Shuttle Questions Q and A (2)

• #200 by mkirk on 17 Jul, 2006 19:13
• Quote

  elmarko - 17/7/2006  10:33 AM
  
  From the Entry Checklist:
  
  HATCH OPENING (ELS)
  Before hatch opening:
  Tabs/Visor - CL
  Green Apple - PULL
  
  Firstly, what is ELS? And secondly, what the heck is the Green Apple?

  
  Jim is right the Green Apple (sometimes called the "granny apple") is the handle that is used to activate the Emergency O2 for the Pressure Suit.  Below is a picture of Reiter taken during egress training at JSC, you can see the little green ball on his right side.
  
  ELS stands for emergency landing site.  Procedures are written differently depending on where the orbiter lands.  The primary landing sites (Kennedy, Edwards, Northrup) have more ground support than a TAL site would have and the TAL sites have more support than an emergency landing site or a contingecy landing site.  In this procedure you listed here, it tells you to activate the O2 because at the ELS there may not be any equipment to detect a potentially hazardous leak from the OMS/RCS thrusters or the APUs...so when you open the hatch at the ELS you automatically assume there is a leak and activate the O2.
  
  Mark Kirkman

  ---

  
• #201 by TheMadCap on 17 Jul, 2006 21:49
• Quote

  NASA_Twix_JSC - 11/7/2006  10:45 AM
  
  If, pretend, there was such a seperation, because they are still going at full thrust, they wouldn't happily drop away, they'd go forward and in various uncontrolled directions. Most likely roasting those on board as they destroy the orbiter and tank. No option.
  
  

  
  
  I believe you would also get a massive deceleration of the remaining stack, leading to destructive aerodynamic forces on the orbiter. In addition to being burned up, of course...
• #202 by elmarko on 18 Jul, 2006 08:58
• Helpful, Mark, thank you
  
  One further question if I may:
  
  When landing at an Emergency Landing Site, what happens to comms? Do they have the frequencies for the approach/tower of all the ELSs? Or is accepted that they will just use 243.000 and hope there's a nice person on the other end monitoring? Or, as a third option, I guess NASA would relay this information ahead and the airport would be.. er... expecting them?
• #203 by MKremer on 18 Jul, 2006 09:01
• I believe NASA has some of its people stationed at every emergency site in constant contact with Houston and with at least the equipment to handle orbiter comms.
  
• #204 by elmarko on 18 Jul, 2006 11:09
• Even the ECALs and the extreme emergency sites? (IE, not TAL sites, but the ones that are listed as being backups in a just in case type of thing
• #205 by Jim on 18 Jul, 2006 12:51
• Quote

  elmarko - 18/7/2006  6:56 AM
  
  Even the ECALs and the extreme emergency sites? (IE, not TAL sites, but the ones that are listed as being backups in a just in case type of thing

  
  the Shuttle uses UHF
• #206 by elmarko on 18 Jul, 2006 13:23
• I know, my point was, what frequency would they use for communication? Stick it on Guard (243.000) or stay on 259.7? Do they even need to talk to the emergency landing site, or do they just carry on talking to Houston?
• #207 by Jim on 18 Jul, 2006 14:03
• Quote

  elmarko - 18/7/2006  9:10 AM
  
  I know, my point was, what frequency would they use for communication? Stick it on Guard (243.000) or stay on 259.7? Do they even need to talk to the emergency landing site, or do they just carry on talking to Houston?

  
  They don't talk the landing site now, why would a change be required.  Houston handles it
• #208 by mkirk on 18 Jul, 2006 22:40
• The Shuttle UHF radios only have the two Frequencies you pointed out (which coincidentally are the same freqs that were used during Mercury, Gemini, and Apollo) and Guard (243.00) so if the agency/tower does not come up on those frequencies then the Shuttle Crew will not be able to communitcate directly with them.
  
  When the Shuttle lands anywhere on the globe. the LSO (Landing Support Officer) in the Mission Control Center is respondible for coordinating with them...this could involve a whole bunch of different people and agencies such as the FAA, ATC (air traffic control), State Department, NASA forward personnel, quick response agencies and so on.
  
  The crew also has a hand held PRC-112 radio for rescue operations and to talk with the Landing Convoy after landing.
  
