Quote by elmarko: Actually, that's a request for L2, potentially. Is there any kind of documentation about the DVIS system? I'd be really interested, as someone who sometimes deals with audio routing and the like (we have radio studios at my university job).
You're wonderful, thank you so much!Is there any kind of orientation training manual kind of thing for new users, or do they just get given the manual?
Quote from: elmarko on 09/03/2009 08:47 amYou're wonderful, thank you so much!Is there any kind of orientation training manual kind of thing for new users, or do they just get given the manual?I don't recall even getting the manual. DVIS is one of those things you learn by having a senior sit next to you and show you how to use it. It has some fancy features but 90% of what a flight controller will ever use it for can be learned in ten minutes.
Quote from: elmarko on 09/02/2009 11:05 amIt's really hard to visualise it.I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...It is actually very easy to visualize. Take a foam orbiter toy. Shove a stick into the belly at a 40 degree angle below the nose. That is the relative wind vector. It is also the X axis of the stability axis frame. That is the key. The bank is performed about stability axes, not body axes.Now orient the toy so that you're looking down the stick at the belly. You're seeing the orbiter from the relative wind point of view. As long as the relative wind is aligned with the stick, the proper angle of attack (alpha) of 40 and sideslip angle (beta) of zero are maintained.Now rotate the orbiter toy about the stick so that the belly is on top and the nose is pointed 40 degrees down. That's a prebank of 180. But the relative wind is still looking at the black belly, not the white tiles.That's the key. When you perform a "roll" during entry you are rolling about the stability axes (the stick) and not the body axes (the nose). If you rolled 180 about the body axes you'd wind up with the top (white tiles) facing the wind. But a roll about stability axes always keeps the black side facing the wind.
It's really hard to visualise it.I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...
Quote from: Jorge on 09/02/2009 07:04 pmQuote from: elmarko on 09/02/2009 11:05 amIt's really hard to visualise it.I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...It is actually very easy to visualize. Take a foam orbiter toy. Shove a stick into the belly at a 40 degree angle below the nose. That is the relative wind vector. It is also the X axis of the stability axis frame. That is the key. The bank is performed about stability axes, not body axes.Now orient the toy so that you're looking down the stick at the belly. You're seeing the orbiter from the relative wind point of view. As long as the relative wind is aligned with the stick, the proper angle of attack (alpha) of 40 and sideslip angle (beta) of zero are maintained.Now rotate the orbiter toy about the stick so that the belly is on top and the nose is pointed 40 degrees down. That's a prebank of 180. But the relative wind is still looking at the black belly, not the white tiles.That's the key. When you perform a "roll" during entry you are rolling about the stability axes (the stick) and not the body axes (the nose). If you rolled 180 about the body axes you'd wind up with the top (white tiles) facing the wind. But a roll about stability axes always keeps the black side facing the wind.Jorge, I have read this explaianation over and over and still can't picture it. where can I find a drawing of this? Even stick figures will help as I am not a member of L2.ThanksOxford750
Ok - stick figures it is :-) And I am not positive that I got this right, but I will try. In my pic, the upper Orbiter is with bottom towards ground and travelling to the 'left' of pic...arrow indicates direction of air/wind that Orbiter is 'seeing' upon its surfaces/wings. (angle0of-attack of wings is approximate but should give general idea)Lower pic is after Orbiter 'rolls' 180 over onto its 'belly', so to speak. However, notice how its the 'bottom' that is striking the 'wind'? Yes, the top is facing downwards, but nothing else has changed for the most part, particularly the angle-of-attack of the wings -v- airflow. Its a position kind of like when an airplane is about to touchdown on landing (if that helps?)...I realize my terms are not standard, but trying to 'dumb it down' (no offense to anyone!). Jorge's explanation got me FINALLY picturing all this in my head, and I am (used to be anyways) a licensed pilot, LOL! Thanks, Jorge..seriously, it helped me more than you may realize!Anyways, hope that helps, and I truly hope that I am showing things correctly... not too shabby for a quick Paint sketch, 'eh?AlexEdit - Jorge beat me to the pic...and I like his pic much better :-)
