SpaceX Falcon 9 v1.1 - Dragon - CRS-5/SpX-5 -Jan. 10, 2015 - DISCUSSION

[Coastal Ron]

I wonder if floodlights will be installed on the ship - that might actually make the barge easier to see from above, as well as seeing the rocket stage slamming on the surface.... 

Floodlights make sense for any humans that may be watching, but the Falcon 9 1st stage won't need it to land.  Also, with all the engine exhaust, lights may not show us much during the landing - it depends on how much interaction there is with the surrounding water.

What would be neat though is if they have a drone aircraft of some sort circling the landing spot.  They will know the GPS coordinates of the platform, and can just have a vehicle standing off (if a copter) or circling (if a plane).  Wouldn't need to be very big, since all it as to carry is a hi-def camera, but it would likely need some endurance depending on how far out the support ship is.

Although if it's a drone copter, it could already be on the landing barge and just activated remotely to take off X minutes before the stage lands, then the drone would just return to the barge to land.  And if they do that they could use multiple drones to make sure they have good coverage.

[freds]

What would be neat though is if they have a drone aircraft of some sort circling the landing spot.  But it would likely need some endurance depending on how far out the support ship is.

Sounds like an excellent idea! Drone wouldn't need much endurance as it really only needs to fly about 1/4 mile away and back. Could rig it up so that it is drawing power until commanded to lift off.

[WHAP]

Additionally, I wonder if this would make visual tracking of the approaching core easier, at least during periods when it is actively thrusting. Beyond that, battery-powered LEDs on the landing legs that activate at landing +30 seconds are pretty much the only thing required.

Turning on lights 30 seconds after landing won't do much for tracking, will it? 

[deruch]

Well there goes the daylight launch out the window. The Jan 6 date is scheduled for 6:18 am ET instantaneous window, sunrise is at 7:16 am ET at the Cape. The launch will in the dark. The first stage landing will be in the dark most likely or slightly before sunrise so I don't know how good of video there will be for that. Night launches are kinda cool once or twice but they are mostly just a bright light that drowns everything else out, perhaps its better if your are there viewing with the naked eye. Kinda of a  bummer, I was really looking forward to viewing this launch and the first stage return.  Have to wait for a later launch for better video it looks like.

Assuming a Jan. 6th launch, the landing won't be totally in the dark.  BMNT (beginning of morning nautical twilight) at the Cape is 6:21 am.  But the landing won't be happening at the Cape.  The landing is planned for a touch north of the latitude of Jacksonville, FL and about 175 nm to its east.  Taking that into account, BMNT in the area of the landing should be around 6:17 am.  We've yet to see how the more significant boostback will affect the flying-time of the stage, but I personally don't expect the landing to happen until at least 10 minutes after launch.  So, in the area of the barge, the landing should be taking place at least 10 minutes after BMNT.  That's not all that much light maybe, but it isn't full darkness either.

[deruch]

I hope we can return to that 20 day turnaround or whatever it was in the near future, and things just get nailed down. I have no clue about the operational aspects of these sorts of things (given how complex rockets inherently are), so maybe that is impossible or nearly so.

But it sure was awesome this past year when they were churning out flights for that brief period.

January schedule is now CRS-5 on the 6th.  And DSCOVR on the 23rd.  That's under 20 days.  Followed by CRS-6 on Feb. 4th (though this will probably change given the slip of CRS-5), again under 20 days.

edit:  Just checked Salo's Launch Schedule and unsurprisingly it's showing just NET February (no specific date set) for CRS-6.  So the turnaround between DSCOVR and CRS-6 may not end up being less than 20 days.  It will depend on what happens with the schedule.

[su27k]

A third factor is the planned barge landing. NASA is granting SpaceX a rather substantial amount of leeway in re-scheduling launches for factors other than immediately related to CRS-5. I don't need to remind you that SpaceX is planning to land the first stage of this particular launcher on a barge out in the Atlantic. At least one recent delay was attributed to this secondary goal.

Could you clarify this part? I don't remember any delays due to the planned barge landing.

[CameronD]

Assuming a Jan. 6th launch, the landing won't be totally in the dark.  BMNT (beginning of morning nautical twilight) at the Cape is 6:21 am.  But the landing won't be happening at the Cape.  The landing is planned for a touch north of the latitude of Jacksonville, FL and about 175 nm to its east.  Taking that into account, BMNT in the area of the landing should be around 6:17 am.  We've yet to see how the more significant boostback will affect the flying-time of the stage, but I personally don't expect the landing to happen until at least 10 minutes after launch.  So, in the area of the barge, the landing should be taking place at least 10 minutes after BMNT.  That's not all that much light maybe, but it isn't full darkness either.

As a rough guide, if it helps, ships are only required to display their navigation lights between the hours of nautical sunset and nautical sunrise.  After nautical sunrise, there's technically enough light to see the horizon and other vessels in the vicinity, so yes not full daylight, but not full darkness either and thus more than enough light to see the stage landing.

[darkenfast]

Do we know for sure if it's a vehicle or a pad problem?

