MSL Landing Timeline: What To Expect Tonight 140
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by
samzenpus
from the break-it-down dept.
from the break-it-down dept.
An anonymous reader writes "When the Curiosity rover lands on Mars later tonight, it'll be executing a complex series of maneuvers. JPL will be relying on the Mars Odyssey orbiter to relay telemetry back to Earth in time-delayed real-time, and if all goes well, we'll be getting confirmation on the success (or failure) of each entry, descent, and landing phase, outlined in detail here."
Not for any definition of "real time" that I know. (Score:3, Informative)
Re:Not for any definition of "real time" that I kn (Score:5, Insightful)
Telemetry will be continuously relayed back to earth, true, but with not much less than about a 15 minute latency, owing to the fact that Mars roughly a quarter of a light-hour from earth right now.
That IS indeed real time. Relativity tells us nothing can have an effect here in less time. I don't know if you're trolling or just ignorant, but by your definition you can never look at the stars, galaxies or nebulae in the sky in real time either because they're all at varying distances and we're seeing light that originated anything from about 4 to several million years ago. With telescopes you can go back billions.
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That IS indeed real time. Relativity tells us nothing can have an effect here in less time. I don't know if you're trolling or just ignorant, but by your definition you can never look at the stars, galaxies or nebulae in the sky in real time either because they're all at varying distances and we're seeing light that originated anything from about 4 to several million years ago. With telescopes you can go back billions.
Unless you live near a big city, in which case most of the light you can see in the sky at night (other than moonlight) originated within the last quarter millisecond.
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Trolling. How is that not obvious?
Re:Not for any definition of "real time" that I kn (Score:5, Interesting)
You're both rude and wrong. GP is correct.
"Relativity tells us nothing can have an effect here in less time." True, but that doesn't mean that it's real time. Here are a few examples that show that it's completely ridiculous to call it real time:
The cosmic microwave background is the glow of the hot early universe, from shortly after the Big Bang. No cosmologist would refer to this as seeing the Big Bang "in real time."
It's possible for a ray of light to travel in a circular orbit around a black hole. That means that it would theoretically be possible for me to face in a certain direction, stick out my tongue, and then turn around 180 degrees, look through a telescope, and, some time later, see myself sticking my tongue out at myself. I'm obviously not seeing myself "in real time."
As a third example, there are distant galaxies whose light hasn't gotten to us yet. I don't think anyone would argue that we are seeing them "in real time" -- we haven't even seen them yet.
It sounds like you're misinterpreting something you heard about the nature of simultaneity in relativity. You can define simultaneity in relativity. You simply have to keep in mind that it's relative, not absolute.
In special relativity, the standard way to do this is Einstein synchronization [wikipedia.org]. The relative motions of the bodies in the solar system, as well as all space probes launched so far, is at velocities much less than c, so it doesn't even matter very much whether you talk about doing your Einstein synchronization in the frame of the earth, of mars, or whatever. This is the sense in which the information from Mars is 15 minutes behind "real time." (There are also gravitational time dilations, and they're also quite small.)
Since you brought up astronomy and cosmological look-back times, it's worth addressing that as well. To describe cosmological scales, you need general relativity, and in general relativity Einstein synchronization doesn't work. However, there is a natural notion of clock synchronization in cosmology that is defined as follows. At any spot in the universe, define a frame of reference that is at rest with respect to the cosmic microwave background (or the local flow of galaxies, which amounts to the same thing). Define a time coordinate as measured by a clock that is at rest in that frame. This is what cosmologists mean when they state the age of the universe as so many billions of years. This time coordinate is also the only reasonable definition of "in real time" for use in cosmology.
Next time, please try being more polite and/or getting your facts right.
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As the AC pointed out, by your criterion nothing occurs in "real time" (unless it's on your own worldline), thus rendering the term effectively meaningless. Your post is just silly overeducated nitpicking (and I say this as someone who went to grad school for GR). You probably scream "there's no sound in space" at the movie screen, too.
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Sorry to intrude, but I just mentioned [slashdot.org] you in a comment. (Also wanted to say that I nitpicked earlier solely to clarify the issue for others.)
But now that I know you're a GR physicist, I wonder if you'd like to read Outlive the stars [dumbscientist.com] and leave a comment?
