SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION

[kevin-rf]

If it is not ice and it flew from the S2 dome forward though, I'd worry about damage to the external payloads.

If it fell out of the trunk onto the S2 dome, (then later floated forward) I would worry about the pointy part of the calipers  puncturing the LOX tank dome... That would be a very difficult fault tree to resolve.

[rockets4life97]

If it is not ice and it flew from the S2 dome forward though, I'd worry about damage to the external payloads.

Shouldn't NASA's inspection of the external payloads prior to removal with the robotic arm reveal any damage? Since the payloads are being removed, it looks like SpaceX got away with a mistake.

[eeergo]

If it is not ice and it flew from the S2 dome forward though, I'd worry about damage to the external payloads.

Shouldn't NASA's inspection of the external payloads prior to removal with the robotic arm reveal any damage? Since the payloads are being removed, it looks like SpaceX got away with a mistake.

Damage need not be visible, and it appears to be coming from the underside of ROSA, which has not yet been removed. Unless the damage was very obvious, I don't see why they wouldn't go ahead with removal though, that's what checkouts are for: checking launch rigors haven't damaged anything.

[Wolfram66]

2-S2 thrust stops and unrestraind object moves into Dragon trunk due to INERTIA.

This would only be true if an external force is applied to S2/trunk. Otherwise inertia applies equally to the whole system S2/dragon/caliper. For the caliper to move relative to S2/trunk it needs a separate force.

Are you saying, when you are in a car and hit the brakes, your movement forward is caused by a seperate force or when you go around a curve the force pushing you to the side is caused by a seperate force?

Please educate me on this non inertial force acting on you and the car separately.

Hitting the brakes is applying a force against inertia. SECO/MECO is switching from acceleration to cruising (e.g. NO external force).

NEWTON people. an object in motion will remain in motion if not acted upon by an external force.  caliper is accelerating at same rate as S2 +Dragon stack. 3 G's at the time suddenly acceleration stops ..SECO. an unrestrained object will drift forward, especially since there is a liquid sloshing around in the S2. This is different than 2 objects traveling a constant velocity.

[eeergo]

Further note: I won't enter the discussion of it being a caliper or not, but it seems weird for a piece of ice to drift off camera in that direction (being first obscured by the S2-Dragon interface ring) and, a few seconds later, *reappear* on the same trajectory and with the same shape, receding into the distance.

I am referring to T+10:34 to 10:40.

[jpo234]

NEWTON people. an object in motion will remain in motion if not acted upon by an external force.  caliper is accelerating at same rate as S2 +Dragon stack. 3 G's at the time suddenly acceleration stops ..SECO. an unrestrained object will drift forward, especially since there is a liquid sloshing around in the S2. This is different than 2 objects traveling a constant velocity.

You fail to account for the fact that when the acceleration stops, everything in the system is an "unrestrained object". The hypothetical caliper drifts forward, but so do S2 and the dragon. For the caliper to get ahead of S2 and bounce into dragon, it needs to accelerate relative to S2 and dragon. To accelerate, it needs a separate force that only applies to the caliper.

I think we are in violent agreement about Newton, but you selectively apply Newton to the caliper and not the rest of the system.

[whitelancer64]

NEWTON people. an object in motion will remain in motion if not acted upon by an external force.  caliper is accelerating at same rate as S2 +Dragon stack. 3 G's at the time suddenly acceleration stops ..SECO. an unrestrained object will drift forward, especially since there is a liquid sloshing around in the S2. This is different than 2 objects traveling a constant velocity.

You fail to account for the fact that when the acceleration stops, everything in the system is an "unrestrained object". The hypothetical caliper drifts forward, but so do S2 and the dragon. For the caliper to get ahead of S2 and bounce into dragon, it needs to accelerate relative to S2 and dragon. To accelerate, it needs a separate force that only applies to the caliper.

I think we are in violent agreement about Newton, but you selectively apply Newton to the caliper and not the rest of the system.

I guess fuel in the stage would never slosh around then? It should just stay down at the bottom after engine shutdown.

[RonM]

If it was calipers (not ice) and if upon shutdown of the second stage it moved forward from the second stage area to impact somewhere near the top of the trunk is it possible that it could have damaged the Dragon heat shield?  I don't recall if there is a barrier at the top of the trunk or if the heat shield should be visible once cargo is removed?

There is a barrier protecting the heatshield.

[Scylla]

Might I suggest that discussion on how Newtonian physics works is starting to drift far afield.

Perhaps a different or new thread is appropriate.

[jpo234]

I guess fuel in the stage would never slosh around then? It should just stay down at the bottom after engine shutdown.

I'm a little bit unsure here, because liquids are strange. There are other forces that would creep in (capillarity, surface tension, evaporation and fluid synamics because the fuel was flowing to the engine). So, generally I would assume that it primarilly stays close to what was the bottom, but I would not be surprised if over time it starts to spread out.

But if it was a heap of sand, than yes, it would stay at the bottom of the tank.

