InSight Surface Operations, 26 Nov 2018- 21 Dec 2022 Options

[Explorer1]

I found a very detailed summary of deployment procedure/timeline here: https://www.nasaspaceflight.com/2018/11/ins...cience-mission/

[monitorlizard]

Just a quick thought about the Insight payload. If the spacecraft did indeed land on a sand sheet or filled crater, it might be a problem for the seismometer. Any thickness of sand would, if I understand seismometers correctly, cause seismic signals to be dissipated before they reach the instrument. Sand, being much less compacted than rock, would not conduct a seismic signal nearly as well. Even soil should conduct better. I would love to be proven wrong. Alternate opinions welcomed.

[MahFL]

Just a quick thought about the Insight payload. If the spacecraft did indeed land on a sand sheet or filled crater, it might be a problem for the seismometer. Any thickness of sand would, if I understand seismometers correctly, cause seismic signals to be dissipated before they reach the instrument. Sand, being much less compacted than rock, would not conduct a seismic signal nearly as well. Even soil should conduct better. I would love to be proven wrong. Alternate opinions welcomed.

It's super sensitive, it can detect half the movement made by the vibration of a hydrogen atom. If something bangs into Mars, it'll detect it.

[PaulH51]

Does anyone know if they have an official mission clock for InSight? Similar to the one we have for Curiosity link that shows the sol and current solar time.

[nprev]

Per the Science article I posted earlier, the team does not seem to be concerned about that; quite the opposite, in fact. I'd guess that level, stable placement is much more critical, and that they are able to compensate for any attenuation that might be induced by a few meters of sand (if there's that much.)

Also provides good digging for the mole, which could help refine their understanding of the sand's properties to further refine their seismic compensation model.

[MahFL]

Does anyone know if they have an official mission clock for InSight? Similar to the one we have for Curiosity link that shows the sol and current solar time.

https://mars.nasa.gov/insight/

[HSchirmer]

Per the Science article I posted earlier, the team does not seem to be concerned about that; quite the opposite, in fact. I'd guess that level, stable placement is much more critical, and that they are able to compensate for any attenuation that might be induced by a few meters of sand (if there's that much.)

Also provides good digging for the mole, which could help refine their understanding of the sand's properties to further refine their seismic compensation model.

Agreed on the mole, guesstimate is about 3 meters of sand, probe has around 5 meters of tether, so they're good for getting to bedrock.
https://mars.nasa.gov/insight/spacecraft/instruments/seis/

Just a quick thought about the Insight payload. If the spacecraft did indeed land on a sand sheet or filled crater, it might be a problem for the seismometer. Any thickness of sand would, if I understand seismometers correctly, cause seismic signals to be dissipated before they reach the instrument. Sand, being much less compacted than rock, would not conduct a seismic signal nearly as well. Even soil should conduct better. I would love to be proven wrong. Alternate opinions welcomed.

If the sand were recent uncompacted dunes like you get on Earth seashore, that might be a problem.
Most dunes on Mars are suspected to be ancient, so the sand is likely filled in with fine dust.
The landing area is on the slope between the highlands and the lowlands,

Check out Figure #9 about possible sediment transport at the Highlands/Lowlands border
http://oro.open.ac.uk/56400/1/The%20Hypani...rly%20Mars_.pdf

if the lowlands were oceans, then mudflats, there ought to be a range of sediment paricle sizes, which bodes well for seismic transmission.

[SpaceListener]

Just a quick thought about the Insight payload. ... Alternate opinions welcomed.

The seismometer is based on electronic components and it doesn't need to be laid on firm land or on a rock. It is like to ASLEP from Apollo missions from 12 to 17 which were laid on the moon's regolith.

[tanjent]

What about the insulating effect of sand on heat flow? Ideally, wouldn't both the seismometer and the heat probe prefer not to be insulated from the bedrock by something porous and absorbent, like a layer of sand? The instruments may have been designed to see through a certain amount of softer material, but I don't see how it can fail to have some muffling effect.

We may hope that the ease-of-placement benefits of the sandy terrain can outweigh the sensitivity costs.

[HSchirmer]

wouldn't both the seismometer and the heat probe prefer not to be insulated from the bedrock by something porous and absorbent, like a layer of sand?

As I understand it, Seis (seismometer) and Hp3 (heat probe) are optimal in opposite situations, but are both workable in the expected middle ground that insight actually got.

The seismometer is designed to be supremely sensitive
https://www.seis-insight.eu/en/public-2/sei...trument/summary
Seems like that experiment wants no regolith to get best vibration, but they're confident that
they can work with regolith.

The heat probe is designed to burrow through up to 5 meters of regolith, then (perhaps) hits bedrock.
https://www.seis-insight.eu/en/public-2/the...her-instruments
That experiment WANTS a deep regolith to get heat flow numbers.

[tanjent]

Thanks!
Those are great articles - they really clarify a lot of issues I had been wondering about!

[7B8]

The PI did say small rocks would be pushed aside by the Mole, but if it hit a big flat rock then that was as far as they could go, it won't go upwards. It's all about risk.

In that context, I found this publication helpful (https://elib.dlr.de/121308/1/Spohn_et_al-20...nce_Reviews.pdf). I also wondered how well the mole would cope with any buried rocks.

They say:

If the Mole encounters a rock larger than a few 10s of cm as it moves forward, it could be blocked from further advancement. The likelihood of such an encounter between the surface and the required (3 m) or target (5 m) depths
has been calculated to be 43% and 59%, respectively. This estimate uses the most pessimistic models, [...]

If less conservative assumptions are made about surface rock abundance (e.g., 2.5% or less) and demonstrated capabilities of the Mole are allowed for (e.g., the Mole can push rocks up to 15 cm out of its way within the regolith, and can also deflect around rocks encountered at angles ≤45 degrees), the probability of success increases to 98% and 90%, respectively.

[dmg]

Does anyone know if they have an official mission clock for InSight? Similar to the one we have for Curiosity link that shows the sol and current solar time.

I found and purchased ($0.99) the iPhone app "Mars-Clock" that has all this info. in detail for the current landed probes on Mars including InSight. It can be found on the app store -- be sure to look carefully as there are other similar apps available that (as of a few days ago) did not have info. for InSight. I'm not sure if there is anything on the web with this detailed info. or for other mobile platforms.

[HSchirmer]

QUOTE
If the Mole encounters a rock larger than a few 10s of cm as it moves forward, it could be blocked from further advancement. The likelihood of such an encounter between the surface and the required (3 m) or target (5 m) depths
has been calculated to be 43% and 59%, respectively. This estimate uses the most pessimistic models, ...

You know, after reading that, deploying the seismometer first and then moving the probe around as a "thumper" to create a 3d
map of the underground location of the big rocks you need to avoid, isn't such a crazy idea after all...

[Guest_Steve5304_*]

We have never drilled more than a scratch under the surface. This is completely uncharted territory. Will the material in the well get analyzed?

Exciting stuff