Shuttle Questions Q and A (2)

• #420 by DaveS on 06 Oct, 2006 19:31
• For some time now, I have been curious on the ECO sensor mod that Endeavour is getting prior to STS-118/13A.1. What does it consist of? And how will it aid in future problems with ECO sensors? And one third final question: Will Atlantis and Discovery get it?
• #421 by shuttlefan on 09 Oct, 2006 21:53
• On what mission was the worst weather conditions NASA actually launched through. No doubt, overall, Apollo 12. But what about the shuttle?
• #422 by Jim on 09 Oct, 2006 22:00
• shuttle never launched through "bad" weather.  There may have been questionable weather at the RTLS and TAL sites.
• #423 by psloss on 09 Oct, 2006 22:13
• The launch that comes to mind was 51-I on 27 August 1985, but only in relative terms -- no idea what the observed or forecast weather conditions were.  I can't remember in what publication(s) a John Young memo was published after the Challenger disaster, but I believe he noted that launch and 51-D.  
  
• #424 by spaceshuttle on 22 Oct, 2006 17:36
• ok, about the roll program
  
  does the magnitude of the roll (i.e. 90, 110, 135, or 157.5 degrees) depend on the altitude in which they are targeting?
• #425 by psloss on 22 Oct, 2006 17:46
• Quote

  spaceshuttle - 22/10/2006  1:19 PM
  
  ok, about the roll program
  
  does the magnitude of the roll (i.e. 90, 110, 135, or 157.5 degrees) depend on the altitude in which they are targeting?

  Launch azimuth, not altitude.
  
• #426 by Jorge on 22 Oct, 2006 17:58
• Quote

  psloss - 22/10/2006  12:29 PM
  
  

  Quote

  spaceshuttle - 22/10/2006  1:19 PM
  
  ok, about the roll program
  
  does the magnitude of the roll (i.e. 90, 110, 135, or 157.5 degrees) depend on the altitude in which they are targeting?

  Launch azimuth, not altitude.
  

  
  And in turn, the launch azimuth depends on the orbit inclination they are targeting.
  --
  JRF
• #427 by spaceshuttle on 22 Oct, 2006 19:44
• GLS copies.  
• #428 by elmarko on 31 Oct, 2006 08:37
• I was just wondering, if the speedbraek in the approach and landing phase is constantly modulated to keep the shuttle to 300 knots, how can a flight be low or high on energy at this point, resulting in a late or early chute. Surely by this stage, every approach (weight limit for touchdown speed not withstanding) should be largely the same?
  
  Edit: Corrected appauling spelling and grammar.
  
  Edit 2: Did I REALLY put shoot when I meant chute? Good lord...
• #429 by Jim on 31 Oct, 2006 11:25
• Quote

  elmarko - 31/10/2006  4:20 AM
  
  I was just wondering, if the speedbreak in the approaching and landing phase is constantly modulated to keep the shuttle to 300 knots, how can a flight be low or high on energy at this point, resulting in a late or early shoot. Surely by this stage, every approach (weight limit for touchdown speed not withstanding) should be largely the same?

  
  You forgot about winds.  Also the energy management starts much earlier
• #430 by elmarko on 31 Oct, 2006 12:17
• Aha! Winds. Fair point.
  
  Edited my post to correct stupid spelling errors, btw.
• #431 by mkirk on 31 Oct, 2006 15:26
• Quote

  elmarko - 31/10/2006  3:20 AM
  
  I was just wondering, if the speedbreak in the approach and landing phase is constantly modulated to keep the shuttle to 300 knots, how can a flight be low or high on energy at this point, resulting in a late or early chute. Surely by this stage, every approach (weight limit for touchdown speed not withstanding) should be largely the same?
  
  Edit: Corrected appauling spelling and grammar.
  
  Edit 2: Did I REALLY put shoot when I meant chute? Good lord...