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The single most important criteria for something to qualify as "real time" in data communications is low latency. 14 and a half minutes is not low.
Then by your definition NOTHING in space is real time. You look up into the sky and everything you're seeing is sending it's light to you from the past.
Re:Not for any definition of "real time" that I kn (Score:4, Interesting)
Then by your definition NOTHING in space is real time. You look up into the sky and everything you're seeing is sending it's light to you from the past.
Duh. Real time is a bit subjective, but it basically is a threshold of control over a system. The strict definition is that a system is real time, if it meets strict time constraints imposed on it (I gloss over some important nuance). So in a sense, one can have real time systems with say, years of lag, for really generous time constraints.
For me, I have an informal definition of real time, namely, a control methodology which wouldn't change, if communication lag were instantaneous.
For example, the human body wouldn't move differently even if human nerves were transmitting signals instantaneously. Walking, running, and such still are the best means for moving. You might be able to try other movement forms (such as cartwheeling), but these wouldn't give you an advantage in normal operation over the usual means of movement.
So in this sense, the human body and its normal means of moving about are "real time". Movement of the MSL and other rovers remotely controlled from Earth have less optimal movement schemes (there's a lot of need to evaluate terrain obstacles, for example, resulting in a lot of move-then-stop operation) than if someone were controlling them from nearby on the Martian surface. So these systems are not real time in my sense.
Now suppose instead of the MSL, one were piloting this fine piece of gear [wikipedia.org], one of the largest excavators in the world. Suddenly that 15 minute lag time is not so significant and the machine probably wouldn't operate all that differently, if the operator was sitting in a cockpit directly rather on distant Earth.
Since I mentioned systems with extremely long lag still qualifying as real time, consider this example. One could set up vast streams of gargantuan slow moving space vehicles carrying basic crude, bulk resources (water, organic compounds, metals, etc) between different planetary systems, say moving at the speed of the Voyager spacecraft. It might take 50,000 years to make the trip and adjustments in trajectory would be very minimal and glacial. Would it matter if one had instantaneous communication? Not really. The years of communication lag have no real effect on the system.
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No, that's just your personal set of criteria that doesn't have anything to do with reality.
Real-Time is without artificial delay. Yes, there's 14 minutes actual delay, but it's not artificial, it is literally the fastest possible time.
If 14 minutes prevents it from being real time, then 14 seconds should too, as should 14 milliseconds, or 14 nanoseconds. All of them are arbitrary amounts of time, all of them are large amounts of latency relative to something.
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Owing to the fact that we will know the lander has already reached the surface (in unknown condition) by the time we get the first signal it has entered the atmosphere, the delay cannot *POSSIBLY* be considered real time because too many events that can or will affect the system will have occurred by then.
But since the information reaches us as quickly as reasonably possible it can still be considered real-time. (I said "reasonably possible", since there's some finite processing time that's incurred when an event is recorded, encoded for transmission to the earth, received, decoded, then broadcast to the world which means that it will take longer to receive the information at home than is physically possible if we all had telescopes that could resolve the landing in "real time").
Otherwise, where would you dr
Re:Not for any definition of "real time" that I kn (Score:5, Insightful)
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You draw the line at any signal latency that is too slow to meaningfully respond to in the context that the signal was originally sent from. There's a reason why interrupt handlers in real-time OS's need to finish their job in as few computing cycles as possible.
So in the event of a fully autonomous landing that wasn't designed for any human input or control, is a 15 minute delay "real time" or not? Once the landing sequence starts, there's no going back or adjusting the sequence until the entire 15 minute landing sequence is over, even if a human was orbiting Mars.
An interrupt handler in a Real-Time OS doesn't need to finish its job in as few computing cycles as possible, it only needs to finish within the guaranteed interrupt latency time, which could be a few mi
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In fact, a hard real time system may have a much higher latency than a general purpose system due to the complexity of making sure that it will meet it's deadline every time with certainty.
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Stupid discussions like this one arise when perfectly useful expressions are replaced by inferior, more complex expressions merely to make people sound more expert or scientific. In the olden days, they would have said "Live images will be beamed back by the lander".
I don't believe saying it's a "live image" would be any less likely to be challenged. "How can it be live if it happened 15 minutes ago!?"
No one would have been in any doubt what that meant and this bullshit discussion would never have needed to take place, in 'real time' or slightly delayed.
