Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Weather-Cocked > FreeForAll
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 11-12-2017, 05:36 AM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default Antares GO for launch

Hello All,

Live coverage of today’s re-scheduled Antares launch preparations is already in progress *here* (see: http://spaceflightnow.com/2017/11/1...-status-center/ and www.nasa.gov/nasalive ), and the launch time is 7:14 AM EST (1214 GMT). Yesterday morning’s stray airplane-caused launch scrub is covered here (see: http://spaceflightnow.com/2017/11/1...yward-airplane/ ), and the readers’ comments about the pilot are priceless—and spot-on! :-)

I hope this material will be useful.
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
  #2  
Old 11-12-2017, 06:47 AM
tbzep's Avatar
tbzep tbzep is offline
Dazed and Confused
 
Join Date: Mar 2005
Location: TN
Posts: 11,610
Default

Assuming audio and video were sync'd, ignition was approximately +1 and liftoff +4 seconds.
__________________
I love sanding.
Reply With Quote
  #3  
Old 11-12-2017, 07:00 AM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Wow—YouTube’ers are fast! One has already (see: www.youtube.com/watch?v=T6L4R9xKtSg ) uploaded a video of this morning’s Antares Cygnus OA-8 launch which occurred just minutes ago, which includes a quick preliminary “slide show” of the Antares launch vehicle and the Cygnus space freighter being prepared for flight, and a collage covering the space career of the late astronaut Eugene Cernan—the last man to walk on the Moon—after whom the Cygnus spaceship is named.
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
  #4  
Old 11-12-2017, 07:08 AM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Quote:
Originally Posted by tbzep
Assuming audio and video were sync'd, ignition was approximately +1 and liftoff +4 seconds.
I noticed that apparent delay or lag, too. For some launch vehicles, though (particularly, ones with liquid propellant first stages), the countdown isn't--as it usually is--set up so that liftoff occurs at T=0. In such cases, T=0 is when the engine(s)' start command is issued by the countdown sequencer, or when the engine(s) ignite, so that ignition and/or liftoff occurs at T plus a few seconds. I don't know if any of these were the cause behind what we saw, or if it was a video/audio synchronization issue. Also:

Interestingly, instead of using "T" (for "Time of launch") for the countdown events ("T minus 6 minutes and counting," "T plus 73 seconds," etc.), the Antares launch crew at Wallops appears to be using "L" (for "Launch") instead. At their latest weather briefing yesterday, the meteorological officer referred to the expected winds and cloud cover "at L minus 0." In addition:

In the old days, of course, launch crews used "X" because the actual moment of liftoff wasn't known precisely (partly because many terminal countdown events had to be sequenced manually back then). The last launch (at the Cape, at least) to use an "X countdown" was that of Explorer 1, where X minus 0 was "Firing command." This was followed by X plus 0 "Open fuel prevalves; close liquid oxygen vent," and after a few more "X plus ..." events, ignition was at X plus 14 seconds and liftoff occurred at X plus 15.75 seconds. The first countdown to use "T" (where either ignition or liftoff occurred at T=0 [it varies from vehicle to vehicle]) was for the launch of Explorer 2 (whose fourth stage failed to fire, so that it failed to orbit).
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 03:53 PM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe © 1998-2024