SpaceX Falcon 9 v1.1 - Jason 3 - SLC-4E Vandenberg - Jan 17, 2016 - DISCUSSION

[deruch]

For those thinking about the amount of damage to the engines, remember that there's a difference between the engines exploding while in use and what happened here.  Firstly, nothing exploded on that barge.  The tanks burst due to pressure and the remaining fuel deflagrated (burned off quickly).  None of the engines were in operation during this event.  Though I suppose it's possible that the turbo pump for the center engine was still in the process of spooling down.  But, this wasn't an instantaneous event like a slammed landing.  The booster touched down softly, the center engine shut off, and then the stage gradually tipped over.  The bang didn't happen for several seconds after shut down.  So, maybe some minor debris impacts and some heat damage.  IMO, there won't be much of any damage at all except for damage to the engine bells/nozzles on the same side as the leg that failed.

[sewebster]

For those thinking about the amount of damage to the engines, remember that there's a difference between the engines exploding while in use and what happened here.  Firstly, nothing exploded on that barge.  The tanks burst due to pressure and the remaining fuel deflagrated (burned off quickly).  None of the engines were in operation during this event.  Though I suppose it's possible that the turbo pump for the center engine was still in the process of spooling down.  But, this wasn't an instantaneous event like a slammed landing.  The booster touched down softly, the center engine shut off, and then the stage gradually tipped over.  The bang didn't happen for several seconds after shut down.  So, maybe some minor debris impacts and some heat damage.  IMO, there won't be much of any damage at all except for damage to the engine bells/nozzles on the same side as the leg that failed.

Yep, it seems like people are generally quite optimistic about the state of these engines. I guess I've always viewed them as "somewhat delicate" but perhaps that is really more a result of the extreme conditions they must endure, rather than their physical fragility (and perhaps the former rules out the latter).

Hypothetical: If an engine falls off the stand during manufacturing, do they just pick if up, inspect it, and keep going? Or do they figure it might be somehow suspect and set it aside?

[Kaputnik]

To my eyes there appears to be much less soot in the engines compared with those of Orbcomm

No boostback burn = reduced sooting?

[geza]

No boostback burn = reduced sooting?

Boostback burn happens in vacuum, so no shooting of the stage can occur during that.

[Torbjorn Larsson, OM]

To my eyes there appears to be much less soot in the engines compared with those of Orbcomm 2.

(modified)

In a few decades, expendable launch will seem as insane as crashing your airplane each time after you eject at your destination.

  Years.

Easily.

Just picture the situation if SpaceX recovers the majority of the cores this year, which is not far fetched at all.

You know how public perception works - memory capacity of a fruit fly.

Within a year, it's not even news.  Rocket goes up, rocket comes down.  Business as usual.

There will be a blip when the first used rocket launches, but since visually it is identical, only space geeks will pay attention.

So barring another failure, I give it a year before things start looking very different in the launch market.

NASA:

"The reason we crash our launchers is because _we_ are going to Mars."

Media:

"... and because it is the public's money."

Never mind that if the airplane industry threw out their passengers in chutes and crashed their planes at landing, and used polluting solid fuels to get off ground, the public outcry would be massive.

Poor NASA.

[Lars-J]

To my eyes there appears to be much less soot in the engines compared with those of Orbcomm 2.

The light conditions are *completely* different, so that is a dubious assertion based on images that are also blurry. (despite the photographers heroic efforts)

[Tnarg]

I may start a poll, and am soliciting help on making a complete list.  It would be titled "I was wrong" and will read

"I posted that SpaceX needs:

1   A bigger barge *
2   A more stable barge *
3   A semisubmersible barge *
4   A seabed anchored barge *
5   A barge with a self-leveling surface *
6   A slower approach *
7   A more even approach *
8   A calmer sea state *
9   A radar altimeter *
10 More radar altimeters *
11 A hydraulic leg deployment *
12 A shock absorbing leg design * #
13 A set of heaters for the legs * #
14 Arresting wires *
15 Wheels under the legs * #
16 Brakes for wheels under the legs *
17 A barge transmitter protected from the rocket plume on descent *
18 A barge barge transmitter that points at a satellite not behind the rocket plume *
19 To turn off the FTS before landing # *
20 To stop hiding their failures *
21 A Chuck-E-Cheese ball pit *   (Thanks Tuts36!)
22 A sky-hook wire system
23 Horizontal landing with shorter legs * (I kid you not)
24 Below deck self-deploying foot grabbing devices or some such thing *
25 Roombas wielding MIG welders # *

* And I was wrong"

# which a really clever person like me can see but *

What is missing from this list?  I am sure there were more such suggestions.

edit: Already added #19, 21-25

Does this count as 14 or does it need to be added to the list?

Also I've learn from Kerbal that you don't need landing legs you can land on the engine cones just fine.
You know it's these tips that Elon should really be paying attention to. :-p

[darkenfast]

IRT soot on the engines: remember that the water cannons played on the "remains" of this landing for an undetermined amount of time.

