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#340 by Avron on 11 Jun, 2007 03:46
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MySDCUserID - 10/6/2007 8:54 PM
Quotegordo - 10/6/2007 6:58 PM
calm down on the grabs from a media conference please.
Thank you for these. Having missed the conference, I was glad to see these screen shots.
Likewise... thanks for the great coverage -
#341 by Jorge on 11 Jun, 2007 03:57
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Chris Bergin - 10/6/2007 12:14 PM
Ku Band Angle Tracking Problem being worked. Temp drop in tracking when being switched from Auto to GPC mode.
Catching up at the end of a long day...
This was the expected behavior of the knob. The KU SELECT rotary knob has four positions; GPC, GPC DESIG, AUTO TRACK, and MAN SLEW. GPC and AUTO TRACK support closed-loop angle tracking while GPC DESIG and MAN SLEW do not. When rotating the knob from AUTO TRACK to GPC or vice versa, a momentary loss of track may sometimes occur while the switch is moving through the GPC DESIG position, depending on how fast the crewmember rotates the knob. -
#342 by Chris Bergin on 11 Jun, 2007 03:57
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Latest article: http://www.nasaspaceflight.com/content/?cid=5129 - gap fillers et al.
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#343 by Jorge on 11 Jun, 2007 03:58
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kneecaps - 10/6/2007 11:11 AM
RENDEZVOUS PRPLT PAD just copied up to Atlantis. Information of note. No Lo Z permitted when L or R RCS QTY < 55 or FRCS QTY < 17
Nope, those were the breakout bingo quantities (blocks 9 and 10). The No Lo Z blocks (7 and
are always N/A for ISS flights.
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#344 by Jorge on 11 Jun, 2007 03:59
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Do Shuttles Dream - 10/6/2007 11:26 AM
I would post this in Shuttle Q&A but it's happening now and others may want to know. Orbiter is whizzing around the world, faster than the ISS, so catching up. So are all these burns slowing down the approach speed in stages?
Some, not all. Of today's burns, NC-4 and Ti were intended to slow the catch-up rate while NCC, MC1, 2, 3, and 4 were correction burns. -
#345 by Chris Bergin on 11 Jun, 2007 04:01
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Jorge - 11/6/2007 4:57 AM
QuoteChris Bergin - 10/6/2007 12:14 PM
Ku Band Angle Tracking Problem being worked. Temp drop in tracking when being switched from Auto to GPC mode.
Catching up at the end of a long day...
This was the expected behavior of the knob. The KU SELECT rotary knob has four positions; GPC, GPC DESIG, AUTO TRACK, and MAN SLEW. GPC and AUTO TRACK support closed-loop angle tracking while GPC DESIG and MAN SLEW do not. When rotating the knob from AUTO TRACK to GPC or vice versa, a momentary loss of track may sometimes occur while the switch is moving through the GPC DESIG position, depending on how fast the crewmember rotates the knob.
Thanks Jorge. This is priceless for the learning curve and I - as I'm sure we all do - appreciate you spending time to give such clarifications at the end of a long day. Heck, I'm shattered and I'm only reporting the mission, so I don't know how you guys do it! -
#346 by Rob in KC on 11 Jun, 2007 04:06
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I'll second that.
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#347 by Jorge on 11 Jun, 2007 04:08
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kneecaps - 10/6/2007 11:03 AM
QuoteThomas ESA - 10/6/2007 5:00 PM
Did anyone at NASA become concerned about RPM? It must have seemed risky in simulations with the orbiter losing sight of its target?
I don't see that it was of any concern for target sighting. The orbiter could spin about all day there (if it wasn't closing in on the station) and know EXACTLY where to turn to to resight the station.
Actually, the RPM did violate the Flight Design Level B Groundrules and Constraints at the time. Not only did it take the target out of the sight of the crew, it also required the crew to take the Digital Autopilot (DAP) to free drift while the orbiter is upside down. This caused a lot of concern and a great deal of analysis had to be performed to prove that the maneuver was safe. The Level B GR&C were amended to add a specific exception for the RPM as analyzed. Analysis uncovered some specific two-deep failure scenarios that could result in unsafe relative motion during the RPM. Flight Rules were written to make the orbiter NO-GO for the RPM when one failure away from these scenarios.
Part of what makes the RPM safe is that it is performed at 600 feet on the Rbar. At this range, orbital mechanics forces are strong enough to pull the orbiter away from ISS over time. The start conditions for the RPM were carefully tuned so that the RPM would complete with the orbiter not much farther from ISS than at the start. In a contingency, the crew could simply keep the orbiter DAP in free drift and harmlessly "fall away" from ISS. -
#348 by Orbiter Obvious on 11 Jun, 2007 04:13
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I'll third that. Thanks for the coverage. 16,500 views half a Sunday? Who said no interest in Shuttle?
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#349 by Jorge on 11 Jun, 2007 04:34
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psloss - 10/6/2007 11:02 AM
QuoteJimO - 10/6/2007 11:52 AM
They might be easy for mission ops people, but could you spell it out for sofa jockeys like me?
