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

[guckyfan]

Assuming the tent is still on the landing pad, they may want to use that flight for an attempt on ASDS landing. They need that to work too. Always a good idea to do tests with equipment that has no more practical value because it is outdated.

[sdsds]

Very true - which begs the question... So what's up with that tent??

Well, either there's a rocket in there, or space-x is just really happy to see their new landing pad.

Logical.

And by the way, welcome!

Prisoner: Who is Number 1?

Number 2: You are Number 6.

[Jcc]

IMHO, they will want to do whatever they can to maximize the chance of stage recovery, evev if it is the last v1.1 w/o FT, as long as there is no negative impact on the chance of mission success. That includes fixing the valves, strengthening the legs, and landing on land, as long as there is sufficient margin. Barge landings are only for when there is not enough margin to return. That will be tested soon enough.

[NovaSilisko]

Heh - recover it, keep it around, reuse it. Good old F9-##, last 1.1 in the fleet...

[Coastal Ron]

IMHO, they will want to do whatever they can to maximize the chance of stage recovery, evev if it is the last v1.1 w/o FT, as long as there is no negative impact on the chance of mission success. That includes fixing the valves, strengthening the legs, and landing on land, as long as there is sufficient margin. Barge landings are only for when there is not enough margin to return. That will be tested soon enough.

The sticky valve is something they would fix, since obviously it was not working as it was designed to work.  Strengthening the legs creates a new configuration, which carries a non-trivial cost, and likely isn't needed because they only needed the strengthened legs for the much heavier FT version.

As to where they will land, since this is not the FT version it may not have enough fuel to return to the landing site.  But they would likely load it up with the latest control software to make a barge landing more potentially successful.

I think the chance of RTLS is close to zero, but that they will try a barge landing.

[sdsds]

I wonder if this booster (assuming it is recovered) would be a logical choice for the first attempt at a reflight? Using it that way seems like it could retire quite a bit of risk, either real or perceived, without endangering the reputation of the F9FT booster.

[Bubbinski]

Is the Jason launch now the next SpaceX flight instead of SES? From looking at Salo's US launch schedule it appears that way.

[Lars-J]

I wonder if this booster (assuming it is recovered) would be a logical choice for the first attempt at a reflight? Using it that way seems like it could retire quite a bit of risk, either real or perceived, without endangering the reputation of the F9FT booster.

No, it would not be a logical flight for a reflight, since it would be a different model than the current FT model. At most it might be used as an F9R-dev2 in NM. But all pads are now being modified for FT, not 1.1.

[Steven Pietrobon]

Is the Jason launch now the next SpaceX flight instead of SES? From looking at Salo's US launch schedule it appears that way.

Yes, as SES 9 is scheduled for late January.

[AndrewM]

I wonder if this booster (assuming it is recovered) would be a logical choice for the first attempt at a reflight? Using it that way seems like it could retire quite a bit of risk, either real or perceived, without endangering the reputation of the F9FT booster.

No, it would not be a logical flight for a reflight, since it would be a different model than the current FT model. At most it might be used as an F9R-dev2 in NM. But all pads are now being modified for FT, not 1.1.

It would be a great stage for a complete teardown.

[baldusi]

Technically, F9R-Dev2 is also a v1.1. So if they recover F19 they will have two v1.1 cores.

[jacqmans]

[cscott]

Grid fins and legs on the rocket, hence landing attempt (of some kind).

[Bubbinski]

So the Jason rocket will have legs & grid fins as per the patch. Which leads to this:

Is there any info about recent SpaceX barge activity in the LA area?  Also is the landing zone at that old launch pad (SLC-3W?) clear and ready to go now?

I'm getting some time off work soon and am considering going to this launch.

[cscott]

Yes, check the ASDS thread for info on the ASDS already berthed in long beach.

The landing pad at Vandenberg is not yet cleared, as far as we know.

[Roy_H]

SpaceX needs to perfect barge landings. They've proven they can land on land, now they need to prove they can land out a sea. Much harder in my opinion.

