Delay in Communications Between Curiosity & Mission Control

This awesome video gives us an update about what’s going on w/r/t Curiosity and the surface of Mars.

Notice what’s going on between :41 and :55-- the team sends a signal to Mars, Curiosity responds, and the team reacts jubilantly.

Except that, by my guesstimations, from the time the team sent the signal to wiggle the wheels until the team saw the evidence that, I’ll be damned, the wheels are moving, must have been half an hour or more.

My reasoning goes like this: the team sends a signal to Curiosity at c (the speed of light). From earth to Mars at c should take [WAG] about 20 minutes. Curiosity receives the signal, does what it’s told, and sends the signal back, at c, taking another 20 minutes for the information to get back.

So that means the team has an agonizing 40-minute wait each time they tell Curiosity to do something, right? Or am I missing something?

Nope, you’re right.

They might be simply waiting for confirmation of a pre-programmed set of checks.

Keep in mind that this marvel has a semi-autonomous mode.
I wonder when that will be activated, or if it already has.

Because Mars needs a semi-autonomous, nuclear-powered, laser-armed robot.

If you’re curious (hah!), this calculator continuously updates the light travel time to Mars. Currently it’s at about 14 minutes, 41 seconds.

It’s actually about 7 minutes now. Of course it depends on the relative position of Earth and Mars.

I’m glad someone finally found something useful to do with the internet. :slight_smile:

Actually, that’s pretty cool!

By my estimate, that shows we’re currently moving apart by about 20,000 mph. So it’s increasing by about 0.2 sec/hr (round-trip).

The “seven minutes of terror” that were being talked about during the landing was the amount of time the rover took to land, from atmospheric entry to touchdown. Because the light transit time was almost exactly twice this, it was also the amount of time between the end of the landing on Mars and the first data from the beginning of the landing process being received on Earth. So it worked something like this:
[ol][]10:11 PM PDT: Curiosity enters the upper atmosphere of Mars.[]10:18 PM PDT: Curiosity touches down on the Martian surface.[]10:25 PM PDT: Mission Control gets word that Curiosity has entered the Martian atmosphere.[]10:32 PM PDT: All the nerds go wild.[/ol]See here.