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SpaceX Vehicles and Missions => SpaceX Reusable Rockets Section => Topic started by: Chris Bergin on 07/22/2014 07:20 PM

Title: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Chris Bergin on 07/22/2014 07:20 PM
Lens iced over for the most part:

http://youtu.be/CQnR5fhCXkQ
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sublimemarsupial on 07/22/2014 07:22 PM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 07/22/2014 07:23 PM
:)  Ours is still better!!!  (The video, I mean)  (and I'm not serious)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Orbiter on 07/22/2014 07:26 PM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."

Flight 13 right now is CRS-4, if anyone was wondering.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Dudely on 07/22/2014 07:26 PM
I find it absolutely hilarious that the recovered video that we fixed was in some ways better than this one!

So who wants to guess what "solid surface" means?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Chris Bergin on 07/22/2014 07:27 PM
Someone remind me which mission Flight 13 is with?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Dudely on 07/22/2014 07:30 PM
Link to their article on it. Has some cool info, including a reference to possibly landing on a floating platform.

http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sublimemarsupial on 07/22/2014 07:31 PM
Someone remind me which mission Flight 13 is with?

Orbcomm was flight 10, so if the manifest stays the way it is then flight 11 will be AsiaSat-8, flight 12 will be AsiaSat-6, and flight 13 will be CRS-4
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: abaddon on 07/22/2014 07:31 PM
Presumably the ice formation on this flight, when there was none on CRS-3, was due to the high trajectory...

Interesting choice of words, land "on a solid surface".  That suggests it might not be on land, which further suggests it will be some sort of floating platform.  I agree with the general forum consensus that such an idea is likely not economical but perhaps as a step to proving they can stick the landing it is reasonable?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mongo62 on 07/22/2014 07:31 PM
A few notes:

1. The Kaboom that Elon mentioned does not happen until after the stage falls horizontal. I'm guessing that it's simply the tanks being ruptured by mechanical stresses, not an actual explosion. edit -- as stated in the SpaceX release I read after posting this.

2. Could the numerous blotches on the camera lens from the first splashdown video have been created by the same entry burn process as seen in this video, not by the "dirty splash" at launch?

3. The rocket plumes are oddly patterned in this video, with a series of parallel "interference patterns", no doubt due to the arrangement of the three firing engines.

4. From the SpaceX release: "Going forward, we are taking steps to minimize the build up of ice and spots on the camera housing in order to gather improved video on future launches." Perhaps a transparent cover over the camera lens that can be ejected, or flipped out of the way, after the entry burn is finished?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: TOG on 07/22/2014 07:34 PM
OMG! OMG! OMG!  That was totally AWESOME!

Wait, when? 

Ok, then, let's send up the next few "expendable configuration" missions and get on with the business of doing a dirt tap dance!

WOW!
(Copied from my post on the party thread)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: styguy on 07/22/2014 07:39 PM
Great video (when the ice isn't in the way), cant wait until the fall for the attempted water landing on CRS-4 and the potential ground landing for OG2!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: wannamoonbase on 07/22/2014 07:39 PM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."

The real story here is flights 14 & 15 on LAND!!  That's before the end of this year.

Does this mean they have gotten precise in hitting a designated landing location?

I wonder if F9R-Dev 2 is going to be needed if they keep collecting data with these flights?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Tuts36 on 07/22/2014 07:40 PM
Quote
We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success.

I'm wondering if that means 14 & 15 first stage will have falcon feathers (grid fins)?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Sohl on 07/22/2014 07:41 PM
Now all we need to do is crowd-source a deconvolution of the icing effects on the lens.  No sweat, right? ::)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: UberNobody on 07/22/2014 07:42 PM
The landing burn almost looked like it was sputtering.  Why would it look like that?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: VulcanCafe on 07/22/2014 07:42 PM
The real story here is flights 14 & 15 on LAND!!  That's before the end of this year.

Not quite, the quote is 'land on a solid surface.'  Could be a stationary stabilized barge etc. I assume the words were carefully chosen to include a variety of possibilities.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: moralec on 07/22/2014 07:42 PM
What an amazing video and exciting information on the road ahead! Let's have our fingers crossed for success meeting the schedule on the upcoming missions, so we can get a real landing by the end of this year!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sdsds on 07/22/2014 07:44 PM
Capturing this bit of text (from the SpaceX website July 22 article) for posterity or "future reference".
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Scylla on 07/22/2014 07:44 PM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."

The real story here is flights 14 & 15 on LAND!!  That's before the end of this year.

Does this mean they have gotten precise in hitting a designated landing location?

I wonder if F9R-Dev 2 is going to be needed if they keep collecting data with these flights?

From the same update...

At this point, we are highly confident of being able to land successfully on a floating launch pad or back at the launch site and refly the rocket with no required refurbishment


Or possibly some sort of barge. :o
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Tonioroffo on 07/22/2014 07:46 PM
How about an old oil platform.  They are perfectly stable.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Xspace_engineerX on 07/22/2014 07:47 PM
'with no required refurbishment' - this is a big deal. Until this launch SpaceX has been saying that they didn't know how much refurbishment was required.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/22/2014 07:49 PM
'with no required refurbishment' - this is a big deal. Until this launch SpaceX has been saying that they didn't know how much refurbishment was required.

I'm not sure what they meant there, but it seems like something they wouldn't be able to state accurately UNTIL they could inspect a star returned to land. (End of this year(?), if flight 14 will land)

The outlier reason might be IF they were able to recover a significant amount of vital hardware. Have we heard if anything was recovered?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Scylla on 07/22/2014 07:53 PM
How about an old oil platform.  They are perfectly stable.

I think the helipad of an old oil platform is kind of small for a first attempt. Besides all the oil platforms I've ever seen are kind of tall, tricky getting a Falcon first stage off of one.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mme on 07/22/2014 07:56 PM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."

The real story here is flights 14 & 15 on LAND!!  That's before the end of this year.

Does this mean they have gotten precise in hitting a designated landing location?

I wonder if F9R-Dev 2 is going to be needed if they keep collecting data with these flights?
From: SPACEX SOFT LANDS FALCON 9 ROCKET FIRST STAGE (http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage)
Quote
At this point, we are highly confident of being able to land successfully on a floating launch pad or back at the launch site and refly the rocket with no required refurbishment. However, our next couple launches are for very high velocity geostationary satellite missions, which don’t allow enough residual propellant for landing. In the longer term, missions like that will fly on Falcon Heavy, but until then Falcon 9 will need to fly in expendable mode.

We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success.
Given the wording, they may target a platform at see first, before attempting to land on land.  Either way, this is way sooner than I expected!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/22/2014 07:57 PM
One implication of the news that they only plan one more ocean 'landing' before trying to land on land, is that the next ocean landing attempt (flight #13 - presumably next CRS mission) will have to demonstrate a pinpoint landing. So presumably that will be the first flight with the grid fins installed.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Elmar Moelzer on 07/22/2014 07:57 PM
'with no required refurbishment' - this is a big deal. Until this launch SpaceX has been saying that they didn't know how much refurbishment was required.

I'm not sure what they meant there, but it seems like something they wouldn't be able to state accurately UNTIL they could inspect a star returned to land. (End of this year(?), if flight 14 will land)

The outlier reason might be IF they were able to recover a significant amount of vital hardware. Have we heard if anything was recovered?
My guess is that they are extrapolating from F9R and the telemetry they received from the stage.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Tonioroffo on 07/22/2014 08:01 PM
Checked the recommended helipad sizes (https://new.rotor.com/portals/1/publication/Heliports_25_Most_Asked_Questions.pdf)

65 square feet to 100 square feet - small indeed.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GusTurbo on 07/22/2014 08:05 PM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."

The real story here is flights 14 & 15 on LAND!!  That's before the end of this year.

Does this mean they have gotten precise in hitting a designated landing location?

I wonder if F9R-Dev 2 is going to be needed if they keep collecting data with these flights?

Very exciting news, indeed.

The real question is, is this news about potentially attempting solid-surface landings part of the post Chris had to hide all those months ago?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Elmar Moelzer on 07/22/2014 08:07 PM
The real question is, is this news about potentially attempting solid-surface landings part of the post Chris had to hide all those months ago?
Yeah, wonder what happened with that! Been meaning to ask... Chris?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Scylla on 07/22/2014 08:08 PM
A thought...

Since SpaceX is talking of a possible landing on a floating platform, a small spot in a very big ocean, or landing on land, presumably near launch site where there are lots of breakable, flameable things scattered about, that part of the last flight was bringing the stage down at a specific spot and they were successful?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Dudely on 07/22/2014 08:09 PM
Maybe they are saying it will be able to fly with no refurbishment because punching through the atmosphere in reverse is a pretty violent exercise and they have now done it multiple times with no failure of the structure. And they know they can use the engines a lot because they have done variable numbers of hot fires.

Presumably if they can light three engines twice and one engine three times and do this reliably then it can light nine again fairly easily.


So it's possible they are going on flight history, and have not seen hardware yet (though if I had to wager a guess I would say they've been able to at least recover whole engines by now).
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 07/22/2014 08:10 PM
So that's a lot of new information, some of it we suspected already, but nice to see it confirmed.

A) They'd rather fly a reusable FH than an expendable F9.  That says something about cost. We suspect it's a no brainer and reusability is a lot more of a cost-saver than what's implied here, but still for those that think a reusable vehicle does not equal cost reduction, here it is, formally:  A reusable triple-barrel flight is cheaper than an expendable single-barrel.

B) No refurbishment re-flight is not a far-off future concept. It's ready.

C) In the near term, no increased performance for F9 that will allow it to fly AsiaSat to GTO.

D) Nothing is off the table regarding what lands where.  At least during the next test, they are entertaining landing on a floating platform. Whether that's only a test necessity or also something they care about, remains to be seen.

E) They already feel confident about GNC between re-entry and landing.  I take it then that the grid fins are there to allow this confidence in higher cross winds, for example.

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: wannamoonbase on 07/22/2014 08:11 PM
Or possibly some sort of barge. :o

Thanks all.  I hope it's land based for a few reasons, it's more meaningful and the word barge sounds rough and crude.  Not to mention unstable.

But perhaps landing in the middle of a painted target will provide the proof needed to be allowed to return to CCAFS.

Great news on confirming larger payloads flying on F9H. 

How much of a trip will it be seeing 3 cores land within seconds of each other!!

Edit: I can only assume that they have held conversation on being approved for return to CCAFS.  Do we know what the terms are for approval?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lourens on 07/22/2014 08:12 PM
Checked the recommended helipad sizes (https://new.rotor.com/portals/1/publication/Heliports_25_Most_Asked_Questions.pdf)

65 square feet to 100 square feet - small indeed.

Actually, according to the linked report, 65 foot square to 100 foot square, i.e. a 65 ft by 65 ft to 100 ft by 100 ft foot area. 65 square feet would be 8ft x 8ft, which would fit only model helicopters :).

For the solid surface, I vote iceberg.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: joshcryer on 07/22/2014 08:13 PM
Any word on how much of this Falcon 9 was recovered? That could go into the refurbishment question.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mme on 07/22/2014 08:15 PM
The landing burn almost looked like it was sputtering.  Why would it look like that?
My guess is that it's just the turbo pump's flame being blown back by the descent.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Tonioroffo on 07/22/2014 08:15 PM

Actually, according to the linked report, 65 foot square to 100 foot square, i.e. a 65 ft by 65 ft to 100 ft by 100 ft foot area. 65 square feet would be 8ft x 8ft, which would fit only model helicopters :).

For the solid surface, I vote iceberg.

Sorry, too excited to think straight :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Darga on 07/22/2014 08:19 PM
Looking at the OG2 launch video, stage 1 sep was at 15:17:58 (T+2:43) and from this video, reentry burn started at 15:23:46 (T+8:31), landing burn 15:25:42 (T+10:27), leg deploy 15:25:57 (T+10:42) and splashdown 15:26:05 (T+10:50) if my math is correct.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: saliva_sweet on 07/22/2014 08:25 PM
I wonder about the audio. Was IainCole involved or did they actually have a microphone this time.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mike_1179 on 07/22/2014 08:27 PM
There was some talk about the center core of a FH not being able to return the launch site because it will be too far downrange at staging.  Makes me think they’re building a floating platform for landing the center core of the (then safing it and lowering it to horizontal and shipping it back) and they’ll use that for floating recovery of the F9 stage.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/22/2014 08:28 PM
How much of a trip will it be seeing 3 cores land within seconds of each other!!

Only two cores landing within seconds of each other.  The center core has more flying to do (and getting it back to the launch site would be a challenge, it might land downrange some).
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Barrie on 07/22/2014 08:30 PM
Striking that they talk about landing on a floating launch pad.

And if they give the next water landing a low probability of success, does that mean they are planning to trim some margins and see if they get away with it?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Joey S-IVB on 07/22/2014 08:35 PM
I read it as saying the next water landing has a low probability of successfully recovering the first stage intact.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Scylla on 07/22/2014 08:37 PM
Striking that they talk about landing on a floating launch pad.

And if they give the next water landing a low probability of success, does that mean they are planning to trim some margins and see if they get away with it?

I think it's more likely they are talking about success of recovery as opposed to "KABOOM".
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mr. mark on 07/22/2014 08:39 PM
I guess it's up to me to ask the stupid question of the day :( How does Blue Origins patent pending effect a SpaceX barge recovery at least in the future. Seems as though their patent claim was never resolved let alone had legs to stand on. Any legal experts out there?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GusTurbo on 07/22/2014 08:42 PM
A pending patent doesn't have any legal force, it simply puts others on notice that a patent has been applied for. It may be accepted or rejected.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Scylla on 07/22/2014 08:44 PM
And what they are claiming for patent appears..dubious..at best.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/22/2014 08:45 PM
If they now have pinpoint accuracy, I wonder if we could maybe see quadcopter footage of a landing in the future.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AncientU on 07/22/2014 08:49 PM
The floating platform option allows full boost-back demonstration (less nominal distance offshore of 5-10 miles?).  This is a missing piece of the soft splashdowns to date, and might be an FAA last demo requirement.

Note: the floating platform will have quadcopters, of course!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: yg1968 on 07/22/2014 08:52 PM
One implication of the news that they only plan one more ocean 'landing' before trying to land on land, is that the next ocean landing attempt (flight #13 - presumably next CRS mission) will have to demonstrate a pinpoint landing. So presumably that will be the first flight with the grid fins installed.

Maybe. Maybe not. If they are using a floating launch pad, pin point acuracy may not need to be demonstrated prior to attempting landing on it. But I agree that it would make more sense to do it the way that you are suggesting.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: yg1968 on 07/22/2014 08:56 PM
A pending patent doesn't have any legal force, it simply puts others on notice that a patent has been applied for. It may be accepted or rejected.

This isn't my area of expertise but I believe that a patent can be accepted by the patent office but still not be valid in court. 
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Danderman on 07/22/2014 08:59 PM
A pending patent doesn't have any legal force, it simply puts others on notice that a patent has been applied for. It may be accepted or rejected.

This isn't my area of expertise but I believe that a patent can be accepted by the patent offfice but still not be valid in court. 

Validity of a patent and a legal determination of patent infringement are two different issues.  A judge will never rule whether a patent is valid or not, that is the function of the patent office, but a judge will rule whether a patent is applicable to a specific case.

I don't want to get into the gory details here, but a patent is basically just a document that gives you standing to sue.

Another issue is the priority date of any patent. It is possible that Blue Origin may indeed secure a patent for barge recovery, but their date of coverage may be in the future. I can't tell without looking at their application.  However, the priority date of a patent may actually pre-date the patent, if a provision application is filed.

Hey, I found the link to the patent application:

http://appft1.uspto.gov/netacgi/nph-Parser?
Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&
r=1&f=G&l=50&s1=%2220110017872%22.PGNR.&OS=DN/20110017872&RS=DN/20110017872

It looks like the priority date is June 14, 2010, assuming their application was accepted by the USPTO.

And then I found the patent itself:

http://www.google.com/patents/US20110017872

Jun 15, 2009 is the actual priority date, based on something or other.

wow, this was not only filed in the USA, but also in Canada, Russia, Japan, Europe, and with some World IP Association.

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: yg1968 on 07/22/2014 09:00 PM
If they now have pinpoint accuracy, I wonder if we could maybe see quadcopter footage of a landing in the future.

What makes you think that they have achieved pinpoint accuracy? Isn't that what the grid fins are about?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GusTurbo on 07/22/2014 09:00 PM
A pending patent doesn't have any legal force, it simply puts others on notice that a patent has been applied for. It may be accepted or rejected.

This isn't my area of expertise but I believe that a patent can be accepted by the patent offfice but still not be valid in court.

Admittedly not my area of expertise either. Also, I shouldn't be wasting my time here since I have the bar exam coming up next Tuesday.  :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/22/2014 09:05 PM
If they now have pinpoint accuracy, I wonder if we could maybe see quadcopter footage of a landing in the future.

What makes you think that they have achieved pinpoint accuracy? Isn't that what the grid fins are about?

What makes you think I said they had?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/22/2014 09:06 PM
I agree that the primary purpose of the floating platform is probably to demonstrate "pin point accuracy" -- so it may be useful even if not practical for "real" use and/or not stable enough to prevent kaboom.  Does anyone know off-hand what sort of vessel/barge positioning accuracy you can get "without too much trouble" in the middle of the ocean?  This sort of position holding is routine for geotechnical exploration, oil rigs, etc, but it would be nice to try to quantify it.  I suspect the lat/long positioning would be much more precise than the altitude positioning -- you need quite a large vessel to even out wave action -- but having a defined non-specular surface would undoubtedly be good for the radar altimeter.

My wild guess is that that outstanding patent is one of the reasons they are hedging about the floating platform.  If there's any chance they won't end up landing on a barge, it's best to avoid making a public announcement of intent to infringe.  Perhaps there's also some quiet simultaneous legal negotiation taking place for a low-cost patent license, since I'm sure the patent holder doesn't want to have to risk having it publicly infringed and then challenged in court.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mr. mark on 07/22/2014 09:08 PM
We keep talking about platforms but, what about a deserted island perhaps. Anything out in the Atlantic and within the flight profile that would meet the criteria? Another wild idea. Could you land it on the deck of an aircraft carrier? Yeah, I know the risks but planes have crashed on decks before.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: laika_fr on 07/22/2014 09:12 PM
several news here

- CRS-5 used to be the last to date "end of the year" target for landing.

- CRS-4 is the new target so SpaceX has made progress (again) and secured this type of approach - NASA agrees.

- The body slam comes from a regular splashdown, a rocket is a rocket and it does not like lateral shocks, trying to fix this may change his purpose from a LV to a expensive alarm clock for cows.

- SpaceX is ready and has everything in hands to revolutionize space access.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Garrett on 07/22/2014 09:14 PM
If they now have pinpoint accuracy, I wonder if we could maybe see quadcopter footage of a landing in the future.
Give a man an inch ...  :P

Seriously though, this is already going at a nice pace. We'll probably be watching a live stream of a returning stage by summer 2015 and all this suspense we're currently being subjected to will be in the past. Where's the fun in that ;)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: yg1968 on 07/22/2014 09:14 PM
If they now have pinpoint accuracy, I wonder if we could maybe see quadcopter footage of a landing in the future.

What makes you think that they have achieved pinpoint accuracy? Isn't that what the grid fins are about?

What makes you think I said they had?

OK. I now see that you said "if they now have pinpoint accuracy". I misunderstood your post.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: DanielR on 07/22/2014 09:14 PM
There is the possibility that flight 14 will be to a floating "launch" pad and then flight 15 will touchdown on land. With respect to CRS-4 having a low probability of success, is it possible that it could be a repeat of Cassiope, where the rocket spins out of control due to lack of legs?


