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

[Dante80]

Could they also be hoping for better weather (less waves) further off shore?

Judging from the date the application was filed, no.

[cuddihy]

Actually from my experience on CVNs not too far away from there you often do get calmer sea states in that area than you do closer to the channel islands or Mexico and SoCal. Not sure why. Maybe has something to do with circulation patterns...

[ZachS09]

For the barging attempt, will SpaceX use "Of Course I Still Love You" or another droneship we've never heard of?

[CJ]

For the barging attempt, will SpaceX use "Of Course I Still Love You" or another droneship we've never heard of?

Of Course I Still Love You is currently in Port Canaveral, Florida, so cannot be used on a west coast launch (not without spending months relocating it). They'll use the as-yet-unnamed ASDS (droneship) that's currently in Long Beach, California.

[ZachS09]

Was the unnamed ASDS built similar to JRTI & OCISLY, or is it a different design with a different paint-job?

[Chris Bergin]

Here's the ASDS fleet via Jesse Smedley's excellent article:

http://www.nasaspaceflight.com/2015/06/spacex-augments-upgrades-drone-ship-armada/

[Retired Downrange]

".... officials have asked for “repeated, successful” demonstrations of a first stage landing on the drone ship before a landing attempt will be allowed at the Cape."

This requirement evidently was waived, after the article was published in June.

[ncb1397]

".... officials have asked for “repeated, successful” demonstrations of a first stage landing on the drone ship before a landing attempt will be allowed at the Cape."

This requirement evidently was waived, after the article was published in June.

It did land successfully on the drone ship repeatedly. It though was damaged and couldn't be reused.

[cscott]

Right. The range concern is targeting, not landing.  The targeting was demonstrated multiple times.

[ZachS09]

".... officials have asked for “repeated, successful” demonstrations of a first stage landing on the drone ship before a landing attempt will be allowed at the Cape."

This requirement evidently was waived, after the article was published in June.

It did land successfully on the drone ship repeatedly. It though was damaged and couldn't be reused.

I thought the cores failed to stick the landings; they both blew up.

[Herb Schaltegger]

Right. The range concern is targeting, not landing.  The targeting was demonstrated multiple times.

That's a very important distinction that I don't think nearly enough people appreciate.

[Kabloona]

".... officials have asked for “repeated, successful” demonstrations of a first stage landing on the drone ship before a landing attempt will be allowed at the Cape."

This requirement evidently was waived, after the article was published in June.

It does seem to me that the Range eventually relaxed their "successful" barge landing requirement. If all the Range had cared about from the start was accuracy, SpaceX could have done accurate water landings with telemetry recorded by Go Quest to prove (by telemetered GPS) to the Range that the stage was landing where intended. No barge needed.

So I don't quite buy that the Range only ever cared about accuracy. Looks to me like they quietly moved the goalposts.

[Lars-J]

".... officials have asked for “repeated, successful” demonstrations of a first stage landing on the drone ship before a landing attempt will be allowed at the Cape."

This requirement evidently was waived, after the article was published in June.

It does seem to me that the Range eventually relaxed their "successful" barge landing requirement. If all the Range had cared about from the start was accuracy, SpaceX could have done accurate water landings with telemetry recorded by Go Quest to prove (by telemetered GPS) to the Range that the stage was landing where intended. No barge needed.

So I don't quite buy that the Range only ever cared about accuracy. Looks to me like they quietly moved the goalposts.

I don't know, proving a water impact accuracy is probably harder than you think. There hasn't been anything left (as far as we know) from previous water splashdown, everything sunk quickly. With a barge, they proved that *despite* malfunctions, they undeniably hit their target 2 out 2 times.

[guckyfan]

It does seem to me that the Range eventually relaxed their "successful" barge landing requirement. If all the Range had cared about from the start was accuracy, SpaceX could have done accurate water landings with telemetry recorded by Go Quest to prove (by telemetered GPS) to the Range that the stage was landing where intended. No barge needed.

So I don't quite buy that the Range only ever cared about accuracy. Looks to me like they quietly moved the goalposts.

I don't know, proving a water impact accuracy is probably harder than you think. There hasn't been anything left (as far as we know) from previous water splashdown, everything sunk quickly. With a barge, they proved that *despite* malfunctions, they undeniably hit their target 2 out 2 times.

To prove accuracy a buoy with ability to keep position and a camera would be enough. Barge is needed because SpaceX is planning to continue to use it.

To prove accuracy a buoy with ability to keep position and a camera would be enough.

[cscott]

But rather than develop a buoy with a camera and thrusters, SpaceX sent an ASDS out there.  Your point?

[guckyfan]

But rather than develop a buoy with a camera and thrusters, SpaceX sent an ASDS out there.  Your point?

My point is, that if they would not intend to continue using an ASDS, they would not build one. A buoy with camera and ability to stationkeep is easier to build. I suspect they could buy them off the shelf, just adding a camera.

[vanoord]

Yes, if targeting was the only requirement then a buoy would have been sufficient.

But, the cost for putting a barge there would not have been massively more (they're modifications to existing commercial barges) - particularly given the possibility of bringing a first stage back (which they nearly did twice).

In any case, despite having brought one first stage back to land, there will remain a need for the ASDSs for flights where the orbital parameters are such that insufficient propellant remains for a return to the launch site.

[chalz]

".... officials have asked for “repeated, successful” demonstrations of a first stage landing on the drone ship before a landing attempt will be allowed at the Cape."

This requirement evidently was waived, after the article was published in June.

It does seem to me that the Range eventually relaxed their "successful" barge landing requirement. If all the Range had cared about from the start was accuracy, SpaceX could have done accurate water landings with telemetry recorded by Go Quest to prove (by telemetered GPS) to the Range that the stage was landing where intended. No barge needed.

So I don't quite buy that the Range only ever cared about accuracy. Looks to me like they quietly moved the goalposts.

No conspiracy required. The Range only wanted accuracy but SpaceX wanted their booster back, so they used a barge.

[Kabloona]

No conspiracy required. The Range only wanted accuracy but SpaceX wanted their booster back, so they used a barge.

No one suggested a conspiracy.

But your statement that the Range wanted "only accuracy" is not consistent with what SpaceX originally said the Range wanted, ie "repeated, successful" barge landings before allowing RTLS. Success requires accuracy, but accuracy in itself does not guarantee a successful landing, as we saw.

Evidently the Range subsequently decided that, even though SpaceX couldn't quite achieve "successful" barge landings, they got close enough for the Range to feel comfortable about allowing RTLS. Which is their prerogative, nothing wrong with that.

My debate is with the implication that the Range *never* cared about anything except accuracy on the barge landings attempts. SpaceX's original statement that the Range wanted "successful" landings, not just demonstrations of accuracy of crash landings, seems to me to disprove that intepretation.

Obviously at some point they decided that "close" was good enough. OK, fine, their prerogative. But that's a lower bar than the "repeated successes" bar they initially set. That's why Retired Downrange suggested the "success" requirement had been waived. Call it whatever you want, "waived," "lowered the bar," whatever. We're simply observing that the initial requirement of "repeated success" of barge landings was relaxed at some point.  No value judgment made or implied.

And I imagine we're all glad the Range didn't hold out for "successful" barge landings before allowing RTLS.

[joek]

No conspiracy required. The Range only wanted accuracy but SpaceX wanted their booster back, so they used a barge.

Accuracy is necessary but not sufficient.  The Range wants more than just accuracy.