I'm seeing about 100 msec of latency to Slashdot from here, so this conversation is not taking place in "real time".
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I don't believe saying it's a "live image" would be any less likely to be challenged. "How can it be live if it happened 15 minutes ago!?"
The problem is the word "ago", which presupposes that there is a time frame that comprises both here and there.
There isn't. Time is a local phenomenon, and doesn't propagate instantaneously - it's bound by the speed of light too.
It hasn't happened yet until the information about it can reach us. Any other interpretation breaks causality, which is a no-no.
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Of course.... but 15 minutes is certainly far too long.
The decent itself will last only 7 minutes. By the time we get a signal that it has just entered the atmosphere, the unit itself may very well have crashed.
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Suggesting that something hasn't happened yet until the information reaches us is like suggesting that the light we see from distant stars right now was only just emitted by that star. It wasn't.
Correct, it wasn't because "was" makes no sense, because you and the remote star don't share a common frame of reference where "was" makes sense. To not violate causality, the remote event happens as you see it in your frame of reference. You know nothing about the remote frame of reference. You can estimate how many light years away it occurred, but light years is a distance, not a time.
For the farthest objects you see the birth of the universe as it happens , not happened . The universe is 16 billion
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That wasn't anywhere even close my point. Perhaps I should have described it more completely.
The light we are seeing from distant stars *WAS* emitted by them many years ago . I have absolutely no idea what you're on about saying that "was" doesn't make any sense. It does.
It doesn't violate causality to know that the lander would have reached the surface of mars nearly 15 minutes before we could possibly receive confirmation of the event, because no real
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The light we are seeing from distant stars *WAS* emitted by them many years ago.
Again, you use words that lack meaning in this context. "Ago" implies a time frame where this time can have passed. This does not exist.
The remote stars are not in our time frame. There isn't such a thing as a universal time that you can apply to both us and them in which the years could have passed.
In our time frame, the stars are being born as we watch them. In the time frame of the traveling photons, they just left the remote stars and arrived instantaneously in a much older part of the universe.
Re:Not for any definition of "real time" that I kn (Score:4, Insightful)
Owing to the fact that we will know the lander has already reached the surface (in unknown condition) by the time we get the first signal it has entered the atmosphere
Relativity says that there is a 14 minute delay in *some* frames of reference. In other frames of reference, the delay is longer. For others (those occupied by the radio signal photons, for example), the landing events and our reception of the signals happen simultaneously.
Getting hung up over what you imagine is the "time delay" between two points in spacetime that are outside of each others' light cones is kind of pointless.
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Owing to the fact that we will know the lander has already reached the surface (in unknown condition) by the time we get the first signal it has entered the atmosphere, the delay cannot *POSSIBLY* be considered real time because too many events that can or will affect the system will have occurred by then.
Sir, you may want to read up a bit on relativity. Before the signal reaches us, it has not already entered the atmosphere. There is no clock that shows a time that's valid for both Mars and Earth, in which you can say that it has landed "now".
The event cone expands at the speed of light, and until it reaches us, nothing has happened.
"Now" and "while" are purely local phenomena which do not apply across distances. Earth and Mars exist in different time frames. There is no universal clock with a "now" th
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Sure there is, there are clocks in both locations, just because we don't receive the information in our light cone does not mean that it has not already happened.
That there are clocks both places doesn't mean that they tick in the same time frame. They most certainly do not.
We can know for an absolute fact that at +15min our time information will be received and at -15 our time information will be transmitted by virtue of there being a light cone.
No, you don't know that. Your problem is thinking the light cone takes 15 minutes to get here. From the point of view of a photon in the light cone, it takes no time at all. Only for a third party observer in rest who gets a signal from Mars when it occurs, and another signal from Earth when we observe it, will it take 15 minutes. In our time frame and the time frame of Mars, that's not true
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How low is 'low'? Everything you sense in the world is already old news due to delay times in nerve conduction. Even more if you consider actual conscious awareness a necessary element.
Re:Not for any definition of "real time" that I kn (Score:4, Funny)
True, but for a blueworlder, the blueworld-received-time is real-time, for any definition of real-time consistent with relativity.