[Robotbeat]

SpaceX needs to perfect barge landings. They've proven they can land on land, now they need to prove they can land out a sea. Much harder in my opinion.

BTW, "barge landings" are called "bargings."

They already overcame the biggest obstacles by building the barge(s) and doing those first few attempts at bargings.

[georgegassaway]

Assuming the core has no technical problems,  key thing is lateral error from the "X". Not whether the X is on land or on a barge deck.

The landing at the Cape, the booster had no technical problems and the landing had very little lateral error.  So, that should have been a safe landing whether landing at the Cape or on the barge (assuming the barge was within its allowed 3 meters or lateral error).

Some tend to forget or gloss over why the two ASDS landings crashed.

First one, the booster ran out of hydraulic fluid for the grid fins (first orbital launch to use the grid fins, underestimation of amount needed).  So, the booster drifted off a few hundred feet (or more) before the engine ignited, and it could not safely maneuver that much horizontally to soft-land on the barge, it was tilted about 45 degrees and moving fast when it hit (I hope they have modified the landing software so that for ASDS landings, if the error is too great, it will self-ditch ad not do another hopeless inevitable Kamikaze barge crash).

The second one, a sticky valve caused the engine to not come up to thrust as quickly as it needed to. So, the booster was cooing down vertically faster than it should at that point. The booster seemed to be pretty much over the ASDS anyway, but it tried some lateral corrections that were over-controlled due to the  the faster descent rate (also the may have needed to fine-tune the landing software P.I.D. values or other aspects.  As the vertical descent rate when it hit the barge was not THAT hard, but it was tilted a bit due to the over corrections, and some horizontal motion, which over-stressed a leg to cause it to break). 

So, in both of those, if they had been trying to land on an "X" on a concrete pad, the result should have been the same (though no parts sunk to the bottom of the Atlantic, and concrete is easier to repair than a barge).

The real difference in making it easier to land   on land would be if the software was programmed to allow for a much greater margin of error for lateral distance, because there is a 650 foot diameter concrete pad to land on.  So, if the Falcon was about to land 200 feet from the X, it would make more sense to let it land SAFELY 200 feet form te X, than to try to do a harsh maneuver to land less than 30 feet from the X for "style points" with a great probability of a crash.  I am a bit troubled to note that the core did seem to do some maneuvering in the last 100 feet or so that indicates it was trying to land on the "X" rather than accept a landing a few meters off, as that implies the same programming regardless of land or sea landings.  Of course a landing on the "X" would be a great P.R. thing, but not a great strategy thing.  As it is, it was a little bit off, but only us space geeks even notice that, the big news for the rest of the world was it landed successfully, period.

But if they have not modified the landing software to accept a much greater lateral error for land landings than for ASDS landings, then it really makes no difference WHERE it is trying to land, the "X" at the Cape, or the "X" at sea. 

Now some have mentioned a pitching barge….. but they don't pitch much in any weather safe to try to land anywhere, and again the two crashes had nothing to do with whether the "X" was on a barge or on concrete.

If the first two attempts had been with Falcon cores that had no technical problems (not run out of fluid, no sticky valve), then very likely SpaceX would have had three safe landings this year, and people would be talking about how SpaceX "finally" proved they could and on land.

Although, there would have been a lot less publicity about the first safe landing at sea, had it happened last January, because of the secrecy, not allowing any live video.

- George Gassaway

[MKremer]

 The returning booster is programmed to reach a particular coordinate in 3D space in a vertical orientation and within a margin of zero velocity, then shut down the engine. Doesn't matter if it's on land or an offshore barge.
We don't know yet if there are any minor guidance programming differences between land and sea, but I can't imagine any changes within the final 100m or so.

[kevinof]

On the barge there is virtually zero tolerance if it's off center. On land it can be programmed to land at X plus or minus say 100m.  That means no last second corrections needed to make the landing. I always thought rtls to land was the much easier option because of this.