Jonesy STS - 19/12/2006 3:00 PMWhat time is undocking?
rdale - 19/12/2006 9:09 AMLanding ground tracks for all three sites now available at http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts116/news/landing.htmlBasic timeline questions are usually answered in the TV schedule: http://www.nasa.gov/multimedia/nasatv/mission_schedule.html
Anybody know what this red dot/arrow thing is?
Speedracer - 19/12/2006 12:04 PM5:09 ET is the undocking. I have the shuttle and station passing over North America at around 5:52 Eastern, so we might be able to see the two spacecraft separating over most of the US East of the Mississippi (From Knoxville, TN where I'm at, pass starts at 5:56 and goes to 6:05). Can someone confirm this?
marsguy - 19/12/2006 1:10 PMAnybody know what this red dot/arrow thing is?
Rob in KC - 19/12/2006 7:33 PMAnother great article by Chris has just turned up on site:http://www.nasaspaceflight.com/content/?cid=4965
JimO - 19/12/2006 7:34 PMFor the East Coast flyover one hour after sep, do we know which will be in front? They will only be completing their fly-around. Undock is CST 4:09, Sep 1 burn 4:38, and sep-2 at 5:06 CST -- so the plume might even be visible to ground observers.
The following items are the only ones left:MDDK:Item 22: BPSMU CablesItem 701: Double Coldbag (w/ samples from MELFI)Item 702: EMU 3015Item 710.3: 4th Plug Attach BoltItems 810 and 810.1: DCS760 Camera and 1.0GB Flash cardsItem 811: Suni WilliamsItem 812: Thomas Reiter
......
brodo - 19/12/2006 2:20 PMDarthVader: look for Item 811.1
jmjawors - 19/12/2006 9:28 PMQuotebrodo - 19/12/2006 2:20 PMDarthVader: look for Item 811.1 Haha... excellent.
brodo - 19/12/2006 2:20 PMlook for Item 811.1
JimO - 19/12/2006 1:34 PMFor the East Coast flyover one hour after sep, do we know which will be in front? They will only be completing their fly-around. Undock is CST 4:09, Sep 1 burn 4:38, and sep-2 at 5:06 CST -- so the plume might even be visible to ground observers.
collectspace - 19/12/2006 3:22 PMFor the story behind 811.1, see: http://www.collectspace.com/news/news-121906a.html
JimO - 19/12/2006 4:21 PM The Weather Channel is now teasing a story that weather is threatening two landing sites for Friday. Are they just hyping their own subject matter?
Weather Channel is like any other TV news and will dress up a story to make it "interesting." Follow the weather facts here - they will tell the whole story!!!
jmjawors - 19/12/2006 1:33 PMWell check that out. That's really cool. And I thought it was just a joke item in the manifest.
JimO - 19/12/2006 4:21 PMThe Weather Channel is now teasing a story that weather is threateningtwo landing sites for Friday. Are they just hyping their own subject matter?
Flightstar - 19/12/2006 4:24 PMThe crew get too much credit for carrying out the flyarouds and RPMs. The orbiter carries it out. The crew simply flick a few switches.
eeergo - 19/12/2006 6:06 PMWhile feeling wordlessly amazed by the images, I was thinking...How does this maneuver work? Still learning orbital mechanics... I figured that maybe they caused some extra velocity in the zenith direction by firing the thrusters, along with some velocity in the aft direction... and because of not having enough orbital velocity to achieve a higher orbit, they fall slowly again. Or do they continously fire the thrusters to control the maneuver? I didn't see any plume though... What I can't grasp is why the shuttle is always properly oriented with respect to their movement...Maybe this should go in the Q&A section, but it seemed on the point right now... however, feel free to change its place, Chris
psloss - 19/12/2006 7:16 PMGood burn, nice video of ignition.
ZeeNL - 20/12/2006 2:05 AMOk, question: in the very unlikely event they can't get the orbiter down on one of the three landing sites on Friday, what will the plan be?
