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Space Forum / Shuttle / November 2007A few questions about terminology...
I was watching the STS-120 landing video, and I heard a call saying "You are on energy approaching the hack"... What exactly does this mean? Heading alignment circle? What does "on energy" mean though. Thanks! Oh, and a few from launch as well..... Is "go at throttle up" the call after the vehicle hits Max Q, and they are cleared to fire the engines fully again? and "negative return" meaning that they can not RTLS right? Single engine OPS-3?? What does that mean. And go for Plus X? >Single engine OPS-3?? What does that mean. Continue to orbit even if only one SSME is firing, I think. OPS-3 is a flight control software mode, I think for Earth orbit operations. Paging Jorge... >And go for Plus X? RCS thruster firing in the forward direction, as opposed to -x, +y, -y, (sideways) +z and -z (up/down). Brian > >Single engine OPS-3?? What does that mean. > [quoted text clipped - 10 lines] > > Brian Oh, and I understand the ATO scenarios, but when they call "press to ATO", are they just saying that they are now at a nominal altitude to ATO? Why use "press"? >>> Single engine OPS-3?? What does that mean. >> Continue to orbit even if only one SSME is firing, I think. [quoted text clipped - 12 lines] > ATO", are they just saying that they are now at a nominal altitude to > ATO? Yes, except the abort boundaries are based on velocity, not altitude. Ah, I see, so press to ATO can be called once the shuttle has reached a certain velocity. Truly fascinating stuff. Jorge, do you work for NASA? Forgive my ignorance, I just discovered this place today. The space shuttle program absolutely fascinates me. I would give anything to even come close to being on a mission. > Ah, I see, so press to ATO can be called once the shuttle has reached > a certain velocity. [quoted text clipped - 6 lines] > The space shuttle program absolutely fascinates me. I would give > anything to even come close to being on a mission. It seems you have about 13 more opportunities to buy a cheapo (a relative term) airline ticket to MCO or MLB, reserve a room at the Econo-Inn and rent a compact car. There are pleanty of threads in the past about the best places to be to watch a launch. If you have the flexibility, choose a location downwind; the rumble is worth the price of admission. Take care . . . John > > Ah, I see, so press to ATO can be called once the shuttle has reached > > a certain velocity. [quoted text clipped - 17 lines] > > John Well, I live in Orlando, and venture over there for each and every launch, but still. Not quite close enough for me... :) > > > Ah, I see, so press to ATO can be called once the shuttle has reached > > > a certain velocity. [quoted text clipped - 23 lines] > > - Show quoted text - Ahhhhh . . . Now I so very much understand *S* . . . I would like to be that close too *S* Take care . . . John On Nov 12, 6:24 pm, duelingdrag...@gmail.com wrote: > > >Single engine OPS-3?? What does that mean. > [quoted text clipped - 15 lines] > ATO? > Why use "press"? Press is another way of "keep going" or "go for it." It means that given current conditions, you can move on to the next ascent milestone. I can remember Press from STS-1, although I do not remember from the Gemini or Apollo days (Jorge?) I suspect the Press call developed as they began procedure development and simulations prior to the first STS flight. Take care . . . John >> Single engine OPS-3?? What does that mean. > [quoted text clipped - 3 lines] > > Paging Jorge... OPS 3 is actually the entry/TAL software (orbit is OPS 2). I'm not an ascent/entry guy, but I think that call represents the first time at which you'd use TAL guidance for a 2-out case as opposed to contingency abort guidance. Danny would know more about that than me. >> And go for Plus X? > > RCS thruster firing in the forward direction, as opposed to -x, +y, > -y, (sideways) +z and -z (up/down). Specifically, the "go for +X" ascent call refers to a manual +X translation performed by the CDR right after the automatic -Z translation following ET sep. The purpose of the +X translation is to "pan" the ET umbilical well camera over the ET at close range to improve post-sep photography for debris assessment. >Oh, and a few from launch as well..... > >Is "go at throttle up" the call after the vehicle hits Max Q, and they >are cleared to fire the engines fully again? No, that call comes after the engines have already throttled back up. It is essentially saying that throttle-up was successful. It if weren't, then the crew would have to start looking at contingency aborts. >and "negative return" meaning that they can not RTLS right? Yes. Brian > I was watching the STS-120 landing video, and I heard a call saying > "You are on energy approaching the hack"... > > What exactly does this mean? Heading alignment circle? From context, yeah, the HAC is the heading alignment circle. > What does "on energy" mean though. I can't respond authoritatively on this, so take it with a grain of salt, but my educated guess is that the call means they're happy with the air speed/altitude they've got, and that they'll soon need to begin their turn. As it's a glider, having sufficient energy in velocity & altitude is important to get em to the landing site. Likely, others here can say more. I found this article that speaks in these terms that might tell you all you wanna know in terms of energies, HAC, and how guidance will modify the entry based on drag and energy, etc: http://spaceflight.nasa.gov/shuttle/reference/shutref/sts/profile.html Best Regards, -- Todd H. http://toddh.net/ |
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