Mars - Curiosity: 7 Minutes of Terror

[ussfletcher]

i thought i heard this one will be much more automated, so it doesnt take 3 days to send and listen for the most basic commands...

Not 3 days, its more like 3 minutes per direction.

 

[Ichinisan]

[brag] I was working on embedded systems on it on one of my internships. I also have my name inscribed on a golden plaque that it carries. [/brag]

If the landing fails, will you be sweating bullets and wondering if they will trace the cause to your code?

 

[Bignate603]

i thought i heard this one will be much more automated, so it doesnt take 3 days to send and listen for the most basic commands...

They weren't worried about the time it took to send and receive commands, they were worried that a string of commands would make it do something that would endanger the rover. With a lag of a few minutes both ways it's extremely hard to react when something starts to go wrong so you test everything you can.

 

[Franz316]

That's going to be a tense few minutes, lets hope everyone got their math right

Hopefully the size of this one will make it get stuck less than Spirit and Opportunity. Those two did an awesome job despite sinking in the ground a few times.

 

[ussfletcher]

If the landing fails, will you be sweating bullets and wondering if they will trace the cause to your code?

Ha, no. I was working on a board that was going to be used primarily for radar processing on this mission. It had a nice FPGA at its core.

 

[olds]

I saw one of the rovers they kept behind for troubleshooting. They actually were planning on building an exact model of the landing area after they got the rover on the ground and could take some pictures. They'd stick the extra rover in the middle of it and then test every single command on their setup on earth before it was sent to the rover on mars.

Actually, they are using all that to fake the landing like they did with the moon.

 

[ussfletcher]

I saw one of the rovers they kept behind for troubleshooting. They actually were planning on building an exact model of the landing area after they got the rover on the ground and could take some pictures. They'd stick the extra rover in the middle of it and then test every single command on their setup on earth before it was sent to the rover on mars.

They have a "Mars Yard" at JPL where they test all the models. Incidentally when Spirit got stuck, they did basically exactly what you are referring to, to try and free Spirit. I have a picture of that somewhere... But anyway, it would be far too time consuming to test every command. As far as I am aware from my tour of mission control, they only update rover commands every few hours and other than that they guide themselves (unless the terrain is particularly worrisome). Its important to note here, that they do not move quickly. As in, they move a mile in the course of months. In the case of MSL (Mars Science Laboratory or Curiosity) they are shooting for ~30m an hour.

They weren't worried about the time it took to send and receive commands, they were worried that a string of commands would make it do something that would endanger the rover. With a lag of a few minutes both ways it's extremely hard to react when something starts to go wrong so you test everything you can.

I can vouch for the fact that the people there test EVERYTHING, extremely thoroughly.

I wish they hadn't cut NASA's budget, I'd love to work there again...

 

[DrPizza]

Not 3 days, its more like 3 minutes per direction.

I agree that it's not on the order of days, and don't know the specific distance from Earth to Mars at its nearest point, but the other half of the time, Mars is on the opposite side of the sun. That puts it around 19 minutes (assuming your 3 minutes is correct.)

 

[TXHokie]

the parachute and the rockets are already mars mission proven. the only difference is they stop 30ft or whatever above the ground and they hoist the rover down, which is very simple.

Just wondering but if the crane is already hovering, why not just land and let the rover roll off? That sequence of lowering the rover from a floating rocket assisted platform seem to involve lots of moving part. Of course what do I know.

 

[Childs]

Just wondering but if the crane is already hovering, why not just land and let the rover roll off? That sequence of lowering the rover from a floating rocket assisted platform seem to involve lots of moving part. Of course what do I know.

They covered that in the video. The boosters would kick up dust and it might get in/on the rover and mess something up. One would think the rover would be built to accommodate dust in case of a dust storm or something, but I'm sure they have their reasons.

 

[Jeff7]

That's going to be a tense few minutes, lets hope everyone got their math right

Hopefully the size of this one will make it get stuck less than Spirit and Opportunity. Those two did an awesome job despite sinking in the ground a few times.

Still doing an awesome job, in Opportunity's case. Still going, more than 8 years after landing.

They covered that in the video. The boosters would kick up dust and it might get in/on the rover and mess something up. One would think the rover would be built to accommodate dust in case of a dust storm or something, but I'm sure they have their reasons.

What I can think of is that having it lowered down on the lines eliminates the chance of the rover's wheels having to support the weight of the Skycrane, even briefly. And it could act as a sort of buffer: Rather than having the entire huge assembly landing, only the rover is landing. The line could potentially lower it down at a controlled speed, allowing for some movement of the Skycrane. I don't know if they built it with that level of control though.

 

[ImpulsE69]

I'm actually kind of curious what this is for...I thought they pretty much decided there wasn't much left to "find" on Mars. Was not even aware they were sending another one...

 

[destrekor]

They covered that in the video. The boosters would kick up dust and it might get in/on the rover and mess something up. One would think the rover would be built to accommodate dust in case of a dust storm or something, but I'm sure they have their reasons.

This is about proving tech and engineering as much as it is collecting data.

If you put extra variables like a "simulated massive dust storm" into the scenario RIGHT after touch down, there is a possibility for immediate and future errors that are difficult to pin point as "oh, that's because of the dust storm we created during the landing sequence" - they'd rather any "bugs" like that to be traced back to a specific point of failure. If it fails immediately, without the storm, they can probably trace it to a specific piece of equipment. If it fails in four months, without the initial storm, they can possibly figure out if a specific piece of equipment failed, or attribute the failure to a natural accumulation of dust causing too many problems.