"Ti" -- you might be amused to learn that when I documented rendezvous crew procedures for the mission operations handbook back in the mid-1980s, people had already forgotten what "TI" stood for, and we had to make up a new meaning for it. "NC" and "NPC" and "NCC" -- those were easy. "Ti" was actually a puzzler, but we invented something that sounded credible.
The following are ground targeted burns. In all cases, the "N" used to be a placeholder for an orbit count (e.g. "2H" would be a height-adjust burn on orbit 2, etc), but that nomenclature is no longer used and the "N" now literally stands for "Nothing".
NH - Height adjust burn, places orbiter at a specified delta-height from the target at a specified future time. Typically only one per profile, and not always required (as was the case on 117).
NPC - Plane change burn, places orbiter in plane with the target at a specified future time. Typically only one per profile, and usually performed on Flight Day 2 to allow time to track out planar error. 117 didn't need one since the plane crossing was close enough to NC-2 to allow the two to be combined.
NSR - Slow rate burn, places orbiter co-elliptic (equal delta-H at both apogee and perigee) with the target. Not performed much any more since the effect of an NSR can be achieved more efficiently by moving an NC or NH burn away from the line of apsides (the line connecting apogee and perigee).
NC - Catchup (phasing) burn, places orbiter at a specified downrange distance (or phase angle) at a specified future time. Typically there is an NC burn at the beginning and end of the crew day. For rendezvous flights, the OMS-2 burn (normally a circularization burn) is actually used as the first phasing burn but keeps the OMS-2 nomenclature.
The following are onboard targeted burns:
NCC - Corrective combination, a fancy midcourse correction burn
Ti - Transition Initiation, the burn that targets the orbiter to the boundary of prox ops with the target vehicle.
MC1, 2, 3, 4 - Midcourse Correction burns
Trivia:
The old coelliptic (Gemini, Apollo) rendezvous profiles had a burn called TPI (Terminal Phase Initiation) that targeted the chaser to intercept the target. TPI is just close enough to Ti to cause confusion, and even now you will occasionally hear someone erroneously describe Ti as "Terminal Initiation", or "Terminal Intercept", or some other weird combination.
The orbiter's onboard Lambert targeting routine uses the terms T1 and T2 to refer to the time of the burn and the time the burn is targeting for, respectively. The reason Ti is always spelled with a lowercase "i" is to attempt to minimize confusion between T1 and Ti, especially important back in the days when procedure pages were sent to the crew using a primitive low-resolution fax machine called TAGS. -
#350 by James Lowe1 on 11 Jun, 2007 04:53
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Orbiter Obvious - 10/6/2007 11:13 PM
I'll third that. Thanks for the coverage. 16,500 views half a Sunday? Who said no interest in Shuttle?
It's always a lot more. The "there are X other users online" and thread counters only catch so many people/clicks. Your point is correct however! -
#351 by Jorge on 11 Jun, 2007 05:14
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Chris Bergin - 10/6/2007 11:01 PM
QuoteJorge - 11/6/2007 4:57 AM
QuoteChris Bergin - 10/6/2007 12:14 PM
Ku Band Angle Tracking Problem being worked. Temp drop in tracking when being switched from Auto to GPC mode.
Catching up at the end of a long day...
This was the expected behavior of the knob. The KU SELECT rotary knob has four positions; GPC, GPC DESIG, AUTO TRACK, and MAN SLEW. GPC and AUTO TRACK support closed-loop angle tracking while GPC DESIG and MAN SLEW do not. When rotating the knob from AUTO TRACK to GPC or vice versa, a momentary loss of track may sometimes occur while the switch is moving through the GPC DESIG position, depending on how fast the crewmember rotates the knob.
Thanks Jorge. This is priceless for the learning curve and I - as I'm sure we all do - appreciate you spending time to give such clarifications at the end of a long day. Heck, I'm shattered and I'm only reporting the mission, so I don't know how you guys do it!
Oops...
Finally got around to reading the L2 MER funny on the angle tracking problem - that is a separate problem from the one I described (the one I described did happen on this flight, and based on the timing of your original comment I assumed that's what you were talking about).
Sorry for the confusion... -
#352 by lsullivan411 on 11 Jun, 2007 06:37
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Don't know if anyones watching the FD highlights, but a huge thanks to the crew for all the detailed inside shots. Best crew footage in a long time!
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#353 by chksix on 11 Jun, 2007 07:29
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Watching the replays now of the middeck video. Nice that they filmed so much! The EMU's look a bit scary when packed, similar to an Incas mummy!
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#354 by psloss on 11 Jun, 2007 10:07
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Jorge - 11/6/2007 12:34 AM
Thanks as always, Jorge.
The following are ground targeted burns. In all cases, the "N" used to be a placeholder for an orbit count (e.g. "2H" would be a height-adjust burn on orbit 2, etc), but that nomenclature is no longer used and the "N" now literally stands for "Nothing".
(snip)
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#355 by James Lowe1 on 18 Jun, 2007 17:14
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Bump to align mission pages in order.
are always N/A for ISS flights.