Bonus: Here is the article saved for posterity: https://web.archive.org/web/20140722210143/http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage (https://web.archive.org/web/20140722210143/http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: yg1968 on 07/22/2014 09:20 PM
For Cassioppe, it wasn't just the lack of legs that caused the rocket to spin. The thrusters weren't stong enough to counter the spin. I suspect that the CRS-4 flight will have legs but it is likely to disintegrate for the same reasons that the last two stages did (waves slamming the rocket after it lands in the ocean).   
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Scylla on 07/22/2014 09:21 PM
We keep talking about platforms but, what about a deserted island perhaps. Anything out in the Atlantic and within the flight profile that would meet the criteria? Another wild idea. Could you land it on the deck of an aircraft carrier? Yeah, I know the risks but planes have crashed on decks before.

Yep. I can just imagine the reaction of the Capt of a ship when asked if they could land their giant, fire shooting rocket first stage that, may or may not, turn into a giant fireball on the deck of his ship.

If "floating platform" is used, I still think it will be a barge.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mr. mark on 07/22/2014 09:26 PM
I don't know about landing rockets on a aircraft carrier but, they did launch a V2 from an aircraft carrier. Of course, you can see how that went.
http://www.youtube.com/watch?v=Eug0uV5ko0s
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/22/2014 09:30 PM
If they now have pinpoint accuracy, I wonder if we could maybe see quadcopter footage of a landing in the future.

What makes you think that they have achieved pinpoint accuracy? Isn't that what the grid fins are about?

Exactly - if they had, I would assume that we would see landing footage from a boat position very close to the intended spot. (and there certainly might be such footage, not yet released)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Scylla on 07/22/2014 09:36 PM
If they now have pinpoint accuracy, I wonder if we could maybe see quadcopter footage of a landing in the future.

What makes you think that they have achieved pinpoint accuracy? Isn't that what the grid fins are about?

Exactly - if they had, I would assume that we would see landing footage from a boat position very close to the intended spot. (and there certainly might be such footage, not yet released)

Of course, this might have been the test for pinpoint accuracy and I certainly wouldn't park a boat anywhere near the test landing spot.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: wxmeddler on 07/22/2014 09:38 PM
The Navy is NOT going to let one of their aircraft carriers to be the LZ for one of SpaceX's still experimental (in landing) rockets. So lets get that out of the way. More likely, as everyone has pointed to, is an anchored un-manned barge with remote camera's and big huge LZ safety zone buffer.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/22/2014 09:43 PM
...And that assumes that it will be a floating platform to begin with, which is questionable. (Yes, they have raised it as a possibility, but they want to do a land landing)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: yg1968 on 07/22/2014 09:47 PM
...And that assumes that it will be a floating platform to begin with, which is questionable. (Yes, they have raised it as a possibility, but they want to do a land landing)

SpaceX might be trying to kill two birds with one stone. It is still not clear if the core of the FH can make it back to the KSC landing pad. The core of the FH might need a floating landing pad at all times. So might as well test the floating landing pad on a F9 flight.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Doesitfloat on 07/22/2014 09:49 PM
The Aircraft Carrier might not be far off.
(http://www.recyclingtoday.com/FileUploads/image/NavySaratoga.jpg)

USS Saratoga sold for scrap to Esco Marine in Brownsville Texas.
Link
http://www.recyclingtoday.com/navy-esco-marine-scraps-carrier.aspx (http://www.recyclingtoday.com/navy-esco-marine-scraps-carrier.aspx)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Scylla on 07/22/2014 09:51 PM
...And that assumes that it will be a floating platform to begin with, which is questionable. (Yes, they have raised it as a possibility, but they want to do a land landing)

SpaceX might be trying to kill two birds with one stone. It is still not clear if the core of the FH can make it back to the KSC landing pad. The core of the FH might need a floating landing pad at all times. So might as well test the floating landing pad with a F9 flight.

They could always land at Britains handy dandy future spaceport. ;)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: yg1968 on 07/22/2014 10:01 PM
Incidentally, here is the Blue Origin patent with the sea going platform:
http://www.google.com/patents/US8678321
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/22/2014 10:03 PM
Incidentally, here is the Blue Origin patent with the sea going platform:
http://www.google.com/patents/US8678321

Granted March 25, 2014!

That's news.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Damon Hill on 07/22/2014 10:07 PM
Launching Falcon 9 Heavy from the planned Texas facility: would the core have velocity/range to make it to Florida or any Gulf Coast location?  I assume not all launch trajectories are going to be straight east?

I'd wondered about the flyback portion--it consumes significant propellant and a floating platform should be robust enough to suffer a bad landing without much damage.  The remaining questions are whether a landed stage can be easily secured and economically returned.  A RTLS does eliminate the time and trouble of a remote recovery.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/22/2014 10:13 PM
Launching Falcon 9 Heavy from the planned Texas facility: would the core have velocity/range to make it to Florida or any Gulf Coast location?  I assume not all launch trajectories are going to be straight east?

I'd wondered about the flyback portion--it consumes significant propellant and a floating platform should be robust enough to suffer a bad landing without much damage. 

If FH flies with cross-feed, it could reach Florida. But remember that they can also choose to launch FH without cross-feed. In that case it would fly like the Delta IV-Heavy, where the core throttles down after liftoff. The DH core could in that case make it back to the launch site.

I guess it all depends on how heavy the DH payload will be.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 07/22/2014 10:18 PM
Now all we need to do is crowd-source a deconvolution of the icing effects on the lens.  No sweat, right? ::)
That would be interesting.

With a reasonably consistent alteration of the picture made by that ice, I wonder whether something 'simple' like using the first image from "the landing burn begins" to create a filter to apply to the rest would work. Of course you'd need to have a clean photo or some basic template of what it should have looked like without the ice.... not so easy.

In any case videographer or fx work rather than fixing the technical underpinnings as in the last video.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: wxmeddler on 07/22/2014 10:19 PM
Launching Falcon 9 Heavy from the planned Texas facility: would the core have velocity/range to make it to Florida or any Gulf Coast location?  I assume not all launch trajectories are going to be straight east?

I'd wondered about the flyback portion--it consumes significant propellant and a floating platform should be robust enough to suffer a bad landing without much damage. 

If FH flies with cross-feed, it could reach Florida. But remember that they can also choose to launch FH without cross-feed. In that case it would fly like the Delta IV-Heavy, where the core throttles down after liftoff. The DH core could in that case make it back to the launch site.

I guess it all depends on how heavy the DH payload will be.

Agreed, it all depends on the payload. If it's a real heavy LEO launch with a low angle orbit then FL is an option, however, I would assume that most payloads like that would like to be high angle or polar. That would require a LZ in the Bay of Campeche or the Yucatan. If it's a GEO or inter-planitary then you could just land it back at Brownsville or a platform in the Gulf of Mexico.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 07/22/2014 10:28 PM
The remaining questions are whether a landed stage can be easily secured and economically returned.  A RTLS does eliminate the time and trouble of a remote recovery.
It may be that even when RTLS is the preferred option, an alternative landing site may be ready if something makes the launch site unusable - though the weather at the launch site shouldn't change much in 10 minutes. 

If they land down range then it's not just the return, they also have to handle the weather at that location, so they'd need to either abort a launch if there was bad weather at the down range landing site, or launch without recovery, or have 3 or 4 options so they can pick the one with good weather. Right?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Nomadd on 07/22/2014 10:36 PM
 Could be both a barge and a carrier. Where's the Ranger now days?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: laika_fr on 07/22/2014 10:39 PM
Flight 14 must be OG2-M2, Orbcomm must be delighted.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Paul_G on 07/22/2014 10:44 PM
I find it absolutely hilarious that the recovered video that we fixed was in some ways better than this one!

So who wants to guess what "solid surface" means?

Are we back to talking about barges, tankers and oil platforms? I know this idea was repeatedly shot down as not allowing fast, low cost stage recycling, together with requiring good weather at the launch site sand landing zone, but if it is something Spacex are looking to do once, are they going to do all that work just to throw it away once they have recovered one stage?

Paul
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/22/2014 10:47 PM
Concrete floats, right?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AncientU on 07/22/2014 10:48 PM
Concrete floats, right?
Concrete ships do
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: kch on 07/22/2014 10:49 PM
The remaining questions are whether a landed stage can be easily secured and economically returned.  A RTLS does eliminate the time and trouble of a remote recovery.
It may be that even when RTLS is the preferred option, an alternative landing site may be ready if something makes the launch site unusable - though the weather at the launch site shouldn't change much in 10 minutes. 


Too bad the weather doesn't know that!  We've had some "squeakers" in both directions:

* the weather cleared just in time to launch (or closed in just after the launch)
* the weather cleared 10 minutes after the window expired (or clobbered-up just in time to stop the launch)



If they land down range then it's not just the return, they also have to handle the weather at that location, so they'd need to either abort a launch if there was bad weather at the down range landing site, or launch without recovery, or have 3 or 4 options so they can pick the one with good weather. Right?


Three or four options (a la STS TAL sites) would be good.   :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: joshcryer on 07/22/2014 10:54 PM
Incidentally, here is the Blue Origin patent with the sea going platform:
http://www.google.com/patents/US8678321

Granted March 25, 2014!

That's news.


This is such a silly patent (and I'm surprised someone hadn't patented it already years ago; maybe someone has and it's just lost in the archives). Is Blue Origin going to enforce it? Or is it just one of those safe patents to keep someone else from stopping you...

Regardless since SpaceX is in the R&D phase any efforts landing on a floating platform will be exempt.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lar on 07/22/2014 11:14 PM
Now all we need to do is crowd-source a deconvolution of the icing effects on the lens.  No sweat, right? ::)
That would be interesting.

With a reasonably consistent alteration of the picture made by that ice, I wonder whether something 'simple' like using the first image from "the landing burn begins" to create a filter to apply to the rest would work. Of course you'd need to have a clean photo or some basic template of what it should have looked like without the ice.... not so easy.

In any case videographer or fx work rather than fixing the technical underpinnings as in the last video.

I'm impressed that they made so many transmission quality improvements... maybe they took some of the advice given in the repair and discussion threads?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lobo on 07/22/2014 11:17 PM
Lens iced over for the most part:

http://youtu.be/CQnR5fhCXkQ

Cool.  Hopefully they'll be able to address that on the next attempt to prefent it getting iced over.  Be great to have a full clean video of it.  Be cool if they can get a video boat out in the area too to get a nice surface video.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mongo62 on 07/22/2014 11:23 PM
Cool.  Hopefully they'll be able to address that on the next attempt to prefent it getting iced over.  Be great to have a full clean video of it.  Be cool if they can get a video boat out in the area too to get a nice surface video.

According to their statement (http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage):

Quote
Going forward, we are taking steps to minimize the build up of ice and spots on the camera housing in order to gather improved video on future launches.

My own guess is that they will have a transparent cover over the camera housing that is ejected or flipped up before the landing burn.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lobo on 07/22/2014 11:30 PM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."

The real story here is flights 14 & 15 on LAND!!  That's before the end of this year.

Does this mean they have gotten precise in hitting a designated landing location?

I wonder if F9R-Dev 2 is going to be needed if they keep collecting data with these flights?

From the same update...

At this point, we are highly confident of being able to land successfully on a floating launch pad or back at the launch site and refly the rocket with no required refurbishment


Or possibly some sort of barge. :o

Maybe rent the Blue Marlin or Black Marlin for a few days.  Put some sort of surface on it to protect it, and have it partially submerge (but keep the deck above water) and it shoudl sit pretty stable in the water I'd think. 

There may be barges that are cheaper, especially if they were planning to have it land close to shore. 

Would a barge pitch too much?  Do they have ways of stabilizing them like these heavy lift ships have. 
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lobo on 07/22/2014 11:35 PM
There is the possibility that flight 14 will be to a floating "launch" pad and then flight 15 will touchdown on land. With respect to CRS-4 having a low probability of success, is it possible that it could be a repeat of Cassiope, where the rocket spins out of control due to lack of legs?


Bonus: Here is the article saved for posterity: https://web.archive.org/web/20140722210143/http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage (https://web.archive.org/web/20140722210143/http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage)

I find it odd they used the words "floating launch pad", when as far as we know, there's not intent to launch an Falcon from a floating platform, is there?
I would think they'd refer to it as a "floating landing pad".

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: CharlieWildman on 07/22/2014 11:40 PM
Lens iced over for the most part:

http://youtu.be/CQnR5fhCXkQ

Cool.  Hopefully they'll be able to address that on the next attempt to prefent it getting iced over.  Be great to have a full clean video of it.  Be cool if they can get a video boat out in the area too to get a nice surface video.
Probably the best system would be what is used for on board racing cameras.  A clear film is stored on rollers and passed in front of the lens carrying all the offending gunk with it.  SpaceX could probably buy the system(s) off the shelf.

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sdub on 07/22/2014 11:43 PM
The implications of a "floating launch pad" are fairly profound.  Forgive me if this has been discussed, but everything I had read indicated this was not the direction they were following.  With a floating launch pad, they could refuel the second stage at sea and then use a suborbital launch to send the first stage back to land.  There it would be integrated for a future flight.

This would seem to provide more payload options if they no longer have to boost back to land.  They should be able to squeeze a little extra delta v if they don't have to boost back.

What about multiple floating launch pads at different points downrange?  They could put two fairly close to land for the outer F9H cores.  Then another pad would be further downrange for the center core running in a crossfeed scenario.  Then the center core could take a suborbital hop either to the midrange launch pads, or directly to land itself depending on the math....

This would remove the requirement to have a barge to transport the rocket.  However, it does require shipping fuel over seas out to the launch pad.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Jim_LAX on 07/22/2014 11:46 PM
Could be both a barge and a carrier. Where's the Ranger now days?
Alas, The Ranger is no more!
http://www.uss-ranger.org/
At 35+ knots the Ranger could beat the pants of any other type of "floating landing pad" in returning Falcon cores back to port.  I served aboard Ranger from '65 to '67.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lobo on 07/22/2014 11:49 PM
The Aircraft Carrier might not be far off.
(http://www.recyclingtoday.com/FileUploads/image/NavySaratoga.jpg)

USS Saratoga sold for scrap to Esco Marine in Brownsville Texas.
Link
http://www.recyclingtoday.com/navy-esco-marine-scraps-carrier.aspx (http://www.recyclingtoday.com/navy-esco-marine-scraps-carrier.aspx)

I don't think so.

First, it wouldn't be on a USN carrier currently in service.  I don't think they'd make one available for a civilian test, and even if they did, it could cost SpaceX a HUGE amount of money if something went really wrong and severaly damaged it.

I don't think they would do an old scrapped carrier like the Saratoga.  It's too expensive for what would essentually be a 1 time test (if it goes well). 

I think they'll do something as cheap as possible.  Rent a barge and fit it with thrust protection, or do some other ship with a large open area like one of those heavy lift ships, and fit it with temporary thrust protection.

Remember, this will just be a one time event if it goes well.  Maybe 2-3 times if they have trouble with the first. for some reason.    Not enough to use a current or old Carrier.

Look at that heavier carrier ship.  It can steam out to the LZ, partially submerge to get nice and stable, recieve the Falcon, with a mobile crane it's carrying, lower the booster into a cradle and secure for the run back to port.  They'd probably arange permission with NASA to have it come back into the turn basin to offload, if it would fit in there.
In fact, that's probably going to be your bottle neck.  Whatever they use will probably have to be able to fit into the turn basin.  It might be hard to get a core onto a dock area somewhere like Port Canaveral and truck it back to LC-40, given it's size.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Quialiss on 07/23/2014 12:13 AM
Background subtraction does not improve the video much, for most of the landing burn the ice is melting/shifting which means any subtraction will show those patterns as well as the interesting ones with no easy way to sort them out as they're happening on the same timescale.  Melting ice has never looked so psychedelic, though!

Comparing a couple points in the video that are easy to visually identify, the timing of the leg deploy relative to landing looks nearly identical.

OG2                                         (timestamps +- 0.1 seconds)
Frame      event                        timestamp
1521        leg deploy starts      15:25:57.0
1786        exhaust hits ocean  15:26:03.5   +6.5 seconds
1858        engine fully out        15:26:05.8   +8.8 seconds


CRS-3
Frame      event                       timestamp
90            leg deploy starts     68.846444
181          exhaust hits ocean  74.919178   +6.1 seconds
224          engine fully out        77.788711   +8.8 seconds
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: ey on 07/23/2014 12:17 AM
I figure the cheapest, safest option would be an unpowered/towed barge. Just a big hunk of floating metal. A ship would tow the barge out, and then leave the vicinity of the landing area for the safety of the crew.

Due to the height, I'm not sure how practical it would be to move it or lift it using a crane from another ship once it lands, but it would at least prove that the Falcon 9 could land intact at a small target location.

There would also need to be some way to prevent the barge from moving too much (or have the first stage be able to compensate for the barge drifting) and stabilize it enough so it doesn't tip over.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: inventodoc on 07/23/2014 12:29 AM
Looking at the video, I was surprised at how late the landing legs deployed.  Kind of thought those would have been used to slow spin but they deployed very late.  Looks like those thrusters were able to null everything out.   As far as the irregular flames, not so sure but wonder if there is some thruster firing there too.

All in all, very anticipated and enjoyable to watch.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lee Jay on 07/23/2014 12:32 AM
If they don't mind it tipping over on landing, they could use a barge.  If they want it to stay vertical, and if the LZ is shallow, they could use a jack up barge.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/23/2014 12:45 AM
Looking at the video, I was surprised at how late the landing legs deployed.  Kind of thought those would have been used to slow spin but they deployed very late.  Looks like those thrusters were able to null everything out.   As far as the irregular flames, not so sure but wonder if there is some thruster firing there too.

As others have pointed out, the legs - even in their undeployed state - acts as fins. Thus they can reduce roll without deploying.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mvpel on 07/23/2014 12:48 AM
Incidentally, here is the Blue Origin patent with the sea going platform:
http://www.google.com/patents/US8678321

They patented reusing space launch vehicles? Am I reading this right?  ::) They patented retropropulsion burns to deorbit a booster?  ::) Talk about "prior art...:
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/23/2014 12:53 AM
It's pretty clear what they're patenting: a system for a vertical landing booster and a barge to talk to each other.

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Robotbeat on 07/23/2014 01:05 AM
Jack-up rig prices:
https://www.rigzone.com/data/dayrates/

I don't think there are likely to be any nearby, though. Might have to buy one.

Good ones aren't cheap, but it doesn't need to be terribly high performance.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mwfair on 07/23/2014 01:07 AM
The discussion of possible future landing tactics is all OT.
I realize that the video gives very little to talk about, but it deserves its own thread undiluted by topics covered elsewhere.  I am interested in comments on event timing, datalink quality, video encoding, etc.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: bilbo on 07/23/2014 01:11 AM
I'm curious, is this the camera smashing through the inter-stage?  ???
I don't really know what this could be other than that.

edit; then to than. :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mwfair on 07/23/2014 01:27 AM
The video doesn't seem to show any data link drop outs, or any bit flips, or even any visible macroblocks!  Is it possible that this was extracted from on-board storage?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: slavim on 07/23/2014 01:34 AM
I'm curious, is this the camera smashing through the inter-stage?  ???
I don't really know what this could be other than that.

edit; then to than. :)

Whoa, what a fantastic find. It certainly looks like it but I'm not sure how it could be so lit up.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AJW on 07/23/2014 01:35 AM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."

If Flight 13 is indeed CRS-4, the 'low probability of success' may be their goal of recovering a stage landing in the ocean.  They may have concluded that toppling a 200' stage and expecting it to stay intact is just not in the cards.  Another possibility is that they may use the opportunity to try grid-fins and don't expect success during the early trials.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Jdeshetler on 07/23/2014 03:10 AM
I'm curious, is this the camera smashing through the inter-stage?  ???
I don't really know what this could be other than that.

edit; then to than. :)

Maybe there is other camera video feed like this during Apollo that somehow end up in the last frame, there might be several cameras at once and only one is for public viewing?
https://www.youtube.com/watch?v=IBWw_QJKAsI
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: CameronD on 07/23/2014 03:11 AM
The video doesn't seem to show any data link drop outs, or any bit flips, or even any visible macroblocks!  Is it possible that this was extracted from on-board storage?