ZeeNL - 19/12/2006 7:48 PMQuick question: Due to what force does the orbiter separate from the ISS? I imagine it can't be a spring force in the docking ring, because the docking port is not in line with the CG of the orbiter. Hmm, the commentator just said that it were indeed the springs Next question: it must induce a slight rotation then, at what distance from the ISS can they use the RCS system?
ZeeNL - 19/12/2006 9:05 PMI don't know if this is still the right place to ask this, but is the force of the RCS jets limited near the ISS and do they worry about the impact of RCS firings on the ISS?
ZeeNL - 19/12/2006 6:48 PMQuick question: Due to what force does the orbiter separate from the ISS? I imagine it can't be a spring force in the docking ring, because the docking port is not in line with the CG of the orbiter. Hmm, the commentator just said that it were indeed the springs Next question: it must induce a slight rotation then, at what distance from the ISS can they use the RCS system?
Jorge - 20/12/2006 3:59 AMQuoteZeeNL - 19/12/2006 6:48 PMQuick question: Due to what force does the orbiter separate from the ISS? I imagine it can't be a spring force in the docking ring, because the docking port is not in line with the CG of the orbiter. Hmm, the commentator just said that it were indeed the springs Next question: it must induce a slight rotation then, at what distance from the ISS can they use the RCS system?Right, the springs in the docking mechanism impart the initial opening rate, but also cause the orbiter to pitch nose-down. When the PLT sees out the aft window that the docking petals are clear, he punches a button allowing the digital autopilot (DAP) to control attitude, using RCS jets to null the pitch rate. For undocking, the DAP is configured to control pitch with the tail upfiring jets with a 10-second delay between firings to minimize plume impingement on ISS. This further increases the opening rate. The PLT then pulses the translational hand controller (THC) to increase the opening rate gradually, first to 0.15 fps, then to 0.2 fps. The PLT maintains 0.2 fps (or faster) until starting the flyaround.-- JRF
ZeeNL - 19/12/2006 8:29 PMThanks for your answer, Jim. I have found this information: "Depressing the low Z push button inhibits all up-firing jets in order to prevent plume damage to payloads or injury to extra-vehicular activity crew members. If a plus Z translation is requested, plus X and minus X jets are fired simultaneously, producing a downward translation because the X jets are oriented in such a way that they have small plus Z thrust components."
ZeeNL - 19/12/2006 9:05 PMDo they use the low Z switch in the early stage? And do they only use the vernier thrusters?
Jorge - 20/12/2006 4:22 AMQuoteZeeNL - 19/12/2006 9:05 PMDo they use the low Z switch in the early stage? And do they only use the vernier thrusters?I think I answered the first question in an earlier post... to answer the second, they use the primary thrusters initially for attitude control (there are no up-firing vernier jets), and select vernier jets one minute after separation.-- JRF
eeergo - 19/12/2006 5:06 PMWhile feeling wordlessly amazed by the images, I was thinking...How does this maneuver work? Still learning orbital mechanics... I figured that maybe they caused some extra velocity in the zenith direction by firing the thrusters, along with some velocity in the aft direction... and because of not having enough orbital velocity to achieve a higher orbit, they fall slowly again. Or do they continously fire the thrusters to control the maneuver? I didn't see any plume though... What I can't grasp is why the shuttle is always properly oriented with respect to their movement...
Flightstar - 19/12/2006 10:30 PMI don't question the skills of astronauts, but the general misconception is they are holding on to a joystick and flying the vehicle.
This is simply not acceptable to the engineers that build look after these vehicles. It's astronaut corp propoganda. Sure they are punching in commands, but its the vehicle that's carrying it out through its engineering.
Jorge - 19/12/2006 11:29 PMI'll have to take some exception to the earlier statements that orbital mechanics are not significant during flyaround... they are, and PLTs spend considerable simulator time during training learning to use this to their advantage. The flyaround can be segmented into quadrants, two within +/-45 degrees of the +/-Vbar, and two within +/-45 degrees of the +/-Rbar.
Jorge - 19/12/2006 10:50 PM Next time you're lurking around OPF2, poke your head into one of those orbiters and check out the hand controllers in the aft flight deck. They aren't just there for decoration.-- JRF
ZeeNL - 19/12/2006 8:43 PMNice stitch work, Avron! And I think at the end of next year, the ISS will be unbalanced again due to the moving of P6 to P5?
