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They mentioned on the live stream that this is because of the shaking antennae.

It has also been discussed on here before why this happens: Why does the video feed always fail during Falcon 9 landings?

But that post doesn't give a solution to the problem. It is asking why it happens, someone confirms this and we have confirmation from SpaceX why this happens.

My question is why can't they just hold the antennae away from the ship? Put the antennae on a buoy. Throw the buoy into the water, let it drift away, and then reel it back when the falcon has landed. Cheap and reusable - the SpaceX way!

zoplonix
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    A) A buoy would be less stable, and the motion of the boat would cause it to rock. B) The buoy would still have to be connected by a wire carrying the feed, so it couldn't be too far away. C) Perhaps most importantly, this is another decently large complication to an already complicated procedure. Engineers prefer to use the KISS principle: Keep It Simple, Stupid. The primary objective is to land a rocket on the ship. The live camera feed is just a little extra. – Phiteros Feb 07 '18 at 05:27
  • @Phiteros about the wire, no. That could be done wirelessly. Maybe not exactly WiFi, but an "omni" antenna and a bit of wattage is all that's needed. I'm also still not 100% convinced the "signal cuts out because of vibrations" to begin with, but that's a different issue completely. – uhoh Feb 07 '18 at 05:55
  • @Phiteros aren't there buoys already hosting antennae or is this just generally not done. I don't see how you would get any less reception then being in a small boat. B) deep sea cables can go pretty far, just a matter of motivation, C) this is already the most complicated procedure ever – zoplonix Feb 07 '18 at 06:19
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    @uhoh the problem with wireless is (spacex is claiming and it makes sense) that the antennae shake to much and this disrupts the signal – zoplonix Feb 07 '18 at 06:20
  • @Phiteros and with tugging you just need slack – zoplonix Feb 07 '18 at 06:23
  • @user1886419 shaking a directional antenna which is beaming video bandwidth to a satellite link would be a problem. Shaking an omnidirectional WiFi-like antenna would not be. – uhoh Feb 07 '18 at 06:28
  • @uhoh a gimbal? – zoplonix Feb 07 '18 at 06:30
  • @Hobbes probably someone asking why this happens not how to fix it – zoplonix Feb 07 '18 at 06:57
  • gets disrupted every landing is untrue. They mentioned on the live stream that this is because of the shaking antennae was speculation, not a fact (at that time). –  Feb 07 '18 at 07:23
  • @JanDoggen what is true then? When the feeds cut out they can still pull a video so its not the camera equipment malfunctioning. The feed cuts out when the rocket gets near so it is related. I am unaware of the boosters causing appreciable radio interference. Last thing is the wireless connection. In the middle of the ocean there is no radio towers you can reach so you need a satellite connection. Satellite requires line of sight. If the satellite is shaking how is it to maintain connection. Do we have confirmation from all the other times it failed that it wasn't wireless related? – zoplonix Feb 07 '18 at 07:33
  • Possible duplicate of Why does the video feed always fail during Falcon 9 landings? – Hobbes Feb 07 '18 at 08:41
  • @Hobbes as i said before, this previous question is asking why it fails and answers that. that answer is in my question and was confirmed in the broadcast. I am asking how do we stop this from happening given that we know why it happens – zoplonix Feb 07 '18 at 09:06
  • Have you read the comments on the linked question? – Hobbes Feb 07 '18 at 09:09
  • @Hobbes why not link to the specific comment you are talking about? Help me instead of putting me on the defensive? – zoplonix Feb 07 '18 at 09:12
  • @Hobbes and I did read them. Nothing about a wired boat or buoy as a solution to the problem. and why would a comment mean a duplicate question? – zoplonix Feb 07 '18 at 09:15
  • @Hobbes really just hungry for info and what you linked me and are claiming is in there I can't find. need a better link – zoplonix Feb 07 '18 at 09:16
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    This is the comment I'm referring to ->Why would they spend $$$ on a fancy feed that doesn't interrupt, when the primary goal of that video camera is to have a record they can analyse at their leisure? The data is stored on the ASDS for later review. – Hobbes Feb 07 '18 at 09:22
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    No need for buoys. If they really wanted those extra few seconds of live coverage, they could use a wide-beam, (and hence more vibration proof), UHF link to one of the support ships and then fire the video up to a satellite from a stabilised antenna in the usual way. – Martin James Feb 07 '18 at 11:25
  • @MartinJames makes sense. is the drone ship already in communication with the support ships directly or does it all relay through satellite? – zoplonix Feb 07 '18 at 19:37
  • @user1886419 I've seen no signs of an ASDS <-> support vessel link, though they may all be connected in the sense that the ASDS and at least Go Quest seem to have satellite data uplinks aboard that presumably are connecting them to the SpaceX corporate network. https://forum.nasaspaceflight.com/index.php?topic=39766.msg1723141#msg1723141 – Saiboogu Feb 12 '18 at 04:09
  • @user1886419 I guess SpaceX was not interested in a better solution for the Falcon Heavy maiden flight. A functioning live stream would have only disrupted the space coast parties. – Everyday Astronaut Feb 12 '18 at 14:01
  • "My question is why can't they just hold the antennae away from the ship?" – Why are you assuming that they can't do that? Isn't it much more likely that they actually can do that, but just don't? – Jörg W Mittag Sep 18 '18 at 12:08
  • Or they could use a drone. Or they could record the landing, and send it after the ship is again stabilized. I am not very satisfied with them in this sense. – peterh Jul 21 '20 at 08:14

