Mars rover Curiosity lands today

http://www.space.com/16917-mars-rover-curiosity-lands-today.html

by LVB • 14 years ago

125 48 14 years ago

swatkat• 14 years ago

Been waiting for this since its launch. NASA's livestream page: http://mars.jpl.nasa.gov/msl/participate/

gibybo• 14 years ago

At the top of the article, it says "Date: 05 August 2012 Time: 12:31 AM ET", lower in the article it says "Aug. 5; 1:31 a.m. EDT" but both of those seem to be mistakes since those times have already passed and nasa.gov says "Aug 6, 2012 1:31 a.m. Eastern". Sorry if this is pedantic, but I think the time is pretty important here.

opminion• 14 years ago

I suspect the BBC radio news announced the wrong date, for that reason.

redwood• 14 years ago

What they meant was 10:30 PM pacific time on Aug. 05. For US East Coast and all areas east (Europe, Asia etc) this means Aug. 06. They posted the article early in the morning on Aug. 05 so they could have it up and relevant for a full 24 hours I guess!

glimcat• 14 years ago

I'm still very nervous about the landing system. It's ambitious, to say the least.

But if it works - oh, if it works! This really is the most exciting project in exogeology since men brought rocks back from the moon.

(Table of localized landing times: http://timeanddate.com/worldclock/fixedtime.html?msg=NASA+Cu...)

robryan• 14 years ago

Yeah, nervous about any landing on Mars really. A failure would be a disaster for a cash strapped NASA and set back the program years.

piffey• 14 years ago

Our 3/10 track record isn't too great on Mars landing successes either. Here's to hoping!

jimktrains2• 14 years ago

3/10 includes a lot of older missions and non-us missions. The US has quite a good track record for Mars missions. As time goes on we get better and better.

More info here: http://www.reddit.com/r/science/comments/xnoog/30_success_ra...

waterlesscloud2• 14 years ago

One way or the other.

avar3• 14 years ago

Here's some good resources on the landing:

* An overview on CosmoQuoest.org: http://cosmoquest.org/blog/2012/08/curiosity-landing-remembe...

* A Google+ hangout that'll be covering the landing: https://plus.google.com/events/c7c2fbd2gil25fjimln1jnr1134/1...

* Conversion of the landing time into various time zones: http://timeanddate.com/worldclock/fixedtime.html?msg=NASA+Cu...

karpathy• 14 years ago

Here are some more I've collected:

Awesome 3D live in-browser visualization of Curiosity's journey: http://eyes.nasa.gov/ [doesn't work on ubuntu :( ]

There are Curiosity landing parties going on around the world, see map: http://bit.ly/NFwMTk

Curiosity Twitter account: https://twitter.com/MarsCuriosity

NASA TV will stream landing live at: http://www.nasa.gov/multimedia/nasatv/index.html

Picture of the 3 generations of rovers next to people for size comparison: http://bit.ly/NZBKb3

A well-produced video of 7 minutes of terror, if you haven't seen it yet: http://www.jpl.nasa.gov/video/index.cfm?id=1090

avar3• 14 years ago

Here's another one: NASA TV again, but in HD: http://www.nasa.gov/multimedia/nasatv/ustream.html

vibrunazo• 14 years ago

That's Fraser Cain's Hangout. There's also the official SETI Hangout going on earlier than that. Then they'll join Fraser Cain later on.

https://plus.google.com/events/c5otcpguo0im3qmgblsf1fadeqs/1...

lincolnq• 14 years ago

If you're in NYC, it's being broadcast in Times Square. http://www.space.com/16833-mars-rover-landing-times-square-n...

jsmcgd3• 14 years ago

Can someone explain to me why it isn't possible to steer the capsule with the heat shield such that it can be used to deplete virtually all of its speed?

I can imagine a system where the capsule pitches up near the end of its run so that it starts gaining altitude and then deploys a parachute for landing once it has reached its apogee.

I appreciate that their system probably is the best design as they are a smart bunch, however I haven't heard the reason's why some of the more conventional mechanisms weren't used.

Another thing is the crane mechanism, which is to protect the rover from the debris kicked up from the rocket motors. I was wondering why the rover couldn't just be encased in a simple lightweight protective box and then placed directly on the deck?

Does anyone have any links to the other designs that were considered and rejected?

gus_massa• 14 years ago

I think that to do that maneuver you must have wings, and the atmosphere of Mars is thin, so you need bigger wings, and the structure to hold the wings in place give them enough strength. So I think it's easier to use a parachute.

Sharlin• 14 years ago

I don't think the capsule has the right aerodynamic properties to allow it to work as a proper lifting body in the 0.01 ATM Martian atmosphere. We don't really have any experience about lifting bodies on Mars, even less than we have about huge supersonic parachutes.

