Mars Rover Perseverance Discussion Thread

[satnet]

I just ran across a good video by Anton Petrov with details about Ingenuity's first 4 flights and a few technical details about the helicopter itself.

Highlights:

• All primary objectives are completed (successfully).
• We have actual video of some of the flight maneuvers downloaded from Perseverence.
• They plan to use it as a scout for as long as it can keep up (they will only fly once a week or so, which I presume is the reason it will fall behind).
• Perseverance will now get the majority of time and effort.
• The 4th flight was a success, but did have another instance of the software glitch that they needed to workaround before the first flight.

 

[kerbiloid]

According to wiki, it has an RTG with 4.8 kg of Pu onboard.
Probably, with no protection.

What is the safe distance of it, or how long can stay a human close to it before they have to replace him with the next one?

I.e. is the thing on the photo an equivalent of Chernobyl tractor?

[JoeSchmuckatelli]

1 hour ago, kerbiloid said:

According to wiki, it has an RTG with 4.8 kg of Pu onboard.
Probably, with no protection.

What is the safe distance of it, or how long can stay a human close to it before they have to replace him with the next one?

I.e. is the thing on the photo an equivalent of Chernobyl tractor?

The Pu is on the Rover, right?  And the human should be in an Exo-Suit.  So...

Why does he need to poke at the Rover again?

[kerbiloid]

14 minutes ago, JoeSchmuckatelli said:

The Pu is on the Rover, right?  And the human should be in an Exo-Suit.  So...

Why does he need to poke at the Rover again?

I just mean that the peaceful and inspiring photos of the rover are probably, actually photos of the radioactive  piece of deadly wasteland.

[JoeSchmuckatelli]

52 minutes ago, kerbiloid said:

I just mean that the peaceful and inspiring photos of the rover are probably, actually photos of the radioactive  piece of deadly wasteland.

... Not sure - but my past reading tells me that the greatest risk from environmental exposure to radioactive materials happens if a person ingests or inhales the substance.  Otherwise, you're mostly at risk from being cooked - like standing too close to an unshielded microwave oven or radar dish.  The 'radiation causes mutation' during cell reproduction (read: cancer risk) turns out to be actually quite low from external sources.

So I'd think your intrepid traveler and Mars Rover fiddler would be at as much risk from sunlight unfiltered by atmosphere as she would from poking Percy with a screwdriver.

[YNM]

2 hours ago, kerbiloid said:

What is the safe distance of it, or how long can stay a human close to it before they have to replace him with the next one?

Given that I'm sure they had to install it on the rover manually before it was launched, probably pretty close unless the containment leaks.

[JoeSchmuckatelli]

@kerbiloid

 

Quote

 

...plutonium is primarily an alpha-emitter and so must enter the body in order to cause significant damage, we are concerned with the routes it takes into the body...

 

Three different types of epidemiological studies are conducted and used to determine plutonium health effects. Epidemiological studies of people who were exposed to plutonium are the most direct. Due to the fact that there have been relatively few human exposures to plutonium in Western countries, there are not many of these types of studies. Several studies have been conducted on US workers exposed to plutonium, namely at the Rocky Flats, Los Alamos and Mound facilities. However, none of these studies found significant elevated cancer rates. There have also been studies recently emerging about Mayak workers, in Russia. These studies have found significantly elevated lung cancer rates. The studies do, however, have some discrepancy in results. The study published by Koshurnikova et al. (1998) found a threshold for plutonium health effects or a minimum exposure value under which no relationship between exposure and cancer rates could be seen. Tokarshaya et al. (1997) found that there was no threshold, or that exposure to plutonium affected cancer rates at any level. (Generally, it is believed that there is no threshold for radiation health risks.

 

Microsoft Word - current 1 plutonium (clarku.edu)

 --- The exposures in the RU studies likely resulted from inhalation, rather than mere external exposure.  So unless your explorer pulls a "Chad" 

 

... she will be fine.

[cubinator]

I seem to recall seeing a video of a documentary host picking up and holding a large chunk of plutonium. He was wearing only gloves for PPE.

[Brotoro]

9 hours ago, kerbiloid said:

According to wiki, it has an RTG with 4.8 kg of Pu onboard.
Probably, with no protection.

What is the safe distance of it, or how long can stay a human close to it before they have to replace him with the next one?

I.e. is the thing on the photo an equivalent of Chernobyl tractor?

The Pu 238 decay chain has alpha and beta decays down to lead 206. Alpha and beta particles are easily shielded. On the surface of Mars, I would worry much more about radiation exposure due to cosmic rays, given the very thin atmosphere. To reduce my radiation exposure, I would sleep underneath the RTGs of the rover.

[Listy]

9 hours ago, kerbiloid said:

According to wiki, it has an RTG with 4.8 kg of Pu onboard.
Probably, with no protection.

What is the safe distance of it, or how long can stay a human close to it before they have to replace him with the next one?

I.e. is the thing on the photo an equivalent of Chernobyl tractor?

