Quote from: Robotbeat on 03/20/2015 11:21 pmHonestly, the electrical connector is the easy bit of this whole thing.Something like a self-aligning Magsafe connector with more (and stiffer) pins and a solenoid or servo locking mechanism to ensure a tight fit.And how small would that connector be without the magsafe feature? That is my point.
Honestly, the electrical connector is the easy bit of this whole thing.Something like a self-aligning Magsafe connector with more (and stiffer) pins and a solenoid or servo locking mechanism to ensure a tight fit.
Quote from: meekGee on 03/20/2015 10:39 pm1. No need for hundreds of pins. That's got to be historical baggage. Serialize the data.2. There's no reason to have the second stage drive the first. The first is already fully autonomous, has identical avionics, and knows all there is to know. It can make the same decisions the second stage does, can drop it off within an envelope that the second stage can continue from. Given that the first stage has to continue flight anyway, I don't see why it has to go through the shock of "switching commanders" on stage separation. The first stage should be working like a carrier airplane.This is another case of historical baggage. An EELV is a single vehicle that's dropping parts until only the upper stage is left. That's why it's built the way it is. An F9R is a different type of beast. A highly reusable first stage that continues flight and RTLS right away, and a an upper stage that even if it comes back, does so much later. They have different operations cycles, and are their own self-contained entities. Fewer failure modes this way, too - rockets have been lost because of failure of inter-stage connectors. (can't remember which right now)<snipped>Quit with the flippant responses. It is not historical baggage. You have nothing to base that assertion on. 1. for the very many reasons I listed. 2. You have been proven wrong on this over and over. How many times do I have say it. Reality is that the second stage controls the first. The first stage is passive until after separation. That is a fact.<snipped>
1. No need for hundreds of pins. That's got to be historical baggage. Serialize the data.2. There's no reason to have the second stage drive the first. The first is already fully autonomous, has identical avionics, and knows all there is to know. It can make the same decisions the second stage does, can drop it off within an envelope that the second stage can continue from. Given that the first stage has to continue flight anyway, I don't see why it has to go through the shock of "switching commanders" on stage separation. The first stage should be working like a carrier airplane.This is another case of historical baggage. An EELV is a single vehicle that's dropping parts until only the upper stage is left. That's why it's built the way it is. An F9R is a different type of beast. A highly reusable first stage that continues flight and RTLS right away, and a an upper stage that even if it comes back, does so much later. They have different operations cycles, and are their own self-contained entities. Fewer failure modes this way, too - rockets have been lost because of failure of inter-stage connectors. (can't remember which right now)<snipped>
And how small would that connector be without the magsafe feature? That is my point.
1. As far as I can tell you only need 2 connections. One for FTS since you don't trust any other system, and one for data communication. You'd probably want redundancy of 2 or 3 on this, so we're talking a max of 6 connections with 12 total conductors. What are we missing? Power is independent between stages.... I'm at a loss.
Seems to me the question is, what launch performance can they demonstrate within the ceilings/range authorized from Spaceport America?
Quote from: SpunkyEnigma on 03/21/2015 01:55 am1. As far as I can tell you only need 2 connections. One for FTS since you don't trust any other system, and one for data communication. You'd probably want redundancy of 2 or 3 on this, so we're talking a max of 6 connections with 12 total conductors. What are we missing? Power is independent between stages.... I'm at a loss.There is more, there are staging breakwires, FTS breakwires, telemetry from the first stage to the second, commanding from the second to the first, some raw data, FTS is more than a few.
Quote from: Jim on 03/21/2015 02:15 amQuote from: SpunkyEnigma on 03/21/2015 01:55 am1. As far as I can tell you only need 2 connections. One for FTS since you don't trust any other system, and one for data communication. You'd probably want redundancy of 2 or 3 on this, so we're talking a max of 6 connections with 12 total conductors. What are we missing? Power is independent between stages.... I'm at a loss.There is more, there are staging breakwires, FTS breakwires, telemetry from the first stage to the second, commanding from the second to the first, some raw data, FTS is more than a few.Ok. Breakwires aside, is there any reason that the rest couldn't be transmitted wirelessly?