You can't land on Mars with just a parachute anyway, not with a 900 kg payload. The main problem with Mars is that its atmosphere is just dense enough that it complicates things but not dense enough that it's really helpful.

jsmcgd3• 14 years ago

Apparently according to this video [1] (about half way through) the capsule is a lifting body however I was thinking of something like a simple guided arrow, perhaps some fins that are extended on a telescopic shaft. You could possibly then put a tractor rocket at the end of this shaft to slow descent and keep the rocket plumes away from the main body and the ground.

Regarding parachutes, is it not the case that if you need more performance, that you simply increase their size?

[1] http://www.youtube.com/watch?feature=player_embedded&v=S...

pigboy• 14 years ago

The capsule and heat shield do deplete virtually all of its speed. With Mars' thin atmosphere, the terminal velocity is still quite high and the parachute/rocket combination is needed to take it all the way down. AFAIK this is a relatively conventional system, with the exception of the very last moment of touchdown, which uses descent rockets and the sky crane.

Perhaps the most similar landing was by Viking, which made the final descent on rockets. Those thrusters were expressly designed (that is, compromised) to produce as little disturbance of the landing site as possible. The only thing Curiosity is doing that is really new is the sky crane. If there are any errors in understanding the dynamics of rocket plus lengthening pendulum in Mars gravity, then all is lost. I think it is likely that some extra attention has been paid to this part of the mission.

lmm2• 14 years ago

>I can imagine a system where the capsule pitches up near the end of its run so that it starts gaining altitude and then deploys a parachute for landing once it has reached its apogee.

The martian atmosphere is really thin (I've heard it said that it would pass for vacuum in a high school science classroom). They've got that giant parachute doing as much deceleration-through-atmospheric-drag as possible, and it's still not enough. (And as a sibling post said, fancy atmospheric manoeuvring would require huge wings)

>Another thing is the crane mechanism, which is to protect the rover from the debris kicked up from the rocket motors. I was wondering why the rover couldn't just be encased in a simple lightweight protective box and then placed directly on the deck?

A box with rocket motors on? That'd still churn up the ground that the rover then has to drive through to go anywhere.

Or do you mean dropping it without the cable? The current rovers (MER) were deployed that way, with airbags, but this one's too big to do that with.

jsmcgd3• 14 years ago

Yeah I was thinking of landing it without the cables, inside a protective box and then opening the box once all the dust and debris has settled or blown away. You wouldn't need any airbags as the current system is able to achieve a descent of only 1.5mph, meaning it could be placed gently on the surface.

maaku2• 14 years ago

> Can someone explain to me why it isn't possible to steer the capsule with the heat shield such that it can be used to deplete virtually all of its speed?

They do exactly that. But Mars' atmosphere is so thin that terminal velocity of the capsule is still supersonic.

> I can imagine a system where the capsule pitches up near the end of its run so that it starts gaining altitude and then deploys a parachute for landing once it has reached its apogee.

Parachutes don't help enough in 0.007atm. Even with the biggest chutes possible (remember: they're heavy!), you'd still be hurtling towards the ground like a missile.

> Another thing is the crane mechanism, which is to protect the rover from the debris kicked up from the rocket motors. I was wondering why the rover couldn't just be encased in a simple lightweight protective box and then placed directly on the deck?

Weight. Believe it or not, the sky crane delivers more payload to the surface.

> I appreciate that their system probably is the best design as they are a smart bunch, however I haven't heard the reason's why some of the more conventional mechanisms weren't used. > > Does anyone have any links to the other designs that were considered and rejected?

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2009000...

ballooney3• 14 years ago

> They do exactly that. But Mars' atmosphere is so thin that terminal velocity of the capsule is still supersonic.

Also, that kind of blunt body is stable hypersonically, but unstable supersonically. As soon as you get to a mach number where a parachute can deploy stably (about mach 1.8 and below) you deploy it to stabilise the thing, and of course the drag is much greater than entry body alone.

>> Another thing is the crane mechanism, which is to protect the rover from the debris kicked up from the rocket motors. I was wondering why the rover couldn't just be encased in a simple lightweight protective box and then placed directly on the deck?

The point of the sky crane is not just to avoid kicking up dust, this notion seems to have become the received wisdom in the media though. The reasons include:

-Having rovers drive off from on top of things is difficult, it puts the CoG of the lander right up and if you have to drive off a sloped ramp having landed on a slope, the ramp can be really very sloped.

-Rocket forces nearer the ground can be quite an interesting control problem, in terms of the forces generated when you're near the ground and where all the exhaust goes.

-Having rocket fuel tanks landing on spikey rocks has the potential to really ruin your day.

