11
$\begingroup$

This is the video released by Perseverance (rover):

enter image description here

Why did NASA release Perseverance (rover) videos with a stop motion effect?

$\endgroup$
23
$\begingroup$

This animated gif is comprised of images that were acquired by the Navigation Camera (Navcam) located on the rover mast, part of the Mastcam-Z instrument. Mastcam-Z is capable of acquiring videos (generally at about 4 frames per second), but sending this data back to Earth could take a long time.

To send data to Earth, the rover transmits a signal to a Martian orbiter (usually the Mars Reconnaissance Orbiter, Mars Odyssey, Trace Gas Orbiter, or Maven), which then relays the data back to Earth via the Deep Space Network. The data rate for each transmission is on the order of 2 megabits per second - and transmission may only occur a few times a day. A video of the rover wheel motion (rather than a series of a few images) would have required more bandwidth, which may have delayed other high priority data products from making it to Earth in a timely manner.

For this particular wheel-checkout test, collecting a few images of the wheels, rather than a video, must have been sufficient to ensure that the system was working.

Sources:

Image source

Mars 2020 Rover Communication Information

$\endgroup$
10
  • 17
    $\begingroup$ In other words: the purpose of the test was to see if the wheels move. You can clearly see that they do. What would more frames of video tell you that you don't already know? $\endgroup$ Mar 27 at 10:18
  • 1
    $\begingroup$ Was video even required for the test? I would imagine they have wheel position telemetry. $\endgroup$ Mar 28 at 1:01
  • 4
    $\begingroup$ @OrganicMarble How do you know the wheel itself is moving and not the linkage with the wheel having broken? Telemetry from a position indicator doesn't tell you that. Having visual indication gives you that bit more confidence something unexpected hasn't happened. $\endgroup$ Mar 28 at 1:10
  • 2
    $\begingroup$ @OrganicMarble No, just speculation from someone thinking about the risks that might have caused them to do it. $\endgroup$ Mar 28 at 1:13
  • 3
    $\begingroup$ I would imagine after this test they'd just trust the telemetry, but I could see this as being a cross-check that what the telemetry is telling them matches what is happening, as well as that the wheel rotates correctly. $\endgroup$ Mar 28 at 1:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.