To whom it may concern:How can the (small compared to ISS) shuttle, or even the russian segment, for that matter, boost the orbit of the ISS? I mean don't you need MORE more thrusters spread out along the truss on both sides (like the shuttle) to boost the mass of ISS.ThanksOxford750
Quote from: AlexInOklahoma on 09/05/2009 02:26 amOk - stick figures it is :-) And I am not positive that I got this right, but I will try. In my pic, the upper Orbiter is with bottom towards ground and travelling to the 'left' of pic...arrow indicates direction of air/wind that Orbiter is 'seeing' upon its surfaces/wings. (angle0of-attack of wings is approximate but should give general idea)Lower pic is after Orbiter 'rolls' 180 over onto its 'belly', so to speak. However, notice how its the 'bottom' that is striking the 'wind'? Yes, the top is facing downwards, but nothing else has changed for the most part, particularly the angle-of-attack of the wings -v- airflow. Its a position kind of like when an airplane is about to touchdown on landing (if that helps?)...I realize my terms are not standard, but trying to 'dumb it down' (no offense to anyone!). Jorge's explanation got me FINALLY picturing all this in my head, and I am (used to be anyways) a licensed pilot, LOL! Thanks, Jorge..seriously, it helped me more than you may realize!Anyways, hope that helps, and I truly hope that I am showing things correctly... not too shabby for a quick Paint sketch, 'eh?AlexEdit - Jorge beat me to the pic...and I like his pic much better :-)Wow I never knew that the shuttle did that to "bleed off speed" or do I have it wrong. After seeing that I realized that I DID have the "right" picture in my mind, I just needed a conformation.Thanks AlexInOklahoma
Wow I never knew that the shuttle did that to "bleed off speed" or do I have it wrong. After seeing that I realized that I DID have the "right" picture in my mind, I just needed a conformation.Thanks AlexInOklahoma
Quote from: oxford750 on 09/05/2009 02:19 amTo whom it may concern:How can the (small compared to ISS) shuttle, or even the russian segment, for that matter, boost the orbit of the ISS? I mean don't you need MORE more thrusters spread out along the truss on both sides (like the shuttle) to boost the mass of ISS.ThanksOxford750It's not so much the quantity or size of the thrusters as much as where they're located and how much time is needed for the burn.Note that either the Russian segment or Progress thrusters can used for reboosts (and usually are).
Thanks for that answer however the other problem I am having is with the center of gravity. I mean is the shuttle "not" on the "wrong" side of the stations center of gravity as opposed to Directly beneth it, (ie the thusters at the nose and the tail of the shuttle are an equall distance from the "middle" of the payload bay) therefore imparting the station to "roll" and or "yaw" and the same thing with the russain segment ?
This probably belongs in ISS Q&A, but anyway... the thrust doesn't have to be exactly through the center of the stacks CG. You can counter the torques with other thrusters, it just burns some additional propellant.Thrust a long the long axis of the station (i.e. a Progress or ATV docked on the end of Zvezda firing rearward facing engines) is pretty close to the CG, and AFAIK this is the preferred configuration to do reboosts.
snipWell, more accurately the orbiter *could* do that if it needed to. To my knowledge, we've never done a prebank of 180. I kinda doubt it's ever gone past 90, actually.
where can I find a drawing of this?
Quote from: oxford750 on 09/05/2009 06:20 amThanks for that answer however the other problem I am having is with the center of gravity. I mean is the shuttle "not" on the "wrong" side of the stations center of gravity as opposed to Directly beneth it, (ie the thusters at the nose and the tail of the shuttle are an equall distance from the "middle" of the payload bay) therefore imparting the station to "roll" and or "yaw" and the same thing with the russain segment ?This probably belongs in ISS Q&A, but anyway... the thrust doesn't have to be exactly through the center of the stacks CG. You can counter the torques with other thrusters, it just burns some additional propellant.Thrust a long the long axis of the station (i.e. a Progress or ATV docked on the end of Zvezda firing rearward facing engines) is pretty close to the CG, and AFAIK this is the preferred configuration to do reboosts.