Edit: I will stop here, as Scylla suggested.

[HVM]

Wrong Dragon...

@ dawei

Yhm... you don't really know what picax really is? There's no way that caliper can inflict any damage to the heat shield. It's not ceramics or carbon carbon, picax structure resemble more to a block of wood or stiff chipboard...

[srcln]

Further note: I won't enter the discussion of it being a caliper or not, but it seems weird for a piece of ice to drift off camera in that direction (being first obscured by the S2-Dragon interface ring) and, a few seconds later, *reappear* on the same trajectory and with the same shape, receding into the distance.

I am referring to T+10:34 to 10:40.

Agreed. If that object seen at 10:34 is the same object, I can't imagine any trajectory for it that would have originated from the ROSA area deep in that trunk.  I can imagine trajectories that originate at the S2/trunk interface area, specifically where all the other separation debris comes from normally.  I suspect that "caliper" is smaller and much closer to the camera than the video makes it seem.

Edit: It's a big IF on that being the same object but it sure looks very similar.

[zubenelgenubi]

Looks like the caliper comes out from one of the payloads inside the trunk. Not a pleasant sight.

Any news that NASA/SpaceX are investigating?

(There's a term from the STS era that I'm thinking of, but forgetting.  An anomaly investigation?)

[tleski]

(There's a term from the STS era that I'm thinking of, but forgetting.  An anomaly investigation?)

Officially there was no anomaly, so no reason to investigate.
The reddit post, which was the source of this information was deleted (but the discussion is still there) and replaced with an unofficial explanation that it was no caliper but an oddly shaped piece of ice. Many people are not buying it though. I don't think SpaceX made any comments related to this.

[jpo234]

(There's a term from the STS era that I'm thinking of, but forgetting.  An anomaly investigation?)

Officially there was no anomaly, so no reason to investigate.
The reddit post, which was the source of this information was deleted (but the discussion is still there) and replaced with an unofficial explanation that it was no caliper but an oddly shaped piece of ice. Many people are not buying it though. I don't think SpaceX made any comments related to this.

Regarding the deleted Reddit post: Funny thing is, that old_sellsword, who is one of the reddit admins, liked Ed Kyles post that says:

That's not ice.

[Lar]

The thought crossed my mind to separate the alleged anomaly discussions out, because we're not going to lock a mission discussion thread. So far, no action.

(not directed at any one person but at all of us) ... But do ask yourself if your post adds significant value or is just a quip or a back and forth with someone else that isn't really key.

Thanks.

[Chris Bergin]

I have zero information on any of this, for what it's worth. And I see no one has anything of substance in the posts that came since so I don't see the validity of it continuing as a conversation UNTIL there is some actual information to discuss.

That's an order.

(Boom! Within 18.2 seconds someone asks me why I'm censoring "chat" - Nope, you've all had a "chat", which got us nowhere and a rumor is dominating a mission discussion thread. I'm saying instead of 50 pages of "to ice or not to ice", we give it a break until there's some actual info to discuss.)

[zubenelgenubi]

https://blogs.nasa.gov/stationreport/2017/06/08/

Yesterday and overnight, Robotic Ground Controllers powered up the MSS cameras and lights and walked the Space Station Remote Manipulator System (SSRMS) off the Node2 Power Data Grapple Fixture (PDGF) onto Mobile Base System (MBS) PDGF1. They then translated the Mobile Transporter (MT) from Worksite 6 (WS6) to WS2.  Finally the Robotics Ground Controllers unstowed the Special Purpose Dexterous Manipulator (SPDM) from MBS PDGF2.  The SPDM is holding the Multiple User System for Earth Sensing (MUSES) payload on the Enhanced Orbital Replacement Unit (ORU) Temporary Platform (EOTP) which will be installed later today on Express Logistic Carrier 4 (ELC4).

What is the timeline for the installation of NICER and ROSA?

[kaa]

https://blogs.nasa.gov/stationreport/2017/06/08/

Yesterday and overnight, Robotic Ground Controllers powered up the MSS cameras and lights and walked the Space Station Remote Manipulator System (SSRMS) off the Node2 Power Data Grapple Fixture (PDGF) onto Mobile Base System (MBS) PDGF1. They then translated the Mobile Transporter (MT) from Worksite 6 (WS6) to WS2.  Finally the Robotics Ground Controllers unstowed the Special Purpose Dexterous Manipulator (SPDM) from MBS PDGF2.  The SPDM is holding the Multiple User System for Earth Sensing (MUSES) payload on the Enhanced Orbital Replacement Unit (ORU) Temporary Platform (EOTP) which will be installed later today on Express Logistic Carrier 4 (ELC4).

What is the timeline for the installation of NICER and ROSA?

You can find a timeline for NICER at https://heasarc.gsfc.nasa.gov/docs/nicer/

[deruch]

Does anyone have the original orbit for CRS-11 Dragon, prior to any post-separation S/C maneuvers?