No idea.. but it would indeed be nice to know if they followed any of the recommendations from the team here this time around eg. non-interlaced video, etc.

Can anyone confirm this from what has been released - or would you need the full transport stream?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Comga on 07/23/2014 03:27 AM
A few notes:
...
3. The rocket plumes are oddly patterned in this video, with a series of parallel "interference patterns", no doubt due to the arrangement of the three firing engines.
...
You noticed that too!

It's a point source variation of the Young's Three Slit optical experiment.  Some here may have seen the two slit version in high school or college done with a laser.  The three slit version produces bright dots with faint dots between them.  Here there are long, bright lines and shorter, less bright lines.

The same pattern was evident in the CASSIOPE retro-burn footage.

It's a feature!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Tonioroffo on 07/23/2014 05:41 AM
Concrete floats, right?
Concrete ships do

Actually, Pykrete does!  http://en.wikipedia.org/wiki/Pykrete - here's a far fetched option for landing ;)

edit: off-topic, mod can remove, sorry :/
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: laika_fr on 07/23/2014 06:09 AM
First news from mass media :

SpaceX Releases Amazing Video of Falcon Rocket's Splashdown
http://www.nbcnews.com/science/space/spacex-releases-amazing-video-falcon-rockets-splashdown-n162506

This will end-up on the New York Times front page by next fall  8)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: su27k on 07/23/2014 06:19 AM
I don't think you need floating platform to demo "pin point accuracy", just a set of GPS coordinates should be enough to convince the authorities, at most you need a floating beacon, platform is overkill.

As for CRS-4 landing's "low probability of success", based on pure speculation, it could be they don't have the enhanced RCS on that flight.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Joel on 07/23/2014 06:42 AM
One implication of the news that they only plan one more ocean 'landing' before trying to land on land, is that the next ocean landing attempt (flight #13 - presumably next CRS mission) will have to demonstrate a pinpoint landing. So presumably that will be the first flight with the grid fins installed.
Makes sense to demonstrate pinpoint accuracy on the next ocean flight. I think that means a different landing algorithm. More specifically, a predictive controller with the terminal state equality constraints being a one-dimensional set (rotation) instead of a three-dimensional set (rotation + translation).
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: CameronD on 07/23/2014 06:56 AM
As for CRS-4 landing's "low probability of success", based on pure speculation, it could be they don't have the enhanced RCS on that flight.

..or it could just be that "body-slam/kaboom" is now an integral part of the flight plan. ;)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: TrevorMonty on 07/23/2014 07:36 AM
There was some talk about the center core of a FH not being able to return the launch site because it will be too far downrange at staging.  Makes me think they’re building a floating platform for landing the center core of the (then safing it and lowering it to horizontal and shipping it back) and they’ll use that for floating recovery of the F9 stage.
I read some where that the FH can deliver 7T to GT0 with all 3 boosters recoverable, I think they all stage at same time. At +7T the middle booster will have to do a down range recovery.

With FH delivering most of GTO  payloads we are going to see a lot of FH launches with the boosters being reused multiple times, especially as launches that require a booster/s to be expended will be far and few between.

Originally I expected recovered F9 boosters to be lost on next expendable launch but sounds there may not be any ELV launches for F9.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: deruch on 07/23/2014 09:39 AM
Reddit user/__R__ posted this over on the SpaceX sub.  I thought it was cool and people here might find it interesting also:

https://www.youtube.com/watch?v=Za7s7JN7YLM

Pretty unbelievable timing!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mikelepage on 07/23/2014 09:46 AM
This post does come to the topic - bear with me :)

I know I saw somewhere (maybe for CRS-3) an exclusion zone map for the second stage coming down off the coast of Western Australia.  Being a resident of Perth WA, I began wondering if SpaceX is likely to attempt to build landing pad(s) somewhere near me, (or maybe if it will be more efficient to give the second stage just enough of an extra boost so it comes down somewhere near Florida after the first full orbit)

Any second stages returning to land on current trajectories would have to come down somewhere on the WA coast.  This could be anywhere within several 1000 kilometers depending on the orbital inclination they are launching to, but since the Cape is ~28N 80W and Perth is ~32S 115E (ie almost directly opposite each other), it figures that if they were going to build a pad they must have somewhere nearby in mind.

The problem will probably be that the entire southern half of the WA coast has pristine beaches and marine parks virtually all the way along it.  There have been many environmental activist vs mining industry fights in recent years and no environmental authority here is just going to rubber stamp that kind of development, even *with* evidence of pinpoint landings.  Then there's the fact that the coast is fairly densely populated south of Geralton (>28.7S) and the northern coast has powerful mining interests (they already vetoed the fledgling Christmas Island Spaceport plans because of overflight concerns).
 
Long story short, I suspect the easiest and best option for landing the second stage is going to be a floating platform ship based in Fremantle (the port of Perth).  That way they will be able to move it to wherever it is most convenient to bring the second stage down, bring it back to port, and transfer it to another ship for transport back to the US.  Any experience landing the first stage on floating platforms is going to pay dividends when it comes to recovering the second stage, which will be easier to recover this way due to being smaller.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: luinil on 07/23/2014 10:11 AM
Or they way that it's orbit bring it back near the launch aera.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MattyJ on 07/23/2014 12:39 PM
Incidentally, here is the Blue Origin patent with the sea going platform:
http://www.google.com/patents/US8678321

Patents are territorial in nature.  To infringe a method claim of a US patent (which all but one of the BO patent claims are), you need to perform each and every step of the claim in the US.  By positioning the landing structure in international waters, Sp-X has a pretty strong argument that they do not infringe the claims of the patent.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: fatjohn1408 on 07/23/2014 12:44 PM
There is the possibility that flight 14 will be to a floating "launch" pad and then flight 15 will touchdown on land. With respect to CRS-4 having a low probability of success, is it possible that it could be a repeat of Cassiope, where the rocket spins out of control due to lack of legs?


Bonus: Here is the article saved for posterity: https://web.archive.org/web/20140722210143/http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage (https://web.archive.org/web/20140722210143/http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage)

I find it odd they used the words "floating launch pad", when as far as we know, there's not intent to launch an Falcon from a floating platform, is there?
I would think they'd refer to it as a "floating landing pad".

They wouldn't dare to land, fuel, take off, land at cape, refurbish, fuel, fly mission? Would they?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Ben the Space Brit on 07/23/2014 12:51 PM
Wow! That icing on the lens didn't obstruct the vision in the way I thought. Given the video cuts off as the vehicle tilts over on the ocean surface, I'd say that's the point the structure failed for whatever reason. Off-axis loads of that kind are obviously more than it could take.

How about an old oil platform.  They are perfectly stable.

Where's Sea Launch's launch platform right now?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mvpel on 07/23/2014 02:06 PM
I'm curious, is this the camera smashing through the inter-stage?  ???
I don't really know what this could be other than that.

Wow! That's one way to get the ice off the lens, I suppose.  :o
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Norm38 on 07/23/2014 02:08 PM
How did I miss this yesterday?  This news is 18 hours old!
Great to see first video of the retro burn, and audio too!  I wonder what the drive flame looks like from the side?  A parabolic bow wave?

As for the ice on the lens, wouldn't a heating element be simpler than the mechanics of an ejectable/flip-up cover?  Of course, heat doesn't help with soot, but that wasn't much of a problem on the last flight.

Exciting times ahead
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: corrodedNut on 07/23/2014 02:10 PM
"Going forward, we are taking steps to minimize the build up of ice and spots on the camera housing in order to gather improved video on future launches."

I would think a simple heater, like the typical automotive electric rear-window defroster, and a super-hydrophobic and oleophobic coating on the camera housing glass would take of most it. Especially if the glass is angled. No moving parts or expendable covers/films needed.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Elmar Moelzer on 07/23/2014 02:11 PM
I don't think you need floating platform to demo "pin point accuracy", just a set of GPS coordinates should be enough to convince the authorities, at most you need a floating beacon, platform is overkill.

As for CRS-4 landing's "low probability of success", based on pure speculation, it could be they don't have the enhanced RCS on that flight.
I am almost certain that the "low probability of success" refers to the low probability that the stage will survive toppling over in the ocean after the soft landing. I am sure they are confident the soft landing and pin point landing itself will work now. I agree that you do not need a floating platform to demo pin point accuracy.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/23/2014 02:18 PM
How did I miss this yesterday?  This news is 18 hours old!
Great to see first video of the retro burn, and audio too!  I wonder what the drive flame looks like from the side?  A parabolic bow wave?

In theory, that's what the NASA observation flight got good pictures of.  One can always hope that those pictures will be released/leaked.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mvpel on 07/23/2014 02:30 PM
The video doesn't seem to show any data link drop outs, or any bit flips, or even any visible macroblocks!  Is it possible that this was extracted from on-board storage?

No idea.. but it would indeed be nice to know if they followed any of the recommendations from the team here this time around eg. non-interlaced video, etc.

Can anyone confirm this from what has been released - or would you need the full transport stream?

It certainly wasn't extracted from on-board storage - they just had solid telemetry this time since the weather was better and the plane had an actual antenna on its radio, instead of a pizza pan wedged in the window.

The video camera is still interlaced NTSC, as it was before - you can tell easily by looking at the last digits in the clock. This isn't surprising, considering that the party thread was started on May 1 when the first launch attempt for this mission was approaching, and we didn't post the final video (https://www.youtube.com/watch?v=CjZ33C9JZTM) until June 22. I wouldn't have expected them to crack open the hull to swap out the camera system in the meantime. However, the footage from the F9R-Dev flights gives me hope for a future of super-sexy luscious video feeds.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: JasonAW3 on 07/23/2014 02:33 PM
Wow! That icing on the lens didn't obstruct the vision in the way I thought. Given the video cuts off as the vehicle tilts over on the ocean surface, I'd say that's the point the structure failed for whatever reason. Off-axis loads of that kind are obviously more than it could take.

How about an old oil platform.  They are perfectly stable.

Where's Sea Launch's launch platform right now?

I'm kind of curious how they thought a red hot, or hotter, rocket motor was going to survive immersion in relatively cold sea water?  (Cold relative to the motor).

     If it didn't immediately explode or distort, I would be VERY suprised.  (Wonder if there were any volitiles left in the stage when they cut off the motor.  If so, they might have also had a BOOM on their hands).
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Llian Rhydderch on 07/23/2014 02:34 PM
From the update on the SpaceX site:

"We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success."

The real story here is flights 14 & 15 on LAND!!  That's before the end of this year.

Does this mean they have gotten precise in hitting a designated landing location?

I wonder if F9R-Dev 2 is going to be needed if they keep collecting data with these flights?

From the same update...

At this point, we are highly confident of being able to land successfully on a floating launch pad or back at the launch site and refly the rocket with no required refurbishment


Or possibly some sort of barge. :o

Maybe rent the Blue Marlin or Black Marlin for a few days.  Put some sort of surface on it to protect it, and have it partially submerge (but keep the deck above water) and it shoudl sit pretty stable in the water I'd think. 

There may be barges that are cheaper, especially if they were planning to have it land close to shore. 

Would a barge pitch too much?  Do they have ways of stabilizing them like these heavy lift ships have.

I think the answer for reducing the pitch might be a semi-submersible platform.  See this other thread discussing the SpaceX floating launch platform:  http://forum.nasaspaceflight.com/index.php?topic=35248.msg1232468#msg1232468 (http://forum.nasaspaceflight.com/index.php?topic=35248.msg1232468#msg1232468)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: jaufgang on 07/23/2014 02:39 PM
I figure the cheapest, safest option would be an unpowered/towed barge. Just a big hunk of floating metal. A ship would tow the barge out, and then leave the vicinity of the landing area for the safety of the crew.

Due to the height, I'm not sure how practical it would be to move it or lift it using a crane from another ship once it lands, but it would at least prove that the Falcon 9 could land intact at a small target location.

There would also need to be some way to prevent the barge from moving too much (or have the first stage be able to compensate for the barge drifting) and stabilize it enough so it doesn't tip over.

Heck, if it comes to a full stop on top of a barge and balances there for a few seconds, and then the barge pitches the whole thing topples over, even that ought to be adequate to have proven the ability to do a pinpoint landing and get clearance to land on solid ground the next time.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Kabloona on 07/23/2014 03:07 PM
Wow! That icing on the lens didn't obstruct the vision in the way I thought. Given the video cuts off as the vehicle tilts over on the ocean surface, I'd say that's the point the structure failed for whatever reason. Off-axis loads of that kind are obviously more than it could take.

How about an old oil platform.  They are perfectly stable.

Where's Sea Launch's launch platform right now?

I'm kind of curious how they thought a red hot, or hotter, rocket motor was going to survive immersion in relatively cold sea water?  (Cold relative to the motor).

     If it didn't immediately explode or distort, I would be VERY suprised.  (Wonder if there were any volitiles left in the stage when they cut off the motor.  If so, they might have also had a BOOM on their hands).

They probably didn't ever expect the engines to survive the thermal shock...at least not the three used for the re-entry and landing burns.

But they had hoped the tanks would survive intact so that the stage could be recovered for inspection. Apparently they are now resigned to the fact that the tanks won't survive the belly flop, so the next step is the "solid surface" landing.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Elmar Moelzer on 07/23/2014 03:10 PM
They probably didn't ever expect the engines to survive the thermal shock...at least not the three used for the re-entry and landing burns.
I can see the middle one being hot (and how hot may be up for debate, since it is regeneratively cooled), but the two others should IMHO have cooled off by then. But I am not a rocket scientist. So I might be off with my assumption there.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rpapo on 07/23/2014 03:16 PM
They probably didn't ever expect the engines to survive the thermal shock...at least not the three used for the re-entry and landing burns.
Only one.  Three are used for the retro/flyback burn, but only one gets used (several minutes later) for the touchdown burn.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Robotbeat on 07/23/2014 03:41 PM
There was some talk about the center core of a FH not being able to return the launch site because it will be too far downrange at staging.  Makes me think they’re building a floating platform for landing the center core of the (then safing it and lowering it to horizontal and shipping it back) and they’ll use that for floating recovery of the F9 stage.
I read some where that the FH can deliver 7T to GT0 with all 3 boosters recoverable, I think they all stage at same time. At +7T the middle booster will have to do a down range recovery.

With FH delivering most of GTO  payloads we are going to see a lot of FH launches with the boosters being reused multiple times, especially as launches that require a booster/s to be expended will be far and few between.

Originally I expected recovered F9 boosters to be lost on next expendable launch but sounds there may not be any ELV launches for F9.
Even if the stages are all flying back to the same point, it is NOT optimal to stage them off all three at once.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Dudely on 07/23/2014 04:01 PM
Even if the stages are all flying back to the same point, it is NOT optimal to stage them off all three at once.

27 merlin engines shutting down simultaneously. . . yeah that would rip the second stage to shreds.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rocketguy101 on 07/23/2014 04:20 PM
How about an old oil platform.  They are perfectly stable.
Not many off the East coast :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Nomadd on 07/23/2014 04:30 PM
There was some talk about the center core of a FH not being able to return the launch site because it will be too far downrange at staging.  Makes me think they’re building a floating platform for landing the center core of the (then safing it and lowering it to horizontal and shipping it back) and they’ll use that for floating recovery of the F9 stage.
I read some where that the FH can deliver 7T to GT0 with all 3 boosters recoverable, I think they all stage at same time. At +7T the middle booster will have to do a down range recovery.

With FH delivering most of GTO  payloads we are going to see a lot of FH launches with the boosters being reused multiple times, especially as launches that require a booster/s to be expended will be far and few between.

Originally I expected recovered F9 boosters to be lost on next expendable launch but sounds there may not be any ELV launches for F9.
Even if the stages are all flying back to the same point, it is NOT optimal to stage them off all three at once.
With an FH, it's not likely they'll have to be anywhere near optimal. They're talking about using it for payloads an expendable F9 could have handled.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Nomadd on 07/23/2014 04:34 PM
They probably didn't ever expect the engines to survive the thermal shock...at least not the three used for the re-entry and landing burns.
I can see the middle one being hot (and how hot may be up for debate, since it is regeneratively cooled), but the two others should IMHO have cooled off by then. But I am not a rocket scientist. So I might be off with my assumption there.
The only time they ever thought of reusing after splashdowns was when it was a pure parachute re-entry, and all engines would have been cool. That went away before the F9 even flew, when the F1s did so poorly after hitting the water.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sghill on 07/23/2014 04:38 PM
Forgive me if this got posted elsewhere, but could NSF members attempt a cleanup of this video too?

The dirt and ice pixels are pretty static.  Can those pixels be removed and replaced with known (or nearby) colors to negate the dirt and ice?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/23/2014 05:30 PM
It would be a completely different process. And NO, the dirt and ice is not static, even if it would appear that way.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MTom on 07/23/2014 05:41 PM
sorry, wrong thread for discussing about the patent of Blue Origin...
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Sohl on 07/23/2014 05:55 PM
It would be a completely different process. And NO, the dirt and ice is not static, even if it would appear that way.

This is correct. Ice on the window in front of the lens will behave like a chaotic collection of little lenses and prisms sending beams of light in various directions in complex ways.  Light that should be 100% in pixel 1 could be spread over most of the other pixels, and vice-versa.

In theory, if you know exactly how the ice layer changes/spreads the light that is normally transmitted by a point source (the "point spread function") you can use that information in a de-convolution algorithm to recover the original, undistorted image.  This approach works well in astronomy (Hubble space telescope's early images were distorted by an incorrectly-made mirror, they were able to process out much of this effect until better optics could be installed in a repair mission) and in microscopy.  In the lab, even high amounts of distortion have been removed in experiments, but that was for a fixed type of distortion.  In the landing video case, the ice is built up over time, then partially melted/blown off as the landing progresses.  So it is very very difficult to determine an accurate point spread function for every frame of video and then process it out.

That's why my earlier post about crowd-sourcing a deconvolution had the rolling eyes ( ::)). ;)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Quialiss on 07/23/2014 06:03 PM
Repairing the CRS-3 landing was restoring a painting that had been put through a shredder.  Repairing this video would be trying to restore a painting where the painter was constantly being interrupted by a toddler drawing all over their canvas as they were working.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: watermod on 07/23/2014 06:52 PM
Regarding patents.   If one is not making money off of using an idea in a test it's  hard to classify it as a patent violation.  If a stage recovered from a floating platform was then used in a for profit launch the situation changes.   

If one looks at it from that POV and one only needs to do it to prove the concept of landing at a desired point to the FAA and spaceport authorities then violation of a patent would be rough to prove. 
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: deadman719 on 07/23/2014 07:06 PM
If you listen closely, it sounds like you can hear the leg actuators moving around the 55 second mark of the video Chris posted at the start of the thread.   Kind of neat if you ask me.   :D
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lar on 07/23/2014 08:27 PM
We have been getting reports that this stage, er thread, is wandering all over, lacking guidance... Let it not be so and stay on topic.... or we may need to invoke the range safety mechanism. (stage, er thread, destruct) Thank you.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: HMXHMX on 07/23/2014 09:18 PM
Incidentally, here is the Blue Origin patent with the sea going platform:
http://www.google.com/patents/US8678321

Granted March 25, 2014!

That's news.


This is such a silly patent (and I'm surprised someone hadn't patented it already years ago; maybe someone has and it's just lost in the archives). Is Blue Origin going to enforce it? Or is it just one of those safe patents to keep someone else from stopping you...

Regardless since SpaceX is in the R&D phase any efforts landing on a floating platform will be exempt.

The patent will likely be invalidated by prior art.  See for example The Rocket Company, page 52 (AIAA, published 2005).  I also proposed both launch and landing from a  floating platform in 1998, and while I didn't specify using a rocket, that is "obvious to one skilled in the art."

Thus I believe SpaceX could certainly attempt a platform recovery on a upcoming flight.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/23/2014 09:21 PM
The patent will likely be invalidated by prior art.  See for example The Rocket Company, page 52 (AIAA, published 2005).  I also proposed both launch and landing from a  floating platform in 1998, and while I didn't specify using a rocket, that is "obvious to one skilled in the art."