Quote from: meekGee on 03/20/2015 10:39 pm1. No need for hundreds of pins. That's got to be historical baggage. Serialize the data.2. There's no reason to have the second stage drive the first. The first is already fully autonomous, has identical avionics, and knows all there is to know. It can make the same decisions the second stage does, can drop it off within an envelope that the second stage can continue from. Given that the first stage has to continue flight anyway, I don't see why it has to go through the shock of "switching commanders" on stage separation. The first stage should be working like a carrier airplane.This is another case of historical baggage. An EELV is a single vehicle that's dropping parts until only the upper stage is left. That's why it's built the way it is. An F9R is a different type of beast. A highly reusable first stage that continues flight and RTLS right away, and a an upper stage that even if it comes back, does so much later. They have different operations cycles, and are their own self-contained entities. Fewer failure modes this way, too - rockets have been lost because of failure of inter-stage connectors. (can't remember which right now)3. Look at spacecraft dockings. Connections are made, after the two heavy bodies mate. And those are free-flying vehicles. You can do much better if the bodies are guided. You can do precision guidance by the jig, or you can have pilot pins and such on the flight hardware.4. The connectors can be rigidly connected to the master bodies and everything connect at once, or you can have them execute a secondary motion after the mechanical mate. Either way, if you pre-plan for automation, it's alot easier than if you try to make automation work in a less structured environment.Quit with the flippant responses. It is not historical baggage. You have nothing to base that assertion on. 1. for the very many reasons I listed.
1. No need for hundreds of pins. That's got to be historical baggage. Serialize the data.2. There's no reason to have the second stage drive the first. The first is already fully autonomous, has identical avionics, and knows all there is to know. It can make the same decisions the second stage does, can drop it off within an envelope that the second stage can continue from. Given that the first stage has to continue flight anyway, I don't see why it has to go through the shock of "switching commanders" on stage separation. The first stage should be working like a carrier airplane.This is another case of historical baggage. An EELV is a single vehicle that's dropping parts until only the upper stage is left. That's why it's built the way it is. An F9R is a different type of beast. A highly reusable first stage that continues flight and RTLS right away, and a an upper stage that even if it comes back, does so much later. They have different operations cycles, and are their own self-contained entities. Fewer failure modes this way, too - rockets have been lost because of failure of inter-stage connectors. (can't remember which right now)3. Look at spacecraft dockings. Connections are made, after the two heavy bodies mate. And those are free-flying vehicles. You can do much better if the bodies are guided. You can do precision guidance by the jig, or you can have pilot pins and such on the flight hardware.4. The connectors can be rigidly connected to the master bodies and everything connect at once, or you can have them execute a secondary motion after the mechanical mate. Either way, if you pre-plan for automation, it's alot easier than if you try to make automation work in a less structured environment.
2. You have been proven wrong on this over and over. How many times do I have say it. Reality is that the second stage controls the first. The first stage is passive until after separation. That is a fact.
The ludicrous number of pins could be so a ground crew could access each sensor and control device directly. That would really help in troubleshooting.
How many times do I have say it. Reality is that the second stage controls the first. The first stage is passive until after separation. That is a fact.
Why am I reading pages of posts about pins?
Quote from: Chris Bergin on 03/21/2015 12:19 pmWhy am I reading pages of posts about pins? Because you know that people can only understand how something works by undersanding the most basic details. The great engineers aren't the ones who memorized the manual the best. They're the ones who understand the machine at the gut level because they know how it works down to the pins and switches. At least, that's my take after a barrel sized mug of beer in a Tunisian bar and grill.
Quote from: Jim on 03/20/2015 11:41 pmHow many times do I have say it. Reality is that the second stage controls the first. The first stage is passive until after separation. That is a fact.let's try a different way for those who can't understand.Reality is not what other launch vehicles do. Reality is how Spacex does it, just as I described.