[Antares]

The beta cut-out is what is driving the magnitude of the delay.  That wasn't mentioned on this thread.

[Avron]

Do we know for sure if it's a vehicle or a pad problem?

Must be vehicle due to length of slip.

[Dudely]

The beta cut-out is what is driving the magnitude of the delay.  That wasn't mentioned on this thread.

Probably one of those things that people assume everyone knows. But yeah, that's why it's so long. Jan 6th is literally the first day the ISS will be in darkness, so that's why it's set to that date.

[edkyle99]

I wonder why SpaceX keeps experiencing hardware problems that crop up during the Cape hot fire tests.  The stages have been test fired at McGregor.  What has changed?  Obviously the company would prefer to iron out any issues in Texas.  Could it be that something about the McGregor testing is causing the problems?

 - Ed Kyle

[Coastal Ron]

I wonder why SpaceX keeps experiencing hardware problems that crop up during the Cape hot fire tests.  The stages have been test fired at McGregor.  What has changed?  Obviously the company would prefer to iron out any issues in Texas.  Could it be that something about the McGregor testing is causing the problems?

Or it could be something in the equipment or setup at the launch site.  They have had connections issues with the erector before.  But I have not heard specifically what it is.

[Razvan]

I wonder why SpaceX keeps experiencing hardware problems that crop up during the Cape hot fire tests.  The stages have been test fired at McGregor.  What has changed?  Obviously the company would prefer to iron out any issues in Texas.  Could it be that something about the McGregor testing is causing the problems?

Or it could be something in the equipment or setup at the launch site.  They have had connections issues with the erector before.  But I have not heard specifically what it is.

I think @edkyle99 has touched a sensitive recurring issue.
I asked myself sometime the same question: why is SpaceX unable to solve these problems like valves, helium, etc. once and forall. It looks like there is a week chain link and McGregor test site could very well be.

[LouScheffer]

I wonder why SpaceX keeps experiencing hardware problems that crop up during the Cape hot fire tests.  The stages have been test fired at McGregor.  What has changed?  Obviously the company would prefer to iron out any issues in Texas.  Could it be that something about the McGregor testing is causing the problems?

 - Ed Kyle

The stage acceptance test can't be precisely the same as a real countdown.  For example, in the real countdown they load the tanks, wait a few hours, then fire.  For the stage acceptance test they might fire as soon as the tanks are loaded, or maybe load the tanks then wait a few extra hours to simulate the longest possible hold, or something in between.  Whatever case they choose while doing acceptance is not likely to be duplicated exactly for a launch.

[ugordan]

I wonder why SpaceX keeps experiencing hardware problems that crop up during the Cape hot fire tests. 

Because the stuff that seems to be failing the most is behaving like lightbulbs do? Just because it worked the last time you turned it on, doesn't necessarily mean it'll work the next time. It does raise questions about quality of the components, though.

Also, a note on observational bias: we have no way of knowing how many issues they see in McGregor during stage testing so it's not prudent to say they're only discovering issues on the launchpad. For all we know, McGregor testing campaigns might be having just as many (or even more) issues.

[rokan2003]

Makes you wonder if/how the 'rapidly reusable' dream will be realised.

[cscott]

The beta cut-out is what is driving the magnitude of the delay.  That wasn't mentioned on this thread.

Probably one of those things that people assume everyone knows. But yeah, that's why it's so long. Jan 6th is literally the first day the ISS will be in darkness, so that's why it's set to that date.

Technically, Jan *7* is the first available ISS day.  But if you launch on the 6th the berthing happens on the 7th.

[cscott]

I wonder why SpaceX keeps experiencing hardware problems that crop up during the Cape hot fire tests.  The stages have been test fired at McGregor.  What has changed?  Obviously the company would prefer to iron out any issues in Texas.  Could it be that something about the McGregor testing is causing the problems?

Or it could be something in the equipment or setup at the launch site.  They have had connections issues with the erector before.  But I have not heard specifically what it is.

Although surely there are *some* vehicle-side issues discovered during static fire, I think it would be a safe guess to assume that most of the issues discovered during static fire are related in some way to the Cape's GSE.  The McGregor GSE is exercised a lot during the series of acceptance tests, but the Cape's GSE is dusted off much less often, just for static fires and launches.  The fittings also wear differently, so even if they were manufactured to have identical parts, they are no longer identical.  The static fire is the first time the new stage is connected to Cape GSE, and small differences in the tolerances of various fittings, etc, can (and have) caused issues.

There's also a well-known bathtub curve for "infant mortality" in many pieces of hardware.  The testing at McGregor may simply not be long enough to get all the parts through the high-failure early part of the bathtub.   One hopes that reuse will eventually get us to the stable bottom of the tub -- before we eventually start complaining about failures caused by parts starting to hit the high wall at the far side.  But there will be many happy days for fans of reuse by the time we've gotten to that point!

[docmordrid]

WRT Falcon and valves, minor Google-fu reveals numerous Atlas V and Delta IV issues and scrubs due to valves as well - including EFT-1.