Thus I believe SpaceX could certainly attempt a platform recovery on a upcoming flight.

They *could*.  But if platform recovery isn't in their long-term roadmap, they may still try to avoid doing one so that Blue Origin doesn't feel compelled to sue them.  Patents can be expensive to invalidate.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mader Levap on 07/23/2014 09:51 PM
I wonder why while this one has ice, previous one didn't?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: bilbo on 07/23/2014 10:13 PM
I wonder why while this one has ice, previous one didn't?
trajectory mostly, this stage had a much steeper trajectory then CRS-3 hence the Ice
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sublimemarsupial on 07/23/2014 10:44 PM
I wonder why while this one has ice, previous one didn't?
trajectory mostly, this stage had a much steeper trajectory then CRS-3 hence the Ice

Don't think it has anything to do with the trajectory, you can see the same ice formation during the video of the reentry burn for the CASSIOPE flight that SpaceX released. Seems like water vapor in the exhaust plume of the engine condenses and then freezes on the camera lens. It likely happened on the CRS-3 reentry burn as well, and it just melted or (more likely) got shaken off from vibration before the the start of the landing burn (and the released landing video).
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AJA on 07/23/2014 11:09 PM
 1. So, no external video? <Groan>. What about the video from the NASA plane which filmed the hypersonic “re-entry”? Come to think of it, you don't even need a surface ship in order to get video. Even if everything goes horribly awry, a Falcon 9 isn't going to dive into the water and behave like a torpedo. Get a few quad-copters on a submarine, and operate them from underwater (are radio buoys – like in 'Crimson Tide' - a real thing?) Or simply float camera buoys from the submarine. :D

2. Did they do any boost-back on this flight? Anyone know the co-ordinates of the splashdown? With the high trajectory (which would also explain the icing – a shallower trajectory on the previous launch probably didn't take the first stage to such freezing altitudes?), I'd guess they didn't have to travel that far back (down-range atleast). AFAIK, they didn't boost back on the previous flight either. Wouldn't they want to demonstrate that they could fly the F9 S1, precisely, and using the same mass-vs-time profile as an S1 that had to carry prop reserve for boost-back? That suggests to me that that the next one will travel a significant distance cross-range (instead of boost-back), and that perhaps there's some uninhabited area (as opposed to the relatively densely populated Space Coast?) that SpaceX can touch down on. It's not immediately obvious where this would be. Again, this depends on how far down-range they are at the time of stage-sep.

3. Plus, I think they'd have to demonstrate more than pin-point landing accuracy. Definitely with the FH atleast. The side cores will presumably separate at the same time, or in quick succession (to avoid the complexities of asymmetry) – and they'd have to follow similar boost-back trajectories without a mid-air collision. So the requirement is for a pin-point trajectory. (EDIT: Couldn't all three S1 cores separate at the same time? They could all throttle down to ensure that there isn't a sudden deceleration of S2. I don't know the current shut-down sequence, but with each core having 9 engines, they could shut 3 down in each, three times over, without subjecting the S2 to any additional forces that it doesn't experience already in an F9 launch..?)

4. I don't understand why a floating platform would be uneconomical. In this current update, they've said that they are thinking of re-flying a returned stage without refurbishment. Maybe they can do gas-and-go, but I would've thought that they'd want to inspect the major bits before it flies again. If they're going to have to do that – they might as well land the stage down-range, dismantle it, and fly the bits back to the launch complex. Even if the design of the stage doesn't facilitate turning it into a knock-down kit each time, what's the problem with the time taken up by shipping? Their business model relies on a high launch cadence anyway. They shouldn't have to wait for a particular rocket to come back in order to launch the next payload... they'll have a fleet. (This offers the advantages of redundancies – in terms of parts and flexibility that this offers, as well as the expected performance margin in saving on prop).
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/23/2014 11:11 PM
So, no external video? <Groan>. What about the video from the NASA plane which filmed the hypersonic “re-entry”?

Chill down. Just because the footage has not been uploaded to YouTube or announced does not mean that it doesn't exist. SpaceX has a lot of footage that isn't released. Some of it (if it exists) may be shown in the future if/when they release a "mission summary video".
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AJA on 07/23/2014 11:19 PM
Chill down.

That should qualify for a "You know you're a space geek when..." entry. I think the popular term's 'chill out'/'calm down'?

Anyway, FWIW, I don't think they'll put it up (if they have it in the first place). As far as SpaceX is concerned, the splashdown concluded their mission. So there's nothing beyond that which they'd need to include in the summary.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: CameronD on 07/24/2014 01:18 AM
Anyway, FWIW, I don't think they'll put it up (if they have it in the first place). As far as SpaceX is concerned, the splashdown concluded their mission. So there's nothing beyond that which they'd need to include in the summary.

Agree totally.  There were conspiracies abounding at the time of the CRS-3 landing video around "how short it was" and "maybe SpaceX are hiding something".  Given that this landing video starts almost a minute earlier than the last one.. it seems some people are never satisfied.  :(

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mvpel on 07/24/2014 03:14 AM
The patent will likely be invalidated by prior art.  See for example The Rocket Company, page 52 (AIAA, published 2005).  I also proposed both launch and landing from a  floating platform in 1998, and while I didn't specify using a rocket, that is "obvious to one skilled in the art."

Thus I believe SpaceX could certainly attempt a platform recovery on a upcoming flight.

I found the Amazon link for The Rocket Company, and was able to reach page 52. (http://www.amazon.com/The-Rocket-Company-Library-Flight/dp/1563476967#reader_1563476967)

Quote
Conceivably the ship could be prepositioned down range so you could land the stage on it.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/24/2014 03:27 AM
The patent will likely be invalidated by prior art.  See for example The Rocket Company, page 52 (AIAA, published 2005).  I also proposed both launch and landing from a  floating platform in 1998, and while I didn't specify using a rocket, that is "obvious to one skilled in the art."

Thus I believe SpaceX could certainly attempt a platform recovery on a upcoming flight.

I found the Amazon link for The Rocket Company, and was able to reach page 52. (http://www.amazon.com/The-Rocket-Company-Library-Flight/dp/1563476967#reader_1563476967)

Quote
Conceivably the ship could be prepositioned down range so you could land the stage on it.

I'm really disappointed to see HMXHMX propagating the myth that patents cover ideas and the mere prior mention of the broad concept, or even a similar concept, can somehow invalidate a patent. By this logic 8,690,104 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8690104.PN.&OS=PN/8690104&RS=PN/8690104) is invalid because Stardust is prior art.

Just leave the lawyerin' to the lawyers, eh? or Bezos and Musk can work out a deal over golf and canapes.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: HMXHMX on 07/24/2014 05:39 AM
The patent will likely be invalidated by prior art.  See for example The Rocket Company, page 52 (AIAA, published 2005).  I also proposed both launch and landing from a  floating platform in 1998, and while I didn't specify using a rocket, that is "obvious to one skilled in the art."

Thus I believe SpaceX could certainly attempt a platform recovery on a upcoming flight.

I found the Amazon link for The Rocket Company, and was able to reach page 52. (http://www.amazon.com/The-Rocket-Company-Library-Flight/dp/1563476967#reader_1563476967)

Quote
Conceivably the ship could be prepositioned down range so you could land the stage on it.

I'm really disappointed to see HMXHMX propagating the myth that patents cover ideas and the mere prior mention of the broad concept, or even a similar concept, can somehow invalidate a patent. By this logic 8,690,104 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8690104.PN.&OS=PN/8690104&RS=PN/8690104) is invalid because Stardust is prior art.

Just leave the lawyerin' to the lawyers, eh? or Bezos and Musk can work out a deal over golf and canapes.


I did leave the lawyering to the lawyers.  I asked my patent attorney for his opinion prior to posting.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/24/2014 05:46 AM
I did leave the lawyering to the lawyers.  I asked my patent attorney for his opinion prior to posting.

Heh, did he give you that horrible attempt at prior art too? How much did he charge you to read the patent?

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: HMXHMX on 07/24/2014 06:28 AM
I did leave the lawyering to the lawyers.  I asked my patent attorney for his opinion prior to posting.

Heh, did he give you that horrible attempt at prior art too? How much did he charge you to read the patent?



Nothing.  He used to work for me and wrote the book.  There are numerous other examples of prior art, none of which are quoted by the patent.  It is utterly indefensible on several grounds – and I do know something about the prior art here.

But we are straying too far off topic.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/24/2014 06:41 AM
Nothing.  He used to work for me and wrote the book.

Oh, Pat.

Quote from: Grandpa Simpson
Why the fax machine is nothing but a waffle iron with a phone attached!

That's how every discussion about patents seems to go on the Internet.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: deruch on 07/24/2014 07:47 AM
Repairing the CRS-3 landing was restoring a painting that had been put through a shredder.  Repairing this video would be trying to restore a painting where the painter was constantly being interrupted by a toddler drawing all over their canvas as they were working.

I really like the shredder description, but the rest falls a bit flat.  The real point is that the CRS-3 repair was about recovering an underlying picture who's data was garbled in transmission.  In this video, the data is transmitted without error, but rather there is an obstruction between the underlying picture and its recording.  Fixing it would be more like taking a cubist painting and trying to recreate the view the artist was looking at when they painted it.  But yeah, different tools and skills would be needed.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rpapo on 07/24/2014 11:21 AM
One tidbit I just noticed.  If you replay the landing video and take the timestamps just before and after the middle fadeout (between the retro burn and the landing burn), you see 15:24:17 and 15:25:39, or only one minute and 22 seconds.  That's a mighty short time period, which implies that the retro burn is occurring at a much lower altitude than I (at least) would expect.  Even if the rocket were still descending at 1000mph after completion of the retro burn, and averaged around 700 mph during the descent (faster at higher altitudes, slower near the end due to thickening air), that works out to only about 15 miles or so.

I am not a rocket scientist, nor an aeronautical engineer.  If my napkin calculation is wrong, please explain.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Dudely on 07/24/2014 11:29 AM
Guys, we really need to lay off the patent discussion, as it's a pretty clear-cut issue. Not only is it not valid, but I'm almost sure they will be doing this operation just a few times, and always in international waters.

Kinda hard to prosecute.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/24/2014 12:56 PM
One tidbit I just noticed.  If you replay the landing video and take the timestamps just before and after the middle fadeout (between the retro burn and the landing burn), you see 15:24:17 and 15:25:39, or only one minute and 22 seconds.  That's a mighty short time period, which implies that the retro burn is occurring at a much lower altitude than I (at least) would expect.  Even if the rocket were still descending at 1000mph after completion of the retro burn, and averaged around 700 mph during the descent (faster at higher altitudes, slower near the end due to thickening air), that works out to only about 15 miles or so.

I am not a rocket scientist, nor an aeronautical engineer.  If my napkin calculation is wrong, please explain.

I think the real question is: what was the timestamp of stage separation?  We know there was some RCS maneuvering immediately after sep.  Did the retro burn immediately follow that, or did they allow themselves to "drift" downrange?  (And if they were targetting RTLS, would they have drifted, or done the burn right away?)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rpapo on 07/24/2014 01:12 PM
One tidbit I just noticed.  If you replay the landing video and take the timestamps just before and after the middle fadeout (between the retro burn and the landing burn), you see 15:24:17 and 15:25:39, or only one minute and 22 seconds.  That's a mighty short time period, which implies that the retro burn is occurring at a much lower altitude than I (at least) would expect.  Even if the rocket were still descending at 1000mph after completion of the retro burn, and averaged around 700 mph during the descent (faster at higher altitudes, slower near the end due to thickening air), that works out to only about 15 miles or so.

I am not a rocket scientist, nor an aeronautical engineer.  If my napkin calculation is wrong, please explain.

I think the real question is: what was the timestamp of stage separation?  We know there was some RCS maneuvering immediately after sep.  Did the retro burn immediately follow that, or did they allow themselves to "drift" downrange?  (And if they were targetting RTLS, would they have drifted, or done the burn right away?)
I think (I don't know) that they skipped the boostback burn altogether on this flight.  So the stage separation and reorientation would have occurred at about the three minute mark, followed by a controlled drift (keeping the stage orientation steady with RCS) for twelve whole minutes, arcing up, and then down.  The reentry burn would have occurred soon after atmospheric drag started to make itself felt.

Looking back at the launch videos (presumably the same clock and same camera), the timer at stage separation was approximately 15:17:50.  So retro burn was about 6:30 afterwards.

Both readings are approximate, since the timer at stage separation was hard to read (white on white), and when we see the retro burn, it had already started.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: dcporter on 07/24/2014 01:14 PM
I did leave the lawyering to the lawyers.  I asked my patent attorney for his opinion prior to posting.
Heh, did he give you that horrible attempt at prior art too? How much did he charge you to read the patent?

Nothing.  He used to work for me and wrote the book.  There are numerous other examples of prior art, none of which are quoted by the patent.  It is utterly indefensible on several grounds – and I do know something about the prior art here.

But we are straying too far off topic.

Maybe Commercial Space Flight General or Space Policy? I would be interested in seeing this discussion continue…
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/24/2014 01:15 PM
1. So, no external video? <Groan>. What about the video from the NASA plane which filmed the hypersonic “re-entry”?
I agree that I'm hoping to see this at some point.  But I don't think SpaceX "owes it to me".
Come to think of it, you don't even need a surface ship in order to get video. [...] Get a few quad-copters on a submarine
Radio waves don't propagate underwater.  (Except for VLF.)

I don't think you need a quadcopter when you have Elon's personal jet in the area.

2. Did they do any boost-back on this flight? Anyone know the co-ordinates of the splashdown?
The nautical keep out area was posted (I'm too lazy to look it up, it might have been in L2) and it was indeed significantly closer to shore than on the previous flight.  We also had real time flight tracking of the various aircraft involved in observing the flight, and the area they were canvassing was consistent with the keep out area.  That's in the public thread, you can go find it.

It's clear there was a retro burn, it's on the video.  Is that "boost back"?  Well, it returned the stage closer to shore than previously.  There might be an earlier burn (either planned or executed), and even if the retro burn was "boost back", it might not be "precision boost back" -- as someone else has noted, when you write the control software you can specify free variables that aren't strictly controlled (in order to save propellant, improve precision on other variables, etc).  Rotation is typically one of them -- no one cares what direction the logo on the rocket is facing when it lands.  We don't know what other free variables were specified on this landing attempt.

Wouldn't they want to demonstrate that they could fly the F9 S1, precisely, and using the same mass-vs-time profile as an S1 that had to carry prop reserve for boost-back?

No, that's what F9R is for.  These landing attempts are about supersonic retropropulsion and reentry heating on the structure, which is the flight regime F9R can't easily test.  (Propellant quantities can be computed, they don't need a test flight for that.)

That suggests to me that that the next one will travel a significant distance cross-range (instead of boost-back), and that perhaps there's some uninhabited area (as opposed to the relatively densely populated Space Coast?) that SpaceX can touch down on.

Crazy talk.  The progression between cassiope, CRS-3 and ORBCOMM flight has been landing closer to shore each time.  And take a look at the map sometime -- the Atlantic isn't filled with tiny islands.  It's empty out there (and the water is *deep*).

3. Plus, I think they'd have to demonstrate more than pin-point landing accuracy.

Sure, that's what telemetry is for.  They know exactly what their error terms are, at every point and for every variable they care about.

(EDIT: Couldn't all three S1 cores separate at the same time? [...])
That would defeat the point.  FH is a three-stage rocket.  The two boosters are the first stage.  Getting rid of a stage has a large negative impact on performance; study the rocket equation.

4. I don't understand why a floating platform would be uneconomical.

Understanding economics would be helpful.  But briefly: additional facilities add overhead, cores which exist but aren't current flying add overhead and initial capital cost, twice the flights (if you're flying the cores back) mean half the useful money-earning life of the rockets, it costs a lot to take things apart and put them back together, and there's always the chance that you put them together wrong, the sea atmosphere is corrosive => at sea operations are especially expensive, the nautical facilities involved have to be built on quite a large scale in order to get acceptable stability, etc.

None of this says it's *impossible*, or that there isn't a way to close the economic case ("big dumb barge", eg), but it's certainly not obvious.  If they plan on doing this, you'd certainly start seeing a gradual development program, because the whole thing is certainly not trivial to make work.  Perhaps the flights after CRS-4 will reveal the start of this development program.  If I were to bet, though, I'd bet "no".
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 07/24/2014 05:50 PM
One tidbit I just noticed.  If you replay the landing video and take the timestamps just before and after the middle fadeout (between the retro burn and the landing burn), you see 15:24:17 and 15:25:39, or only one minute and 22 seconds.  That's a mighty short time period, which implies that the retro burn is occurring at a much lower altitude than I (at least) would expect.  Even if the rocket were still descending at 1000mph after completion of the retro burn, and averaged around 700 mph during the descent (faster at higher altitudes, slower near the end due to thickening air), that works out to only about 15 miles or so.

I am not a rocket scientist, nor an aeronautical engineer.  If my napkin calculation is wrong, please explain.

I think the real question is: what was the timestamp of stage separation?  We know there was some RCS maneuvering immediately after sep.  Did the retro burn immediately follow that, or did they allow themselves to "drift" downrange?  (And if they were targetting RTLS, would they have drifted, or done the burn right away?)
I think (I don't know) that they skipped the boostback burn altogether on this flight.  So the stage separation and reorientation would have occurred at about the three minute mark, followed by a controlled drift (keeping the stage orientation steady with RCS) for twelve whole minutes, arcing up, and then down.  The reentry burn would have occurred soon after atmospheric drag started to make itself felt.

Looking back at the launch videos (presumably the same clock and same camera), the timer at stage separation was approximately 15:17:50.  So retro burn was about 6:30 afterwards.

Both readings are approximate, since the timer at stage separation was hard to read (white on white), and when we see the retro burn, it had already started.

You are right.  I care less about how long it was since stage separation - what matters is the backwards timeline, working from splashdown back up to the retro-burn, and they are indeed awfully close, if the timer is consistent.

1 minute and 22 seconds at terminal velocity is not much at all.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mike_1179 on 07/24/2014 06:13 PM
Wasn't this a more lofted trajectory than normal?  Is it possible they didn't need a large boost-back because the first stage went higher and less downrange than previous?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rpapo on 07/24/2014 06:18 PM
Wasn't this a more lofted trajectory than normal?  Is it possible they didn't need a large boost-back because the first stage went higher and less downrange than previous?
Frankly, I'm not sure they did any boostback at all.  They ran one seriously lofted trajectory this time.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/24/2014 06:50 PM
1 minute and 22 seconds at terminal velocity is not much at all.

I believe the retro burn began shortly after stage separation; we don't see the start of the burn on the video.  If makes sense to null out the horizontal velocity as soon as possible.  My guess is that the 1-2 minute glide is basically the performance/safety margin for the boostback; if reentry drag were lower or mass was higher etc the glide would be even shorter.  I bet there's a good reason why the retro burn wants to distribute the thrust over as long a time period as possible; otherwise they'd relight all nine engines and get their delta-v 3x quicker.  (For one, the nozzles will become more efficient as the stage re-approaches the ground.)

It's interesting that they still need to turn off the engines completely for 1-2 minutes.  I'm sure they'd get rid of the second relight of the center engine if they could. 

The description SpaceX posted on the video clearly states "restart main engines twice".  I suppose it's possible that the first restart is a boost back burn right after stage sep, and the second is the retro burn shown in the video... and then the center engine does not shut down but continues to run throttled down until the start of the "landing burn" (which is just the throttle-up point, not a relight).

If that were the case, I'd say that the first boost back burn would be designed to put the stage on a ballistic trajectory that will still impact safely off shore if something goes wrong (like the engine fails to relight, or the stage breaks up during reentry max Q).  The "retro" burn might be primarily designed to move the trajectory on-shore over the landing zone and serves as the final engine check and decision point.  This would be broadly similar to the Dragon v2 landing profile, which contains a higher altitude "engine check" before the final brown-pants landing burn.

ps. we know SpaceX has video footage from that camera from liftoff through staging and then to landing.  They probably have their reasons for not releasing all of it.  I bet they would have preferred not to reveal even the brief footage of the "retro" burn we got, but felt they needed to do so to explain the ice buildup.