The flyaround is indeed initiated with a thrust in the zenith direction. Prior to this, the orbiter is separating along the +Vbar (i.e. along the ISS velocity vector) in a tail-to-Earth, belly-forward attitude. During the initial separation, the PLT uses the translational hand controller (THC) to maintain the ISS docking target within an 8 degree corridor on the centerline (C/L) docking camera. The flyaround is actually initiated with two actions. First, the crew commands the orbiter to point the payload bay at the Earth. This causes the orbiter to pitch nose-up, and causes the ISS docking target to rise in the C/L camera. The PLT reacts to this by pulsing the THC "up" to gradually null the motion until ISS once again appears motionless in the C/L camera. So while an outside observer sees the orbiter thrusting in the zenith direction, to the PLT it's just a matter of keeping the target centered. That probably also answers your question about how the orbiter is always properly oriented with respect to movement.Now, if the crew does nothing else, in about eleven minutes the orbiter will reach the payload-bay-to-Earth attitude and stop rotating. To keep the flyaround going, the crew next commands the orbiter to point the nose at the Earth, then 90 degrees later, the belly, then 90 degrees later, the tail. And the PLT just keeps performing THC pulses to keep ISS in the C/L camera field of view, and maintain range between 600 and 700 ft.I'll have to take some exception to the earlier statements that orbital mechanics are not significant during flyaround... they are, and PLTs spend considerable simulator time during training learning to use this to their advantage. The flyaround can be segmented into quadrants, two within +/-45 degrees of the +/-Vbar, and two within +/-45 degrees of the +/-Rbar.In the Rbar quadrants, the predominant orbital mechanics effect is a tidal effect caused by the orbiter and ISS being different distances from the Earth. This tends to pull the two vehicles apart. It's commonly called, oddly enough, the "Rbar effect". In these quadrants, the PLT mostly has to use THC "in" pulses to keep from drifting outside 700 ft, and "down" pulses (especially when moving toward the Rbar) to keep ISS in the C/L camera.In the Vbar quadrants, the predominant orbital mechanics effect is a coriolis effect due to the orbiter's radial velocity that causes the trajectory to "curl in" toward ISS. This could be countered by using THC "out" pulses, but since the orbiter DAP is in Low Z (see earlier posts for explanation), braking uses a lot of propellant and is avoided by all right-thinking PLTs. The preferred PLT technique is to "power through" the Vbar using THC "up" pulses... while this actually increases the orbiter's radial velocity, it delays the "curl in" until the orbiter is past the Vbar and once again heading toward the Rbar, when the Rbar effect takes over again.
northanger - 20/12/2006 3:46 AMHope this is OT. Somebody got a list of all possible Shuttle landing locations? Not just for STS-116, but all of them? And the list of TALs too if you got em.
northanger - 20/12/2006 8:48 AMfound this.....DoD Support to STS-116 (Discovery)http://www.norad.mil/newsroom/news_releases/2006/120606_e.html
rdale - 20/12/2006 4:22 AMQuotenorthanger - 20/12/2006 3:46 AMHope this is OT. Somebody got a list of all possible Shuttle landing locations? Not just for STS-116, but all of them? And the list of TALs too if you got em.Check the shuttle Q&A thread, I'm pretty sure it's in there, and the full manual with runway markings / pictures / etc is on L2.
FransonUK - 20/12/2006 5:05 AMQuoterdale - 20/12/2006 4:22 AMQuotenorthanger - 20/12/2006 3:46 AMHope this is OT. Somebody got a list of all possible Shuttle landing locations? Not just for STS-116, but all of them? And the list of TALs too if you got em.Check the shuttle Q&A thread, I'm pretty sure it's in there, and the full manual with runway markings / pictures / etc is on L2.There's a huge PDF on L2, with hundreds of the landing sites (all of them) and images of each one and diagrams on how to land at them. There's even one in England! Was shocked that there's so many landing sites in case of an emergancy. 23 megs and nearly 400 pages long.There's also the same version for Soyuz Rescue/Emergancy.