Speaker K'Breel knows the instant the Martian Defense Force succeeds in its mission, or fails, and either way he has enough time to throw a Junior Reporter's gelsac beneath the spot where the Skycrane will crash-land. At the moment of impact/invasion, the most recent transmissions from his spies on the Blue World will show a clock dated 10:14 PDT, but that's irrelevant. As far as the blueworlders are concerned, they find out at 10:31 PDT. Loyal Martian Citizens can start celebrating/covering their gelsacs early, but have to wait another 15 minutes (until their view of the blueworlders' clocks show 10:31) before they can enjoy true schadenfreude at the blueworlders' pain, or have hopefully protected their gelsacs in preparation for the ever-merciful Speaker for the Council's reaction to his view of the blueworlders' whoops of joy.
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Has anyone collected all these dispatches from the Martian Council over the years? Every time the Earthlings throw a probe at the homeworld, there'll be an update from the Speaker regarding the success or failure of the defences. I've actually come to anticipate the next entry - they're generally quite funny.
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A bit of googling found this:
http://atomfullerene.wordpress.com/dispatches-from-the-red-planet/ [wordpress.com]
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I agree; there is a massive opportunity here to capitalize on the synergy of Martian Control and lolcats. I sense an RSS feed in the making.
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Given this post, and all the other by you below, I think they should have just told you (and only you, as the rest of us have no problem with this) that the landing was happening about 15 minutes later than it is. I bet you'd be happy then :)
(Meant in good fun!)
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Telemetry will be continuously relayed back to earth, true, but with not much less than about a 15 minute latency, owing to the fact that Mars roughly a quarter of a light-hour from earth right now.
So you'll be sitting in the crowd watching one direction (or whatever you kids are into these days) complaining that you should be closer to the front because the light from the stage is taking multiple nanoseconds to reach you, which is unacceptable because you paid full price for a live performance.
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Did Send Your NameTo Mars happen (Score:1)
Anyone know if the "Send Your Name To Mars" chip actually made it onto the rover? Would love to be able to tell my wife and kids our names are on Mars.
http://marsparticipate.jpl.nasa.gov/msl/participate/sendyourname/
I showed my son (just turned 4) a couple of the publicity videos made by Nasa including the Shatner narrated landing.and he wanted to know if we could buy the toy of it. I had to explain there was none, but apparently Hotwheels has come out with one (just the rover itself though, not the whole d
crazy (Score:1)
the amount of engineering, programming and math that went into this... (among other things i'm sure) I hope it goes well
Re:crazy (Score:4, Funny)
Don't forget the imperial to metric conversions!
Re:crazy (Score:5, Funny)
Not many people know this, but the Stonehenge scene in "This is Spinal Tap" was based on something that really happened to Black Sabbath. The band wanted a life-sized replica of Stonehenge for their stage show, just like in the movie. They drew up the plans, but at some point (nobody's sure where) 14 feet became 14 meters... So they wound up with this giant thing that cost way more than they planned, and worst of all, it wouldn't even fit on any of the stages they were playing. After this, and a series of similar mishaps, NASA stopped hiring members of Black Sabbath.
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Close(ish) to some fact. Read the real story by the singer at the time:
http://www.gillan.com/anecdotage-12.html
Re:crazy (Score:4, Interesting)
Geezer Butler tells a completely different story. [archive.org]
It had nothing to do with me. In fact, I was the one who thought it was really corny. We had Sharon Osbourne's dad, Don Arden, managing us. He came up with the idea of having the stage set be Stonehenge. He wrote the dimensions down and gave it to our tour manager. He wrote it down in meters but he meant to write it down in feet. The people who made it saw fifteen meters in stead of fifteen feet. It was 45 feet high and it wouldn't fit on any stage anywhere so we just had to leave it the storage area. It cost a fortune to make but there was not a building on earth that you could fit it into.
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Re:crazy (Score:4, Funny)
As long as it doesn't require nvidia drivers for Linux, it should be ok!
Re:crazy (Score:4, Funny)
Don't worry, I only used a couple of GOTO statements.
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I only used one...
GOTO MARS;
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It's OK, they included Clippy to guide the lander.
"Hello, I see you're trying to land on a planet, would you like some help with that?"
Re:crazy (Score:5, Informative)
. The whole thing has an amazingly sci-fi feel to it, like it's the opening scene of a sci-fi blockbuster movie. We really do live in amazing times when you think about it.
