MSL Landing Timeline: What To Expect Tonight 140
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:0, Informative)
Real time simply means that there are deadlines on the system (in the technical sense).
Here the deadline is simply so relaxed that using that term becomes useless.
The real question we should be asking is what does time-delayed mean?
Is there some other non-temporal delay that I'm not aware of?
Space delayed? why are they even saying delayed? Doesn't the travel time automatically delay the signal, or are they adding extra delay?
Maybe they are using negative time delay to make the signal "real time".
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!
Re:When is it landing? (Score:4, Informative)
Re:Why the skycrane? (Score:5, Informative)
Here is live stream (Score:3, Informative)
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]
Countdown (Score:4, Informative)
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.
Re:crazy (Score:2, Informative)
Close(ish) to some fact. Read the real story by the singer at the time:
http://www.gillan.com/anecdotage-12.html
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.
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.
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