3 Answers3

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For SpaceX there is no drawback to having a brief interruption in the broadcast. The live transmission is for entertainment/PR purposes only, and they're already elbow deep in good PR so don't need any more.

The ASDS stores the video onboard. SpaceX often publishes the landing video later. Even for crash landings, with the stage exploding on the barge, the video recordings remain intact. The video is available for engineering analysis a few hours after the landing, which is soon enough.

There would be a significant cost to making sure the transmission is uninterrupted.

You can't use a buoy. There's a satcom antenna (i.e. a steerable dish) on the ASDS. You'd have to provide a reasonably stable platform for that antenna. So that means a boat or barge.

I've indicated one of the antennas in this image: ASDS satcom (original here) There's another on on the other side of the barge. They're pretty big (I estimate about 1 m diameter).

That boat means another item whose position needs to be controlled to make sure it doesn't crash into the ASDS. It needs an engine, an azimuth drive or two. Now the boat needs to be big enough to hold these.

Now, instead of recovering just the ASDS, the crew has to recover 2 vessels after the landing, doubling the workload. You need to tow the antenna boat, so that means another tug.

With all this, you still have a wireless link between ASDS and antenna boat. Can't use a wire (will get tangled in a propeller). So still a wireless link with a transmitting antenna that will be right underneath a rocket exhaust, and can be interfered with by the landing radar. A crash landing on top of the antenna will still take out the transmission.

So you'll spend a lot for no benefit. This is why SpaceX won't bother improving the live landing feed. Not until large-scale BFR operations become a reality and turnaround time needs to drop below 24h - then SpaceX might benefit from having the landing video available sooner for analysis.

Hobbes
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Come at it from a different angle --

What is the impact to SpaceX when they lose comms?

There is a momentary interruption in the stream. The livestream is impacted mildly. We have no signs there's a greater impact. We have evidence the impact is actually far more mild than what the public sees -- see the video wall over the hosts shoulder, where you can see the ASDS camera feed clearing moments after the landing attempt.

They are also concerned with telemetry as well as video - even more so, likely. However the ASDS has multiple shipping containers of equipment onboard that could very easily contain a ground station to store data during interruptions in the uplink. Also if the vehicle is recovered, they are likely to have onboard storage too.

So ultimately, you may have a solution searching for a problem. SpaceX doesn't seem to have any problems getting sufficient data from landings.

Saiboogu
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UPDATE: It doesn't get disrupted completely on every landing!

For example here's the SpaceX video from the ANASIS-II Mission.

Pardon the ugly GIF, I don't know how to make a better one...

GIF from ANASIS-II Mission

video cued at 23:19 or T+ 08:22

uhoh
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