The skycrane/rover detach from the parachute at around 2:00 and you can watch as the sky crane lowers the rover at 2:48. It does seem a little too elaborate, and my gut feeling watching it is that using such a complicated landing mechanism is just asking for something to go wrong. But then again... well, think about it. Pulleys are pretty simple machines, and we've been using them for thousands of years. There are a lot of machines on this rover that are vastly more complicated than pulleys and cables- the heat shield, the parachute, the nuclear reactor, the onboard computer, the antenna, the camera that finds the landing site, the rocket motors, the software.
I sure as hell hope it all works, though. Unlike the last mission, there's just the one rover, and there's a hell of a lot riding on it. With the cuts to NASA's planetary science program, we won't be headed back to Mars for a long, long time, and it will be a lot harder to get the program started again if Curiosity fails.
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They're already hyping the danger part with the little graphic that says "Earth 15, Mars 24".
K'Breel and the council will be pleased!
Re:crazy (Score:4, Informative)
They have already fumbled once - the mechanism for rotating the observer failed.
That's not a fumble. That's a ten-year-old spacecraft, long past its primary mission, with a temporary problem that they were able to work around.
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Liar.
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Not only that, but it is critical that not only can you do something like rotate the observer several different ways, but those ways are all different ways of doing it. In other words, you want redundant systems that will survive whatever tempest took out the main system.
True, there are certain phases of the mission where you can recover from a malfunction. If there's a software problem en route to Mars, or a hardware malfunction once the rover is on the ground, you can try to find a way to fix or work around the problem. The problem with the landing, obviously, is that you've just got one shot. If the pulleys jam or the cables tangle, if the explosives don't cut the skycrane free, if it selects a bad landing spot or comes in too fast... and it's all happening 15 light-minu
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Having said that, you pointing out the mechanism for rotating the observer. Understand this, in projects like this there is NEVER EVER ANYTHING THAT CAN ONLY BE DONE A SINGLE WAY.
Not only that, but it is critical that not only can you do something like rotate the observer several different ways, but those ways are all different ways of doing it. In other words, you want redundant systems that will survive whatever tempest took out the main system.
Absolutely, but that doesn't mean it's not a failure. If your main parachute doesn't deploy, it's good if your spare deploys, but that doesn't mean whoever packed or produced your parachute didn't screw up.
And, as others have said, for the descent tonight, they only have ONE chance, no backup systems, and a boatload of things that can go wrong. We just have to keep our fingers crossed.
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And the good news is that it has landed.
NASA really needed this one - I'm glad.
"Time Delayed Real Time" (Score:3, Interesting)
"Time Delayed Real Time"
More like "Real Time as constrained by the Speed of Light", it's not like NASA is doing what NBC is doing with the olympics... :rolleyes:
You're right. Not like Olympics (Score:1)
Meh... really?...
"Time Delayed Real Time"
More like "Real Time as constrained by the Speed of Light", it's not like NASA is doing what NBC is doing with the olympics... :rolleyes:
You're right. No one ever threw an object all the way to Mars as part of the Olympics ;-)
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Speaking of which, have you seen the latest shots of the Curiosity crash site? Man that thing went down har... uh... I mean... uh... Look how the markets reacted to another NASA failu... Um, no, wait... Tune in "live" to see the landing in just four more hours! Will Phelps take gold? Will the skycrane smash down right on top of the rover? The world waits in rapt anticipation!
When is it landing? (Score:2)
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http://www.nasa.gov/mission_pages/msl/index.html
Re:When is it landing? (Score:4, Informative)
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It is tonight (the night of Sunday Aug. 5 in the US).
However, on the east coast, and in UTC, this is actually early in the morning on Aug 6, so by some definitions you could call it 'tomorrow'.
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Hollywood Treatment (Score:5, Informative)
I'm really excited, but I doubt the live broadcast will measure up to the bitchin' action movie NASA made of Curiosity's "Seven Minutes of Terror!"
http://www.youtube.com/watch?v=pzqdoXwLBT8 [youtube.com] Enjoy!
Why the skycrane? (Score:2, Interesting)
Re:Why the skycrane? (Score:5, Informative)
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Dust. You don't want martian dust stirred up by the rockets covering all of the mechanics once you have landed.
Couldn't they just pack a hoover and some feather dusters to cope with the dust menace?
