[Launch Alert] Thursday Evening Launch (CORRECTION)

[Launch Alert]

A previous Launch Alert gave an incorrect address for obtaining launch/countdown status from the ULA web site. The correct URL is:

   www.ulalaunch.com

Launch/countdown status will also be available from:

   spaceflightnow.com

Here's the latest news on the launch courtesy of the ULA:

"Subject: Media Update: ULA Atlas V NROL-42 Launch Set for September 21
Date: Sep 20, 2017 3:56 PM
Good afternoon – the ULA launch readiness review was completed today everything is progressing toward the ULA Atlas V NROL-42 launch in support of national security. The mission, for the National Reconnaissance Office, is set to lift off on a ULA Atlas V rocket on Thursday, Sept. 21 from Space Launch Complex-3 at Vandenberg Air Force Base in California. Today’s L-1 weather forecast continues to show 60% favorable conditions for launch. The launch time is 10:38 p.m. PDT.
 
Atlas V NROL-42 mission profile located here: https://youtu.be/4UjeoySzxPo
 
Launch Day Forecast
Overall probability of violating weather constraints: 40%
Areas of concern: Launch Visibility, Ground Winds
 
Overall probability of violating weather constraints for 24 Hour Delay: 10%
Areas of concern: Ground Winds
 
Launch Broadcast Satellite Coordinates + Webcast
ALL TIMES PACIFIC
TRANSMIT TEST – SEPTEMBER 20, 2017
12:00 – 12:30 P.M.
 
LAUNCH – SEPTEMBER 21, 2017                                     
BARS AND TONE – 9:47 P.M.
PROGRAM START – 10:18 P.M.
 
TRANSMISSION FOR DIGITAL HIGH DEFINITON
SATELLITE: SES 3
TRANSPONDER: 24
BAND: C-Band Digital
ORBITAL POSITION: 103 degrees west
HD BANDWIDTH: 18 MHz (Half Transponder ‘CD’)
UPLINK FREQ: 6,414.000 MHz (Horizontal)
DOWNLINK FREQ: 4,189.000 MHz (Vertical)
SYMBOL RATE: 13
FEC: ¾
DATA RATE: 17.9705
DVBS-QPSK
MPEG-2
AUDIO EMBEDDED"