  Mark Kirkman
• #209 by elmarko on 19 Jul, 2006 09:09
• Thanks for the replies everyone, very interesting I just had a look at that handheld radio on the web, it looks like it's specifically for rescue ops, given that it has all the guard frequencies and 282 (which I'm guessing should be 282.8, which from my memory I believe is allocated to NATO scene and search for SAR ops).
  
  Is that radio used after landing at a "normal" landing site or just for aborts/emergencies/whatever?
  
  And speaking of the LSO, i would assume his/her job would be made much harder if it was a landing on foreign soil, with all the coordination with their local agencies. All that bureaucracy and red tape... heh.
• #210 by Jim on 19 Jul, 2006 11:29
• Quote

  elmarko - 19/7/2006  4:56 AM
  
  Thanks for the replies everyone, very interesting I just had a look at that handheld radio on the web, it looks like it's specifically for rescue ops, given that it has all the guard frequencies and 282 (which I'm guessing should be 282.8, which from my memory I believe is allocated to NATO scene and search for SAR ops).
  
  Is that radio used after landing at a "normal" landing site or just for aborts/emergencies/whatever?
  
  And speaking of the LSO, i would assume his/her job would be made much harder if it was a landing on foreign soil, with all the coordination with their local agencies. All that bureaucracy and red tape... heh.

  
  the orbiter UHF is used on the ground.  Handheld is only for contigencies.  
  
  It would be an extreme small probabilty that the orbiter would land at a site where there isn't a NASA rep at.  If not, there would be some time to plan for it.  
  There is a NASA rep at the TAL sites that handles most of the work load.  There is also DDMS who help.  
  
  The LSO has a back room to handle stuff like this.  It just wouldn't be hem
• #211 by Bruce H on 19 Jul, 2006 18:46
• Quote

  norm103 - 19/7/2006  1:25 PM
  
  if the shuttle would land at the capes sikd stip cold it just be towed over to the opf or would they have to mate it to the sac?

  
  ?? Can't understand your writing, use a spellchecker to help.
• #212 by Jim on 19 Jul, 2006 18:56
• If the orbiter could make its way to the Skid Strip, it could make it to SLF.  There wouldn't be that much energy difference.   But to answer your question, it would be towed  or instead lifted on the OTS and go via land that way.  Whatever would be the cheapest.  (there would be some minor tow route mods)
• #213 by ruthsarian on 19 Jul, 2006 20:51
• I've seen people on here talk about an "ascent assist" where OMS engines are fired during ascent and that the primary purpose for this is to dump excess weight in the form of fuel. People have also said that OMS engines provide relatively little thrust. If that's the case, why carry that much fuel to begin with?
  
  In this picture there's a red-colored shell of some sort around the large nozzle on the OMS pod. Is there any particular reason why these are covered like that and the SSME nozzles are not? And at what point in the processing of the orbiter are they removed?
  
  This picture shows an inside view of the SSME nozzle. This image provides the same view but there's a cover over the MCC. Is that just for protection or does it serve another purpose? At what point is it removed before flight?
  
  Thanks
• #214 by DaveS on 19 Jul, 2006 20:58
• Those red covers are "Foreign Object Debris" covers. The ones at the base of the SSMEs are removed when the vehicle is in the VAB prior to rollout while the OMS FOD covers are removed at the pad a few days prior to launch.
• #215 by HKS on 19 Jul, 2006 20:59
• i have heard that NASA said that the P3/P4 trusses going up on Atlantis on mission STS-115 is to heavy for Discovery. How big is the difference on the weight to ISS for the three remaining orbiters?
  
  And what makes this difference?
• #216 by Jim on 19 Jul, 2006 21:17
• Quote

  ruthsarian - 19/7/2006  4:38 PM
  
  I've seen people on here talk about an "ascent assist" where OMS engines are fired during ascent and that the primary purpose for this is to dump excess weight in the form of fuel. People have also said that OMS engines provide relatively little thrust. If that's the case, why carry that much fuel to begin with?
  
  In this picture there's a red-colored shell of some sort around the large nozzle on the OMS pod. Is there any particular reason why these are covered like that and the SSME nozzles are not? And at what point in the processing of the orbiter are they removed?
  
