SpaceX Falcon 9 FT - ORBCOMM-2 - Dec. 21, 2015 (Return To Flight) DISCUSSION

[Lars-J]

So if the booster gave around 170GJ of energy to the payload (0.5*125*1.65²)then how did it manage to come back to the launch site? Is the 120GJ  an understatement or was the payload significantly lighter than 125 tonnes?

Because it was much lighter? Once the 2nd stage and payload separated, the first stage and remaining propellant is pretty light, and it takes much less energy to make it come back to the launch site.

[bstrong]

I spoke too soon:

http://www.challenges.fr/entreprise/aeronautique/20151222.CHA3140/le-lanceur-spatial-reutilisable-de-spacex-une-equation-economique-incertaine-pour-arianespace.html

The most interesting part of that article was that "silicon valley players" are pushing Arianespace for sub $10M launches for small payloads. That's the most direct evidence I've seen so far that there is, in fact, elasticity in the launch market, with a whole new class of customers waiting for launches to drop below some threshold.

That fact undermines most of his arguments.

[the_other_Doug]

Quoting a post from the Updates thread, to actually discuss the new landing pictures SpaceX has posted (and not post the same pics again, thus doubling the server space hit):

SpaceX added more landing pictures to their Flickr page, from cameras pre-positioned at the landing site: https://www.flickr.com/photos/spacexphotos

Looks to me like the stage was, once again, completing a final translation maneuver as it came in to land.  At the very least, it wasn't completely vertical and coming straight down until the very, very last second.

I want to see some of the videos from ground level, now, to be able to better assess the vehicle dynamics as she came down through the final 100 meters or so.  I'm sure we'll see them in the next few days, if not hours.

Edit:  Link came through in the quote, attached pics did not... oh, well, the pics I'm referring to are right at the link, I guess that'll do... 

[CraigLieb]

Webcast screen shot:
Did anyone take notice of the quickly shown capsule still when they were discussing the goal of manned missions to Mars? I was remembering a vehicle was shown and that maybe we were seeing a concept for a MARS vehicle. However, on review it looks like a Dragon 2 over the Moon.  I am including a wide shot showing the whole screen so that folks can quickly find it in the referencing the video count or countdown clock.  Sorry it is not clear, but it was the best I could do taking an image with my phone from an Ipad.

{edit: content editing and... Anyone know the original source of the image used?}

[woods170]

Classic.  The "it ain't proven yet" line starts at the top.

If it were his own company, he might have worried about the possibility that it might actually work instead of clinging to the hope that it won't.

Typical ostrich behaviour.

[Lars-J]

Webcast screen shot:
Did anyone take notice of the quickly shown capsule still shown in when they were discussing the goal of manned missions to Mars? it looks like a Dragon 2 over the moon, or am I seeing things?  I am including a wide shot showing the whole screen so that folks can quickly find it in the referencing the video count or countdown clock.  Sorry it is not clear, but it was the best I could do taking an image with my phone from an Ipad.

Its from a video showing a Dragon 2 landing on Mars. Also known as "Red Dragon".

[the_other_Doug]

Webcast screen shot:
Did anyone take notice of the quickly shown capsule still shown in when they were discussing the goal of manned missions to Mars? it looks like a Dragon 2 over the moon, or am I seeing things?  I am including a wide shot showing the whole screen so that folks can quickly find it in the referencing the video count or countdown clock.  Sorry it is not clear, but it was the best I could do taking an image with my phone from an Ipad.

It's a Red Dragon entering the atmosphere over Mars.

[MKremer]

Looking at those new crane lift pics it made me wonder how they got the lift slings attached to the top of the interstage - did someone ride a basket to the top to attach them, and how did they get back down after that?

[cambrianera]

Musk didn't answered to Bezos yet?
Pity, I would imagine something like this:
"Jeff, thanks for the congrats: unfortunately I've no time to spend in your small circle.
Ya know, there is a cigar waiting for me in the orbital launchers club..."

[rpapo]

Musk didn't answered to Bezos yet?

Actually, compared to how Musk responded to Bezos' trolling the other week, I prefer it this way.  Don't feed the trolls.

[abaddon]

So, from the update thread, looking at just 1st stage events:

Here's a transcription of the numbers:

F9 Orbcomm-2 launch  12/21/2015 20:33 EDT (+23:00 in youtube.com / watch?v=O5bTbVbe4e4)
time         events
+0:02:26    MECO / sep
+0:03:50     boostback  
+0:04:20     boost cutoff  
+0:08:12     reentry burn
+0:08:40     reentry cutoff
+0:09:11     landing burn
+0:09:49     touchdown

Trying to make a rough* characterization of fuel consumption for each burn relative to total fuel consumption:

launch: 146s burn, 9 engines, 100% thrust
boostback: 30s burn, 3 engines, 100% thrust(?)
reentry: 28s burn, 3 engines, 100% thrust(?)
landing: 38s burn, 1 engine, 70% thrust?

We get the following figures:

146*9+30*3+28*3+38*.7=1314+90+84+27=1515 total engine-seconds of burn at 100% thrust

launch: 1314/1515=86.73%
boostback: 90/1515=5.94%
reentry: 84/1515=5.54%
landing: 27/1515=1.78%

Comments/suggestions/corrections welcome...

* Not accounting for throttle-down for max-q (don't know how long or how far, 70%?), and assuming a straight 100% thrust for the three-engine burns and 70% thrust for the one-engine landing burn, also ignoring startup/shutdown transients.

[TrevorMonty]

Musk didn't answered to Bezos yet?

Actually, compared to how Musk responded to Bezos' trolling the other week, I prefer it this way.  Don't feed the trolls.