[Alastor]

As many here, I did not think the engines would have sustained so little apparent damage. Enen just from the toppling down (so not counting the explosion that ensued), I would have thought there would be significant damage to the bells. This goes quite a way to show how robust these things are, and is very good news indeed !

Anyway, I'm sure there is lots of interesting stuff to investigate. And I guess they are able to piece together aircraft parts etc from crashes and actually learn a lot so maybe I just don't realize how easy it is to distinguish between damaged caused by X vs Y.

Remember that a data point coming from stuff like an explosion still is a data point, just in rather different conditions, so it can provide interesting informations !

Also, I wouldn't say that any of this is easy. It is in all likelyhood incredibly difficult to piece together a precise scenario of what happened to debris from an accident investigation.
I would however tend to belive that the people doing that are just very very good at what they do.

You are falling into the very common trap of believing that because we can do things, it is easy. Even things that we can do routinely, like sending and landing rockets as SX will no doubt very soon be doing do not become easy because we do it so often.
The people who do that just become incredibly good at performing these tasks !

[rpapo]

There seems to be quite a bit of leg hardware left from at least 3 legs. They may get lucky and still have the collapsed strut still on board.

Especially since it was the leg underneath the stage, and the force of the explosion is less likely to have tossed it overboard.

[Zed_Noir]

Anyone think one of the engines could be reflown?

[ugordan]

Reflown on what? These are not full thrust engines.

[Zed_Noir]

Reflown on what? These are not full thrust engines.

Maybe in the Dragon inflight abort test launcher.

[ugordan]

That stage is already complete and sitting in the VAFB hangar.

[CorvusCorax]

yeah no point in reflying them. But it would be really cool AND really educative from a data point of view to get them on a test stand in mc gregor and run each and every one of them that still runs until failure.

It's not operational engines - they did their job for the money and they are unsuitable for refly. But it's still Merlin 1-D types (the full thrust modifications to engines are supposedly minor as the 1D was from the get go designed for the higher thrust, they just didn't have the fuel densification infrastructure and tanks yet)

So whatever data they can learn from them will have some validity for their current operational engines, and they have nothing to loose.

On the contrary, a youtube vid of the engine on the test stand running for minutes on end - saying "this is #3* engine from the Jason 3 launch - the one that was at the bottom when the rocket fell over" would be really cool for public relation and sales - especially when it comes to making potential customers trust reused cores later.

(* i have no clue which engine was actually at the bottom, number picked randomly )

like <flown - landed - exploded - dusted off - and still as good as new>

[AncientU]

A treasure trove of data is coming back this year!
They'll probably test a few, but they are already moving on... they have a complete stage in hand that has been refired at the pad and a queue of them to follow.

A year from now, they'll have flight data -- possibly on more than one re-flown stage.

[JamesH]

As many here, I did not think the engines would have sustained so little apparent damage. Enen just from the toppling down (so not counting the explosion that ensued), I would have thought there would be significant damage to the bells. This goes quite a way to show how robust these things are, and is very good news indeed !

Well, the engines in the top of the picture should be almost completely undamaged - they didn't hit anything on the way down, the RUD went mostly sideways, and there is the octoweb between the RUD and the engines.

Pretty good condition I reckon.

[JamesG123]

Anyone think one of the engines could be reflown?

I bet they find most of the cores and machinery are fine. They could send them back thru the engine shop for a referb (to the latest mark of Merlin?) and fly them again. In that, this "failure" was a success.

[laszlo]

In a few decades, expendable launch will seem as insane as crashing your airplane each time after you eject at your destination.

Or throwing away bottles just because you emptied them once. Or throwing used paper into landfills while destroying mega-hectares of virgin forest so you can plant pulp trees instead. Or producing mega-liters of clean, fresh potable water just so you can crap in it and flush. Or growing enough grain to meet the nutritional needs of every man, woman and child on the planet, then feeding it to cattle which throw away 90% of it as manure that then leaks into the water supply while a fair portion of the population simply starves. Or... (pick one).

My point is, never underestimate the success of some business models when there's large amounts of cash involved and all consequences don't have to be considered. Ideally, we'll have reuseable boosters one day, but sometimes looking at what else is going on makes me a pessimist.

[wardy89]

To my eyes there appears to be much less soot in the engines compared with those of Orbcomm 2.

I remember seeing in the engine update thread a picture of a merlin 1D with a black thermal coating that was being tested. https://forum.nasaspaceflight.com/index.php?topic=32983.msg1417111#msg1417111

I also don't remember seeing a picture of the engines on the ORBCOMM-2 core before takeoff, could it be that the upgraded version of the engine uses a black thermal coating? And that the majority of the black we are seeing on the ORBCOMM-2 engines is actually this coating rather than soot?