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#560 by NASAGeek on 12 Feb, 2008 22:08
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I found a way to subscribe to the shuttle processing email years ago but forgot how to now. anyone know the email address to send a request to subscribe to?
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#561 by DaveS on 12 Feb, 2008 22:32
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To subscribe to the list, send a blank message to: [email protected]
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#562 by SiameseCat on 13 Feb, 2008 01:51
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For the PASS TRAJ display, what is the altitude and velocity range required for the triangle to be visible? Also, do the predictors take into account guidance commands or do they assume constant velocity/thrust?
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#563 by mkirk on 13 Feb, 2008 03:54
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SiameseCat - 12/2/2008 8:51 PM
For the PASS TRAJ display, what is the altitude and velocity range required for the triangle to be visible? Also, do the predictors take into account guidance commands or do they assume constant velocity/thrust?
It was always my understanding that the PASS ASCENT TRAJ was originally developed as an abort display. This explains why the nominal ascent trajectory line (lower right corner) makes up only a small portion. The triangle, which represents the current NAV state, and the guidance predictors (two small circles) represent where the vehicle would be – based on the current NAV state – 20 and 30 seconds into the future. The predictors are available right away; however, they tend to remain all bunched up initially. Velocity is represented by the horizontal axis of the display(increasing from left to right), so the triangle and predictors will begin to separate and track up the trajectory line as the velocity increases.
Ironically it is the BFS (Backup Flight System) ASCENT TRAJ displays which have the better fidelity and serve as the primary visual means of assessing the space shuttle’s ascent trajectory.
I am not sure I understand the second part of your question but I think you are asking if the predictors take into account future guidance commands (such roll to heads up, or 3 g throttle down) before they happen. The answer to that is no. The predictors represent the future path of the shuttle based on the current NAV state – i.e. where it is headed based on a “Snap shot” of the shuttle’s current acceleration and thrust.
Mark Kirkman
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#564 by Andy_Small on 13 Feb, 2008 04:16
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Zephon907 - 12/2/2008 10:29 PM
I didn't get to watch any of the proceedings today, but in a later rerun of one of the Q & A sessions I noticed they were playing with a rubber ball, which presented a question: If they were to bounce the ball in a perfectly straight and perpendicular line between two parallel walls in the ISS, in other words, getting it to bounce back and forth between the walls, would it continue to bounce perpetually? Or would the atmosphere in the ISS eventually slow it down? Or would some other force act on it to slow it down?
It would be interesting to see just how long the ball would bounce.
I'm no expert
But I think the air would provide resistance to slow the ball down.
I'm also not sure but I think when the ball bounced on the wall it would impart some of it's energy into the wall.
But it would stay bouncing for a longer time than on earth!
Welcome to the site! -
#565 by pippin on 13 Feb, 2008 08:17
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Zephon907 - 13/2/2008 5:29 AM
Same as on earth. Gravity in this case is not a loss but just provides some energy conservation.
I didn't get to watch any of the proceedings today, but in a later rerun of one of the Q & A sessions I noticed they were playing with a rubber ball, which presented a question: If they were to bounce the ball in a perfectly straight and perpendicular line between two parallel walls in the ISS, in other words, getting it to bounce back and forth between the walls, would it continue to bounce perpetually? Or would the atmosphere in the ISS eventually slow it down? Or would some other force act on it to slow it down?
It would be interesting to see just how long the ball would bounce.
Losses are from air drag and from inelastic bouncing of the ball (turning the compression of the ball while hitting the wall into heat)
So it's the same as dropping the ball with the same speed and let it bounce off the gound -
#566 by pippin on 13 Feb, 2008 08:51
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Suggestion: How about a Physics Q&A thread? This may be a fun case but there were harder ones under "Advanced Concepts" recently, or is this out of scope for this site? It's quite a bit essential for spaceflight, isn't it?
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#567 by ckiki lwai on 13 Feb, 2008 14:56
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Lawntonlookirs - 12/2/2008 4:21 PM
I know this question has been answered before, but I am not able to find it in the search. How do you copy a picture from NASA TV and post it in the forum?
Another item, for someone new on the forum, the question and answere section is so big that it is hard to find a specific item although the information is very informative.
An easy and free to do that is download vlc player, and play NASATV with it.
Use Ctrl+Alt+S to make a screenshot.
You also have to change the picture extension by going to Settings=>Preferences, Video=>Outputmodules=>Image file there you got to change PNG in JPG.
The snapshots are normally saved in "my pictures". -
#568 by SiameseCat on 14 Feb, 2008 02:58
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On the PASS TRAJ display, how closely does the shuttle follow the 'nominal trajectory line'? If the shuttle followed this line, it should be climbing throughout ascent, whereas it actually descends partway through ascent.
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#569 by GLS on 14 Feb, 2008 12:58
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SiameseCat - 14/2/2008 3:58 AM
On the PASS TRAJ display, how closely does the shuttle follow the 'nominal trajectory line'? If the shuttle followed this line, it should be climbing throughout ascent, whereas it actually descends partway through ascent.