UPDATE: as mwfair says in a different thread:
The flight radar track shows that F900 was 336 km downrange from the pad.  [...]  I'll have to run the numbers, but that seems pretty close to a ballistic trajectory.
If it's a ballistic trajectory and the closer return was due solely to the lofted launch, then most of my reasoning above is bogus.  Oh, well.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mwfair on 07/24/2014 08:22 PM
I didn't see any aggregated listing of time and altitude for 1st stage (or second), so here is my analysis of the videos:

time    alt  speed range  note
         km   mps   km
launch video
15:14:30    0   0   0       
+1:00    13  450     2.5     
+2:20    54  1400    21     
+2:25                40    sep
+2:40    112 1700    51    MVAC   
+4:30    240 1800    130   NewHampshire   
+5:30    334 2200    209     
+6:30    420 2700    305     
+7:30    511 3600    460     
+8:45    600 5700    150???     
+9:30    620 7200    1000  2ndStage cutoff
landing video                   
+9:13     start of music 
+9:23     ?   ?    ?         retro burn 
+9:49     ice
+11:09    ?   ?    ?         oceanvisible   
+11:12    ?   ?    ?         landing RCS
+11:20    ?   ?    ?         roll stopped   
+11:27    ?   ?    ?         legs   
+11:33    ?   ?    ?         full plume 
+11:36    ?   0    330     engine out 
+11:39    ?   0    330     splash subsides
+11:41    ?   0    330     start tipover   
+11:43    ?   0    330     kaboom 
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/24/2014 09:08 PM
+11:12                     landing RCS

On the video this is titled "landing burn".  Don't know if it's worth trying to hyperparse wording.

If you use the (pre) and (/pre) tags around your table the columns will line up better.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mwfair on 07/25/2014 03:27 AM
On the video this is titled "landing burn".
I don't believe the wording in the video, at least not precisely.  Obviously an engine is burning.  But there is a big difference in the flame size at +11:12 vs +11:33 , and the earlier one has a pulsating pattern.
Also, time to decelerate from terminal velocity to hover is T = V / a where a = (F-W)/m = (F/m - g) => T = V/(F/m - g) .   Guesses of V=100m/s, F = 600 kN, m = 18000 kg yields deceleration of 23m/s2 and firing time of 3 seconds, which is consistent with my parsing of the video.  However, the video label "landing burn" occurs 24 seconds before splashdown.

EDIT: changed embarrassing algebra and unit and arithmetic mistakes.  original had a = 30g, should be 23 m/s2 = 2.3g.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 07/25/2014 03:58 AM
Oh, one thing I don't think we knew before - the re-entry burn uses 3 engines.

We knew the boost-back burn uses 3 (from the video, and it's clear you need to turn back as fast as possible, and the stage is still heavy) and we knew the landing burn uses 1 (empty stage, hover-slam) but the secret-sauce burn is a little less secret now.  We know when it occurs, and we know it uses 3 engines.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mwfair on 07/25/2014 04:12 AM
Not sure if anyone has done a terminal velocity calculation.
Drag = Cd * 0.5 * rho * V^2 * Area_wetted.    Long cylinder has Cd = 0.8.  rho = 1.2 kg/m3.  Area = length * pi * D^2 = 400 sq.meters.   Thus V_terminal = sqrt ( 2 * Weight / Cd * rho * A_wetted).   empty F9 masses 18 tons = 180 kN.    Vt = about 40 m/s.  Seems slow to me.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mwfair on 07/25/2014 04:18 AM
We knew the boost-back burn uses 3 (from the video, and it's clear you need to turn back as fast as possible, and the stage is still heavy) and we knew the landing burn uses 1 (empty stage, hover-slam) but the secret-sauce burn is a little less secret now.  We know when it occurs, and we know it uses 3 engines.
A reddit user TheVehicleDestroyer ran the numbers more than a week ago. The best fit for the available data is a ballistic trajectory from separation. No boostback.
The video does look like 3 engines are burning, at least at time Separation+6:00.  However, we don't know how long it burned.  It also seems clear that it was not a 'boost-back', since range kept increasing. 
Perhaps they executed a short burn for the benefit of the WB-57?
What is the maximum altitude at which the atmosphere would support icing?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/25/2014 04:53 AM
On the video this is titled "landing burn".
I don't believe the wording in the video, at least not precisely.  Obviously an engine is burning.  But there is a big difference in the flame size at +11:12 vs +11:33 , and the earlier one has a pulsating pattern.
Also, time to decelerate from terminal velocity to hover is T = V * a where a = m / (F-W) = 1/(F/m - g) => T = V/(F/m - g) .   Guesses of V=100m/s, F = 600 kN, m = 18000 kg yields deceleration of 30g and firing time of 3 seconds, which is consistent with my parsing of the video.  However, the video label "landing burn" occurs 24 seconds before splashdown.

I think you are seeing the exhaust begin to interact with the water, and confusing this with a throttle up.  If you look at the F9R and Grasshopper flights, it is obvious the 'landing burn' is longer than 3 seconds.  And a 30g deceleration would be brutal.  See the CRS-3 video discussion.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AJA on 07/25/2014 06:04 AM
I don't think you need a quadcopter when you have Elon's personal jet in the area.

I doubt Elon's personal jet would be allowed to get as close. One, or even two precision landings aren't exactly a comprehensive base for predicting the performance of the subsequent attempt. It's not trivial to track a fast-moving object from another fast moving object. Hence the "convoluted" submarine idea.

Quote
We don't know what other free variables were specified on this landing attempt.
...
These landing attempts are about supersonic retropropulsion and reentry heating on the structure, which is the flight regime F9R can't easily test.  (Propellant quantities can be computed, they don't need a test flight for that.)

But we do know the variables that need to be specified, in order for something to meet the pin-point criterion. Wasn't this landing different enough from what would be required for RTLS, that it's insufficient to demonstrate future landing accuracy in itself?

Yeah, but the mass distribution would affect retropropulsion, control and re-entry heating. Something with more propellant, and sloshing around to boot, would have different dynamic (and perhaps even static stability), or need more control inputs to follow a programmed trajectory. I don't know. Sure, you can simulate it, but then, you can simulate most things.

Quote
Crazy talk.  The progression between cassiope, CRS-3 and ORBCOMM flight has been landing closer to shore each time.

I did look at a map. I was suggesting somewhere up/down the East coast itself (or in the Carribean). But I may be grossly over-stimating how far the first stage travels in assuming it has the legs to attempt going feet dry over an area more desolate and cordoned off than the Cape.

Quote
That would defeat the point.  FH is a three-stage rocket.  The two boosters are the first stage.  Getting rid of a stage has a large negative impact on performance; study the rocket equation.

I get the concept of staging. But it's not like SpaceX are pursuing maximum performance everywhere. The hit in performance could be compensated by being able to get all three cores to RTLS. I was only offering a counter to the argument that losing all three first stages would rip S2 to shreds.

Lastly, I'd considered all the reasons you mentioned that go against an off-shore base, but to it's only an assumption that the pros don't weigh up to the cons.

[Greater overheads + increased turn-around time (immaterial if it's not on the critical path)] vs [increased payload margins + maybe decreased complexity + ability to retrieve core stages on FH class launches + redundancy + catering to sub-orbital research payload market]. The Cape isn't too far from the coast, and they already operate in the "salt air" (admittedly they can have huge facilities and climate controlled rooms and all that when based on a land, and connected to a grid).

Economics is pretty pliable. It hasn't been too long ago since the days when discussions of cheap re-usability itself was heresy; yet here SpaceX are... making the economics work.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: douglas100 on 07/25/2014 09:30 AM

...Economics is pretty pliable. It hasn't been too long ago since the days when discussions of cheap re-usability itself was heresy; yet here SpaceX are... making attempting to make the economics work.

Fixed that for ya. And even SpaceX can't defy the financial law of gravity: it must keep costs down and get the revenue stream up or go bust. Spending on complicated offshore infrastructure does not seem to me a good way to do either.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mvpel on 07/25/2014 11:04 AM
On the video this is titled "landing burn".
I don't believe the wording in the video, at least not precisely.  Obviously an engine is burning.  But there is a big difference in the flame size at +11:12 vs +11:33 , and the earlier one has a pulsating pattern.

The orange flames you see at +11:12 are not "RCS", they're the fuel-rich turbine exhaust. The pulsating you see is that exhaust flapping in the wind of the descent.

The RCS is cold nitrogen in any case - you can see it in action, as a little white plume on the right side of the stage, in the OG-2 launch video just after stage sep (http://youtu.be/lbHnSu-DLR4?t=18m5s), as the stiffener ring falls away from the M1-D nozzle extension.

If you look at at the 1km F9R-Dev flight with the cows (http://youtu.be/ZwwS4YOTbbw?t=1m22s), you'll see the flapping orange flame quite clearly about a minute and a half in. The actual exhaust plume of the engine is never visible to the camera, as it's being directed straight down in a supersonic pillar.

The +11:33 white circle is not flame, it's a huge splash of water being hurled outward by 140,000 pounds of thrust in the moments before landing. We've seen what Merlin engines can do with water (http://youtu.be/Od-lON4bTyQ?t=39m42s) on the CRS-3 launch.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mader Levap on 07/25/2014 12:00 PM
It hasn't been too long ago since the days when discussions of cheap re-usability itself was heresy; yet here SpaceX are... making the economics work.
Nope. They are in progress of making it work technically.

It remains to be seen if it will be economic. I think it will be, but it is not proven at this point and we are at least decade away from that.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/26/2014 12:16 AM
Quote from: SpaceX
At this point, we are highly confident of being able to land successfully [..] and refly the rocket with no required refurbishment.

I don't know how they can make any claims about refurbishment if they haven't recovered a stage yet.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/26/2014 03:14 AM
Quote from: SpaceX
At this point, we are highly confident of being able to land successfully [..] and refly the rocket with no required refurbishment.

I don't know how they can make any claims about refurbishment if they haven't recovered a stage yet.

They haven't recovered an intact stage.  They *have* recovered parts from the water.  (And five complete dragons, of course.) That may be enough to give them confidence that they have not made any major mistakes in their understanding of the reentry environment.  There are four engine relights & burns (with full telemetry) *after* supersonic reentry, so they know that the reentry isn't significantly harming the engines.  And, of course, they've fired the engines *many* times, recycled propellant, etc, so they have a pretty good handle on the service life of the components.

"Feeling confident" that they are "able" doesn't exactly mean that they *plan* to do so immediately.  I strongly suspect the first landed stage will be fully torn down and every part examined before it's reflown.

And note that they only said "refly the rocket", not "refly the rocket 50 times" without refurbishment.  So the claim is not quite as bold as it may initially seem.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/26/2014 03:19 AM
There's more than just the engines to consider. I just think it was an overly bold statement. (From SpaceX? Never!)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Robotbeat on 07/26/2014 03:26 AM
They've flown F9R-dev1 at least 20 times (they don't release video of every time). That's probably where such a statement comes from.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/26/2014 03:28 AM
What's that got to do with anything? It's the reentry that does the damage currently unknown wear (if any).
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Robotbeat on 07/26/2014 03:30 AM
What's that got to do with anything? It's the reentry that does the damage (if any).
On the contrary, launch and landing are probably harder on the vehicle than a few Mach reentry. Or at least, SpaceX likely believe so.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/26/2014 03:32 AM
What's that got to do with anything? It's the reentry that does the damage (if any).
On the contrary, launch and landing are probably harder on the vehicle than a few Mach reentry. Or at least, SpaceX likely believe so.

I'm not arguing that. The point is they can't possibly know that yet. Until they recover a stage, they won't know how beaten up it is.

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Robotbeat on 07/26/2014 03:39 AM
What's that got to do with anything? It's the reentry that does the damage (if any).
On the contrary, launch and landing are probably harder on the vehicle than a few Mach reentry. Or at least, SpaceX likely believe so.

I'm not arguing that. The point is they can't possibly know that yet. Until they recover a stage, they won't know how beaten up it is.
We're talking about SpaceX, here. BFR, Mars Colony of a million people who pay just $500,000 SpaceX. They know it doesn't blow up until it topples over. That's better proof of not being beat up than anything they have about a Mars colony.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Robotbeat on 07/26/2014 03:41 AM
Also, the stages are instrumented with strain gauges and such and they've gotten telemetry all the way down to the water. They know what kind of beating the stage has taken from that right there.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/26/2014 03:42 AM
That's certainly better than nothing, but I don't think it's sufficient for the claim they've made here. They need to recover the stage.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sojourner on 07/26/2014 03:48 AM
Hey, just had a thought and wasn't sure what the best thread to put this in was.

Is it possible that the fact that SpaceX hasn't done the boost back phase on any flight contributing to the stage "kabooming" when it falls over in the ocean? By that I mean, could it have extra weight from the unused fuel (particularly the oxygen in the upper part of the stage) contributing with how hard it hits?  Might including the boost back before the water landing increase the chance of recovering an intact stage?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mme on 07/26/2014 03:57 AM
Quote from: SpaceX
At this point, we are highly confident of being able to land successfully [..] and refly the rocket with no required refurbishment.

I don't know how they can make any claims about refurbishment if they haven't recovered a stage yet.
They are claiming they are confident, not that they know it for a fact.  They don't have the stage but they have the telemetry and whatever simulations they've run.  They have a fair idea the stresses the stage encountered on reentry and they know everything was functioning as they expected.

When they recover one, especially if they land one, then they'll know for a fact.  Maybe it will turn out they are wrong, but I can't see the problem with them saying they are confident at this point.

Edit: I really need a proof reader.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: QuantumG on 07/26/2014 04:06 AM
Quote from: SpaceX
At this point, we are highly confident of being able to land successfully [..] and refly the rocket with no required refurbishment.

I don't know how they can make any claims about refurbishment if they haven't recovered a stage yet.
They are claiming they are confident, not that they know it for a fact.  They don't have the stage but they have the telemetry and whatever simulations they've run.  They have a fair idea the stresses stage encountered on reentry and they know everything was functioning as they expected.

When they recover one, especially if they land one, then they'll know for a fact.  Maybe it will turn out they are wrong, but I can't see the problem with being them saying they are confident at this point.

Fair enough. Point taken.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: deruch on 07/26/2014 04:37 AM
When's the last time SpaceX wasn't highly confident about something?  That's sort of their defining trait isn't it? :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: docmordrid on 07/26/2014 04:43 AM
When's the last time SpaceX wasn't highly confident about something?  That's sort of their defining trait isn't it? :)

The times they've said a stage only had a small chance of making it down intact? Saying they'd crater a Grasshopper? Etc.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Llian Rhydderch on 07/26/2014 05:12 AM
That's certainly better than nothing, but I don't think it's sufficient for the claim they've made here. They need to recover the stage.

In the US, that kind of a statement made by a company is known as a "forward-looking statement."  However, since SpaceX is not publically traded on the open stock exchanges, any legal and jurisprudential standards for such statements (and potentially "misleading" investors) are much lower than they are for publically-traded companies.

Overall, when Must/SpaceX speaks "confident", I think that is just vernacular English for "highly likely", or maybe P > (say) 0.9 or so.  Net:  Musk really believes his test program to date has shown him that the big hurdles can be solved by good engineering in the ongoing SpaceX reusable technology development program, and that he believes they can (eventually or soon) recover and refly a stage.

For my money, I would think they do have sufficient data from the (now) three-pronged test program (Grasshopper, F9R Dev flights in Texas; plus the three controlled descent tests from high altitude and high Mach) to say what they have said.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: aero on 07/26/2014 05:18 AM
I'm still wondering why we haven't seen any surface video of the return. They show surface video of the Dragon returns after all and surface video goes a long way toward proving that they know where it will touch down. Video shot from aircraft is good, (Casiope) but one could argue that an airplane could move several miles toward the touch down while the stage is returning. A boat can't move far at all during the return.

A boat with a GPS and ship to shore radio setting a sea anchored buoy then standing off and filming the buoy while the stage touches down beside (on top of) it would work. Need the radio in case of a scrub  :(
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: deruch on 07/26/2014 06:44 AM
Decent chance of that with "sold surface" landings planned for flights 14 &15.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: guckyfan on 07/26/2014 06:54 AM
I'm still wondering why we haven't seen any surface video of the return.

I have wondered that too. It may be because they keep a larger distance until precision landing is proven. A rocket stage descending under engine power poses a bigger risk than a capsule under a parachute.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mikelepage on 07/26/2014 08:33 AM
I was probably too wordy in my earlier post to encourage replies (http://forum.nasaspaceflight.com/index.php?topic=35243.msg1232564#msg1232564), but I did want to make the point that any future recovery of the second stage in flights from the Cape to LEO would likely have to be on a ship-based platform off Western Australia (as opposed to a land-based platform).  Therefore, experience recovering the first stage on a ship-based platform will be useful, even if the eventual plan is to bring first stages back to the pad.  I'm looking forward to flights 14 & 15 :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: guckyfan on 07/26/2014 08:59 AM
I was probably too wordy in my earlier post to encourage replies (http://forum.nasaspaceflight.com/index.php?topic=35243.msg1232564#msg1232564), but I did want to make the point that any future recovery of the second stage in flights from the Cape to LEO would likely have to be on a ship-based platform off Western Australia (as opposed to a land-based platform).  Therefore, experience recovering the first stage on a ship-based platform will be useful, even if the eventual plan is to bring first stages back to the pad.  I'm looking forward to flights 14 & 15 :)

Why would you think that? More likely they will bring the second stage back to the launch pad, too. After ~12 hours it shouuld pass over that point again.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: douglas100 on 07/26/2014 09:31 AM
This post does come to the topic - bear with me :)

I know I saw somewhere (maybe for CRS-3) an exclusion zone map for the second stage coming down off the coast of Western Australia.  Being a resident of Perth WA, I began wondering if SpaceX is likely to attempt to build landing pad(s) somewhere near me, (or maybe if it will be more efficient to give the second stage just enough of an extra boost so it comes down somewhere near Florida after the first full orbit)

Any second stages returning to land on current trajectories would have to come down somewhere on the WA coast....

No they wouldn't. Just because SpaceX chose to de-orbit the second stage in that area for this flight doesn't mean a future re-usable stage would do that. Why would they ever chose to bring the stage down  in an area which has the maximum distance to transport the stage home? Bear in mind a recoverable second stage is a spacecraft. It essentially has to do what Dragon has to do for re-entry and landing. Why would they consider landing the stage on a platform at sea (extra cost and complexity of operations) when they can land it anywhere on land between the latitudes of the orbital inclination?

But I notice we're getting OT here and I'm contributing to it. I shall reprimand myself and say no more!


Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mikelepage on 07/26/2014 11:34 AM
This post does come to the topic - bear with me :)

I know I saw somewhere (maybe for CRS-3) an exclusion zone map for the second stage coming down off the coast of Western Australia.  Being a resident of Perth WA, I began wondering if SpaceX is likely to attempt to build landing pad(s) somewhere near me, (or maybe if it will be more efficient to give the second stage just enough of an extra boost so it comes down somewhere near Florida after the first full orbit)

Any second stages returning to land on current trajectories would have to come down somewhere on the WA coast....

No they wouldn't. Just because SpaceX chose to de-orbit the second stage in that area for this flight doesn't mean a future re-usable stage would do that. Why would they ever chose to bring the stage down  in an area which has the maximum distance to transport the stage home? Bear in mind a recoverable second stage is a spacecraft. It essentially has to do what Dragon has to do for re-entry and landing. Why would they consider landing the stage on a platform at sea (extra cost and complexity of operations) when they can land it anywhere on land between the latitudes of the orbital inclination?

But I notice we're getting OT here and I'm contributing to it. I shall reprimand myself and say no more!

