Viewing a single comment thread. View all comments

trimeta t1_j6lobqy wrote

Maybe someone can explain to me: why does Perseverance drop samples, instead of keeping them stored onboard? Wouldn't it be easier for some future rover to just go to wherever Perseverance is and collect all the samples at once, rather than needing to trace Perseverance's entire journey to pick up the samples?

38

lustie_argonian t1_j6lou9t wrote

There are samples onboard. These are backups.

50

Locha6 t1_j6mbf45 wrote

Won’t they be covered in dust? How do we find them later?

6

lithuanianD t1_j6mbuik wrote

The path is probably recorded and the position they are dropped in that path

16

The_Flying_Alf t1_j6mqxvd wrote

Hopefully they also have some kind of transponder in case they are blown by the wind.

0

GoForPapaPalpy t1_j6mruzo wrote

The Martian Atmosphere is incredibly sparse / low pressure. Even the fastest wind on Mars wouldn’t be able to move much besides dust. There’s just not enough molecules of atmosphere to enact significant force into anything of substance.

This is part of the reason why the Ingenuity drone’s blades have such a high revolution rate.

14

The_Flying_Alf t1_j6mt2z9 wrote

Cool, I just assumed since there are dust storms it might have some more strength

2

GoForPapaPalpy t1_j6mtx4l wrote

No worries! As did I at some point in my life. So if you watch “The Martian” with Matt Damon - great movie, awesome book - the whole concept of the dust storm pushing the escape vehicle over and blowing a radar dish into Mark Watney is complete BS. Andy Weir tried to keep most things true to the science / believable, but I think I’ve read somewhere that he regretted that whole part because it is just not what Martian Wind is capable of doing.

8

mrflippant t1_j6oo1tq wrote

Since the atmospheric pressure on Mars' surface is about 0.6% of the atmospheric pressure at sea level on Earth, standing in a Martian dust storm probably feels a lot like having little styrofoam pellets blown around you by a very mild breeze.

1

big_duo3674 t1_j6lyn9m wrote

To add on to the other comment, these deposits are made in very carefully selected locations that would be used as a backup in case the main samples are unable to successfully be returned to earth. They'll get a little dusty, but with the way it works on Mars they will be able to sit perfectly sealed for many years before they'll be covered with enough dust to be hard to locate

24

Not-the-best-name t1_j6lzy3x wrote

Simply because we don't know how long perseverance would still be working to hand over the samples.

And it's not dropping them along a path. This is called a depot, it's one place where it is placing a bunch.

14

trimeta t1_j6m1rsj wrote

I wasn't necessarily assuming that Perseverance would be functional to hand the samples over; rather, I thought it might intentionally store the onboard samples in a fashion where another rover could easily grab them without direct intervention from Perseverance itself. Something like a tray or rack of tubes with each sample having exposed grips.

The comments made by others suggest that Perseverance does have onboard samples like this, and the dropped ones are secondary (in case something happens to Perseverance to destroy all its onboard samples -- I don't know, catastrophic damage to its radioisotope power generator? Or perhaps more realistically, it gets stuck in a sandy area which is too dangerous for other rovers to approach without also getting stuck), which makes more sense.

6

Not-the-best-name t1_j6m8cv4 wrote

I just love the type of thinking required to design this mission.

Get stuck in sand on a safari - no issue - get stuck in sand on Mars - two decades of planning between the smartest minds of many national space agencies.

3

HeebieMcJeeberson t1_j6m53s9 wrote

The retriever won't have to trace any of Perseverance's journey, it will go directly to Perseverance and transfer the samples, or if there's a problem with that it will go directly to the depot as a backup.

8