Elon couldn't resist a "Congratulations Blue Origin, BUT..." tweet so don't surprised when Jeff does the same.

At least Tory Bruno and George Sowers have done a simple "Congratulations SpaceX", which is all that is required.

[yg1968]

New photos just posted on SpaceX's Flickr feed - https://www.flickr.com/photos/spacexphotos

Downloaded and clicked "Set Desktop Picture" 

One of the image has the sign "Landing Zone 1" and is dated November 29th. So it has officially been changed. It is no longer "Landing Complex 1" which was frankly confusing.

[edkyle99]

So, from the update thread, looking at just 1st stage events:

Here's a transcription of the numbers:

F9 Orbcomm-2 launch  12/21/2015 20:33 EDT (+23:00 in youtube.com / watch?v=O5bTbVbe4e4)
time         events
+0:02:26    MECO / sep
+0:03:50     boostback  
+0:04:20     boost cutoff  
+0:08:12     reentry burn
+0:08:40     reentry cutoff
+0:09:11     landing burn
+0:09:49     touchdown

Trying to make a rough* characterization of fuel consumption for each burn relative to total fuel consumption:

launch: 146s burn, 9 engines, 100% thrust
boostback: 30s burn, 3 engines, 100% thrust(?)
reentry: 28s burn, 3 engines, 100% thrust(?)
landing: 38s burn, 1 engine, 70% thrust?

We get the following figures:

146*9+30*3+28*3+38*.7=1314+90+84+27=1515 total engine-seconds of burn at 100% thrust

launch: 1314/1515=86.73%
boostback: 90/1515=5.94%
reentry: 84/1515=5.54%
landing: 27/1515=1.78%

Comments/suggestions/corrections welcome...

* Not accounting for throttle-down for max-q (don't know how long or how far, 70%?), and assuming a straight 100% thrust for the three-engine burns and 70% thrust for the one-engine landing burn, also ignoring startup/shutdown transients.

I had the reentry burn at 20 seconds based on the various spectator YouTube videos now out there.  The landing burn came in at perhaps 32-34 seconds from the same sources.

 - Ed Kyle

[psloss]

Bill Harwood of CBS wrote a big picture article today:
http://www.cbsnews.com/news/experts-applaud-spacex-landing-cautious-about-outlook/

(Apologies if this was posted elsewhere already.)

[Chris Bergin]

Chris, don't know if you said anything about it yet but how did the servers do?

Edit: Nm, saw you posted about it last night and everything was good.

Yeah! I honestly thought we'd stand no chance. Not as in going down, but going into protective mode by removing the guests. Webmaster Mark kept an eye on the ever-improving server hamsters and their wheels were going like crazy, but none of them fell off. We removed some strains like how the forum tracks and counts member activity, as that overloads the software (or something, I don't understand it all). We peaked at 1,118 requests a second on the embedded Google Analyticals tool for a short while....which is nuts and a site record. No one mashed F5 from what I can tell, which really helped.

Was so happy with how the site and servers performed, but it really is thanks to Mark who's got the packages really souped up, such as separate database servers now and that means the attachments and such don't crash us under heavy demand.

Not an advert, but thanks again also to the L2 members. Without them we wouldn't be able to afford these fancy servers. Without them we wouldn't have a site and its really cool community. Very humbling when people back this site with their own money.

[Jakusb]

Chris, don't know if you said anything about it yet but how did the servers do?

Edit: Nm, saw you posted about it last night and everything was good.

Yeah! I honestly thought we'd stand no chance. Not as in going down, but going into protective mode by removing the guests. Webmaster Mark kept an eye on the ever-improving server hamsters and their wheels were going like crazy, but none of them fell off. We removed some strains like how the forum tracks and counts member activity, as that overloads the software (or something, I don't understand it all). We peaked at 1,118 requests a second on the embedded Google Analyticals tool for a short while....which is nuts and a site record. No one mashed F5 from what I can tell, which really helped.

Was so happy with how the site and servers performed, but it really is thanks to Mark who's got the packages really souped up, such as separate database servers now and that means the attachments and such don't crash us under heavy demand.

Not an advert, but thanks again also to the L2 members. Without them we wouldn't be able to afford these fancy servers. Without them we wouldn't have a site and its really cool community. Very humbling when people back this site with their own money.

Worth every penny! Hell it actually is a bargain..
All kudos to you and your team for this amazing site!
The perfect partner for this amazing future of undoubtedly many big advances in the space industry.
Good times and many more ahead!

[rocx]

No one mashed F5 from what I can tell, which really helped.

My guess is that SpaceX's detailed coverage and non-stop action made people feel the need to get their updates from the forum quite a bit less. At least it did for me.

[TrevorMonty]

Classic.  The "it ain't proven yet" line starts at the top.

If it were his own company, he might have worried about the possibility that it might actually work instead of clinging to the hope that it won't.

A Arianespace factory worker has less to worry about in near term from the F9 recovery than SpaceX factory worker. Every recovered booster is one less that SpaceX needs to produce and SpaceX are not known for carrying surplus workers.

[edkyle99]

No one mashed F5 from what I can tell, which really helped.

My guess is that SpaceX's detailed coverage and non-stop action made people feel the need to get their updates from the forum quite a bit less. At least it did for me.

The commentators got more air-time than the rocket itself.  They did a fine job, but their excessive face time was at the expense of pre-launch views of the launch vehicle itself. 

Then there was the loss of image frame caused by the bottom-positioned time-bar thingy.  Compare yesterday's frame with a frame from an earlier launch.  The event itself is crowded out by the graphics.

 - Ed Kyle