Ah right, I see I was confused about why that landing zone was chosen.  My bad.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/26/2014 03:09 PM
I'm still wondering why we haven't seen any surface video of the return. They show surface video of the Dragon returns after all and surface video goes a long way toward proving that they know where it will touch down. Video shot from aircraft is good, (Casiope) but one could argue that an airplane could move several miles toward the touch down while the stage is returning. A boat can't move far at all during the return.

The NASA crew failed to obtain video: it was too hard to track the rocket.  They will reportedly try again for CRS-4.  There might be other video, but remember this is only the *first* shot they've had at capturing landing video -- the CRS-3 flight has terrible weather, so they didn't even get to try then.  Yes, we have good surface video of Dragon now --- but there have been five Dragons.  I seem to recall the first dragon didn't have great surface splashdown photos either.  And remember that parachute landings are quite leisurely compared to the propulsive landing process.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Comga on 07/26/2014 11:50 PM
I'm still wondering why we haven't seen any surface video of the return. They show surface video of the Dragon returns after all and surface video goes a long way toward proving that they know where it will touch down. Video shot from aircraft is good, (Casiope) but one could argue that an airplane could move several miles toward the touch down while the stage is returning. A boat can't move far at all during the return.

The NASA crew failed to obtain video: it was too hard to track the rocket.  They will reportedly try again for CRS-4.  There might be other video, but remember this is only the *first* shot they've had at capturing landing video -- the CRS-3 flight has terrible weather, so they didn't even get to try then.  Yes, we have good surface video of Dragon now --- but there have been five Dragons.  I seem to recall the first dragon didn't have great surface splashdown photos either.  And remember that parachute landings are quite leisurely compared to the propulsive landing process.

We were told that the NASA plane went to record the hypersonic retro-burn.   Where was is said that they would attempt to photograph the landing?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/27/2014 02:35 AM
I didn't. Perhaps my use of the pronoun "they" confused you.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: PeanutGallery on 07/27/2014 03:53 AM
Considering SpaceX's lawsuit against the Air Force, I guess it's very unlikely they'll agree to allowing the use of their RC-135S Cobra Ball to observe/video the booster return, even if it was available...this is their regular job...
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/27/2014 05:39 AM
Considering SpaceX's lawsuit against the Air Force, I guess it's very unlikely they'll agree to allowing the use of their RC-135S Cobra Ball to observe/video the booster return, even if it was available...this is their regular job...


The Air Force has been sued before by contractors (even current ones... hmm), but that isn't part of the picture that a certain competitor is trying to spread.

The Air Force are big boys, they can handle it.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Dave G on 07/27/2014 10:45 AM
Considering SpaceX's lawsuit against the Air Force, I guess it's very unlikely they'll agree to allowing the use of their RC-135S Cobra Ball to observe/video the booster return, even if it was available...this is their regular job...

Quote from Elon Musk:
Quote
"It’s not as though we’re battling the whole Air Force. That’s not the case at all.  I think we’re on very good terms with the vast majority of the Air Force. Our concern really relates to a handful of people in the procurement area of the Air Force.”
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 07/27/2014 02:54 PM
Looking at the video, I was surprised at how late the landing legs deployed.<snip>
I've read a few comments about timing of the legs, and consistency with the CRS-3 landing. So I decided to do a split screen video on both landings and watch them side by side - and this lead to me adding one thing after another until my wife said I've spent too much time on this.

So here's a link to my 2 minute combination of 5 videos showing the reusability of the first stage. :)

https://www.youtube.com/watch?v=o-3zYpbw53I



Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: guckyfan on 07/27/2014 03:19 PM
Looking at the video, I was surprised at how late the landing legs deployed.<snip>
I've read a few comments about timing of the legs, and consistency with the CRS-3 landing. So I decided to do a split screen video on both landings and watch them side by side - and this lead to me adding one thing after another until my wife said I've spent too much time on this.

So here's a link to my 2 minute combination of 5 videos showing the reusability of the first stage. :)

Great video. Thanks. So the legs deploy in parallel.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Tuts36 on 07/27/2014 05:43 PM

I've read a few comments about timing of the legs, and consistency with the CRS-3 landing. So I decided to do a split screen video on both landings and watch them side by side - and this lead to me adding one thing after another until my wife said I've spent too much time on this.

So here's a link to my 2 minute combination of 5 videos showing the reusability of the first stage. :)

Great video. Thanks. So the legs deploy in parallel.

No no, you spent JUST ENOUGH time on it - thank you for this!

I notice the same "bounce" in the (edit: deployement of the) landing legs both times, and the elapsed time between leg deploy & splashdown looks VERY precise for both.  Does that imply something about how the first stage detects the landing surface?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MTom on 07/27/2014 08:26 PM
Looking at the video, I was surprised at how late the landing legs deployed.<snip>
I've read a few comments about timing of the legs, and consistency with the CRS-3 landing. So I decided to do a split screen video on both landings and watch them side by side - and this lead to me adding one thing after another until my wife said I've spent too much time on this.

So here's a link to my 2 minute combination of 5 videos showing the reusability of the first stage. :)


Very good comparison.

What I see: the last part of the landing, while the engine blows the dust/vapor away has other length at the test flights and at the ocean landings:
- 1:49-1:52 at ocean landings
- 1:49-1:57 at F9R landings

Maybe the landing speed is higher (this is my guess as explanation) at ocean landing? More aggressive deceleration in this case? Or the engine was shut down earlier because of the water?

I tried to measure the velocity of objects on the video before 1:49. The waves at CRS-3 seems to be more speedy going away from the rocket, than the object on the F9R videos, but I don't know if the video restoring was enough accurate to use for this measurement.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 07/27/2014 09:57 PM
Thanks for the feedback I'm glad you liked it :)

Very good comparison.

What I see: the last part of the landing, while the engine blows the dust/vapor away has other length at the test flights and at the ocean landings:
- 1:49-1:52 at ocean landings
- 1:49-1:57 at F9R landings

Maybe the landing speed is higher (this is my guess as explanation) at ocean landing? More aggressive deceleration in this case? Or the engine was shut down earlier because of the water?
Yes I was wondering about the same things.

Your second guess appears correct - the engines get doused earlier in the water, at about the same time in the video as the F9R stops moving. The F9R seems to keep the engines going 5 more seconds, perhaps it's some sort of stability (slow reduction in power?) or landing checks before powering down? 

edit: I'm certainly not sure of my interpretation. The rocket may be moving slightly. In any case, if it's designed to be very slow in the last seconds, a wave would put an end to that...?

Quote
I tried to measure the velocity of objects on the video before 1:49. The waves at CRS-3 seems to be more speedy going away from the rocket, than the object on the F9R videos, but I don't know if the video restoring was enough accurate to use for this measurement.
I would say that at the beginning of the F9R descent in the video, it's moving more slowly (much more slowly?) than the water landings. By the time they reach ground/water level they all seem to move equally slowly.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: deruch on 07/28/2014 01:06 AM
Great vid!  The only minor critique I have is that we're pretty sure that there wasn't a boost-back, just re-entry and landing burns.  So, if I was making this video (I'm in no way skilled enough to make one anywhere near as good as your is though), I don't think I would show one even in animation.  But this is a fairly minor technical point.  Great job!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Robotbeat on 07/28/2014 01:50 AM
A long enough reentry burn is the same as a reentry burn... There's not a sharp line, there. :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: deruch on 07/28/2014 03:59 AM
A long enough reentry burn is the same as a reentry burn... There's not a sharp line, there. :)

I'm guessing one of those "reentry"s is supposed to be something else.  I think you're saying either [1] that a long boost-back burn is the same as a re-entry burn or [2] that a long re-entry burn is the same as the landing burn.  As my post was related to the boost-back bit, that's the way I'm leaning.

[1] In theory, the boost-back burn could continue through the stage's interaction with the upper atmosphere and thus accomplish both the boost-back and the re-entry slowing burn, thereby eliminating the need for an additional relight of engines on an RTLS flight.  I'm perfectly willing to accept that there isn't necessarily a sharp dividing line between the two.  However, according to my understanding of the practice of this particular landing, the booster stage flew a purely ballistic trajectory that did not include what would colloquially be considered a "boost-back towards the launch site".  i.e. Its two engine relights were accomplished with the goals of A) surviving re-entry and B) achieving a soft landing.

[2] I don't think this is what you meant, but if it is you're wrong.  The re-entry burn uses 3 engines.  The landing only uses 1.  I'm pretty sure that the stage isn't continuously firing all the way from re-entry to touchdown (even if it's just the center engine, with the two side engines shut off after sufficient slow down).  Plus, SpaceX explicitly said there were two relightings of engines.  I pointed out above why I don't believe a distinct boost-back burn was one of those relightings.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Robotbeat on 07/28/2014 04:19 AM
Neither, sorry for the typo!. A long reentry burn is like a boost-back burn. (On the way back, entry velocity is much lower.)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 07/28/2014 04:40 AM
Great vid!  The only minor critique I have is that we're pretty sure that there wasn't a boost-back, just re-entry and landing burns.  So, if I was making this video (I'm in no way skilled enough to make one anywhere near as good as your is though), I don't think I would show one even in animation.  But this is a fairly minor technical point.  Great job!
Thanks Deruch :)

I also though about that... as well as the animation of the rocket descending and legs opening while still at quite an altitude - when it seems that the actual attempts have opened much lower(?). I think reusability plans have evolved in the last 2 years (the animation still has the square layout of engines too).

I wasn't trying to emulate the 2 'land'ings so much as give a good story of the overall process we're seeing developed. It was partly a "side by side" of the 2 successful attempts, and partly an upgrade to the animation via as much real footage as possible - because both of the supplied videos have weaknesses. They're not clear, and too easy for the casual viewer to misinterpret the landing videos as having the engines ignite only at the last second. In the side-by-side I wanted to show the common leg movements, matching flames, and the similar flame activity in the F9R when near real ground (with a linking wide shot for some perspective).

But yeah... the purist in me wants to keep it entirely consistent with the OG2!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: guidanceisgo on 07/28/2014 05:15 AM
Anyone know if they are going to do a hover / translation on any of the upcoming flights. (ie, hover then start translating towards the coast.)  It seems like that would be a logical step in the test plan.  I suppose they would have to do something like this prior to coming onshore to land at the Cape since a boost IIP on the land would be scary.  It would be really cool to see!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: deruch on 07/28/2014 05:26 AM
Great vid!  The only minor critique I have is that we're pretty sure that there wasn't a boost-back, just re-entry and landing burns.  So, if I was making this video (I'm in no way skilled enough to make one anywhere near as good as your is though), I don't think I would show one even in animation.  But this is a fairly minor technical point.  Great job!
Thanks Deruch :)

I also though about that... as well as the animation of the rocket descending and legs opening while still at quite an altitude - when it seems that the actual attempts have opened much lower(?). I think reusability plans have evolved in the last 2 years (the animation still has the square layout of engines too).

I wasn't trying to emulate the 2 'land'ings so much as give a good story of the overall process we're seeing developed. It was partly a "side by side" of the 2 successful attempts, and partly an upgrade to the animation via as much real footage as possible - because both of the supplied videos have weaknesses. They're not clear, and too easy for the casual viewer to misinterpret the landing videos as having the engines ignite only at the last second. In the side-by-side I wanted to show the common leg movements, matching flames, and the similar flame activity in the F9R when near real ground (with a linking wide shot for some perspective).

But yeah... the purist in me wants to keep it entirely consistent with the OG2!
I haven't been paying much attention to it lately, but in the CRS-3 video interpretation thread (http://forum.nasaspaceflight.com/index.php?topic=34794.msg1227591#msg1227591), user sittingduck is working on creating an accurate animation of the CRS-3 booster landing.  You might be interested in the final product.  I'm not sure how far along it is though.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: TrevorMonty on 07/28/2014 07:21 AM
Assume video.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rpapo on 07/28/2014 10:16 AM
Anyone know if they are going to do a hover / translation on any of the upcoming flights. (ie, hover then start translating towards the coast.)  It seems like that would be a logical step in the test plan.  I suppose they would have to do something like this prior to coming onshore to land at the Cape since a boost IIP on the land would be scary.  It would be really cool to see!
I agree it would be cool to see, but hover isn't going to happen on any real flight, because to do that they would have to have enough fuel left over in the rocket to where the T/W ratio is one or less when throttled down to 60%.  The only reason the Grasshopper and F9R-Dev1 rockets have been able to hover is because they are ballasted with much more fuel than would be present on a real return from launch.

Translation may occur, to a small extent, during the landing burn.  Grid fins should have the effect of minimizing this.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Dudely on 07/28/2014 11:36 AM
Anyone know if they are going to do a hover / translation on any of the upcoming flights. (ie, hover then start translating towards the coast.)  It seems like that would be a logical step in the test plan.  I suppose they would have to do something like this prior to coming onshore to land at the Cape since a boost IIP on the land would be scary.  It would be really cool to see!
I agree it would be cool to see, but hover isn't going to happen on any real flight, because to do that they would have to have enough fuel left over in the rocket to where the T/W ratio is one or less when throttled down to 60%.  The only reason the Grasshopper and F9R-Dev1 rockets have been able to hover is because they are ballasted with much more fuel than would be present on a real return from launch.

Translation may occur, to a small extent, during the landing burn.  Grid fins should have the effect of minimizing this.

I disagree. I thought that was why they were choosing a pad next to the ocean- the return will target a patch of water 200-400 meters offshore and the rocket will use the landing burn to translate to the pad.

Otherwise they risk damage to the pad. Bare concrete pads still cost a significant amount of money.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rpapo on 07/28/2014 11:51 AM
I disagree. I thought that was why they were choosing a pad next to the ocean- the return will target a patch of water 200-400 meters offshore and the rocket will use the landing burn to translate to the pad.

Otherwise they risk damage to the pad. Bare concrete pads still cost a significant amount of money.
I didn't say translation would not occur, only that it would be minimal.  There's only so much translation you can do when your entire burn lasts only about 24 seconds.  And there will be no hovering . . . unless Mueller and his staff manage pull a rabbit out of a hat and suddenly discover how to get a Merlin 1D to throttle down more than 50%.

Yet another rabbit, that is.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/28/2014 02:23 PM
Anyone know if they are going to do a hover / translation on any of the upcoming flights. (ie, hover then start translating towards the coast.)  It seems like that would be a logical step in the test plan.  I suppose they would have to do something like this prior to coming onshore to land at the Cape since a boost IIP on the land would be scary.  It would be really cool to see!

The falcon is incapable of hovering.  Thrust/weight is always greater than 1 for the rocket (even with only one engine firing -- the rocket is very light when almost all the fuel has been burned).  It lands with a "hoverslam" approach, where it reaches zero velocity precisely at zero altitude.  Any significant translation occurs during the "boostback" and/or "retro burn".

The question of whether/how SpaceX is going to do a "boost back" has been oft asked in these forums.  Nobody knows yet.  But Flights 15 and 16 will involve a "solid" landing, which is likely to involve some amount of boost back.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Elmar Moelzer on 07/28/2014 03:09 PM
unless Mueller and his staff manage pull a rabbit out of a hat and suddenly discover how to get a Merlin 1D to throttle down more than 50%.
Yet another rabbit, that is.
Wasn't that confirmed already at some point? I distinctly remember a quote from Musk about the surprisingly large throttle range of the Merlin 1D (anyone here who can dig it up?).
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: cscott on 07/28/2014 03:12 PM
Wasn't that confirmed already at some point? I distinctly remember a quote from Musk about the surprisingly large throttle range of the Merlin 1D (anyone here who can dig it up?).

If I recall correctly, it was a twitter quote that was much debated.  IIRC he said "40% throttle" or some such, and readers were sharply divided over whether he meant "throttle down 40%" (aka, total thrust 60% of maximum) -- which would not be surprising -- or "total thrust of 40% of maximum", which would be surprising.

Evidence since then has not supported the surprising interpretation.

UPDATE: swapped 60% and 40% to make my recounting accurate.  Thanks to sublimemarsupial for digging up the original twitter exchange.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sublimemarsupial on 07/28/2014 03:19 PM
Wasn't that confirmed already at some point? I distinctly remember a quote from Musk about the surprisingly large throttle range of the Merlin 1D (anyone here who can dig it up?).

If I recall correctly, it was a twitter quote that was much debated.  IIRC he said "60% throttle" or some such, and readers were sharply divided over whether he meant "throttle down 60%" (aka, total thrust 40% of maximum) -- which would be surprising -- or "total thrust of 60% of maximum", which would be less surprising.

Evidence since then has not supported the surprising interpretation.

Jon Goff asked how far the M1d could throttle, and Elon replied "~40%". What that meant was not clarified.

Here's a link to the tweets in question: https://twitter.com/elonmusk/status/462104679116050432
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 07/28/2014 04:13 PM
The M1D can throttle down to at least 50% - at least the vacuum version, I have seen this in a NASA presentation. I assume the same holds for the 'plain' M1D.

So when "~40%" was mentioned, the only reasonable interpretation (IMO) is that they can now throttle it even deeper than previously published information.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AJA on 07/31/2014 07:49 PM
What would be acceptable vertical velocity limits for "hovering"? 0 +/- 5 m/s? Can the stage do that by pulsing the engines, or even by slewing the throttle up and down constantly? If the response time of the engine, and the rates are fast enough, then you wouldn't need the T/W to be ~= 1 at all. (Although, obviously that does help).


Basically, can they playing a game of flappy bird, with a Falcon?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rpapo on 07/31/2014 10:39 PM
I don't think you can pulse the Merlins like you can the Dracos.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Dudely on 08/01/2014 02:25 PM
What would be acceptable vertical velocity limits for "hovering"? 0 +/- 5 m/s? Can the stage do that by pulsing the engines, or even by slewing the throttle up and down constantly? If the response time of the engine, and the rates are fast enough, then you wouldn't need the T/W to be ~= 1 at all. (Although, obviously that does help).


Basically, can they playing a game of flappy bird, with a Falcon?

No, because of instabilities with the prop in the engine. Basically the same reason they can't throttle down beyond a certain point- because the propellant has to mix and combust at a certain rate and if it doesn't you might get too little combustion for a brief moment, then a spike in pressure as the buildup of uncombusted, poorly mixed propellant finally combusts. And there goes your engine.

I think the dracos can pulse because their fuel is hypergolic.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: HMXHMX on 08/01/2014 05:59 PM
What would be acceptable vertical velocity limits for "hovering"? 0 +/- 5 m/s? Can the stage do that by pulsing the engines, or even by slewing the throttle up and down constantly? If the response time of the engine, and the rates are fast enough, then you wouldn't need the T/W to be ~= 1 at all. (Although, obviously that does help).


Basically, can they playing a game of flappy bird, with a Falcon?

No, because of instabilities with the prop in the engine. Basically the same reason they can't throttle down beyond a certain point- because the propellant has to mix and combust at a certain rate and if it doesn't you might get too little combustion for a brief moment, then a spike in pressure as the buildup of uncombusted, poorly mixed propellant finally combusts. And there goes your engine.

I think the dracos can pulse because their fuel is hypergolic.

The primary issue with regard to depth of throttle is flow separation from the nozzle; this statement is true provided proper care has been taken in designing the injection orifices to permit the desired throttle setting.  The pintle injector has an advantage in this situation since it can be face-throttled as was done with the Lunar Module LMDE.  But I'm fairly sure SpaceX is not face throttling the Merlin 1D; they may be face-throttling the SuperDraco.  Propellant choice is not really a major factor in throttling.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: abaddon on 08/01/2014 06:24 PM
I think the dracos can pulse because their fuel is hypergolic.

I thought it was because they were pressure fed... much easier to smoothly change the throttle than a pump-fed system.  Or maybe it is both...
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Nomadd on 08/01/2014 06:29 PM
I think the dracos can pulse because their fuel is hypergolic.

I thought it was because they were pressure fed... much easier to smoothly change the throttle than a pump-fed system.  Or maybe it is both...
There's a big difference between opening and closing a valve and spinning up turbo pumps.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Lars_J on 08/01/2014 09:40 PM

I think the dracos can pulse because their fuel is hypergolic.

