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Mars Science

MSL Landing Timeline: What To Expect Tonight 140

Posted by samzenpus
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."
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MSL Landing Timeline: What To Expect Tonight

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  • by mark-t (151149) <markt@lynx . b c.ca> on Sunday August 05, 2012 @07:20PM (#40889739) Journal
    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.
    • by Anonymous Coward on Sunday August 05, 2012 @07:25PM (#40889775)

      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.

      • by NF6X (725054)

        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.

      • Trolling. How is that not obvious?

      • by bcrowell (177657) on Sunday August 05, 2012 @11:35PM (#40891151) Homepage

        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.

        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.

        • 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.

          • by khayman80 (824400) *

            I say this as someone who went to grad school for GR

            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?

    • by Anonymous Coward on Sunday August 05, 2012 @07:41PM (#40889885)

      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.

      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.

    • 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.

      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!)

    • by jamesh (87723)

      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.

  • by Anonymous Coward

    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

  • by Anonymous Coward

    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)

      by skipkent (1510) on Sunday August 05, 2012 @07:26PM (#40889785)

      Don't forget the imperial to metric conversions!

      • Re:crazy (Score:5, Funny)

        by M. Baranczak (726671) on Sunday August 05, 2012 @08:17PM (#40890083)

        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.

        • Re: (Score:2, Informative)

          by Anonymous Coward

          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)

            by M. Baranczak (726671) on Sunday August 05, 2012 @10:38PM (#40890835)

            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.

    • by hlavac (914630)
      That's what is worrying me, especially the programming part. My prediction is total failure due to a stupid software bug.
    • Re:crazy (Score:5, Informative)

      by flyingsquid (813711) on Sunday August 05, 2012 @09:20PM (#40890437)
      If you haven't already caught it, here's the animation showing how the whole thing is supposed to work: http://www.youtube.com/watch?v=BudlaGh1A0o [youtube.com]

      . 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.

      • Well, almost exactly the same system [youtube.com] worked well for Spirit and Opportunity, so it should be fine for Curiosity. Actually, things should work out better for Curiosity, since it isn't going to be dropped like a stone and bounced all over the planet, but placed ever so gently onto the surface.
  • by BBF_BBF (812493) on Sunday August 05, 2012 @07:24PM (#40889767)
    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:

    • by Anonymous Coward

      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 ;-)

    • by Malf.me (2697131)
      NBC is probably too busy with a closeup shot of a crying young Russian girl after the Fobos-Grunt incident [wikipedia.org] to cover the MSL. With plenty of derisive commentary of course.
    • by pla (258480)
      it's not like NASA is doing what NBC is doing with the olympics... :rolleyes:

      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!
  • I'm seeing conflicting reports... Is it tonight (as in a few hours from now) or tomorrow (27 hours from now)?
  • 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)

    by Anonymous Coward
    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.
    • Re:Why the skycrane? (Score:5, Informative)

      by andsens (1658865) on Sunday August 05, 2012 @07:44PM (#40889911)
      Dust. You don't want martian dust stirred up by the rockets covering all of the mechanics once you have landed.
      • by tehcyder (746570)

        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?

    • by Anonymous Coward

      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.

    • by trout007 (975317)

      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.

  • There's NBC with their time delay again.
  • by Anubis IV (1279820) on Sunday August 05, 2012 @07:55PM (#40889965)

    ...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.

    • by Convector (897502)

      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.

  • Warning *Plug*

    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)

    by GoodNewsJimDotCom (2244874) on Sunday August 05, 2012 @08:13PM (#40890059)
  • Countdown (Score:4, Informative)

    by DarwinSurvivor (1752106) on Sunday August 05, 2012 @08:44PM (#40890263)
    Would it really be so much to ask for a link to the Countdown [nasa.gov]?!?
  • 10:28:46 PM: At this point, MSL has decelerated to less than 500 m/s. It fires off six 25kg tungsten weights that it was using to offset its center of gravity straight out the side of the aeroshell to rebalance itself, reducing its angle of attack to close to zero.

    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

    • by chalker (718945) on Sunday August 05, 2012 @09:43PM (#40890583) Homepage

      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.

      • by jackbird (721605)

        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?

        • by hawguy (1600213)

          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

  • by Camel Pilot (78781) on Sunday August 05, 2012 @09:30PM (#40890501) Homepage Journal

    Well great... publicize the time and location and you are just making the formidable Mars Homeland Security's job easy. Loose lips sinks ships.

  • Go Sounders! Oh, wait. *MSL*.
  • we'll be getting confirmation on the success (or failure)

    An interesting definition of "all going well"...

  • This is the year 2012, no 3D animation on what the MSL is doing right now? Jeez!
  • 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)

    by jomama717 (779243) <jomama717@gmail.com> on Sunday August 05, 2012 @10:52PM (#40890891) Journal
    Here are some good links that I have cobbled together mostly from previous slashdot articles:

    Happy viewing! Fingers crossed!

    p.s. watching the simulation while listening to the beautiful blue danube is kind of fun :)

  • I want to know what's going to happen This Afternoon.

    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.
  • If one of them catches and tries to eat it, it will be a case of the cat killing Curiosity.

    * rimshot *

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