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Then you make the thing even more top heavy then the already dangerously off balanced design you'd have with retrorockets, and further increase the risk of landing on your side (falling over). You also introduce two more sources of mission failure (1) the ramp you'd need from using a legged lander, and (2) failure of the cover to detach.
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The Viking landers were about the same size and used classic retro-rockets. Why does the Curiosity use this much more complex arrangement? I couldn't find an easy answer. Is it so the rocket blast doesn't damage the wheels? Is it so the rover doesn't lug around the dead weight of the rockets once it's landed? I really don't get it.
The "7 minutes of terror" video Nasa put together quoted dust fouling up the rover as the reason. I don't know why they couldn't let the dust settle, then blow off a thin housing of some description, but there is no question that would add some weight. In any case people spent YEARS coming up with this design so it is unlikely anything someone is going to come up with in a few minutes of pondering has not been thought of already.
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The mass of curiosity is much more than Viking if you include the mass of the sky crane. If you put it all in the surface it would be about 2-3 times more massive.
I think it all came down to mass. You could of had the exact same system with 3 legs on the sky crane and just wait until after landing to lower the rover. But that would add the mass of some very large structure which due to the damn rocket equation would push them beyond what they could launch.
Olympics (Score:2)
I've long thought it would... (Score:3)
...be interesting to have a "news" program that only aired news reports which were, say, a year old, that way people could look back with hindsight and see how trivial the things were that seemed so big at the time, thus hopefully giving them some perspective on the world as a whole, but I always thought it was just a pipe dream. This whole thing has me thinking that, "In other breaking news from yesterday..." might become a real catch-phrase.
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You can get a bit of that by watching old episodes of the Daily Show or the Weekend Update segments of old episodes of Saturday Night Live. In other news, Generalissimo Francisco Franco is still dead.
For those interested (Score:1)
I was looking for a sidebar gadget for NASA TV and found the ones out there out of date (and not working). For those who care, you can grab my 2 hours of boredom in creating a working sidebar app at: https://docs.google.com/open?id=0BydS_KYWdjtXMVNTbkdjZjdsWE0 [google.com]
It isn't perfect, but I am enjoying it. I hope you do as well.
Here is live stream (Score:3, Informative)
Countdown (Score:4, Informative)
150 kg dead weight? (Score:2)
Can one of the rocket scientists on here explain why, when every gram to orbit is accounted for, 150kg of dead weight was the only way to do this? Couldn't they have at least put some kind of small stationary experiments, retroreflectors for eart
Re:150 kg dead weight? (Score:5, Informative)
It all has to do with shifting the center of mass. From the official NASA press kit: http://mars.jpl.nasa.gov/msl/news/pdfs/MSLLanding.pdf [nasa.gov]
After the turn to entry, the back shell jettisons two solid tungsten weights, called the “cruise balance mass devices.”
Ejecting these devices, which weigh about 165 pounds (75 kilograms) each, shifts the center of mass of
the spacecraft. During the cruise and approach phases, the center of mass is on the axis of the spacecraft’s
stabilizing spin. Offsetting the center of mass for the period during which the spacecraft experiences dynamic
pressure from interaction with the atmosphere gives the Mars Science Laboratory the ability to generate lift,
essentially allowing it to fly through the atmosphere. The ability to generate lift during entry increases this mission’s
capability to land a heavier robot, compared to previous Mars surface missions.
The spacecraft also manipulates that lift, using a technique called “guided entry,” to steer out unpredictable
variations in the density of the Mars atmosphere, improving the precision of landing on target.
During guided entry, small thrusters on the back shell can adjust the angle and direction of lift, enabling the
spacecraft to control how far downrange it is flying. The spacecraft also performs “S” turns, called bank reversals,
to control how far to the left or right of the target it is flying. These maneuvers allow the spacecraft to
correct position errors that may be caused by atmosphere effects, such as wind, or by spacecraft modeling
errors. These guided entry maneuvers are performed autonomously, controlled by the spacecraft’s computer
in response to information that a gyroscope-containing inertial measurement unit provides about deceleration
and direction, indirect indicators of atmospheric density and winds.
After the spacecraft finishes its guided entry maneuvers, a few seconds before the parachute is deployed, the
back shell jettisons another set of tungsten weights to shift the center of mass back to the axis of symmetry.
