RE: Verify your Atlantis predictions.

From: Erkenswick, Tom M. (JSC-DM3) (tom.m.erkenswick@nasa.gov)
Date: Thu Jun 21 2007 - 16:30:58 EDT

  • Next message: Dale Ireland: "RE: Verify your Atlantis predictions."

     
    Chris,
    
    That is not what was meant by "earlier opportunity."  The purpose of the burn is to change the orbit's major axis, thus affecting the orbit's nodal regression, which brings Edwards into the crossrange limits one rev earlier than with the current orbit - in other words, it "buys" us an extra deorbit opportunity on an earlier rev, and based on the quote below it sounds like they're trying to land prior to the forecasted wind increase.  I believe the burn is posigrade, which means Atlantis will be later than current elements.  
    
    Tom
    
    
    The opinions expressed are my own and not those of NASA.
    
    
    
    -----Original Message-----
    From: Chris Jones [mailto:clj@panix.com] 
    Sent: Thursday, June 21, 2007 2:39 PM
    To: seesat-l@satobs.org; brad.young@domain-engineering.com
    Subject: Re: Verify your Atlantis predictions.
    
    Brad Young wrote:
    > Pardon my orbital ignorance, but wouldn't a scrub mean they would just
    > continue their present orbit, slowly falling further behind ISS (since still
    > higher) until de-orbit burn less than an hour before landing? So,
    > practically speaking, look for ISS and wait, similar path a few minutes
    > later?
    
    This is an excerpt from the "CBS Space News" mailing list sent out by William 
    Harwood:
    
       astronaut Dominic "Tony" Antonelli radioed [Atlantis]... "At Edwards, the
       winds are going to pick up. So what we've come up with is in about three
       hours, we're going to do an 11-foot-per second (rocket firing) and what
       that's going to do for us is pull in an earlier Edwards opportunity"
    
    so it would seem that, after the rocket firing, Atlantis will be arriving 
    along its orbit earlier than the current elements would predict.
    
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