The PASS TRAJ display doesn't show all the ascent... but the BFS ASCENT TRAJ 2 does, and it shows the *little descend* (does it have a name?). -
#570 by ntschke on 14 Feb, 2008 13:04
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Interesting photo. I've heard of the "black team" or something like that are sheltered in bunkers near the pad during launch. In this photo these guys are in "tanks" somewhere close to the pad.
Anyone know where this and what role they play in launch emergency plans?
Mods, if this is in the wrong place please move it or let me know where it should go.
Thanks
"Firefighters exit M113 tanks as space shuttle Atlantis lifts off from pad 39A at the Kennedy Space Center, Thursday Feb. 7, 2008 in Cape Canaveral, Fla. Atlantis' seven member crew are on a 11-day mission to deliver Columbus, a laboratory module built by the European Space Agency, to the international space station."
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#571 by Jim on 14 Feb, 2008 13:16
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They are to help with emergency evacuation/rescue of the crew if needed
They are actually armored personnel carriers
Shuttle Q&A is the right spot -
#572 by refsmmat on 14 Feb, 2008 14:08
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I was at KSC for the launch on the Causeway, it was great.
The next day these two M-113s were still in place on the shoulder, padwards of the MT service station at:
http://tinyurl.com/3dn974
(Google Maps link)
That's about as close as one would want to get, definitely overtime pay for these guys.
24 hrs after launch we took a 'NASA Up Close' bus tour out north of Pad A, where the foliage looked gray with aluminum oxide dust. -
#573 by mkirk on 14 Feb, 2008 14:45
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SiameseCat - 13/2/2008 9:58 PM
On the PASS TRAJ display, how closely does the shuttle follow the 'nominal trajectory line'? If the shuttle followed this line, it should be climbing throughout ascent, whereas it actually descends partway through ascent.
The bug and predictors will track up the line fairly well on the PASS but as I said in my previous post they tend to be bunched up initially and the PASS TRAJ line does not really have the fidelity that the BFS does. As I said this is because the display was originally designed as and ABORT Display. The trajectory lines that are to the left of the nominal ascent display (refer to the diagram in my earlier post) would be used for an RTLS.
For nominal ascents the PASS display is just one of many instruments/displays that make up a good cross check for the crew to assess the overall status of the ascent.
If the crew were flying the space shuttle manually for some reason (for example Guidance is bad but NAV is still good) then the BFS TRAJ would be primary for trajectory pitch control in second stage. During first stage the crew would rely on the ADI and ADI Cue Card for pitch control.
Although the BFS is the backup system and is not in control, it is supposed to be “paying attention” (i.e. tracking NAV and Guidance) so that it is ready to take control at any moment should the need arise. The BFS also has important systems management functions during nominal ascents.
The displays for the BFS (see the diagrams I attached) have much more fidelity and are broken up into first and second stage displays (TRAJ 1 and TRAJ2 respectively). During ascent the crew will compare the BFS attitude digitals (R, P, and Y) with the ADI and ensure the Bug and Predictors are tracking up the TRAJ lines. They will also cross check the guidance commanded throttle setting (T) with the MPS throttle tape displays. Just after staging – i.e. SRB SEP – the crew will also compare the estimated time of MECO (TMECO: for time of main engine cutoff) on both the PASS and BFS displays. This is to ensure that both the primary and backup computers agree on the shuttle's current trajectory – this is what they are referring to when they say “guidance has converged”. If the times do not converge on roughly the same MECO time (should be within a couple of seconds of each other) by about 10 seconds staging, then something is wrong and the crew and mission control would need to assess which system to trust and act accordingly.
The small dip you referred to in your question is visible in the BFS TRAJ 2 display because of the increased scale of the altitude verses velocity plot. This dip is NOT visible on the PASS TRAJ because the altitude/velocity scale of the plot is too small.
Mark Kirkman
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#574 by daj24 on 14 Feb, 2008 17:15
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I have just watched the handheld recorder for the ET. There were many flashes and streams. Was this just tank venting? Is this controlled or just what is going on? TIA
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#575 by rdale on 14 Feb, 2008 17:29
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That's what happened - if you look at the FD1 thread you'll see extensive discussion of it.
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#576 by Jim on 14 Feb, 2008 17:33
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daj24 - 14/2/2008 1:15 PM
I have just watched the handheld recorder for the ET. There were many flashes and streams. Was this just tank venting? Is this controlled or just what is going on? TIA
just uncontrolled venting -
#577 by brahmanknight on 15 Feb, 2008 20:02
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How exactly is oxygen transfered to the high pressure tanks on Quest? I assume it goes through piping on the outside of PMA 2.
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#578 by Lee Jay on 16 Feb, 2008 17:54
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The OMS assist performed during launch happens after SRB separation. Why isn't this performed as soon as possible after throttle up, once high enough in the atmosphere to safely fire the OMS engines?
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#579 by GLS on 16 Feb, 2008 18:03
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I think it's because MM102 doesn't have OMS firing capability... but MM103 has, and MM103 comes after SRB sep so...