  This picture shows an inside view of the SSME nozzle. This image provides the same view but there's a cover over the MCC. Is that just for protection or does it serve another purpose? At what point is it removed before flight?
  
  Thanks

  
  Here is my take on OMS assist.  (MKirk will correct me if I am off)
  There are many reasons.  But to sum it up, full tanks is a easier starting point from ground ops and flight analysis prospectives.  
  
  They are all protective covers.  The OMS engines are more fragile than the SSME's  They are removed in the countdown.
• #217 by mkirk on 20 Jul, 2006 00:47
• This was originally posted in the STS-121 Re-entry and Landing Thread and I just noticed I made a mistake in the last paragraph about Theta T.  Fortunately nobody called me on it since that would have been embarrassing, but I mixed up my angles.
  
  Since I can’t go back and edit it, here is how the entire post should have read:
  
  Some of the discussions on other threads about OMS Burns make me want to clarify some things about the De-Orbit Burn.
  
  Tomorrow at about 8:07 eastern time Discovery will fire both OMS engines from a heads down, tail forward, wings level position (pitch will be adjusted as needed prior to the burn - usually +/- 20 degrees). The burn will last for 3 minutes and 2 seconds and will decrease Discovery’s orbital velocity by 302 feet per second (or about 206 statute miles per hour). These numbers will be adjusted slightly tomorrow as the burn targets are more finely tuned by Mission Control. The numbers are also slightly different for each landing opportunity.
  
  The objective of the De-Orbit Burn is to decrease the orbital velocity and in turn decrease the perigee (lowest point) of the orbit. The resulting orbit will be highly elliptical and the path of the orbit is designed such that Discovery will be at an altitude of 400,000 feet at a range from the landing sight of 4449 nautical miles. I never really paid attention to the perigee on the De-Orbit Maneuver Display since I was more interested in other parameters such as time to entry interface, and burn residuals/errors…but I believe that most of the time the perigee of the orbit after the burn is between 5-25 nautical miles. So considering that Discovery will have an apogee (highest point of in the orbit) of around 185 miles, you can see just how elliptical the resulting orbit is.
  
  Anyway my point is the De-Orbit Burn targets a point we call Entry Interface (EI) which is defined as 400,000 feet at a specified range from the runway, in this case 4449 nm for tomorrow’s first opportunity to KSC (for the second opportunity EI occurs at 4375 nm).
  
  For you orbital mechanics experts, the computers refer to the range parameter to EI as Theta T. Theta T is the angle formed by a line drawn from the center of the earth to the OMS engine ignition point and a line drawn from the center of the earth to the orbiter's EI point…I believe this angle is around 160 degrees or so. Theta T is not defined this way for Ascent OMS Burns, but I won’t get into that here.
  
  On average the time from OMS ignition to EI is approximately 30-35 minutes.
  
  Mark Kirkman
• #218 by Jim on 20 Jul, 2006 17:48
• I have a question.  Of the remaining ET's required for the flyout, how many are structurally complete, those only that only require foam and instrumentation etc.
  
  If there was an ET schedule published on a other thread, please point me to it
• #219 by Chris Bergin on 20 Jul, 2006 21:22
• Quote

  Jim - 20/7/2006  6:35 PM
  
  I have a question.  Of the remaining ET's required for the flyout, how many are structurally complete, those only that only require foam and instrumentation etc.
  
  If there was an ET schedule published on a other thread, please point me to it

  
  This is a first, answering a question for Jim!
  
  From L2 MAF ET manifest status:
  
  "ET-123 in now over in Cell A at MAF.
  
  ET-124 is next and will replace ET-123 in Cell A when shipped.
  
  ET-117 is in holding ready - after returning from KSC - ready to enter the flow.
  
  "Our plate is filling up," said deputy ET project manager Mark Bryant (MAF/Lockheed)."
  
  So up to ET-117 is a tank structure. ET-120 is a tank proper, as is ET-93, but were used as test articles...so will need some serious work.
  
  The rest of the tanks are likely to be just a LOX tank here, an intertank there.
  
  That's the last I heard from MAF, but will ask again for an update.