History Making First Recovery for SpaceX - Orbcomm-2 Launch

[Discoducky]

that is an excellent read - and if he really did write that 15 minutes before launch its no wonder he's such an over-achiever.

Totally! I love rocket science! (Or more properly, engineering)

Really interesting read, thanks for the link. I assume that Elon wrote that post (his name is at the bottom) and it was posted 15 minutes before the OrbComm-2 Falcon lift off.
I struggle to understand orbital mechanics, 40 years after taking basic physics and calculus in university, but I think I get the gist of it. Super interesting stuff, to be sure! Any indication that a first stage recovery will be attempted with that launch?

He totally wrote it, says so in the post-landing interview and then goes on to say that he heard the sonic boom right when the stage was landing and thought it was a failure (he only gave 60 to 70% chance of success). So amazing to hurl 125 tons at 5000 mph to 100 km and then bring it back again....perfectly. Pure science fiction...not anymore! It is worth listening to as I've never heard Elon be dumbfounded with exuberance.

Also, the plan seems to be that they will keep this stage grounded. This seems perfectly logical as it is truly unique.

 

[evp]

By the soot patterns in the tank wall, there were at least a half of tank of LOX during Atmospheric Retropropulsion Burn. I don't know is this good or bad? They reserved it that much or that much is needed for landing burn?

.... They probably gave themselves a lot of extra fuel to get it done. WAGging it, I'd say they'll be fine tuning this much more as time goes on as they get more and more landings under their belt....

No. There had to have been a very small fuel margin for the landing. This site claims that 160 seconds of first stage burn are used out of an available 185 seconds when a return to launch site maneuver is attempted, so no more than 14% remaining fuel or about 53,500kg. The second stage and propellant mass less than 100,000 kg, and the payload to LEO is about 13,000kg. So even raising fuel for the return to 17% would completely wipe out the payload capacity.

Actually, it's probably less fuel than that, since the engines are throttled down during the last minute or so to reduce acceleration as the stack gets lighter.

 

[HVM]

...13,000kg...

172 kg *12 = 2064 kg, that's quite heavy satellite dispenser you have there...

 

[lolachampcar]

My wife wants "Space" penned in just in front of the "X".... A new logo for the company.

The audio on this is terrible. Wind is blowing but Elon is interviewed post-landing.

Overview:
00:00. Elon recounts the flight
05:24. Plans for the booster
07:31. Historical significance
10:16. Reflight challenges
12:24. Emotion rollercoaster
14:34. Path to reusability
17:28. Previous successes
19:30. Falcon Heavy vertical landing

Date: December 21, 2015
Elon was 44 years old.

 

[Nevek]

My wife wants "Space" penned in just in front of the "X".... A new logo for the company.

Great idea! A refinement on what they have now. The idea has a "Musk" aura about it.

 

[Johan]

Thank you grendal for posting that interview. It was hard to hear because of the wind, but at one point I thought I heard Elon saying: soon we will have quite a big fleet ofboosters seeing as we are building about one every three weeks. Was this correct? If so they will have quite an amazing fleet of boosters just next year! Basically, if everything goes to plan, they will have taken over the entire launch industry within one or two years. No one is going to be able to compete on price.

 

[Electroman]

Can a kind soul take the trouble of transcribing it? I Ana having a hard time understanding anything at all.

 

[dhanson865]

Thank you grendal for posting that interview. It was hard to hear because of the wind, but at one point I thought I heard Elon saying: soon we will have quite a big fleet ofboosters seeing as we are building about one every three weeks. Was this correct? If so they will have quite an amazing fleet of boosters just next year! Basically, if everything goes to plan, they will have taken over the entire launch industry within one or two years. No one is going to be able to compete on price.

Can a kind soul take the trouble of transcribing it? I Ana having a hard time understanding anything at all.

Listen to this version Orbcomm 2 Teleconference with Elon Musk (de-winded) - YouTube ignore the image, it is much easier to understand. Still not perfect but a vast improvement.

 

[Johan]

Listen to this version Orbcomm 2 Teleconference with Elon Musk (de-winded) - YouTube ignore the image, it is much easier to understand. Still not perfect but a vast improvement.

Excellent! (I live watching Kyle from Southpark too so the image bothers me not).

Anyway, at 15:00 Elon does say they're building Falcon (9?) boosters at a rate of one every three weeks. That's 17 being built in 2016! Remember 2+1 modified Falcon 9 is needed to make a Falcon heavy.

Can't wait for the Falcon Fatman (1 modified Falcon 9 for second stage surrounded by 9 Falcon 9 boosters in a ring formation. That's 90 Merlin engines!)

He went on to say he expects 2/3 to survive return flights, but they'll approach 100% survival in the nearish future.

 

[HVM]

http://shitelonsays.com/transcript/postlanding-teleconference-with-elon-musk-2015-12-22

 

[Electroman]

Thanks for the transcription.

 

[HVM]

Ok, now it looks bit too casual...

(non SpaceX pic) Source: https://www.instagram.com/alternativeauto_2.0/

 

[Ben W]

My wife wants "Space" penned in just in front of the "X".... A new logo for the company.

Here's an attempt...

 

[dsm363]

Here's an attempt...

View attachment 105446

Nice work!

 

[lolachampcar]

wife approved!!!

 

[Patrick W]

More pictures:

SpaceX Photos | Flickr - Photo Sharing!

 

[evp]

172 kg *12 = 2064 kg, that's quite heavy satellite dispenser you have there...

Good point, this flight used nowhere near the final useful load of the vehicle. But I think my math still stands - even with no net payload at LEO, there cannot be more than about 17% fuel left in the first stage if the second stage is going to make it into orbit, certainly not 50%. We must search for another explanation for the interesting soot pattern on the paint.

But the other side of the equation is, of course - how much fuel do they need to make it back to land? Does 17% constitute "a lot of extra fuel"? We know the speed down-range and altitude at staging. We know the time in flight after staging, the mass of the stage, the specific impulse of the engines. I think that's enough to calculate the total delta-vee and thus the necessary mass-fraction of fuel. I'll have to pull out Wolfram Alpha and see if I can get a good estimate. It's only rocket science, after all.

 

[Electroman]

Don't know why that website is named that way - quite crass. But has lot of interesting Elon quotes and transcripts.

This one caught my attention:

"With each successive launch - we have several more launches this year - we expect to get more and more precise with the landing and, if all goes well, I am optimistic that we'll be able to land the stage back at Cape Canaveral by the end of the year."

 

[woof]

That's a lot of carbon scoring there. Looks like that booster's seen a lot of action!

 

[malcolm]

That's a lot of carbon scoring there. Looks like that booster's seen a lot of action!

I see what you did there :biggrin: