Author Topic: LIVE: MSL Curiosity Rover ENTRY, DESCENT, LANDING - Aug 5-6, 2012  (Read 217611 times)

Offline marshallsplace

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A few new images have been downlinked, in full resolution this time. Mount Sharp in view!

How totally cool! Great to see the martian terrain and Curiosity's wheels in so much detail this early on.

Offline iamlucky13

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A few new images have been downlinked, in full resolution this time. Mount Sharp in view!

And that's a fisheye view. It makes things look distant and small. Mt Sharp is up close and big! I can't wait to see the Navcam images.

Also, that soil looks like a rover driver's dream. The wheels don't appear to have settled in at all, but there are a few pebbles visible inside the left wheel. I wonder if that is due to the thruster plume.

Offline Pheogh

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A few new images have been downlinked, in full resolution this time. Mount Sharp in view!

And that's a fisheye view. It makes things look distant and small. Mt Sharp is up close and big! I can't wait to see the Navcam images.

Also, that soil looks like a rover driver's dream. The wheels don't appear to have settled in at all, but there are a few pebbles visible inside the left wheel. I wonder if that is due to the thruster plume.

It also might bode well for MARDI images if the plane is relatively free of lighter sandy material. Still would love to know where she is??
« Last Edit: 08/06/2012 07:29 PM by Pheogh »

Offline ugordan

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I can't wait to see the Navcam images.

Or until someone linearizes one of these images  ;)

Offline DaveH62

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Does anyone know how much bandwidth the rover has?

Online Chris Bergin

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Offline iamlucky13

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Well, since I was the cognizant engineer on these now-world-famous dust covers, I guess I can stop lurking and talk about them a little bit.

The covers are indeed are restrained by a metal rod, which was cut by a dual NSI pyro cable cutter.  The cutter is massive overkill for the job, but....

Very informative post. Thanks!

I think I found a spec sheet for the NSI:
www.hstc.com/Download.aspx?ResourceId=28223

There's actually not much propellant in it - almost all of the volume of the NSI is the housing and the electrical connector.

In your application does it cut by mechanical overload, or burning through the pin?

Offline Svetoslav

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Offline stevnim

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Rear hazcam: some dust on lens but otherwise alright and survived pyro event. A ridge on the horizon (crater rim?), looking into sun causing some saturation on the image.
Would that lens dust be from blowing the cover too early, or just the blowing itself?

Quote
If pyros look like pyros, they're probably oversized. The animation clearly shows a spring on the cover, but it was likely restrained by some sort of catch severed by a pyro. It could alternatively have been solenoid released like a pop-up flash on a camera, but usually a pyro is the lightest, simplest, and most reliable way. It could be as simple as thin wire coated in a little bit of powder that creates enough gas pressure to push a pin out of a slot or burns through a severable link.

Well, since I was the cognizant engineer on these now-world-famous dust covers, I guess I can stop lurking and talk about them a little bit.

The covers are indeed are restrained by a metal rod, which was cut by a dual NSI pyro cable cutter.  The cutter is massive overkill for the job, but....

These dust covers were one of the last things added to the rover.  The MSL HazCams are build-to-print copies of the MER HazCams.  On MER, the cameras were protected inside the lander, and in over 10 rover-years on the ground they haven't seen dust building up enough to be worrysome.  The Skycrane system was supposed to reduce the plume ground pressure during landing to the point where dust wouldn't be an issue for MSL.

But after Phoenix landed and everyone saw the pictures of pebbles *on top of* the pads on the bottom of the lander legs, and the legs themselves coated with a sticky looking layer of dust, some concerned folks looked at the issue more closely.  It turned out there is a core flow in the Mars Lander Engines on the descent stage that stays strong all the way to the surface, even hanging at the end of the skycrane.  And that can kick up a lot of dust+reaction products during the skycrane maneuver, some of which would go back towards the rover.  There was a review of hardware in danger of being coated with "sticky" dust; everything was determined to be dust tolerant *except* the HazCams.

Oh, but the HazCams were already done, and so were their mounting interfaces onto the rover, and the mounting hardware was already built....

I was given the task of working around all the geometric constraints of were the cameras needed to be to do their job, carving out a volume for the covers to open, making sure they end up above the belly pan of the rover so they don't impede mobility after they are open, etc (just finding room for the covers to swing with the vehicle design where it was in late 2009 was....fun).  The covers were a "do no harm" best effort - the idea was not to impact the existing HazCams.  Some of the constraints in that area meant they couldn't be 100% sealed, hence the dust particles that got past them.  But the front images from last night especially showed a LOT of caked-on dust blocking a significant amount of the images - and that's what we were really trying to protect against - caked on dust or impacts from small pebbles damaging the coating on the cameras.

Another consequence of being a late addition to the design was that we didn't have time to procure a custom mini-cable-cutter, and we had to fire something with the same electrical characteristics as a NASA Standard Initiator.  The cutters I used had been ordered for another part of MSL and then went unused because of a design change in that other subsystem.

