm not finding the article that talked about it so I might be remembering wrong. Fair enough. I'll shut up about it. Cheers.