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#180
by
whitelancer64
on 28 Oct, 2019 13:40
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#181
by
whitelancer64
on 28 Oct, 2019 15:59
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New DLR blog post - apparently the mole came out of the hole with only a few tens of hammer strokes!!
Bold emphasis is mine.
Logbook entry 28 October 2019
More surprises on Mars! Unfortunately, we saw that the Mole had backed-out of the Martian soil instead of going deeper as we had expected. How could that happen? After all, this Mole does not have a reverse gear as the Mole that DLR built for the ill-fated European Beagle II lander had. (That probe was designed as a sampling device that would go down and then come up again with a sample.)
But we have seen the phenomenon of backing-up before: in the lab at small atmospheric pressure such as on Mars. Remember, the Martian atmospheric pressure is only 0.6 percent of the Earth’s! At Earth’s atmospheric pressure, if the Mole starts to rebound and if the rebound is not compensated by friction on the wall, the Mole rapidly opens a cavity below the tip of the Mole. The difference in pressure in the expanding cavity and in the atmosphere creates a suction effect that helps damping the rebound. The atmospheric pressure on Mars, however, is so small that the suction effect does not play a role and cannot really help the Mole. This is another reason why the friction on the Mole hull is so important! It is the major force to balance the recoil! In addition to the recoil you need some collapsing of the borehole at the tip in order to let the Mole move up.
When we analyzed the images from the previous hammering, we had an indication that the Mole´s forward motion had slowed down towards the end of that session. Therefore, we played it safe by commanding a smaller than originally planned number of hammer strokes and then a readjust of the pushing of the arm and scoop on the soil.
I, for one, would have never thought that the Mole could back out as much during a few tens of hammer strokes. Maybe, if we were out of luck, it would not penetrate or possibly come up a bit. Well, operating on Mars is not only time consuming. It is full of surprises! The interactions of low atmospheric pressure, low gravity, unknown regolith mechanical properties and Mole dynamics are a challenge.
What to do next? First, we want to be sure that the Mole will not tip over. Then, we want to inspect the hole it is sitting in, the view of which is blocked by the scoop. We may then do another pinning trying to bring the Mole back to where it was before the recent hammering. And start again to get it to dig below the surface. But give us some time to think!
Stay tuned, it is not at all over, but the Mole is not making our lives easier these days! It is good that we have such a great team from JPL and DLR working on the problem. And it is great that NASA and DLR continue to support us. After all, our goal is to eventually go much deeper!
https://www.dlr.de/blogs/en/desktopdefault.aspx/tabid-5893/9577_read-1090/
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#182
by
whitelancer64
on 21 Nov, 2019 23:04
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Good news! The mole is moving downwards again. Same method that worked before, pressing the scoop against the side of the mole.
My mole is on the move again and back to digging. Using my arm to put pressure on the mole from the side has helped it move down ~1.25 inches (~32 millimeters). My @NASAJPL & @DLR_en team’s efforts to #SaveTheMole continue.
https://twitter.com/NASAInSight/status/1197594417667772416
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#183
by
theinternetftw
on 08 Dec, 2019 21:28
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After a ~11 sol pause from the above 11/21 dig, the mole dug today.
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#184
by
harrystranger
on 15 Dec, 2019 07:33
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Some more movement from Sol 373
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#185
by
Rondaz
on 18 Dec, 2019 14:37
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#186
by
eeergo
on 23 Dec, 2019 13:27
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#187
by
redliox
on 23 Dec, 2019 14:19
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https://twitter.com/landru79/status/1208823799661154306
Small backwards bounce at the end, and return to deepest position immediately thereafter. Seems to be approximately at the same point it was before the "big bounce out" - so the next few sols should be interesting.
Could that imply the mole has momentum issues? If they keep a slow pace the bouncing could be minimized. Perhaps on Earth gravity stops this effect but on Mars it's weak enough that the mole bounces more easily.
