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

[toruonu]

Crossing fingers for the next F9R launch attempt, here there are my updated contribution to the topic.

I wanna thanks all the folks who helped me to improve my graphics jobs...

The name of the graphic is CRS-1, but as this is for CRS-5 thread and the labels also have grid fins mentioned, then the graphic probably should also include the boostback burn that happens after MECO and separation.

[archipeppe68]

Crossing fingers for the next F9R launch attempt, here there are my updated contribution to the topic.

I wanna thanks all the folks who helped me to improve my graphics jobs...

The name of the graphic is CRS-1, but as this is for CRS-5 thread and the labels also have grid fins mentioned, then the graphic probably should also include the boostback burn that happens after MECO and separation.

Let me explain a little: the name CRS1 is referred to the second version of the graphics released (respect the first issue of some days ago) is not linked to the CRS mission number at all, the current graphics tries to depict (as much as possible) the flight profile of the upcoming Falcon 9R/Dragon CRS-5 mission.

[toruonu]

Let me explain a little: the name CRS1 is referred to the second version of the graphics released (respect the first issue of some days ago) is not linked to the CRS mission number at all, the current graphics tries to depict (as much as possible) the flight profile of the upcoming Falcon 9R/Dragon CRS-5 mission.

Ok, in that case still the boostback burn is missing It's not a full boostback, but from what I've understood the stage is partially boosted back after separation just to go through the motions of a standard planned return even if the boostback is only partial.

[rpapo]

Ok, in that case still the boostback burn is missing It's not a full boostback, but from what I've understood the stage is partially boosted back after separation just to go through the motions of a standard planned return even if the boostback is only partial.

It also means that BargeX doesn't need to go as far out to sea.

[cscott]

I wonder if the stage tries to approach aligned with the wind, like an airplane does. It would make sense if the ASDS was aligned with the wind/waves (like a runway is).

But my guess was that they'd ignore the wind/waves and instead try to line up the ASDS so that the rocket was coming in perpendicular, so that (a) it wouldn't overfly the equipment sheds, and (b) slight over- or undershoot would drop it into the sea, not on top of the containers.

[ElGuapoGuano1]

So if they do decide to replace the actuator, what are the odds they can make the Friday Morning launch attempt?

[Lars-J]

Crossing fingers for the next F9R launch attempt, here there are my updated contribution to the topic.

I wanna thanks all the folks who helped me to improve my graphics jobs...

Ciao
Giuseppe

A very nice graphic, but a couple of errors if you want to correct them:
1. Your F9 doesn't appear to be thin enough. Have you tried overlaying the F9 graphic from the SpaceX F9 page to check your proportions? http://www.spacex.com/falcon9
2. The center engine on the first stage is not any bigger than the other, nor does it hang that low. (see the graphic at http://www.spacex.com/falcon9 )
3. The cargo Dragon trunk is the same diameter as the F9.
4. The first stage has three restarts, not two. http://www.spacex.com/news/2014/12/16/x-marks-spot-falcon-9-attempts-ocean-platform-landing

[cscott]

4. The first stage has three restarts, not two. http://www.spacex.com/news/2014/12/16/x-marks-spot-falcon-9-attempts-ocean-platform-landing

And to be extra clear, as Hans did during the prelaunch press conference: this means the first stage engine burns *four times*, including the liftoff burn.

[Tonioroffo]

So if they do decide to replace the actuator, what are the odds they can make the Friday Morning launch attempt?

Any word on this?

[Comga]

So if they do decide to replace the actuator, what are the odds they can make the Friday Morning launch attempt?

Any word on this?

Actualy, yes, but in the wrong thread:
http://forum.nasaspaceflight.com/index.php?topic=36326.msg1311775#msg1311775
From Florida Today:

SpaceX is evaluating whether to replace a rocket component responsible for scrubbing Tuesday morning's attempt to launch an International Space Station resupply mission from Cape Canaveral Air Force Station.
It was not clear how the launch schedule might be impacted if the company decides to replace a faulty actuator in the system that controls steering of the rocket's upper-stage engine nozzle.