  
  The speed brake actually has many purposes during entry.  Under normal conditions the speed brake is opened at MACH 10 to 81% to act as a trim device.  This keeps the elevons from reaching full deflections (i.e. becoming saturated).  Beginning at around MACH 3.2 the brake starts to ramp down (i.e. close).  Below .9 MACH it really acts as an energy control tool.  As the orbiter rolls out on final it tranforms into an airspeed control device.
  
  While at any time manual control by the Commander or Pilot is possible the guidance system is the best tool for modulating the correct settings assuming guidance and nav are good.  At 3000 feet the brake is retracted to an angle determined by the GPCs (general purpose computers) based on wind speed, vehicle weight, velocity, density altitude, selected aim point and crew settings specified in the GPC Horizontal Situation Display.  It is adjusted again at 500 feet and then goes to full open at touchdown.
  
  For those who have seen the Entry Video on L2, you can hear Dan Burbank and Chris Ferguson making the speed brake callouts for Brent Jett.
  
  Mark Kirkman
  
• #432 by spaceshuttle on 01 Nov, 2006 12:08
• possibly a jessica simpson-type question...okay, when they say [39] degree inclination, do they mean that the shuttle orbits 39 degrees AGAINST the equator (like an Angle symbol from geometry class) or [39] degrees ABOVE the equator?
• #433 by cabbage on 01 Nov, 2006 12:41
• If you drew the track of the shuttle on the ground as a line, that line would make an angle of 39 degrees where it crossed the equator. For higher-inclination orbits, the ground track gets to higher latitudes. This is why geostationary satellites (zero degree inclination - they orbit over the equator) are easier to launch from near the equator than from higher latitudes.
• #434 by RamjetFDO on 01 Nov, 2006 13:51

• Quote

  spaceshuttle - 1/11/2006 6:51 AM possibly a jessica simpson-type question...okay, when they say [39] degree inclination, do they mean that the shuttle orbits 39 degrees AGAINST the equator (like an Angle symbol from geometry class) or [39] degrees ABOVE the equator?

  Inclination is the angle of the orbit plane in relation to the equator.  So, in your question above, it is the "against" answer... 

   http://liftoff.msfc.nasa.gov/academy/rocket_sci/orbmech/orbit/orb_pic/orb2.gif" width="372" border="0" />

• #435 by spaceshuttle on 01 Nov, 2006 18:20
• cool! GLS copies.
  i did notice a pattern:
  space stations are at 51 degrees, satellites are usually at 28 degrees, and everything else is right inbetween at 39.
• #436 by Jim on 01 Nov, 2006 18:32
• Not exactly.  The ISS is at 51.6 degrees because that is the lowest the Russians can fly to.  28 is the lowest that launch vehicles can fly out of the Cape without a plane change.  0 degress is used by comsats and the launch vehicle have to provide the plane change.  90-100 degrees are flown out of VAFB and weather, recon, earth resource and mapping satellites use them
  
  39 degrees is not used by anything except for a few shuttle missions that had timing requirements
• #437 by spaceshuttle on 01 Nov, 2006 18:52
• Quote

  Jim - 1/11/2006  1:15 PM
  
  Not exactly.  The ISS is at 51.6 degrees because that is the lowest the Russians can fly to.  28 is the lowest that launch vehicles can fly out of the Cape without a plane change.  0 degress is used by comsats and the launch vehicle have to provide the plane change.  90-100 degrees are flown out of VAFB and weather, recon, earth resource and mapping satellites use them
  
  39 degrees is not used by anything except for a few shuttle missions that had timing requirements

  
  WOW...there's copious factors for everything! lol
• #438 by spaceshuttle on 06 Nov, 2006 23:27
• he-he...okay next question
  
  i know why the front of the tanks USUALLY end up lighter than rest (the RSS covers that general area), but howcome some of the tanks have weird blotches, rings, and dashes on them?

  ---

  
• #439 by Jim on 06 Nov, 2006 23:53
• repairs and modifications
  
  Wow, save the STS-106 photo for all the discussions on the sunlight darkening the foam.  The RSS shadowing is very pronounced.