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#188
by
russianhalo117
on 23 Dec, 2019 18:07
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https://twitter.com/landru79/status/1208823799661154306
Small backwards bounce at the end, and return to deepest position immediately thereafter. Seems to be approximately at the same point it was before the "big bounce out" - so the next few sols should be interesting.
Could that imply the mole has momentum issues? If they keep a slow pace the bouncing could be minimized. Perhaps on Earth gravity stops this effect but on Mars it's weak enough that the mole bounces more easily.
IMO, We don't know if it's lose soil or solid rock under it. Also this is an updates thread so we all need to find the discussion thread.
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#189
by
redliox
on 24 Dec, 2019 21:48
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Looks like the mole still has the 'hiccups'.
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#190
by
edzieba
on 30 Dec, 2019 07:29
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DLR blog updated!
Current working theory is that below the upper soil surface there is a layer of very low friction sand. When the mole penetrates this sand and without any pressure pinning it down, each 'bounce' of the mole is followed by sand flowing into the hollow vacated beneath the mole.
Options for future advancement include pushing directly down on the backcap with the scoop (rather than the current lateral pinning, which risks impacting the tether is the scoop slips and moves sideways across the cap), the previously attempted technique of compressing the soil next to the mole but with the mole starting from a deeper position, and filling in the pit around and over the mole.
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#191
by
falcon19
on 20 Jan, 2020 15:20
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The mole backed out a little again. Must be very frustrating for the operations and science team.
https://twitter.com/landru79/status/1219276913740603392... for contributing something to the fiasco last night ... ... from 380 to 407 with the IDC aligned to the pebble below the edge inf. from the shovel ... removing the disparate hours ... Sol 380-407: Instrument Deployment Camera (IDC)
NASA 's InSight Mars lander
zubenelgenubi: Fixed your quote code and added Google translation of text to English, hashtags removed.
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#192
by
Star One
on 25 Feb, 2020 11:16
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Things go bump on Mars on a fairly regular basis. That's the conclusion of a year of listening for quake signals on the planet by the InSight lander.
The US space agency-led probe has detected over 450 significant seismic events since touching down in 2018.
None are particularly big - at most, they're only 3 to 4 on the magnitude scale, which you might feel if you were standing directly above the tremors.
The quakes' size and frequency is actually not that dissimilar to the UK.
https://www.bbc.co.uk/news/science-environment-51616830
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#193
by
edzieba
on 25 Feb, 2020 15:57
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#194
by
eeergo
on 27 Feb, 2020 07:56
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#195
by
edzieba
on 05 Jun, 2020 16:06
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New DLR blog post with details of the pushing operations and a very nice gif of the pressing operation including arm-retract cycles. The gif is only set to loop once, so you may need to refresh the page to get it to play.
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#196
by
theinternetftw
on 09 Jun, 2020 05:17
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A link to a looping version of that full dig sequence gif, made a video as it's so large:
https://streamable.com/a3whzhThe video file itself is attached just below for posterity.
Also attaching the latest dig gif. The scoop is now clearly pushing against dirt.
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#197
by
Star One
on 09 Jun, 2020 16:55
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New DLR blog post with details of the pushing operations and a very nice gif of the pressing operation including arm-retract cycles. The gif is only set to loop once, so you may need to refresh the page to get it to play.
Just a warning to people that website doesn’t format properly on mobiles, well on my iPhone all the text was squashed over to one side of the screen.
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#198
by
theinternetftw
on 14 Jun, 2020 21:53
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With this week's dig, the scoop has now driven down enough to hit the hard crust. Once it did that, the mole continued to dig for a few more drives. Based on the ribbon cable, it seems to lose traction at first, but then regain it just before the dig stops.
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#199
by
redliox
on 16 Jun, 2020 04:23
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With this week's dig, the scoop has now driven down enough to hit the hard crust. Once it did that, the mole continued to dig for a few more drives. Based on the ribbon cable, it seems to lose traction at first, but then regain it just before the dig stops.
Does this mean it might finally have begun to crack through the duracrust and hit a sweet spot of soil it was designed to handle?