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
  #11  
Old 01-10-2018, 10:12 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 aeppel_cpm
I saw a report from the amateur sat trackers that the 2nd stage had been sighted over east Africa venting fuel (normal) at a time/place that implied a -higher- than initially guessed orbit.

And the 2nd stage is in-orbit when it's done. Other second stages have taken weeks to months to deorbit. If it came down in the Indian Ocean, it was because of a disposal burn - also common practice.

So, if the satellite didn't separate correctly, and a pre-programmed disposal burn brought it back down, I think the 2nd stage would have re-entered long - further SE of Australia than normal - because of the extra (unplanned) mass of the satellite making the disposal burn less effective.
I agree with your analysis. I think the witnessed propellant venting involved LOX (some of which would have to be vented, at least at intervals, to prevent over-pressurization and rupture of the LOX tank, and since they now use super-chilled, densified LOX, this would be an even more pressing--no pun intended!--need). They may even--although I'd have to check the Falcon 9 payload users' guide to be sure--vent a little LOX (or even just boiled-off gaseous oxygen) continuously during inter-burn coasting periods to provide "ullage thrust," to keep the LOX and RP-1 packed down on their respective inlets to the Vacuum Merlin engine. Also, pieces of a satellite (which would--usually--be denser and more massive [especially per unit of frontal area, giving a higher ballistic coefficient] than pieces of the hollow, lightweight second stage) would have a further tendency to land long, and:

The disposal burn of the Falcon 9 second stage is easily visible from the ground when skies are clear; *here* (see: www.youtube.com/watch?v=AlIQbmmxjus , www.youtube.com/watch?v=RiFBl1RQLbo , and www.youtube.com/watch?v=To9DXDzTCRU ) are ground views of the Stage 2 disposal burn that occurred during the CRS-10 Dragon flight to the ISS on 2/19/17 (the launch and Stage 1 landing can be seen here: www.youtube.com/watch?v=g2G8sUnvHak ). Because this event is visible from a pretty large area on the Earth's surface, even if there was bad weather (*some* patch of ground or ocean in the area should have clear skies), maybe one or more videos showing the disposal burn will turn up on YouTube (perhaps listed as UFO footage, as the above-linked CRS-10 second stage disposal burn videos were). Technically, they *were* UFOs to those witnesses, because they couldn't identify what they were seeing and videoing in the sky... :-)
__________________
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
  #12  
Old 01-10-2018, 11:54 AM
aeppel_cpm aeppel_cpm is offline
Ciderwright
 
Join Date: Apr 2013
Location: Burlington, WI
Posts: 633
Default

http://www.theregister.co.uk/2006/0...006_episode_23/

"The actual question was 'is that a 747-200F or a 747-200C'?" the PFY says.

"Yes?" the Boss says.

"And you said something like 'I dunno' didn't you?" the head asks.

"Well, I don't know anything about planes," he replies defensively.

"And what do we call a flying object that you can't identify?" the PFY asks.
__________________
Charles McGonegal
Ciderwright
AEppelTreow Winery & Distillery
Ad Astra Tabernamque!
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 03:31 PM.


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