The RTG's NASA uses are quite well shielded by layers of iridium, graphite & ceramic to protect it in the event of a launch mishap. The one on Apollo 13 could not be deployed on the Moon & subsequently survived a very fast unplanned reentry & is now sitting intact at the bottom of the Pacific.

They put out a decent amount of heat, so curling up to an RTG might be a good way to stay warm on those cold cold Martian nights

[cubinator]

32 minutes ago, Listy said:

The one on Apollo 13 could not be deployed on the Moon & subsequently survived a very fast unplanned reentry & is now sitting intact at the bottom of the Pacific.

They put out a decent amount of heat, so curling up to an RTG might be a good way to stay warm on those cold cold Martian nights

You just have to wonder if some strange clump of algae has wrapped itself around that thing and managed to feed off of it during all these years.

[tater]

1 hour ago, Brotoro said:

The Pu 238 decay chain has alpha and beta decays down to lead 206. Alpha and beta particles are easily shielded. On the surface of Mars, I would worry much more about radiation exposure due to cosmic rays, given the very thin atmosphere. To reduce my radiation exposure, I would sleep underneath the RTGs of the rover.

Congratulations, you win the forum today!

[Listy]

23 hours ago, cubinator said:

You just have to wonder if some strange clump of algae has wrapped itself around that thing and managed to feed off of it during all these years.

Apparently someone at NASA did comment in the media at the time that the RTG would 'probably keep a few fish warm'.

[YNM]

On 5/19/2021 at 8:13 AM, cubinator said:

managed to feed off of it

Hydrothermal vents work due to the minerals that they also spew in addition to the heat energy. Unless plutonium is useful chemically (or any of the daughter isotopes) I don't see anything of the same sort.

[SpaceFace545]

How long do you guys figure Ingenuity’s service life will be, the motor will have to fail at some point.

[kerbiloid]

Quote

What is the lifetime of a drone?

150 hours, about the lifespan of the electric motors... Could last longer, but the risk of failure increases exponentially after this time. From what I've read about small brushless motors, they tend last a lot longer than 150 hours on average.

Not more than 150 h.

[SpaceFace545]

48 minutes ago, kerbiloid said:

Not more than 150 h.

Yikes, thats short but the flights are short so this should last a while. The most substantial risk would be if sand or a small rock got lodged in the motor or gears.

[tater]

1 minute ago, SpaceFace545 said:

Yikes, thats short but the flights are short so this should last a while. The most substantial risk would be if sand or a small rock got lodged in the motor or gears.

I think it has a battery life that only allows flights of ~2 minutes for a nominal flight. 150 hours is 4500 flights.

[cubinator]

3 hours ago, SpaceFace545 said:

How long do you guys figure Ingenuity’s service life will be, the motor will have to fail at some point.

I think the battery would be the more likely point of failure, in the cold.

[tater]

50 minutes ago, cubinator said:

I think the battery would be the more likely point of failure, in the cold.

Or landing. for use as a scout it needs to be able to move forward, scout, then land, all it would take is one bad landing, and poof.

[kerbiloid]

Spoiler

 

Edited May 25, 2021 by kerbiloid

[JacobCooper]

I  thought the copter's lifespan is more than 150 hours...However, judging by the duration of flights, Ingenuity will manage to do a lot of useful things before it stops wotking forever. 

[kerbiloid]

2 hours ago, JacobCooper said:

I  thought the copter's lifespan is more than 150 hours...

They explain that it's the average. Accurate flights may let it live longer. 
Though, unlikely on Mars.

Edited May 31, 2021 by kerbiloid

[Hannu2]

150 hours flight time is extremely overoptimistic. Electronic damage due to thermal cycling with low minimum, dust and wear in bearings or battery degradation is probable limits. Crashing due firmware error is also much more probable than motor damage (it was quite near already). Ingenuity's protection has not been done for months use. It will be good if it can do few scouting flights but I would not expect several months service life.

[SpaceFace545]

1 hour ago, bearnard1244 said:

Curiosity Rover has captured stunning images of the rare, shimmering clouds that exist on Mars. clouds are rare on the Red Planet due to its thin, dry atmosphere. Clouds can typically be found at the planet’s equator during the coldest parts of a Martian year when Mars is farthest from the sun. https://hypebeast.com/2021/5/mars-curiosity-rover-clouds-photos?utm_source=instagram&utm_medium=social&utm_campaign=ig_bio

Your links aren’t working

On 6/1/2021 at 6:50 AM, Hannu2 said:

150 hours flight time is extremely overoptimistic. Electronic damage due to thermal cycling with low minimum, dust and wear in bearings or battery degradation is probable limits. Crashing due firmware error is also much more probable than motor damage (it was quite near already). Ingenuity's protection has not been done for months use. It will be good if it can do few scouting flights but I would not expect several months service life.

Ingenuity is just plain cool, it’s probably pointless and just a Martian air hog but it’s a proof of concept and the technology used can be applied to much larger things.