They want to see if they can do all this, and start figuring out where they can go from here for future mission ideas/concepts - and they also want to be able to figure out exactly what went wrong so they can correct it for future missions.

Otherwise, they could probably devise a way to survive the initial dust storm, or figure a way to minimize the impact.

Exact reasons, of course, could be totally different - but that's how my brain is approaching that scenario with what limited information I have.

 

[destrekor]

I'm actually kind of curious what this is for...I thought they pretty much decided there wasn't much left to "find" on Mars. Was not even aware they were sending another one...

In short, more sophisticated equipment that can: A) look for things the older rovers couldn't possibly detect; B) look at things with a "better eye" when compared to the lesser-capable sensors/tech on the older rovers.
Also: C) prove concepts and new technology/approaches to "problems"

 

[Red Squirrel]

That's awesome!

For some reason I had the impression this had already touched down though. Maybe I'm confusing it with another.

 

[Jeff7]

I'm actually kind of curious what this is for...I thought they pretty much decided there wasn't much left to "find" on Mars. Was not even aware they were sending another one...

We've closely examined perhaps a few square miles of the planet.

Take a look outside the windows of your house, and then conclude that you know everything about Earth.

 

[ussfletcher]

We've closely examined perhaps a few square miles of the planet.

Take a look outside the windows of your house, and then conclude that you know everything about Earth.

I'm on my phone now so I can't provide a list, but MSL carries some instruments that would have been impossible with the older craft.

 

[Paratus]

The command lag for the rovers is really interesting. With the ISS I can generally get a command response back in less than 30 seconds. I imagine the commanding to the rovers is a lot different then what we do in LEO.

We recently did some simulations at JSC to work out issues with command delays for a pretend manned expedition.

 

[BladeVenom]

For those that don't remember the Pathfinder landing system. http://www.youtube.com/watch?v=7G75kQm7pSE

 

[Dr. Zaus]

they are shooting for ~30m an hour.

For everyone not from Europe or SCIENCE this is just shy of 2ft a min.

I wish they hadn't cut NASA's budget, I'd love to work there again...

My frist thought was "why are they using un-proven technology".

As asked in this thread "why aren't they using the air-bags";

That it is 'too big' does not answer the question because we still don't know why they should be spending the money and risking the resources to do this instead of doing more with air-bag style technology.

Why are we going to get a better scientific return on investment from this than from doing X# more air-bag robots?

 

[Jeff7]

...
My frist thought was "why are they using un-proven technology".

As asked in this thread "why aren't they using the air-bags";

That it is 'too big' does not answer the question because we still don't know why they should be spending the money and risking the resources to do this instead of doing more with air-bag style technology.

Why are we going to get a better scientific return on investment from this than from doing X# more air-bag robots?

The airbags were also unproven technology not too long ago.

 

[Dr. Zaus]

The airbags were also unproven technology not too long ago.

Sure I get that.

But it seems that the risk v. reward (maximizing scientific progress under the condition of limited dollars) may be askew because NASA likes playing with new toys instead of getting the most out of the ones it creates.

So why is this multi-stage deployment of a mini-cooper more important than sending X number more air-bag rovers? If we've maximized what we can get out of such technology, or if we are maximizing it (investing to get everything we can out of it already) then move on to a new direction: but sometimes it seems we geeks do things because its cool and not because we have the greater goal in mind.

 

[DrPizza]

Sure I get that.

But it seems that the risk v. reward (maximizing scientific progress under the condition of limited dollars) may be askew because NASA likes playing with new toys instead of getting the most out of the ones it creates.

So why is this multi-stage deployment of a mini-cooper more important than sending X number more air-bag rovers? If we've maximized what we can get out of such technology, or if we are maximizing it (investing to get everything we can out of it already) then move on to a new direction: but sometimes it seems we geeks do things because its cool and not because we have the greater goal in mind.

I'm sure the geeks at NASA are smart enough to crunch numbers and decided that this mission has a good enough chance of success.

 

[ussfletcher]

Sure I get that.

But it seems that the risk v. reward (maximizing scientific progress under the condition of limited dollars) may be askew because NASA likes playing with new toys instead of getting the most out of the ones it creates.

So why is this multi-stage deployment of a mini-cooper more important than sending X number more air-bag rovers? If we've maximized what we can get out of such technology, or if we are maximizing it (investing to get everything we can out of it already) then move on to a new direction: but sometimes it seems we geeks do things because its cool and not because we have the greater goal in mind.

There are several reasons that we are not using the older rovers. First, they are not large/powerful enough to carry some of the instrumentation that NASA has deemed worthwhile to the mission. Second, the new rovers is run on a plutonium power source which means that it can run continuously for years, whereas the current rovers can't run in the martian "winter" or when there are dust storms. There are more reasons but these should give a glimpse into the importance of the new technology.

What I have always been more interested in, is when MSL cuts itself from the umbilical to the rocket platform, the platform flies off and crashes somewhere. There are some intriguing points that this brings up in regards to tainting martian soil.

 

[ussfletcher]

I agree that it's not on the order of days, and don't know the specific distance from Earth to Mars at its nearest point, but the other half of the time, Mars is on the opposite side of the sun. That puts it around 19 minutes (assuming your 3 minutes is correct.)

Don't quote me on that number, I was just putting the number on the correct order of magnitude. The delay in transmission time is obviously dependent on the orbits of the planets.