Author Topic: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3  (Read 713047 times)

Offline rpapo

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #600 on: 04/19/2016 03:24 PM »

All SpaceX needs to do is to get Stark Industries to build them THIS so they can fly to an Equatorial launch site, launch the Falcon, then do a mid-air "catch" of the booster on the deck, and fly back.

Who needs "Sea Launch" and Elsbeth III when you can do Air Launch and Air Catch, anywhere,  with "Of Course I Still Have Not Just Read The Instructions"?   

Wee bit of an issue with the theoretical cost, and even more than just a bit of an issue with reality.....   :)


If that could be built, then there is no need for Falcon.  Just use its power system on winged vehicles to go into orbit. In fact, it probably could go into orbit itself.
There are a lot of neat gadgets in the alternate worlds of science fiction.  Some of them actually become true, but that generally only happens when said gadgets don't violate the laws of physics.
An Apollo fanboy . . . fifty years ago.

Online speedevil

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #601 on: 04/20/2016 07:38 PM »
There are a lot of neat gadgets in the alternate worlds of science fiction.  Some of them actually become true, but that generally only happens when said gadgets don't violate the laws of physics.
Several dozen Raptors on a launch platform wouldn't violate the laws of physics.
Economics, maybe.

Offline Lar

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #602 on: 04/20/2016 08:37 PM »
Well that escalated quickly.

(insert generic admonition to stay on topic here, although with JIM talking science fiction, my heart just isn't in it)
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline OxCartMark

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #603 on: 04/21/2016 04:10 PM »
Meanwhile, how are things in the port of LA / Long Beach?

And (this is such a long shot I shouldn't even be writing this) - I don't suppose there's any activity around the Sea Launch ships?

Offline Lar

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #604 on: 04/22/2016 01:03 AM »


I may have to report myself if you guys (and gals) can't stay more on topic.  Don't make me turn this barge around.
« Last Edit: 04/22/2016 11:19 PM by Chris Bergin »
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline CJ

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #605 on: 04/22/2016 06:52 AM »
Sorry to ask an apparently off-topic (it has nothing to do with flying aircraft carriers  :P) question, but does anyone happen to know if the two ASDS's, in their current configuration, have anemometers and wind direction indicators?  I've been looking at photos and can't see them, though I foggily recall seeing one in the past.

I'm thinking that knowing wind speed and direction at the ASDS would be important, but can't imagine why they would not have not have an anemometer and wind vanes for that purpose?

Offline CameronD

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #606 on: 04/22/2016 07:11 AM »
Sorry to ask an apparently off-topic (it has nothing to do with flying aircraft carriers  :P) question, but does anyone happen to know if the two ASDS's, in their current configuration, have anemometers and wind direction indicators?  I've been looking at photos and can't see them, though I foggily recall seeing one in the past.

I'm thinking that knowing wind speed and direction at the ASDS would be important, but can't imagine why they would not have not have an anemometer and wind vanes for that purpose?

It's at the top of the tower - port side, aft forward:



(Image credit te_atl: https://forum.nasaspaceflight.com/index.php?topic=40002.msg1520225)


Whew!! We're back on board and I can breathe again..   :)

Edit:  Got the front and back of this thing mixed up again.   :-[
« Last Edit: 04/25/2016 11:26 PM by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline IntoTheVoid

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #607 on: 04/22/2016 02:22 PM »
It's at the top of the tower - port side, aft:

I'm no sailor, but that's not the port side, aft.

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #608 on: 04/22/2016 06:23 PM »
I'm thinking that knowing wind speed and direction at the ASDS would be important, but can't imagine why they would not have not have an anemometer and wind vanes for that purpose?

I've wondered about 'perfect' 5s weather forecasts.

A cylinder of 30 or so cheap drones 200m in radius, launched a couple of minutes before landing, or doppler LIDAR/RADAR.
Being able to perfectly predict the weather for 5s as you're measuring a complete shell at the wind velocity seems in principle interesting at least.

Online meekGee

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #609 on: 04/22/2016 07:21 PM »
I'm thinking that knowing wind speed and direction at the ASDS would be important, but can't imagine why they would not have not have an anemometer and wind vanes for that purpose?

I've wondered about 'perfect' 5s weather forecasts.

A cylinder of 30 or so cheap drones 200m in radius, launched a couple of minutes before landing, or doppler LIDAR/RADAR.
Being able to perfectly predict the weather for 5s as you're measuring a complete shell at the wind velocity seems in principle interesting at least.

Admit it.  You bought 30 cheap drones on an impulse (I can relate!) and now you're looking for an offloader.
« Last Edit: 04/22/2016 07:21 PM by meekGee »
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Offline Chris_Pi

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #610 on: 04/22/2016 08:50 PM »
I'm thinking that knowing wind speed and direction at the ASDS would be important, but can't imagine why they would not have not have an anemometer and wind vanes for that purpose?

I've wondered about 'perfect' 5s weather forecasts.

A cylinder of 30 or so cheap drones 200m in radius, launched a couple of minutes before landing, or doppler LIDAR/RADAR.
Being able to perfectly predict the weather for 5s as you're measuring a complete shell at the wind velocity seems in principle interesting at least.

Admit it.  You bought 30 cheap drones on an impulse (I can relate!) and now you're looking for an offloader.

Alcohol+Amazon can be a weird combination sometimes. Who knows what shows up a few days later!  :o

That might actually be useful especially if it extended up a thousand feet or two. Doesn't take much to fly out and just hold position for a minute or two, then come back down.

Online cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #611 on: 04/22/2016 08:59 PM »
The thing about well-tuned control loops is: you don't need perfect information about the environment.  It's magic.

