
Mars rover Curiosity lands today - LVB
http://www.space.com/16917-mars-rover-curiosity-lands-today.html
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avar
Here's some good resources on the landing:

* An overview on CosmoQuoest.org: [http://cosmoquest.org/blog/2012/08/curiosity-landing-remembe...](http://cosmoquest.org/blog/2012/08/curiosity-landing-remember-to-breath/)

* A Google+ hangout that'll be covering the landing: [https://plus.google.com/events/c7c2fbd2gil25fjimln1jnr1134/1...](https://plus.google.com/events/c7c2fbd2gil25fjimln1jnr1134/110701307803962595019)

* Conversion of the landing time into various time zones: [http://timeanddate.com/worldclock/fixedtime.html?msg=NASA+Cu...](http://timeanddate.com/worldclock/fixedtime.html?msg=NASA+Curiosity+Mars+Rover+Landing&iso=20120805T2230&p1=137)

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karpathy
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>

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

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tch
Link to the JPL site <http://mars.jpl.nasa.gov/msl/>

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glimcat
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...](http://timeanddate.com/worldclock/fixedtime.html?msg=NASA+Curiosity+Mars+Rover+Landing&iso=20120805T2230&p1=137))

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

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jimktrains2
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...](http://www.reddit.com/r/science/comments/xnoog/30_success_rate_landing_on_mars_is_anyone_else/)

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ck2
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>

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Achshar
> 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.

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ck2
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.

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maaku
No. Mars having less atmosphere is exactly the point. Such an entry system
hitting Earth's atmosphere would be like slamming into a brick wall--it
wouldn't survive. And the greater density air on Earth would make the sky
crane segment completely unstable. Not to mention that Earth's gravity is
simply too large--components of the system would be crushed under their own
weight.

Believe it, because it's true.

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AngryParsley
I don't know about most of your points, but the components being crushed under
their own weight doesn't seem right. The probe was built in Earth gravity and
had to undergo 4-5G of acceleration during launch. Also, it's going to
experience 13G of deceleration when entering the Martian atmosphere.

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DanielBMarkham
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.

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ChuckMcM
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.

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mturmon
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...](http://en.wikipedia.org/wiki/Mars_Polar_Lander#Communications_loss)).

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.

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

Fair point.

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mturmon
I am not meaning to be too picky. It's a big distinction from some
perspectives at least. ;-)

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gibybo
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.

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redwood
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!

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

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jsmcgd
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?

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Sharlin
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.

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jsmcgd
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...](http://www.youtube.com/watch?feature=player_embedded&v=SwXe_X4UKoM)

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Tuna-Fish
Unless the atmosphere is so thin that the added weight of the parachute and
it's support hurts more than it helps. 0.6 kPa is really that bad.

The effectiveness of a parachute grows at a square of your airspeed. This
means that every planet has a minimum speed you can successfully slow down to
using parachutes with a given system. For realistic loads and conventional
materials, on Mars that is about 50m/s. Which is just too fast.

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guscost
I love how the old media fears robotic spacecraft.

A great day!

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waterlesscloud
One way or the other.