The cover flips open (in 10-20ms depending on if it's the front or the rear) into a honeycomb energy absorber that bring it to stop with a constant deceleration.  The honeycomb absorbers I used had been fabricated 10 years ago as flight spares for the TES mission and kept in their purge/baked out bags with all the certifications by the engineer who built them.  I went to review my absorber design with him one day, showed him the size and shape, and he said - "I already built that, I have 60 flight certified units in storage". Once the covers are open, the spring force from the torsion springs holds it in place against ever moving again.  Because the springs are oversized to meet design practices for moving mechanism torque margins, they have plenty of torque to simply hold the covers open forever.  No latches or other mechanism needed.


Excellent explanation and thank you for "covering" us.

-Steve Nimchuk

Offline Carreidas 160

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http://mars.jpl.nasa.gov/msl/multimedia/raw/?rawid=FLA_397506083EDR_F0010008AUT_04096M_&s=0

Mount Sharp in view

There's a Left and Right version of that picture (http://mars.jpl.nasa.gov/msl/multimedia/raw/?s=0), should make for a nice stereoscopic image when combined!

Offline Hungry4info3

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Online ChrisC

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To all on Twitter. Please link the post or the thread, not the "attachment" as it's simply using bandwidth and the people clicking it are not coming to the site, just the attachment.

Note that you can get the URL for a specific post (not just a thread) via the "title" of the post, above the reply number text at the top of any post (e.g. 631 for this one).
« Last Edit: 08/06/2012 07:56 PM by ChrisC »
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Offline Beckler

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This is an amazing image!  I've always wished for external images of missions; they're rare.  I think video of the entire landing sequence could have been possible too: just before landing (a min. or so?) shoot out a small camera that embeds or otherwise lands into the soil.  Then it tracks and records video--imagine seeing the whole thing in HD.  Would have been incredible, not to mention extremely useful for capturing general public interest...

Not feasible.  The camera would be a lander itself and would require many services.

Fair enough, but I'm thinking to keep it very small and simple since it's not mission-critical.  All we need is a way to eject it safely, and then perhaps its own engine fires it down into the ground, so it hits before the rover.  Think of a model rocket. 

So if it's a tube then, it just drives itself into the ground, with the camera left sticking out at the end.  This should be easy to refine and test on Earth, and the entire thing is self-sufficient with battery power.  Then much later as time permits, it transmits its data back to the rover.  It would be also invaluable I would think, to have external video of the rover driving around, from say 200' away!  Of course then it will drive up and say hello.  :)

Offline andy_l

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Quote
Excellent explanation and thank you for "covering" us.

-Steve Nimchuk

+1, it's great to get an engineering backstory like that, thanks.
« Last Edit: 08/06/2012 08:11 PM by andy_l »

Offline Carreidas 160

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This is an amazing image!  I've always wished for external images of missions; they're rare.  I think video of the entire landing sequence could have been possible too: just before landing (a min. or so?) shoot out a small camera that embeds or otherwise lands into the soil.  Then it tracks and records video--imagine seeing the whole thing in HD.  Would have been incredible, not to mention extremely useful for capturing general public interest...

Not feasible.  The camera would be a lander itself and would require many services.

Fair enough, but I'm thinking to keep it very small and simple since it's not mission-critical.  All we need is a way to eject it safely, and then perhaps its own engine fires it down into the ground, so it hits before the rover.  Think of a model rocket. 

So if it's a tube then, it just drives itself into the ground, with the camera left sticking out at the end.  This should be easy to refine and test on Earth, and the entire thing is self-sufficient with battery power.  Then much later as time permits, it transmits its data back to the rover.  It would be also invaluable I would think, to have external video of the rover driving around, from say 200' away!  Of course then it will drive up and say hello.  :)

Unfortunately, dedicating precious kgs to something that has great entertainment value but little scientific value otherwise (and multiple failure modes on top of that) is a no-go. That weight^H^H^H^H mass goes to scientific instruments...

I keep seeing comments on the internet about lack of video. Are we being spoilt in 2012? In the old days, "we" were happy to land in one piece :)
« Last Edit: 08/06/2012 08:28 PM by Carreidas 160 »

Offline Svetoslav

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I was personally happy to see all the live coverage, images+ photo of the landing from orbit. I came to realization (well, I always knew about that, but hm.. never actually thought about it) that new technology is really advanced. This skycrane looks crazy and suspicious, but it's much more elegant than past landing systems like the one of Mars 3 employing plastic foam for landing cushion.

Offline savuporo

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I keep seeing comments on the internet about lack of video. Are we being spoilt in 2012? In the old days, "we" were happy to land in one piece :)
You know, if you gave them realtime video feed, they'd be complaining about getting it 14 minutes later than folks on the other side ;)
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Offline Pheogh

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I just wanted to give Chris and Co. a quick thank you and shout out for the incredible consistency and stability of this site especially at a times like this. So far the unmanned side of spaceflight has been a bit buggy and it is hell-a frustrating. The main thread over there disappeared for some reason without explanation. In all sincerity Chris and all, thank you!!

Offline Lee Jay

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I can't wait to see the Navcam images.

Or until someone linearizes one of these images  ;)

I don't have lens data, so this isn't very well done, but it's entertaining anyway.

Offline ugordan

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Word has it there will be some amazing EDL images released at the press conference in about 1.5 hrs. Just a heads up that according to the plan, we were supposed to get 18 MARDI thumbnails (192x144 pixel) and *maybe* one full color frame (1600x1200 pixels)
« Last Edit: 08/06/2012 09:36 PM by ugordan »

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