-Knowing when to turn the rocket engines off (i.e. successfully detecting landing) is actually quite a hard problem. It's a very noisy problem, and getting it wrong was what destroyed Mars Polar Lander (i.e. it thought it landed when it was still up in the air, and so fell out of the sky). The skycrane has the rocket motors on the whole time and goes off an crashes.

Lots of this is explained in the video I linked to somewhere else in this family of comments.

ballooney3• 14 years ago

Everybody just watch this. It's Tom Rivellini, one of the lead mechanical designers of the landing mechanism, explaining how it works and how it evolved and what was considered and what was rejected. It's not a pithy over-produced 4 minute video, it's the real stuff for the technically interested. It answers all your questions.

http://www.jpl.nasa.gov/events/lectures_archive.cfm?year=200...

> I haven't heard the reason's why some of the more conventional mechanisms weren't used.

What's a conventional mechanism when you're landing on another planet?

ck22• 14 years ago

So they completely beta tested this landing system on earth right?

Any videos? Sure hope they did more than this with just a "lab test"

http://www.youtube.com/watch?v=89YfPWTpWN0

I'd be testing it by throwing it out of a plane and see if it can land intact?

ps. not a drop test but still interesting http://www.youtube.com/watch?v=vkGpnLrX-_g

Achshar2• 14 years ago

> So they completely beta tested this landing system on earth right?

That is not possible. Some things like gravity and atmospheric pressure/density cannot be replicated in the scale required to test here on earth. They have to rely on testing in parts and in some cases on calculations and data from previous visits and landings.

ck22• 14 years ago

Mars has LESS pressure. So the landing would be easier here, so it should have been tested?

I find it impossible to believe it wasn't tested all together as a unit and just connecting individually tested parts.

Kind of strange they would not share such a video, which if made by a government entity is public domain anyway.

mturmon3• 14 years ago

Here are some nice pictures, including testing the radar descent measurement system from a helicopter, testing the parachute in the largest wind tunnel in the world, and testing various assemblies in a large thermal/vacuum chamber: http://www.theatlantic.com/infocus/2012/08/curiosity-just-da...

Worth a look, I promise. You get a sense of all the work to assemble a piece of hardware with this size and complexity.

DanielBMarkham• 14 years ago

I have been waiting for this for quite a while. Very excited about the potential for new discoveries.

Having said that, it still looks like the craziest Rube Goldberg set of hacked together systems I've ever seen for landing on a planet. Here's hoping it all comes off without a hitch. I have a feeling it'll become an object lesson in engineering whether it works or not.

bane• 14 years ago

"it still looks like the craziest Rube Goldberg set of hacked together systems I've ever seen for landing on a planet"

It almost makes slamming into the planet and bouncing around in a giant airbag look like a perfectly reasonable and drama-free landing approach.

dugmartin• 14 years ago

It reminds me of the results of my highschool art class project 25 years ago. We were given a sheet of construction paper, a few straws, some glue and a couple of rubber bands. The challenge was to build something that would keep a light bulb from breaking when dropped from the top of a ten foot ladder.

I spent a week of class periods building what looked like a replica of the Lunar Module with fins - the legs were springs to absorb the impact. It worked great when I tested it but failed on the testing day because the teacher was holding it upside down when he dropped it.

My friend, who goofed off the whole week drawing comics in class spent 5 minutes wrapping his bulb in straws, then crumpled up the paper, uncrumpled it and then wrapped that around the straws. A couple of loops of tape and he made a landing "vehicle" that worked every time.

avar3• 14 years ago

The team directly addressed that crazy landing system v.s. the alternatives in a press conference just a few days ago: http://www.youtube.com/watch?v=SwXe_X4UKoM#t=30m16s

ChuckMcM2• 14 years ago

One of the things that came out of discussion with NASA scientists was a deliberate 'science of disaster' sort of thinking. There are a number of sensors in the landing shell, in curiosity, and in the sky crane, that start transmitting as soon as they can. Further the goal of having the Mars Odyssey in position was so that as much data could be collected as possible.

Basically you have to ask the question "What science can I do at this stage?" so that during every possible outcome you extract the most data you can.

I find that a fascinating way to structure your thinking about a project.

mturmon3• 14 years ago

I thought the main driver for collecting telemetry and having Mars Odyssey (an orbiter) in sight to relay data is due to the earlier loss of Mars Polar Lander (http://en.wikipedia.org/wiki/Mars_Polar_Lander#Communication...).

The review board analyzing the loss of MPL could not narrow down the cause for certain, although they did identify a most likely cause. It was resolved in the future to have as much data collected as possible so that an unexplained loss could not occur again.

One key ingredient in this is line of sight to a relay orbiter.

But this is not a science driver, it is an engineering driver.

guscost• 14 years ago

I love how the old media fears robotic spacecraft.

A great day!

Mars rover Curiosity lands today

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