I thought it was because they were pressure fed... much easier to smoothly change the throttle than a pump-fed system.  Or maybe it is both...
There's a big difference between opening and closing a valve and spinning up turbo pumps.

Yes, that's exactly the point he was making. If you want a responsive thruster able to pulse rapidly, it has to be pressure fed. No matter if the propellant is hypergolic or cryogenic.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: baldusi on 08/02/2014 01:54 AM


I think the dracos can pulse because their fuel is hypergolic.

I thought it was because they were pressure fed... much easier to smoothly change the throttle than a pump-fed system.  Or maybe it is both...
There's a big difference between opening and closing a valve and spinning up turbo pumps.

Yes, that's exactly the point he was making. If you want a responsive thruster able to pulse rapidly, it has to be pressure fed. No matter if the propellant is hypergolic or cryogenic.
I believe that's the case with closed cycle TP, but on an open cycle, like that Gas Generator, couldn't you just put a throttling valve between the TP pump and the injectors and simply restrict flow while reducing the gg gas flow?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: NovaSilisko on 08/02/2014 02:09 AM
Seems to me like the repeated shock of rapid-fire on-off cycles would be a really nice way to disintegrate an engine like Merlin...
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: HMXHMX on 08/02/2014 03:42 AM


I think the dracos can pulse because their fuel is hypergolic.

I thought it was because they were pressure fed... much easier to smoothly change the throttle than a pump-fed system.  Or maybe it is both...
There's a big difference between opening and closing a valve and spinning up turbo pumps.

Yes, that's exactly the point he was making. If you want a responsive thruster able to pulse rapidly, it has to be pressure fed. No matter if the propellant is hypergolic or cryogenic.
I believe that's the case with closed cycle TP, but on an open cycle, like that Gas Generator, couldn't you just put a throttling valve between the TP pump and the injectors and simply restrict flow while reducing the gg gas flow?

That's essentially what you do with face throttling.  You have to avoid pump stall, but that just means throttling the GG, which is how the Merlin apparently does it. 

http://jasc-controls.com/jasc-industry-listing/space/space-fluid-management/bi-propellant-valve/
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AJA on 08/02/2014 01:00 PM
I believe that's the case with closed cycle TP, but on an open cycle, like that Gas Generator, couldn't you just put a throttling valve between the TP pump and the injectors and simply restrict flow while reducing the gg gas flow?

That's essentially what you do with face throttling.  You have to avoid pump stall, but that just means throttling the GG, which is how the Merlin apparently does it. 

http://jasc-controls.com/jasc-industry-listing/space/space-fluid-management/bi-propellant-valve/ (http://jasc-controls.com/jasc-industry-listing/space/space-fluid-management/bi-propellant-valve/)


Why would you need to throttle the GG at all? Split the flow downstream of the main fuel valve (http://blogs.nasa.gov/wp-content/uploads/sites/212/2013/06/1035780main_gasgenerat6r.jpg) (and/or the main oxidiser valve), prior to the injector, and add a second flow path back to the tank, controlled by a valve. Now, if this back-to-tank valve is fully closed, the engine operates as it did previously. If it's open, then the pressurised fuel/oxidiser that exits the turbo-pump simply makes its way back to the tank instead of the combustion chamber.

You wouldn't get rid of the combustion stability, and transition forces issues that would be introduced by pulsing/rapid deep-throttling, but you would - in my head atleast - be able to throttle the engine, without needing to change the speed of the turbo-pumps, or throttling the gas generator.

There would be new problems of course. One I can think of is with respect to maintaining the back-to-tank flow path at cryogenic temperatures - in case of the LOX, as well as avoiding getting filler gas bubbles flowing back into the pipe etc. You could do it only on the fuel side, but that would mean that whenever you throttled down, you'd be burning oxidiser-rich, and probably a lot hotter than the design of the nozzle/combustion chamber was designed to cope with.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: HMXHMX on 08/02/2014 04:05 PM
I believe that's the case with closed cycle TP, but on an open cycle, like that Gas Generator, couldn't you just put a throttling valve between the TP pump and the injectors and simply restrict flow while reducing the gg gas flow?

That's essentially what you do with face throttling.  You have to avoid pump stall, but that just means throttling the GG, which is how the Merlin apparently does it. 

http://jasc-controls.com/jasc-industry-listing/space/space-fluid-management/bi-propellant-valve/ (http://jasc-controls.com/jasc-industry-listing/space/space-fluid-management/bi-propellant-valve/)


Why would you need to throttle the GG at all? Split the flow downstream of the main fuel valve (http://blogs.nasa.gov/wp-content/uploads/sites/212/2013/06/1035780main_gasgenerat6r.jpg) (and/or the main oxidiser valve), prior to the injector, and add a second flow path back to the tank, controlled by a valve. Now, if this back-to-tank valve is fully closed, the engine operates as it did previously. If it's open, then the pressurised fuel/oxidiser that exits the turbo-pump simply makes its way back to the tank instead of the combustion chamber.

You wouldn't get rid of the combustion stability, and transition forces issues that would be introduced by pulsing/rapid deep-throttling, but you would - in my head atleast - be able to throttle the engine, without needing to change the speed of the turbo-pumps, or throttling the gas generator.

There would be new problems of course. One I can think of is with respect to maintaining the back-to-tank flow path at cryogenic temperatures - in case of the LOX, as well as avoiding getting filler gas bubbles flowing back into the pipe etc. You could do it only on the fuel side, but that would mean that whenever you throttled down, you'd be burning oxidiser-rich, and probably a lot hotter than the design of the nozzle/combustion chamber was designed to cope with.

Lots of reasons why you don't want to pump back into the tank, but mainly what you are suggesting is similar to something we work to avoid – geysering.  At least in the Merlin 1D case, GG already throttles, so no harm in coupling to it.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: S.Paulissen on 08/02/2014 09:07 PM
Furthermore, you'd be wasting the prop flow through the GG to uselessly pump prop back into the tank, which compounds the ISP loss inherent to using a GG cycle.  Since it's pretty common to run engines throttled during launch to limit acceleration Gs it'd amount to a significant penalty. 
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MP99 on 08/03/2014 07:31 AM




I think the dracos can pulse because their fuel is hypergolic.

I thought it was because they were pressure fed... much easier to smoothly change the throttle than a pump-fed system.  Or maybe it is both...
There's a big difference between opening and closing a valve and spinning up turbo pumps.

Yes, that's exactly the point he was making. If you want a responsive thruster able to pulse rapidly, it has to be pressure fed. No matter if the propellant is hypergolic or cryogenic.
I believe that's the case with closed cycle TP, but on an open cycle, like that Gas Generator, couldn't you just put a throttling valve between the TP pump and the injectors and simply restrict flow while reducing the gg gas flow?

That's essentially what you do with face throttling.  You have to avoid pump stall, but that just means throttling the GG, which is how the Merlin apparently does it. 

http://jasc-controls.com/jasc-industry-listing/space/space-fluid-management/bi-propellant-valve/

LOX @ +100F! Wasn't expecting that. ;-)

Cheers, Martin
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: rpapo on 08/03/2014 09:05 AM
LOX @ +100F! Wasn't expecting that. ;-)
Question for the real rocket scientists around here: If this valve claims to tolerate LOX at 100 degrees Fahrenheit, then what is the state of the "liquid" oxygen then?  Gaseous, or pressure-induced liquid?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Kaputnik on 08/03/2014 10:45 AM
I presume, then, that it's not especially easy to run a GG on its own, without actually firing the engine attached to it? Just that if you could, it would open up possibilities for very low thrust for manoeuvring and landing burns...
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: SoulWager on 08/03/2014 12:28 PM
I presume, then, that it's not especially easy to run a GG on its own, without actually firing the engine attached to it? Just that if you could, it would open up possibilities for very low thrust for manoeuvring and landing burns...
GG exhaust is low pressure, low velocity, so you aren't going to get useful thrust out of it. If you changed that, you'd just make it less efficient at powering the pumps.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: HMXHMX on 08/03/2014 03:32 PM
LOX @ +100F! Wasn't expecting that. ;-)
Question for the real rocket scientists around here: If this valve claims to tolerate LOX at 100 degrees Fahrenheit, then what is the state of the "liquid" oxygen then?  Gaseous, or pressure-induced liquid?

I have no idea why they wrote that into the spec.  Perhaps someone else does?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: HMXHMX on 08/03/2014 03:34 PM
I presume, then, that it's not especially easy to run a GG on its own, without actually firing the engine attached to it? Just that if you could, it would open up possibilities for very low thrust for manoeuvring and landing burns...
GG exhaust is low pressure, low velocity, so you aren't going to get useful thrust out of it. If you changed that, you'd just make it less efficient at powering the pumps.

Depends on your definition of "useful."  The 1.5E6-lbf F-1 generates 40K-lbf thrust with its GG exhaust after spinning the turbine and being used as a heat exchanger fluid.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: CameronD on 08/04/2014 04:42 AM
LOX @ +100F! Wasn't expecting that. ;-)
Question for the real rocket scientists around here: If this valve claims to tolerate LOX at 100 degrees Fahrenheit, then what is the state of the "liquid" oxygen then?  Gaseous, or pressure-induced liquid?

I have no idea why they wrote that into the spec.  Perhaps someone else does?

I think you'll find it's a typo, and they meant to write "-100"... but, either way, it's a pretty impressive piece of kit.

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: SoulWager on 08/04/2014 05:09 PM
I presume, then, that it's not especially easy to run a GG on its own, without actually firing the engine attached to it? Just that if you could, it would open up possibilities for very low thrust for manoeuvring and landing burns...
GG exhaust is low pressure, low velocity, so you aren't going to get useful thrust out of it. If you changed that, you'd just make it less efficient at powering the pumps.

Depends on your definition of "useful."  The 1.5E6-lbf F-1 generates 40K-lbf thrust with its GG exhaust after spinning the turbine and being used as a heat exchanger fluid.
Only when it's pumping fuel to the main engines. If you tried to do that without an equivalent load on the turbopump you'd just blow it up from overspeed.   Thrust isn't linear with respect to throttle, most of it comes at the very end, when the flow is restricted enough by the throat of the nozzle that your chamber pressure and exhaust velocity climb. Think of the combustion chamber like a balloon. If you let the gasses through a narrow constriction, they go fast, and in one direction, so you get thrust. If you let the gasses go anywhere without restriction, you get very little thrust, like a campfire.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MP99 on 08/04/2014 07:01 PM


LOX @ +100F! Wasn't expecting that. ;-)
Question for the real rocket scientists around here: If this valve claims to tolerate LOX at 100 degrees Fahrenheit, then what is the state of the "liquid" oxygen then?  Gaseous, or pressure-induced liquid?

I have no idea why they wrote that into the spec.  Perhaps someone else does?

Might that be useful to perform a quick test with water?

Cheers, Martin
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Maciej Olesinski on 08/04/2014 07:44 PM
@jeff_foust  12 min.
Jurvetson showed video (not previously shown outside of SpaceX) of the reentry, ocean touchdown of latest F9 1st stage. #smallsat2014
Link: https://twitter.com/jeff_foust/status/496378128021745664

@jeff_foust  12 min.
Jurvetson said the video had been shot from aircraft, though a glitch caused the vehicle to go out of frame around touchdown. #smallsat2014
Link: https://twitter.com/jeff_foust/status/496378322247360512
Ok now we wait
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/05/2014 12:36 AM
LOX @ +100F! Wasn't expecting that. ;-)
Question for the real rocket scientists around here: If this valve claims to tolerate LOX at 100 degrees Fahrenheit, then what is the state of the "liquid" oxygen then?  Gaseous, or pressure-induced liquid?

Since the tubes are of comparable diameters, I'd say the densities are comparable, and so both fluids are the same and very likely liquid.

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Chris Bergin on 08/05/2014 02:47 PM
Ok, so first of all I want to explain a few things.

1) This video was provided to us by a L2 member and it was placed in there as a pre-empt to what we assumed would be a speedy turnaround of the actual video you see on the screen, by SpaceX.

2) In what is a very rare incident, it was leaked out of L2 by a Reddit member. Note: 99 percent of Reddit SpaceX fans are absolutely fine, some are actually really great and a lot are crossover fans, but there's a tiny group - people who were banned from here for profanity and attacking SpaceX - and specifically Elon - with lies, who appear to have taken it upon themselves to attack NSF at every opportunity, and myself. We assume it was one of those who leaked this. We were going to turn it around, but we are a media site, not a social media gathering, and as such we seek actual permissions.

3) Thankfully, we now have permission to post this openly, without having to use the links of those who clearly have absolutely no regard for sourcing or accreditation. I appreciate NSF members' patience in waiting for a sanctioned upload, which has been uploaded to one of the CRS-3 Propulsive Landing Video youtube accounts.

http://youtu.be/IBcj38ilNn4
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Elmar Moelzer on 08/05/2014 03:08 PM
Very cool, Chris!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AncientU on 08/05/2014 03:20 PM
Hey Chris,
Since this is a video of a video, has the original been released. 
Assume it has better detail and additional content...
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Elmar Moelzer on 08/05/2014 03:27 PM
I hope we will see this when they release videos of the most recent launch and the most recent F9R (McGregor) test flight.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/05/2014 03:27 PM
Hey Chris,
Since this is a video of a video, has the original been released. 
Assume it has better detail and additional content...
Having watched this 20 times already, at least half of them before I picked my jaw up off the desk, I concur with this request.

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Chris Bergin on 08/05/2014 03:30 PM
Hey Chris,
Since this is a video of a video, has the original been released. 
Assume it has better detail and additional content...

SpaceX will be the ones to do that as noted in my post. Really looking forward to that!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Elmar Moelzer on 08/05/2014 03:43 PM
It is really hard to see in the video, but does it seem like the stage is not completely straight upright when by the time the video cuts out?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: abaddon on 08/05/2014 03:44 PM
I wouldn't expect additional content.  It's already been noted above via tweet that "a glitch caused the vehicle to go out of frame around touchdown".  Doh!

Even so, what is there is spectacular, and I can't wait for the direct feed version to be released.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: bunker9603 on 08/05/2014 03:49 PM
Chris- Thank you for posting the video! It's an incredible to sight to see!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/05/2014 03:50 PM
It is really hard to see in the video, but does it seem like the stage is not completely straight upright when by the time the video cuts out?

It seems tilted a bit, and it could have been that it was "crabbing" against wind like airplanes do while landing in crosswind, but:

A GNC computer is not a helicopter pilot, and there's no need to null out horizontal speed or fly vertical until the very last second.  It doesn't have to feel "lined-up" when coming down.  Any propellant spent on such things too early will just get wasted when some random gust adds them back... 

There's a "firing solution" which terminates at zero speed and zero altitude and zero tilt, and there's no reason for it to be vertical anywhere but in the last meter.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/05/2014 03:53 PM
Hey Chris,
Since this is a video of a video, has the original been released. 
Assume it has better detail and additional content...

SpaceX will be the ones to do that as noted in my post. Really looking forward to that!

And when they do, they should split-screen it with the on-board camera footage.   :)

I'm really happy about how NSF is handling these things, in contrast to (oh, for example) reddit.


Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Ohsin on 08/05/2014 08:03 PM
It seems the camera switches between infrared and normal visual at around 16-17 seconds mark as it looks like a continuous shot you can make out a blurry falling object before the switch and no sign of lit up engines in those and after that we go directly to splashdown.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mongo62 on 08/05/2014 08:28 PM
It seems the camera switches between infrared and normal visual at around 16-17 seconds mark as it looks like a continuous shot you can make out a blurry falling object before the switch and no sign of lit up engines in those and after that we go directly to splashdown.

It was suggested upthread that these are two clips from a longer video, pasted together. The portion of the video between the two clips, which would include the stage passing through clouds and then lighting up, was not shown.

My hope is that SpaceX releases the full-length video. Although I don't know if they ever will, they never released the Cassiope video either.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Ohsin on 08/05/2014 11:07 PM
>Talk about coming in hot!

Looking at the stark black color of stage on IR and ice on camera?  ;D
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/05/2014 11:46 PM
There's something to be learned from this video, when comparing it to the CASSIOPE "3 meter" picture (below).

There was discussion back then on whether the engine "really fired" or whether it just "burped" and SpaceX was misrepresenting it as a "prematurely terminated firing" or some such.  (The usual conspiracy theories)

In that CASSIOPE picture, the smoke/vapor doughnut is well formed, and the engine is already off.

In this video, we see that the engine ignites rather early, and fires for a pretty good duration before the doughnut forms, and surface contact occurs only 2-3 seconds after the doughnut forms.

The conclusion is that CASSIOPE ignited and had a nice controlled burn before the engines starved - otherwise the supposed "burp episode" would have occurred too high to form the doughnut.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sdsds on 08/06/2014 04:13 AM
I took the liberty of creating a few screen shots.

First sequence:
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: sdsds on 08/06/2014 04:15 AM
Second sequence:
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Helodriver on 08/06/2014 07:03 AM
There's something to be learned from this video, when comparing it to the CASSIOPE "3 meter" picture (below).

There was discussion back then on whether the engine "really fired" or whether it just "burped" and SpaceX was misrepresenting it as a "prematurely terminated firing" or some such.  (The usual conspiracy theories)

In that CASSIOPE picture, the smoke/vapor doughnut is well formed, and the engine is already off.

In this video, we see that the engine ignites rather early, and fires for a pretty good duration before the doughnut forms, and surface contact occurs only 2-3 seconds after the doughnut forms.




The conclusion is that CASSIOPE ignited and had a nice controlled burn before the engines starved - otherwise the supposed "burp episode" would have occurred too high to form the doughnut.


That's what I've long thought looking at the CASSIOPE photo. I'd heard talk from a SpaceXer that they came "very close" to a soft landing. Its obvious they got slow and within a stage length of the water before it went a bit pear shaped.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/06/2014 07:27 AM
There's something to be learned from this video, when comparing it to the CASSIOPE "3 meter" picture (below).

There was discussion back then on whether the engine "really fired" or whether it just "burped" and SpaceX was misrepresenting it as a "prematurely terminated firing" or some such.  (The usual conspiracy theories)

In that CASSIOPE picture, the smoke/vapor doughnut is well formed, and the engine is already off.

In this video, we see that the engine ignites rather early, and fires for a pretty good duration before the doughnut forms, and surface contact occurs only 2-3 seconds after the doughnut forms.




The conclusion is that CASSIOPE ignited and had a nice controlled burn before the engines starved - otherwise the supposed "burp episode" would have occurred too high to form the doughnut.


That's what I've long thought looking at the CASSIOPE photo. I'd heard talk from a SpaceXer that they came "very close" to a soft landing. Its obvious they got slow and within a stage length of the water before it went a bit pear shaped.

For sure, I remember the arguments as if it were yesterday [shimmery flash-back effect]...  It was clear unless you were intent on painting SpaceX's statement as purposely obfuscated. [/effect] But with the recent video, there photographical proof.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mvpel on 08/06/2014 05:20 PM
Looks like this is the PG-13 version - the camera fades out before the shocking and graphic RUD.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/06/2014 06:15 PM
Betcha that if you split-screen and synchronize the on-board and the external videos, you'll see that the external video cuts out earlier than the on-board.

It also has the rocket going out of frame, and that motion started a few seconds early.

So unless they can predict the future, I think it's a genuine screw-up.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: abaddon on 08/06/2014 07:09 PM
As per above, we already know it was a genuine screw-up:

Quote
@jeff_foust  12 min.
Jurvetson said the video had been shot from aircraft, though a glitch caused the vehicle to go out of frame around touchdown. #smallsat2014
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MTom on 08/06/2014 08:25 PM
Looks like this is the PG-13 version - the camera fades out before the shocking and graphic RUD.

Oh, you have right!
And the whole leg-deployment (inclusive start of landing burn) also missing!