This set of six weights, the “entry balance mass devices,” each has a mass of about 55 pounds
(25 kilograms). Shedding them re-balances the spacecraft for the parachute portion of the descent.
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So it's actually 300 kg dead weight, but allows them to actually land a bigger rover? That's really cool.
Any reason not to try to embed little experiments in the weights though?
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Any reason not to try to embed little experiments in the weights though?
My guess is density - it's the densest common metal (1.7 times the density of lead), so it takes up less much space than an experiment pod would use. Plus the center of gravity of the tungsten weight is easy to calculate, while an experiment pod's center of gravity could shift if the materials inside move around. 150kg of Tungsten takes up the space of a cube of around 20cm on each side. Even if the experiment pod was a block of solid aluminum, each side of the cube would need to be around 40cm, so would be
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And why tungsten anyway?
Because its the densest material around that isn't also absurdly expensive (Platinum, Iridium, Osmium, or Gold), or radioactive (Plutonium), so they can use smaller weights.
Mars Homeland Security (Score:3)
Well great... publicize the time and location and you are just making the formidable Mars Homeland Security's job easy. Loose lips sinks ships.
Yay team! (Score:2)
If all goes well (Score:2)
An interesting definition of "all going well"...
What? No 3D animation? (Score:2)
I can respect the geek appeal of the engineering (Score:2)
I can respect the geek appeal of the engineering. However I compare it to writing a console app in java when a bash,perl or python script would have gotten it done without including 400 jar files.
Some links (Score:4, Informative)
Happy viewing! Fingers crossed!
:)
p.s. watching the simulation while listening to the beautiful blue danube is kind of fun
Bugger The Tonight Crap (Score:2)
Ustream NASA JPL ("media" stream) http://www.ustream.tv/nasajpl2 [ustream.tv]
Ustream NASA Public (ie 'media' stream plus inserted clips, talking heads, etc) http://www.ustream.tv/nasahdtv [ustream.tv]
The Circus starts approx 3pm (Australian Eastern) and the fireworks (or not) around 3:30pm.
Space tigers (Score:2)
* rimshot *
Re: (Score:2)
Never seen the time !! Does anybody really know what time it is ?? Does anybody really care ?? Know what time ??
If you'd have clicked through to the article, you'd see the whole timeline. Though I'm not sure why you were modded down as a troll, it's a valid question and it seems that many news sources only say "late Sunday night" without giving any times. in any case:
The landing stage separates from the cruise stage at 10:14:34pm PST.
Here's the last few seconds of the timeline (again, see the linked article [ieee.org] for the full timeline):
10:31:08 PM: At about 20 meters above the surface, MSL keeps decelerating down to 0.75 m/s. /quote>
10:31:14 PM: Less than 20 meters from the surface, the sky crane shuts off four of its eight engines as the rover separates and begins to descend on cables.
10:31:15 PM: MSL releases its "bogie" wheels, getting ready for touchdown.
10:31:30 PM: TOUCHDOWN! WOOHOO!!! Curiosity knows when she's on the ground when the load on the tether that she used to get from the skycrane to the ground goes slack.
10:31:33 PM: Cables connecting Curiosity to the skycrane are cut, and the skycrane flies off for a crash landing.
Re:So WHAT'S THE FUCKING TIME ALREADY !! (Score:5, Informative)
Just noticed a typo in the article -- it's actually PDT, not PST.
NASA has a convenient countdown timer here:
http://www.nasa.gov/mission_pages/msl/index.html [nasa.gov]
Re: (Score:3)
Re: (Score:1)
It would kind of suck if all we were getting were digits and shots of the control room.
I don't think NASA pays too much attention to the PR side of things...probably why budgets are being slashed.
Talk about a troll!
Google "7 minute of terror" for proof NASA pays attention to PR. Then consider the justification of doubling the cost so that we can have a second craft or adding a boom and camera to take the kind of video you want to see...assuming it's even possible. I have no idea what the schedule will be for the deployment of the mast, and first images but if they could factor it in to a live broadcast I'm sure they will.
This isn't a Hollywood movie or Star Trek. This is real.
Re: (Score:2)
+1 yay!
Mars is a tough place to land, and the folks at JPL managed to do something magnificent. Here's to another decade of good science from the red planet!