Community > Forum > Technology & Science > How simple can a manned craft be?

How simple can a manned craft be?

Posted by: Andy Hill - Mon Feb 18, 2008 10:39 pm
Post new topic Reply to topic
 [ 42 posts ] 
How simple can a manned craft be? 
Author Message
Moon Mission Member
Moon Mission Member
User avatar
Joined: Mon Nov 01, 2004 6:15 pm
Posts: 1233
Location: London, England
Post    Posted on: Sat Mar 01, 2008 12:22 pm
Another advantage with a simple craft is less to go wrong. Take luxury cars for example, crammed with the latest gadgets. It is more often than not that it is these gadgets that fail and require attention.

In other threads the possibility of converting ESA's ATV into a crew vehicle has been discussed, I think that would be a big mistake due to its size and complexity. There is no real point to having an automated docking system on a crew vehicle when some of your astronauts are pilots, the extra complexity and opportunity for another system failure should be avoided.

I would like to see a small craft, grossing no more than 5,000-6,000kg able to carry upto 6 crew to the ISS and back. Such a craft would be able to be launched on a range of boosters and could be developed jointly by a group of space agencies to be used as a general utility vehicle. Simplifying its design and using more widely available aviation technology where possible would also make things like managing ITAR easier.

_________________
A journey of a thousand miles begins with a single step.


Back to top
Profile WWW
Launch Director
Launch Director
avatar
Joined: Tue Feb 19, 2008 7:02 pm
Posts: 19
Post    Posted on: Sat Mar 01, 2008 7:03 pm
"Another advantage with a simple craft is less to go wrong. Take luxury cars for example, crammed with the latest gadgets. It is more often than not that it is these gadgets that fail and require attention."

Not that I want to be a jerk or anything, but I would need to see support for this assertion. Simplicity is not a virtue in as of itself. Redundancy and complex safety systems make a design MORE reliable and safe, not less.

2.71


Back to top
Profile
Moon Mission Member
Moon Mission Member
User avatar
Joined: Mon Nov 01, 2004 6:15 pm
Posts: 1233
Location: London, England
Post    Posted on: Sat Mar 01, 2008 8:17 pm
2.71 wrote:
"Not that I want to be a jerk or anything, but I would need to see support for this assertion. Simplicity is not a virtue in as of itself. Redundancy and complex safety systems make a design MORE reliable and safe, not less.


I can only speak from personal experience, when I owned an old ford in the 80s it never went wrong, later cars I had were fitted with engine management systems and other goodies that required a lot of attention in the local garage. Another example is MS Windows, I always found windows 3.1.1 much more bomb proof than windows 2000 or XP. Some of those additional features seemed to be more trouble than they were worth.

While I agree that certain systems require backups make them simple mechanical/electrical devices where possible and not dependant on computer software or multi-sensor inputs.

_________________
A journey of a thousand miles begins with a single step.


Back to top
Profile WWW
Space Station Member
Space Station Member
User avatar
Joined: Mon Nov 29, 2004 1:04 pm
Posts: 254
Location: Norway
Post    Posted on: Sun Mar 02, 2008 12:12 pm
But if you don't have multi sensor-inputs, how do you know where and when something is wrong?

Using your example with a car from the early 80s without a engine management system, you could spend 5-6 hours trying to figure out what was wrong, while in your new car, you just flip a switch, and the car tells you that it is the distributor cap, which you can exchange within 15 minutes. It could also tell you that it's getting strange readings from it sometimes, and warn you before somethings do go wrong.

I have to agree with 2.71 - simple is not the same as reliable / safe

By the way - XP is like heaven compared to win 3.11 ;)


Back to top
Profile ICQ
Moon Mission Member
Moon Mission Member
User avatar
Joined: Mon Nov 01, 2004 6:15 pm
Posts: 1233
Location: London, England
Post    Posted on: Sun Mar 02, 2008 2:26 pm
IrquiM wrote:
But if you don't have multi sensor-inputs, how do you know where and when something is wrong?


You dont need 27 sensors all telling you the same thing. And is it always necessary to know exactly where a problem is if you cant do anything about it? A sensor saying there is something wrong with a fuel valve buried in the engine plumbing is all very clever but isn't it enough that the engine shut down because inputs from other sensors told it to. Such an event would require a major strip down which would not be possible in space so why does an astronaut need to know about a problem he cannot fix?