"A replacement of the component is likely, but no firm decision has been made,"
http://www.floridatoday.com/story/tech/science/space/spacex/2015/01/07/spacex-targets-friday-launch-while-evaluating-rocket-component/21386343/

[ElGuapoGuano1]

Well, according to my Space Twitter, no, they can't make the Friday Launch opportunity
@SpaceX CRS-5 will make its next launch attempt from #CCAFS on Saturday, Jan. 10 at 4:47am  EST. @NASA TV coverage will begin at 3:30am.

[Lars-J]

Well, according to my Space Twitter, no, they can't make the Friday Launch opportunity
@SpaceX CRS-5 will make its next launch attempt from #CCAFS on Saturday, Jan. 10 at 4:47am  EST. @NASA TV coverage will begin at 3:30am.

Which tweet are you quoting? It is a good idea to either provide a direct link or the name/handle of the twitter user that posted the message. @SpaceX did not tweet it.

[ElGuapoGuano1]

Sorry Lars-J, I never know when to put in links or usernames, I've been scolded before. The Twitter handle was @Spaceport_Mag
SPACEPORT MAGAZINE

[ElGuapoGuano1]

@NASAKennedy is now reporting the same thing...

[Lars-J]

Sorry Lars-J, I never know when to put in links or usernames, I've been scolded before. The Twitter handle was @Spaceport_Mag
SPACEPORT MAGAZINE

Thanks!

[robertross]

Well, according to my Space Twitter, no, they can't make the Friday Launch opportunity
@SpaceX CRS-5 will make its next launch attempt from #CCAFS on Saturday, Jan. 10 at 4:47am  EST. @NASA TV coverage will begin at 3:30am.

ouch, that's early.
At least I'm on Atlantic time, so 1 hour more sleep for me. 

[Lar]

Here's a blog link also saying Saturday AM

https://blogs.nasa.gov/spacex/
specifically

https://blogs.nasa.gov/spacex/2015/01/07/next-spacex-launch-attempt-saturday-jan-10/

Posted here rather than updates because I'd never heard of this blog before seeing it mentioned on FB

[Remes]

There would have to be a force physically causing the drift.  Recalibration would be insufficient without determining where that force is coming from then either eliminating it or determining it can be withstood in flight.

That's assuming there was actual physical drift as opposed to signal drift from a bad LVDT or other electronic component in the position feedback system. Also, since the actuator is fueldraulic, a leaky servovalve could also cause drift without external force being applied.

Contamination of the servovalve might also be an issue.

May just need to replace the whole actuator.

They have to drain the hydraulic system (you don't want to have oily fluid everywhere), remove the actuator, adding a new one, taking care of contamination (typically these things are handled in lower class clean rooms) and afterwards the system must be flushed to remove entrapped air. Which takes some time. The dark side of hydraulic.

[robertross]

There would have to be a force physically causing the drift.  Recalibration would be insufficient without determining where that force is coming from then either eliminating it or determining it can be withstood in flight.

That's assuming there was actual physical drift as opposed to signal drift from a bad LVDT or other electronic component in the position feedback system. Also, since the actuator is fueldraulic, a leaky servovalve could also cause drift without external force being applied.

Contamination of the servovalve might also be an issue.

May just need to replace the whole actuator.

They have to drain the hydraulic system (you don't want to have oily fluid everywhere), remove the actuator, adding a new one, taking care of contamination (typically these things are handled in lower class clean rooms) and afterwards the system must be flushed to remove entrapped air. Which takes some time. The dark side of hydraulic.

Add to that the integrated electrical testing that must be completed.
Removing any and all trapped air in the hydraulics can be tricky for cylinders that can have dead spots. Advanced designs typically have bleeder screws at the highest points to get those air bubbles out. Air in hydraulic oil is a bad thing - indeed the dark side of hydraulics.

[yokem55]

Hydraulic actuators are finicky things and can behave in unexpected ways in extreme thermal situations. The 737's rudder actuator problems in the 90's comes to mind...