Visibility of Shuttle Orbiter & External Tank on Thursday

Date: Sun Dec 02 2007 - 06:23:48 UTC

  • Next message: Russell Eberst: "2007DEC1-2.OBS"

    On Friday, NASA managers cleared the shuttle Atlantis and its crew for  
    blastoff Dec. 6 to the International Space Station (STS-122). 
    Atlantis is scheduled to lift off from pad 39A at the Kennedy Space  Center 
    at 4:31:44 p.m. EST next Thursday, roughly the moment when Earth's  rotation 
    carries the launch pad into the plane of the orbit of the ISS.
    As I noted a few weeks ago, the stage is now set for a most  interesting 
    scenario for observers in the NYC Area because the time of liftoff  comes just 
    five minutes after local sunset.
    There is a precedent dating back more than 16-years ago: 
    Back on September 12, 1991, STS-48 was launched at 7:11 p.m.  That was  only 
    one-minute after local sunset for NYC.  And yet, I still consider that  as the 
    best Shuttle launch I've ever seen from the NY area because the Shuttle  
    orbiter and its orange external fuel tank were illuminated by sunlight as it  
    moved parallel to the US East Coast.  This made the Shuttle appear  incredibly 
    bright . . . from Levittown, Long Island (where I was living back  then) I 
    estimated the total magnitude of the "stack" (orbiter & external  tank) at -5 -- 
    brighter than the planet Venus!  
    Moreover . . . instead of flickering out into invisibility at MECO (main  
    engine cutoff ~ 8.4 minutes after liftoff), what was observed was a "puff" of  
    vapor emanating from the Shuttle.  Thereafter, the orbiter continued to be  
    visible as it rapidly sailed off toward the northeast.  Moreover, through 7  x 35 
    binoculars, I could actually see the separation of the whitish orbiter from  
    the dull orange external tank, which occurs at an altitude of about 73-miles  
    about 400 miles southeast of NYC.  This was indeed a rare and spectacular  
    I have been waiting all these years since for another shuttle launch that  
    similarly would coincide with a time just after local sunset and it now appears  
    that next Thursday (weather conditions permitting, of course) another  
    opportunity will finally come my way.
    Interestingly, at Cape Canaveral, the launch occurs 54-minutes before  local 
    sunset in a bright daytime sky.  But as Atlantis gradually plods  
    northeastward, paralleling the southeast and middle Atlantic coastline, it will  move 
    toward the Earth's terminator line, separating daylight from darkness.  
    From the NYC area, the Shuttle will probably first become visible very low  
    above the southern horizon about 7 to 8 minutes after liftoff (4:38 to 4:39 
    p.m.  EST).  It then will move rapidly over to the south-southeast, where at MECO 
     (4:40.1 p.m.) it will reach a maximum altitude of 8.5-degrees above the  
    It will then race to the east-southeast where both orbiter and the external  
    tank should disappear about a minute or so later.
    This display will also be visible from southern New England and might even  
    be observable from locations to the south of NYC, even from where the Sun will  
    still be just above the southwestern horizon (such as Ocean City,  Maryland). 
    -- joe rao    
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