IrquiM wrote:
Using your example with a car from the early 80s without a engine management system, you could spend 5-6 hours trying to figure out what was wrong, while in your new car, you just flip a switch, and the car tells you that it is the distributor cap, which you can exchange within 15 minutes.


No one told me about a magic switch somewhere (it was probably mentioned in the Harry Potter version of the workshop manual, have you a copy you can lend me?), I always assumed you needed a £100k of diagnostics equipment. :)

As for 5-6 hours tracking down a problem, very unlikely, I once changed a head gasket on a friend's Ford escort in my lunch hour. It would take me an hour just to remove all the bits around the engine so that I could access the head on my current Ford focus.

_________________
A journey of a thousand miles begins with a single step.


Back to top
Profile WWW
Space Station Member
Space Station Member
User avatar
Joined: Mon Nov 29, 2004 1:04 pm
Posts: 254
Location: Norway
Post    Posted on: Sun Mar 02, 2008 11:37 pm
Andy Hill wrote:
No one told me about a magic switch somewhere (it was probably mentioned in the Harry Potter version of the workshop manual, have you a copy you can lend me?), I always assumed you needed a £100k of diagnostics equipment. :)

As for 5-6 hours tracking down a problem, very unlikely, I once changed a head gasket on a friend's Ford escort in my lunch hour. It would take me an hour just to remove all the bits around the engine so that I could access the head on my current Ford focus.


All you need is a paper clip - you don't need fancy £100k diagnostics equipment. Haynes manual will tell you that. On OBD1 connectors, you short pin A and B and the engine check light will give you the error code, not sure on the pins on OBD2, but think it's the same.

I fix cars myself as a hobby, so I know it can be easy, if the error is obvious. If it's not - like it is on mine right now with a small hole in one of the vacuum tubes - you have to spend time or money to figure it out. Lucky me though, I had a paper clip available :)


And yes, your focus has an OBD2 connector :)


Back to top
Profile ICQ
Moderator
Moderator
avatar
Joined: Mon Feb 09, 2004 4:01 am
Posts: 747
Location: New Zealand
Post    Posted on: Mon Mar 03, 2008 7:41 am
An Integrated health management system is one of the easiest upgrades you can make. Its good to know what actually exploded and where.

On Apollo 13 they weren't even sure something had gone seriously wrong till the dude noticed the view in the mirror.

_________________
What goes up better doggone well stay up! - Morgan Gravitronics, Company Slogan.


Back to top
Profile ICQ YIM
Space Station Member
Space Station Member
avatar
Joined: Thu Jan 27, 2005 12:34 am
Posts: 450
Post    Posted on: Mon Mar 03, 2008 7:14 pm
Ekkehard Augustin wrote:
Hello, Horus,

to your last point I can't agree that way. If the orbiter is reusable and if the suborbital stages are NOT reusable then this still is more economical than if even teh orbiter would be expendable.

Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


Of course anything you can bring back has some value and can save money – IF BRINGING IT BACK IS FREE! At a modest $5000/pound cost to orbit payload, if the “capsuleâ€


Back to top
Profile WWW
Space Station Commander
Space Station Commander
User avatar
Joined: Wed Aug 18, 2004 8:47 am
Posts: 521
Location: Science Park, Cambridge, UK
Post    Posted on: Tue Mar 04, 2008 1:06 pm
Prime example of overly complex car? Anything by Renault. What a PITA those things are.

As to engine management systems, I'll tell you a story...

I race cars as a hobby, very simple ones with Xflow (Escort) engines. These are very simply to fix etc, and I have some experience doing it (I also make kits cars). So I am not unfamiliar with cars and engines in general.

However, I have a Honda Civic and the engine light came on and I was getting a ocasional shuddering from the engine. So, I purchased a diagnostic device (OBDII or whatever) to read the code - no easy way to do it unlike my previous car which flashed its engine light. The diagnostic code indicated a problem with the VTEC system. Oh S**t I think - that sounds expensive.

So, I google around for more infromation on this and its appears to be caused by a fault in the VTEC hydraulic system. Sounding worse and worse. Then I find a post from someone somewhere saying this is usually caused by a lack of activation oil getting to the VTEC system.

Low and behold. I check the oil. The engines practically empty. Fill it up, clear the error code, problem goes away.