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: edkyle99 on 08/06/2014 11:56 PM
Talk about coming in hot! She's really moving.
Moving, but decelerating too and under control, which all makes this such an usual sight.  I also suspect that camera movement may have made the stage appear to be moving faster than it really was when it broke through the clouds.

As for the question of whether or not this particular video cameraman simply messed up and missed the final result, that I think is beside the point.  SpaceX, surely, has better engineering video of the entire event.  Perhaps it will release the original of this one that conveniently misses the end.  Perhaps not.  But I doubt it will release the fully detailed video or videos that show everything.   

 - Ed Kyle
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: e of pi on 08/07/2014 02:35 AM
As for the question of whether or not this particular video cameraman simply messed up and missed the final result, that I think is beside the point.  SpaceX, surely, has better engineering video of the entire event.  Perhaps it will release the original of this one that conveniently misses the end.  Perhaps not.  But I doubt it will release the fully detailed video or videos that show everything.
Ed, they've released segments or stills from a video of this quality twice, both times stated to be from a plane in the area. My suspicion is that this is the engineering video from the plane, just as CASSIOPE was, and that they simply mis-timed some camera motion, not some conspiracy to "hide" the end of the video. I mean...we've seen what the reception did to the video from CRS-3, and the ice on OrbComm. Even people who can bring a rocket down from orbit are occasionally limited by the systems they have set up to document it.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: edkyle99 on 08/07/2014 03:43 PM
Ed, they've released segments or stills from a video of this quality twice, both times stated to be from a plane in the area. My suspicion is that this is the engineering video from the plane, just as CASSIOPE was, and that they simply mis-timed some camera motion, not some conspiracy to "hide" the end of the video. I mean...we've seen what the reception did to the video from CRS-3, and the ice on OrbComm. Even people who can bring a rocket down from orbit are occasionally limited by the systems they have set up to document it.
The future path of this entire company depends on the results of this breakthrough testing - testing that costs a good bit of money.  Do you really believe that SpaceX is depending on only one hand-held camera to capture the results?

 - Ed Kyle
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mongo62 on 08/07/2014 03:59 PM
Ed, they've released segments or stills from a video of this quality twice, both times stated to be from a plane in the area. My suspicion is that this is the engineering video from the plane, just as CASSIOPE was, and that they simply mis-timed some camera motion, not some conspiracy to "hide" the end of the video. I mean...we've seen what the reception did to the video from CRS-3, and the ice on OrbComm. Even people who can bring a rocket down from orbit are occasionally limited by the systems they have set up to document it.
The future path of this entire company depends on the results of this breakthrough testing - testing that costs a good bit of money.  Do you really believe that SpaceX is depending on only one hand-held camera to capture the results?

 - Ed Kyle

I thought that these tests were essentially free -- the rocket stage is going into the drink anyways, so you might as well try what tests you can with any residual propellant after staging.

The only significant marginal costs that I know of would be for flying a chase plane to record video/telemetry, and the cost of the bolt-on landing legs (for those flights which allow the extra mass). Considering the return in test results, the costs are minimal.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AncientU on 08/07/2014 04:03 PM
And recall that NASA had its dedicated aircraft scheduled to record supersonic retro-propulsion burns and missed two consecutive opportunities, one for icing (didn't fly at all) and the second due to pointing or sun angle, I believe.  SpaceX got something on each flight, though not as much as we'd wish... and also retro-propulsion and landing data from onboard camera, though again not completely clean (or even marginally decipherable) footage.  I still think telemetry will tell what is needed engineering-wise, and the vids are more for public consumption.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Kabloona on 08/07/2014 04:40 PM
Well, the good news is that we're likely to see a barge landing in less than 2 months. Imagine the video from an observation boat moored nearby, or even from land if the barge is just offshore. THAT will be impressive.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Hauerg on 08/07/2014 04:52 PM
Well, the good news is that we're likely to see a barge landing in less than 2 months. Imagine the video from an observation boat moored nearby, or even from land if the barge is just offshore. THAT will be impressive.

Imagine the video from the barge itself. looking upward into a live Merlin getting bigger and bigger and CUT.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/07/2014 05:29 PM
This is where the phrase "looking up and into the business end of the rocket" REALLY applies... :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: abaddon on 08/07/2014 06:15 PM
The future path of this entire company depends on the results of this breakthrough testing - testing that costs a good bit of money.  Do you really believe that SpaceX is depending on only one hand-held camera to capture the results?

No, they're relying on telemetry, the video is a bonus.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: ugordan on 08/07/2014 06:27 PM
Do you really believe that SpaceX is depending on only one hand-held camera to capture the results?

As a matter of fact, yes, I *can* believe that. This video is very likely an afterthought, for documentation purposes. There is little a telephoto lens video from a distance will add to what they already know from telemetry. First you were suspicious of the stage moving out of frame, implying it was deliberate. Now you seem to accept the fact it might have been accidental and are now surprised they didn't have more than one camera onboard? You might as equally ask NASA why they didn't have more than one plane to try catching the reentry burns they're so interested in.

Have you ever tried tracking something with a long focal length from a small plane? I haven't. I can imagine it's not as trivial as it looks, though. People can have trouble tracking a rocket going *up*, while standing on firm ground and using a tripod. Is this supposed to be any easier?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: edkyle99 on 08/07/2014 07:12 PM
Do you really believe that SpaceX is depending on only one hand-held camera to capture the results?
As a matter of fact, yes, I *can* believe that.
If so, you are willing to believe that this company is just a bunch of amateurs.  I am certain that it is not. 

Engineering video during launch vehicle R&D is standard stuff.  Engineers put recoverable film video cameras on board Redstone and Atlas and Thor and Titan and Saturn, etc., during the 1950s and 60s to capture key information, even with masses of telemetry available.  They used numerous long-range tracking cameras, including some on ships down range for some missions.

Maybe you want to believe that SpaceX has experienced nothing but perfection, that there is no detailed record of the "interesting" hiccups.  But successful launch vehicle R&D will inevitably have imperfect moments.  SpaceX has recorded those moments, including, I believe, the sudden dis-assembly of the Orbcomm first stage after its successful landing.  The company has not shown those moments in their finest detail to the public.  That is fine, but lets not pretend that the records do not exist or that the hiccups never happened.

 - Ed Kyle
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: ugordan on 08/07/2014 07:43 PM
If so, you are willing to believe that this company is just a bunch of amateurs.  I am certain that it is not. 

I don't see how your conclusion follows from that. I am willing to believe they start simple and then work their way up. Their approach is not overkill right from the get-go. If they find out hand-held (or whatever method they're using from their "private" jet) doesn't cut it, and for some reason they *need* this video in the future, they improve and adapt. Their whole approach to recovery is just an example of that.

Engineering video during launch vehicle R&D is standard stuff.  Engineers put recoverable film video cameras on board Redstone and Atlas and Thor and Titan and Saturn, etc., during the 1950s and 60s to capture key information, even with masses of telemetry available. 

Why do you maintain this is engineering video? Besides, not nearly as much telemetry was available then as it is now.

In the 11 flights of F9, they haven't implemented a way to keep the onboard camera clean of ice and dirt. Why? Because in the end the footage is not that important.

Maybe you want to believe that SpaceX has experienced nothing but perfection, that there is no detailed record of the "interesting" hiccups. 

Please. You're not talking to a naive fanboy. Not everyone who sees that not everything is roses at SpaceX has to subscribe to conspiracy theories. How is my claim that remote video footage can be imperfect related in any way to other problems they might have? Sometimes a cigar is just a cigar.

Frankly, I'm suprised you didn't dissect the "convenient" video dropouts of the onboard CRS-3 video (even though you've most certainly complained about them not releasing the footage) or the "convenient" fogging up of the lens for Orbcomm onboard video, I'm sure SpaceX is hiding something there!

SpaceX has recorded those moments, including, I believe, the sudden dis-assembly of the Orbcomm first stage after its successful landing.  The company has not shown those moments in their finest detail to the public.  That is fine, but lets not pretend that the records do not exist or that the hiccups never happened.

By all means, share with us your source that says they *do* have perfect footage of the Orbcomm landing. Also, please tell us, once more, why *we* are entitled to see that footage, especially in light of an already public statement that the stage went kaboom. Who, exactly, is pretending here that no hiccup has occured?

Really, Ed, how far is your sense of entitlement willing to go? How come you're not nearly as displeased with NASA's inability to capture some lousy airborne footage at all, after two attempts in a row?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: abaddon on 08/07/2014 07:59 PM
We're getting firmly into tin-foil hat land here.  Next suggestion will be that the ice over the camera on the Orbcomm was digitally added to obscure critical details that SpaceX wants kept secret!  If you sincerely believe the other things that are being thrown around, that's certainly plausible.

We have a quote of Steve Jurvitson when presenting the video we have seen a recording of indicating that the view of the landing went out of frame due to a "glitch".  Unless someone can provide evidence -- any evidence -- that this is in fact not what happened, I would strongly urge you not to offer up unsubstantiated speculation to the contrary.  Frankly, I think it hurts the reputation of this site as basing discourse on substantiated sources, and that's really unfortunate.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Chris Bergin on 08/07/2014 08:19 PM
We're getting firmly into tin-foil hat land here. 

Agreed.

I want members here to not stray into conspiracy theories. I can tell you, from the people I know at SpaceX, such talk is nonsense and this nonsense ends right now.

(http://i.imgur.com/1zFpjp9l.jpg)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: AncientU on 08/08/2014 05:04 PM
Recall that the corrupted (now reconstructed) video feed on the first soft landing with legs was recorded aboard a personal jet with a handheld, pizza pan antenna held to the window -- if the EM reported method can be believed.  Cool, but not so much sophisticated. 

What matters is, it did soft land.  Telemetry had already told SpaceX that it soft landed and lost signal after eight seconds (when it tipped over).  The reconstructed video was frosting on the cake. 

Tinfoil need not apply.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mmeijeri on 08/08/2014 05:24 PM

Heh, is that a picture of your good self + cat?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meekGee on 08/08/2014 06:09 PM

Heh, is that a picture of your good self + cat?

Or more interestingly, of your good self photobombed by a weird bearded guy?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: llanitedave on 08/09/2014 01:28 AM
If the cat doesn't meow with a British accent, then somebody's hiding something!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 08/09/2014 11:51 PM
I've made a draft update to my video combining Orbcomm, CRS restore, the animation - to add the landing video.

I'm having trouble working out a few things. In my mind I've split the landing video into 4 segments
1) blur
2) long distance cloud shot... can't see much
3) fast decent through cloud
4) landing

So what's in #2? Is there anything worth showing?

#3 is before engine ignition, but the current side mounted camera has a lengthy shot of the engines firing, so coming through the clouds must be at least 20 seconds before #4 starts. Is that right?

- I've added and cropped in #3
- I've added cropped and stabilised #4.
- sped up the stage 1 decent animation to match the real shot speed
- sped up the grasshopper side mount (it's much slower than the stage 1)
(no speed changes to any actual landing shots of course!)
- removed the music from the beginning but kept the second music+audio because the Orbcomm video has audio of the engines. There's now no sound of thrusters while in orbit.

One big question is ... what's the timing on the landing shot? The smoke/vapour starts much earlier in the new video than in the side mounted cameras, so I presume that the "close-up" side cameras simply don't see the same vapour (just like when you're in a cloud you don't really see it) - instead they see as the thrust hits water.

Lastly... do I need a slo-mo copy of the final 20 seconds? There's a lot happening.
Any suggestions for improvements would be welcome!

(newer version of video below)
Title: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mvpel on 08/10/2014 12:54 AM
Epic!

Is the Orbcomm external and internal lined up? The external sploosh starts earlier than the internal sploosh, but I wonder if that might be steam that's not visible to the internal camera, rather than the actual sploosh. In the restoration one of the iframes showed the beginning of the disturbance on the surface of the water.

The "MVac ignition" call comes what seems like a beat or two too much later than the ignition of the MVac.

There's websites that you can use to generate music - maybe ujam.com?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: ugordan on 08/10/2014 01:02 AM
The external sploosh starts earlier than the internal sploosh, but I wonder if that might be steam that's not visible to the internal camera, rather than the actual sploosh.

I'm thinking the last few seconds of the external video are actually slowed down from realtime. SpaceX has widely used 60 fps capable cameras for launch (http://www.bandpro.com/blog/falcon9-launch/) and Grasshopper (http://vimeo.com/73984690)-related videos. If the footage is being played back at 30 fps it would make sense for it to appears to last 2x as long.

Come to think of it, the entirety of that Jurvetson's video might have been running at 1/2 speed, we have no way of knowing.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 08/10/2014 01:08 AM
Epic!

Is the Orbcomm external and internal lined up?

Thanks :)

That's the trouble I'm having. It's really easy to just line up the beginning of the vapour on both shots ... but the engine hitting the water is way off time. So I'm hoping for some advice on whether I'm lining up right, or how to better do it.

Quote
The "MVac ignition" call comes what seems like a beat or two too much later than the ignition of the MVac.

I'll take a look...
Actually that's the audio directly connected to that shot so timing was actual (though as he starts speaking I cut to a different shot)

Quote
There's websites that you can use to generate music - maybe ujam.com?
Youtube has some free stuff too. I think it'd be worth adding if I remove the second song, otherwise it's quite a short duration of 'silence' anyway. Youtube also has a beta system to try to extract the music without affecting the rest of the audio... so I could keep the engine sounds and change the song if it works.

I'm thinking the last few seconds of the external video are actually slowed down from realtime. SpaceX has widely used 60 fps cameras for launch (http://www.bandpro.com/blog/falcon9-launch/) and Grasshopper-related videos. If the footage is being played back at 30 fps it would make sense for it to appears to last 2x as long.

Yeah that might be it.... damn it's so short already... I'll change the speed to see.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 08/10/2014 01:23 AM
Hmm. No it's not a half speed thing. Or at least if it is there's more to it.

I doubled the speed and it can almost line up - but it still starts earlier than the side mounted cameras and the engine is still going when the side cameras show the engine is out.

There is a different characteristic to the long distance mist - it seems to start quite large then grow, rather than grow from a point like the side camera infers.

I'm leaning more towards it being a thin mist. A thin mist in the shape of a disc wouldn't be visible from the side when the disc is small, only once it gets to a certain size that makes you look through a fair bit of mist. And a thin mist viewed vertically through the disc will not be visible. But I'm stretching!
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mvpel on 08/10/2014 02:03 AM
If you look at the AS-8 launch you get a good understanding of how long the exhaust plume is in the dark - and the OG-2 launch showed the umbilicals flapping in the plume, giving an idea of how far the effects reach.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 08/10/2014 02:41 AM
Hmm.
The resolution and quality is bad, but there appears to be another vapour/donut that starts later. Basically the mist disc is quite thin, then a second thicker disc starts. Very subtle.

If I line that up with the side camera it is almost perfect....

To the viewer... I don't think they'll pick a difference though.

(btw: Youtube can remove audio very well! Any suggestions for music welcome :) )

https://www.youtube.com/watch?v=Ny1IyHQz9BM
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: guckyfan on 08/10/2014 05:25 AM
Hmm.
The resolution and quality is bad, but there appears to be another vapour/donut that starts later. Basically the mist disc is quite thin, then a second thicker disc starts. Very subtle.


Wonderful work, thanks a lot.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Ohsin on 08/10/2014 11:37 AM
(btw: Youtube can remove audio very well! Any suggestions for music welcome :) )

May be use music by Kevin MacLeod who did SpaceX broadcast score.
https://www.youtube.com/watch?v=Q7EL1nTnOI8

Royalty free CC 3.0 licensed
http://incompetech.com/music/

EDIT: Ok i am not sure if Kevin did that but still free music on that site!
Title: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 08/10/2014 01:49 PM
Thanks for that ohsin, I looked there and think I found something. I'll add tomorrow and see how it sounds :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Jdeshetler on 08/10/2014 07:10 PM
How about "The Blue Danube" and it is free... ;)

https://archive.org/details/BlueDanubeWaltz
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: LouScheffer on 08/11/2014 12:23 PM

That's essentially what you do with face throttling.  You have to avoid pump stall, but that just means throttling the GG, which is how the Merlin apparently does it. 

http://jasc-controls.com/jasc-industry-listing/space/space-fluid-management/bi-propellant-valve/
The spec specifically states the valve is used on the vacuum Merlin.  Any idea why they would use a different valve on the second stage?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MP99 on 08/11/2014 12:59 PM



That's essentially what you do with face throttling.  You have to avoid pump stall, but that just means throttling the GG, which is how the Merlin apparently does it. 

http://jasc-controls.com/jasc-industry-listing/space/space-fluid-management/bi-propellant-valve/
The spec specifically states the valve is used on the vacuum Merlin.  Any idea why they would use a different valve on the second stage?

Vac throttles more deeply than SL variant.

SL may need to do more rapid adjustments to throttle during landing?

Cheers, Martin
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Mangala on 08/12/2014 06:58 PM
Hmm.
The resolution and quality is bad, but there appears to be another vapour/donut that starts later. Basically the mist disc is quite thin, then a second thicker disc starts. Very subtle.

If I line that up with the side camera it is almost perfect....

To the viewer... I don't think they'll pick a difference though.

(btw: Youtube can remove audio very well! Any suggestions for music welcome :)

Very good and nice job. :)

Thus, if i can suggest, maybe you can replaced some parts of the reusable spacecraft animation (at maxQ in this case) by some parts of this:
https://www.youtube.com/watch?v=i5TVufxKSdI (https://www.youtube.com/watch?v=i5TVufxKSdI)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: GregA on 08/12/2014 10:47 PM
Good idea :)
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: meadows.st on 08/14/2014 06:47 PM
Hmm.
The resolution and quality is bad, but there appears to be another vapour/donut that starts later. Basically the mist disc is quite thin, then a second thicker disc starts. Very subtle.

If I line that up with the side camera it is almost perfect....


Unbelievably gorgeous not to mention significant and an interesting tool for further informed speculation on the recover-ability of the first stage from the water!  Well done.

The external view of the Orbcomm "alightment" is spectacular to see in context with the down-facing inter-stage camera.  I want to view that video in more detail because the F9S1 appears to settle much deeper in the water than I initially expected it would (based on the expected landing vertical velocity and soda can hypothesis for buoyancy and overall density).  I will look at the external video in more detail and see what can be gleaned from it.


ADDED: Looks like I am not the only one. :)
http://forum.nasaspaceflight.com/index.php?topic=35410.msg1243183#msg1243183
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MTom on 09/07/2014 07:47 PM
Has anybody in remind if we have the time of the first stage reignition?

On the recent flight (Asiasat 6) we could hear at 7:07: "(first?)stage reignition".
Only for checking whether the time is matching with Orbcomm first stage relight.

http://forum.nasaspaceflight.com/index.php?topic=35554.msg1252112#msg1252112
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: Noah on 09/09/2014 04:07 AM
I don't think the times would match, because Orbcomm was Leo and asiasat was gto. But they say 1st stage relighting on Cassiope. You should watch that again.
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: mwfair on 09/09/2014 01:12 PM

time    alt  speed range  note
         km   mps   km
+1:00    13  450     2.5     
+2:20    54  1400    21     
+2:25                40    sep
+9:23     ?   ?    ?         retro burn 
+11:12    ?   ?    ?         landing burn
+11:43    ?   0    330     kaboom 

Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: MTom on 09/09/2014 07:41 PM
Orbcomm was significantly lighter than AsiaSat6.
I have nothing to do with rockets but I would guess the first stage needed some throttling down and therefore a longer flight of the first stage. It would explain the difference. Or am I wrong with it?
Title: Re: Falcon 9 v1.1 ORBCOMM - First Stage Ocean Landing Video
Post by: SoulWager on 09/13/2014 06:14 PM
Orbcomm was significantly lighter than AsiaSat6.
I have nothing to do with rockets but I would guess the first stage needed some throttling down and therefore a longer flight of the first stage. It would explain the difference. Or am I wrong with it?
More likely had to do with vertical velocity at MECO. If you take a steeper initial trajectory, you have more time before the reentry burn.