APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

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Expand view Topic review: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by Chris Peterson » Tue Dec 11, 2018 12:46 am

Jim Armstrong wrote: Mon Dec 10, 2018 11:00 pm I followed the link in the article "sensitive seismometer" and found:
"During these brief but severe events, the InSight spacecraft will have to absorb considerable accelerations of a few hundred g or more."
I can't find anything more than 7.6g in other material.
I'm sure some body will set me straight. (That is, if this feature has decided to work)
They're talking about shock forces, which are different from sustained acceleration forces. Shocks are typically very high g forces, but for very short times. In this case, they're probably saying that the device can survive a few hundred gs occurring over some short interval, like a millisecond. That's on the same order as what a light weight, rigid object will experience when dropped a few tens of centimeters. It's easy to believe that between launch and landing there could be many such shocks. The 7.6 g value sounds reasonable for the maximum sustained g force encountered in either launch or landing.

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by neufer » Tue Dec 11, 2018 12:38 am

Jim Armstrong wrote: Mon Dec 10, 2018 11:00 pm
I followed the link in the article "sensitive seismometer" and found:

"During these brief but severe events, the InSight spacecraft will have to absorb considerable accelerations of a few hundred g or more."

I can't find anything more than 7.6g in other material. I'm sure some body will set me straight.
The 7.6 g number sounds right.

It is possible that the recommended specs went up to a few hundred g just to be on the safe side
for sudden temporary jolts such as the parachute opening or a heavy drop to the surface.

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by Jim Armstrong » Mon Dec 10, 2018 11:00 pm

I followed the link in the article "sensitive seismometer" and found:
"During these brief but severe events, the InSight spacecraft will have to absorb considerable accelerations of a few hundred g or more."
I can't find anything more than 7.6g in other material.
I'm sure some body will set me straight. (That is, if this feature has decided to work)

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by Jim Armstrong » Mon Dec 10, 2018 10:58 pm

Tried four times to post. Problems there or here?

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by JohnD » Mon Dec 10, 2018 10:53 pm

Thanks, disefanom and Chris!

And nice one, Mark!
John

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by MarkBour » Mon Dec 10, 2018 5:24 pm

Lovely image of the situation, all looks well.

So Insight is like a head-waiter that has been sent to Mars to present it with a delicacy or two.
  • First it will pick up SEIS and gently present it as it is ... "SEIS L'Orange".
  • Next it will cover it for a grander presentation, "SEIS Under Glass".
  • Of course, Mars is not expected to eat these offerings, so in addition, some food will be forced into her (HP3).
And then Insight will listen to the rumblings in Mars' tummy, hoping that she is satisfied with the meal.

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by Chris Peterson » Mon Dec 10, 2018 4:37 pm

JohnD wrote: Mon Dec 10, 2018 10:05 am A slight question - what are the optical targets for, that are scattered liberally over this and other lander probes? They remind me of the NCAP (European car safety testing org) logo, which uses similar targets to measure deformation of the car in laboratory car crash filming. Curiosity has them too.
Why needed on a planetary probe?
John
Keep in mind that the two cameras on this probe are not really intended for imaging the surrounding landscape, except secondarily (note that they use color sensors, which are very limited). The primary purpose of these cameras is for handling and deploying instruments using the arm. So it is very useful to have a set of precisely fixed 3D reference points in the FOV for calibrating such motion.

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by neufer » Mon Dec 10, 2018 4:21 pm



`Ah, well! It means much the same thing,' said the Duchess,
  • digging her sharp little chin into Alice's shoulder
    as she added, `and the moral of THAT is--
"Take care of the sense, and the sounds will take care of themselves."'

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by RAWXALLO » Mon Dec 10, 2018 3:59 pm

JUST WHY A STUDY OF MARS ? IT HAS ABSOLUTE USAGE FOR THE PHYSICAL
WORLD.Robert L.Grisham/12/10/18

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by distefanom » Mon Dec 10, 2018 10:52 am

I think for arm position alignement calibration purposes

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by JohnD » Mon Dec 10, 2018 10:05 am

A slight question - what are the optical targets for, that are scattered liberally over this and other lander probes? They remind me of the NCAP (European car safety testing org) logo, which uses similar targets to measure deformation of the car in laboratory car crash filming. Curiosity has them too.
Why needed on a planetary probe?
John

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by distefanom » Mon Dec 10, 2018 8:27 am

...anyone noticed that the SKY colours are OPPOSITE than on Earth?
During day, the sky is (usually) blue on Earth, white-Orange on Mars...
at DAWN COLORS we have pink-orange on Earth, white-blue on Mars???
On Earth:
Image
On Mars:
Image

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by distefanom » Mon Dec 10, 2018 7:57 am

...already covered with DUST ?? :? :?
(not too much, of course, but it's already there!)
:shock:

Re: APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by bystander » Mon Dec 10, 2018 6:11 am

APOD: Sound and Light Captured by Mars InSight (2018 Dec 10)

by APOD Robot » Mon Dec 10, 2018 5:06 am

Image Sound and Light Captured by Mars InSight

Explanation: Your arm on Mars has unusual powers. For one thing it is nearly 2 meters long, has a scoop and grapple built into its hand, and has a camera built into its forearm. For another, it will soon deploy your ear -- a sensitive seismometer that will listen for distant rumblings -- onto the surface of Mars. Your SEISmomet-ear is the orange box in the foreground, while the gray dome behind it will be its protective cover. Your arm is attached to the InSight robotic lander that touched down on Mars two weeks ago. Somewhat unexpectedly, your ear has already heard something -- slight vibrations caused by the Martian wind flowing over the solar panels. Light from the Sun is being collected by the solar panels, part of one being visible on the far right. Actually, at the present time, you have two arms operating on Mars, but they are separated by about 600 kilometers. That's because your other active arm is connected to the Curiosity rover exploring a distant crater. Taken a week ago, rusty soil and rocks are visible in the featured image beyond Insight, as well as the orange sky of Mars.

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