This to me is a great example of an overcomplicated system. Why could the oil light not just light up????????? It was because the engine managment light came on that I thought there was something much more badly wrong with the car than there actually was. Goodness knows what I would have been charged at a garage, who would probably have replaced the VTEC control unit BECAUSE THATS WHAT THE ERROR CODE SAID.

James 'Much chagrined as my incompetance'


Back to top
Profile
Moderator
Moderator
avatar
Joined: Mon Feb 09, 2004 4:01 am
Posts: 747
Location: New Zealand
Post    Posted on: Tue Mar 04, 2008 1:48 pm
That is a poor Management system. Obviously the Oil levels should have indicated first, or at least at the same time. Also you have the ability to visually inspect the dip stick.

Having to 'visually' inspect things is why the shuttle has to be pulled to pieces all the time.

_________________
What goes up better doggone well stay up! - Morgan Gravitronics, Company Slogan.


Back to top
Profile ICQ YIM
Moon Mission Member
Moon Mission Member
User avatar
Joined: Mon Nov 01, 2004 6:15 pm
Posts: 1233
Location: London, England
Post    Posted on: Tue Mar 04, 2008 2:05 pm
This was one of my points about over complication, why not just have something simple?

PS I have used a paper clip to make a light flash on the dashboard and then the internet to interpret what the code meant but this all took a few hours and required access to a computer (bit difficult if stuck in the middle of nowhere which luckily I wasn't at the time).

_________________
A journey of a thousand miles begins with a single step.


Back to top
Profile WWW
Space Station Member
Space Station Member
User avatar
Joined: Mon Nov 29, 2004 1:04 pm
Posts: 254
Location: Norway
Post    Posted on: Tue Mar 04, 2008 4:35 pm
Andy Hill wrote:
This was one of my points about over complication, why not just have something simple?

Why are we not still using T-Fords?


Back to top
Profile ICQ
Launch Director
Launch Director
avatar
Joined: Tue Feb 19, 2008 7:02 pm
Posts: 19
Post    Posted on: Tue Mar 04, 2008 7:02 pm
I think this is a semantic problem. "Simple" is not what we want. "Good" is what we want. And "complex" is being used here with the meaning "excessive and wasteful".

We can all find as many stories of individual designs that are either good or bad on both ends of the complexity spectrum. Here's one: an old MG roadster is simpler than a Lexus. Yet, the MGs I have worked with (only 2, mind you) were neither safer nor more reliable.

Shuttle tiles do not fall off because they are complicated. They fall off because the materials don't stick. Simple. Dangerous.

So the question of "How simple can man-rated be?" is perhaps better phrased "what is the minimum feature set for safe human orbital launch". And then we can start to argue about whether a launch abort system is required for "safety", and whether or not we have all turned into sissies who are afraid to take risks (handlebars on an SRB, anyone?). It all comes down to what you want the system to do. Once that is decided the engineers can go to work.

2.71


Back to top
Profile
Space Station Member
Space Station Member
User avatar
Joined: Mon Aug 16, 2004 7:09 pm
Posts: 485
Location: Maastricht, The Netherlands
Post    Posted on: Tue Mar 04, 2008 9:07 pm
It's only a semantic problem when you don't know what is meant or if you're a lawyer ;)

But yes, your phrase is more specific.

But the engineers aren't stupid. If you could design a [insert name of product which requires regular or extensive maintenance] so much better then it currently is, you are making yourself obsolete.

Just this week, or last week, i read an article that legislators were happy to save most of the jobs in one of the nasa centers. So, for NASA, the only reason they are still a 'player' in space is because they have a ridiculous a mount of money and workforce to do random stuff.


Back to top
Profile
Space Station Member
Space Station Member
User avatar
Joined: Mon Nov 29, 2004 1:04 pm
Posts: 254
Location: Norway
Post    Posted on: Wed Mar 05, 2008 8:07 am
Stefan Sigwarth wrote:
So, for NASA, the only reason they are still a 'player' in space is because they have a ridiculous a mount of money and workforce to do random stuff.


Which is why it's called an agency and not a corporation


Back to top
Profile ICQ
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 42 posts ] 
 

Who is online 

Users browsing this forum: No registered users and 19 guests


cron
© 2014 The International Space Fellowship, developed by Gabitasoft Interactive. All Rights Reserved.  Privacy Policy | Terms of Use