Quote from: ChrisWilson68 on 04/28/2015 11:54 pmQuote from: DaveS on 04/28/2015 11:07 pmQuote from: StarGeezer on 04/28/2015 10:58 pmI haven't seen anything so far indicating how the craft is 'spinning'. From my geometry days we have x axis (front to back) y axis (left right) and z axis(up down). From edkyle's gif it appears rotating around z axis. How hard is it to correct rotation in one, two or all three axes?Well, you should not read too much into Ed's gif as it's a very simple 2D animation. Based on the video downlinked, it is in a multi-axis spin, so it would require a 3D visualization.Unless different forces are acting on different parts of an object, it always rotates around a single axis. The question is just where that axis is. It might not be close to the x, y, or z axes of the spacecraft.Not true; in torque-free rigid body motion, the angular velocity vector is not stationary in the body (vehicle) axes.
Quote from: DaveS on 04/28/2015 11:07 pmQuote from: StarGeezer on 04/28/2015 10:58 pmI haven't seen anything so far indicating how the craft is 'spinning'. From my geometry days we have x axis (front to back) y axis (left right) and z axis(up down). From edkyle's gif it appears rotating around z axis. How hard is it to correct rotation in one, two or all three axes?Well, you should not read too much into Ed's gif as it's a very simple 2D animation. Based on the video downlinked, it is in a multi-axis spin, so it would require a 3D visualization.Unless different forces are acting on different parts of an object, it always rotates around a single axis. The question is just where that axis is. It might not be close to the x, y, or z axes of the spacecraft.
Quote from: StarGeezer on 04/28/2015 10:58 pmI haven't seen anything so far indicating how the craft is 'spinning'. From my geometry days we have x axis (front to back) y axis (left right) and z axis(up down). From edkyle's gif it appears rotating around z axis. How hard is it to correct rotation in one, two or all three axes?Well, you should not read too much into Ed's gif as it's a very simple 2D animation. Based on the video downlinked, it is in a multi-axis spin, so it would require a 3D visualization.
I haven't seen anything so far indicating how the craft is 'spinning'. From my geometry days we have x axis (front to back) y axis (left right) and z axis(up down). From edkyle's gif it appears rotating around z axis. How hard is it to correct rotation in one, two or all three axes?
So we're coming up on this attempt of communicating with the spacecraft. About an hour away I believe.
How many units of prop do they need to make it to the ISS if the can stabilize the craft?The time for the ground pass is now upon us but I didn't see anything about it on NASA TV, they were talking about new wing designs for planes.
Quote from: Bubbinski on 04/29/2015 12:54 amHow many units of prop do they need to make it to the ISS if the can stabilize the craft?The time for the ground pass is now upon us but I didn't see anything about it on NASA TV, they were talking about new wing designs for planes.The system selected is not ISS refill Prop so they could use that. No clue on what is required to get to ISS.
Quote from: russianhalo117 on 04/29/2015 12:58 amQuote from: Bubbinski on 04/29/2015 12:54 amHow many units of prop do they need to make it to the ISS if the can stabilize the craft?The time for the ground pass is now upon us but I didn't see anything about it on NASA TV, they were talking about new wing designs for planes.The system selected is not ISS refill Prop so they could use that. No clue on what is required to get to ISS.Progress M-25M which also used a Soyuz 2-1A had 195.0 units of prop when it showed up at a range of 690 m: http://forum.nasaspaceflight.com/index.php?topic=28784.msg1278924#msg1278924
Quote from: Chris Bergin on 04/28/2015 03:17 pmThat's clearly not the point that was made. If there's a problem with the next Dragon, then Dragon is stood down. That's the problem....not the vehicle failing to arrive, but the vehicle being stuck on the ground for a lengthy period of time before being able to launch again.Exactly - the crew is fine now, and would be for a good few months even in the event of a Dragon failure, but if Dragon/F9 failed and had to be stood down for a number of months, and Cygnus RTF got delayed (which I suspect it will - since when does anything go to schedule in this business), then that will leave only one HTV to resupply ISS for rest of year. Even with Progress flying, that would make things tight.Essentially, what I'm saying is that ISS is now zero fault tolerant to another resupply craft failure - with ATV gone, Cygnus' failure last year, today's Progress failure, and only one HTV this year, a Dragon failure would essentially cut ISS' regular supply line to Earth. If they couldn't get it back quickly, that would be the issue.
That's clearly not the point that was made. If there's a problem with the next Dragon, then Dragon is stood down. That's the problem....not the vehicle failing to arrive, but the vehicle being stuck on the ground for a lengthy period of time before being able to launch again.
30 units of Prop apparently is where computer GNC and flight safeties tripped because flight computer was not operating in deorbit mode.
Quote from: russianhalo117 on 04/29/2015 12:50 am30 units of Prop apparently is where computer GNC and flight safeties tripped because flight computer was not operating in deorbit mode.Does the "P" number indicate the amount of propellant remaining?
Any word if contact has been established yet?
Events of April 29Another attempt to communicate with Progress M-27M was apparently made during the mission's 13th orbit, in the early hours Moscow Time, however it was also fruitless.
Ah damn!Anatoly Zak @RussianSpaceWeb 7m7 minutes agoSources: Another attempt to talk to a stranded #ProgressM27M cargo ship bears no fruit tonight.
Quote from: Chris Bergin on 04/29/2015 02:10 amAh damn!Anatoly Zak @RussianSpaceWeb 7m7 minutes agoSources: Another attempt to talk to a stranded #ProgressM27M cargo ship bears no fruit tonight.this reminds me of Phobos grunt