In order to justify this, you'd need to show that perfect forecast actually saved fuel or increased landing reliability.  I think any such effects would be far down in the noise: you're competing with the control loop gain, which pushes any benefits down a couple of orders of magnitude.

Simplified hand-wavy example: with a control loop gain of (say) 100 and a very simple proportional control loop, every one unit improvement in your feedback parameter just giving you .01 unit less in your error term, which is what modulates your thrust.  So 1m better position accuracy is only 1cm less error term, and very little fuel saved.
« Last Edit: 04/22/2016 11:39 PM by cscott »

Offline acsawdey

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #612 on: 04/22/2016 09:23 PM »
I'm thinking that knowing wind speed and direction at the ASDS would be important, but can't imagine why they would not have not have an anemometer and wind vanes for that purpose?

I've wondered about 'perfect' 5s weather forecasts.

A cylinder of 30 or so cheap drones 200m in radius, launched a couple of minutes before landing, or doppler LIDAR/RADAR.
Being able to perfectly predict the weather for 5s as you're measuring a complete shell at the wind velocity seems in principle interesting at least.

Well, if you put 30 or more drones in a circle and they have cameras, that opens the way to:

Bullet-time Falcon 9

Offline CJ

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #613 on: 04/22/2016 10:01 PM »
Sorry to ask an apparently off-topic (it has nothing to do with flying aircraft carriers  :P) question, but does anyone happen to know if the two ASDS's, in their current configuration, have anemometers and wind direction indicators?  I've been looking at photos and can't see them, though I foggily recall seeing one in the past.

I'm thinking that knowing wind speed and direction at the ASDS would be important, but can't imagine why they would not have not have an anemometer and wind vanes for that purpose?

It's at the top of the tower - port side, aft:



(Image credit te_atl: https://forum.nasaspaceflight.com/index.php?topic=40002.msg1520225)


Whew!! We're back on board and I can breathe again..   :)

Thank you!

That rohn tower does indeed have a combined anemometer/direction indicator, and it's ultrasonic.

Looks very similar to this one.
http://www.kintech-engineering.com/media/uploads/image/178.jpg
(I'm using a link rather than attaching the pic, because it may well be copyrighted due to being a commercial product and I am guessing this is NSF's preferred method in that case?).

Ultrasonic anemometers aren't anywhere near as cheap as the old cups-on-a-spindle style, but they are more suitable for the salt air environment (no moving parts). Something like this would run around $2000 retail.

I'm a bit confused as to the placement though; there's nothing similar on the port forward rhon tower, so it looks like the only one is the one you found, on the starboard aft tower. I'd have thought that placing it forward rather than aft would be preferred for accuracy (drag effects of the forward structures). Edit: it actually is on the bow, I goofed.

I'd also be willing to bet that somewhere aboard is an accelerometer/tiltmeter, to give them data on the exact attitude and motion of the ASDS at the moment of touchdown (for later analysis, not realtime use).  Might also be useful to know before launch if conditions are marginal (assuming they'd delay a launch for a landing issue). 

Edit: fixed my mistaking the bow for the stern. 
« Last Edit: 04/23/2016 03:33 AM by CJ »

Online cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #614 on: 04/22/2016 11:41 PM »
Accelerometer/tilt meter is probably part of the position-hold package already.

Offline CuddlyRocket

It's at the top of the tower - port side, aft:

I'm no sailor, but that's not the port side, aft.

Yep, if that tower is at the stern, it's on the starboard side! (Alternatively, it's on the port bow.)

Offline CJ

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #616 on: 04/23/2016 03:30 AM »
It's at the top of the tower - port side, aft:

I'm no sailor, but that's not the port side, aft.

Yep, if that tower is at the stern, it's on the starboard side! (Alternatively, it's on the port bow.)

I'm afraid I've added to the confusion here. That (in the photo CameronD included) is definitely the bow, so the tower is on the port bow. I'll go edit my post. Thanks.

Online meekGee

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #617 on: 04/23/2016 04:33 AM »
To all the regular people out there:

Port is Left  ("the ship just left port")
Bow is front (you bow forward, right?)

On ASDS, the side with one row of containers and two walls (blast wall and wave wall) is the front.


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Online meekGee

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #618 on: 04/23/2016 06:00 AM »
I'm thinking that knowing wind speed and direction at the ASDS would be important, but can't imagine why they would not have not have an anemometer and wind vanes for that purpose?

I've wondered about 'perfect' 5s weather forecasts.

A cylinder of 30 or so cheap drones 200m in radius, launched a couple of minutes before landing, or doppler LIDAR/RADAR.
Being able to perfectly predict the weather for 5s as you're measuring a complete shell at the wind velocity seems in principle interesting at least.

Well, if you put 30 or more drones in a circle and they have cameras, that opens the way to:

Bullet-time Falcon 9

The landing sequence is such a good fit for this.  It would be stunning.  no need for drones though.
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Offline sanman

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #619 on: 04/23/2016 09:32 AM »

All SpaceX needs to do is to get Stark Industries to build them THIS so they can fly to an Equatorial launch site, launch the Falcon, then do a mid-air "catch" of the booster on the deck, and fly back.

Who needs "Sea Launch" and Elsbeth III when you can do Air Launch and Air Catch, anywhere,  with "Of Course I Still Have Not Just Read The Instructions"?   

Wee bit of an issue with the theoretical cost, and even more than just a bit of an issue with reality.....   :)


Sounds like you really want...

http://forum.nasaspaceflight.com/index.php?topic=39944.0

A large floating airship could be beneficial. Not only could the airship act as a landing pad, but it could later even act as a launch pad, perhaps allowing rockets to be launched from upto 20 miles above sea level.

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