Virgin Galactic safety
Discussion
As much as I admire Burt Rutan and his design for the Virgin spacecraft, I almost equally admire Virgin's ambition of truly pushing the boundaries for commercial travel. I can't help but wonder about the safety aspects though...I'm not an engineer in any way, and although they appear to have removed significant areas of risk there's still a couple of things that I'm curious about and wondered if anyone had any insight/more detailed knowledge on the topic.
- The feathering tail is a great idea in many respects. What happens if the feathering mechanism doesn't work at either stage? Does each side work independently of the other as well leaving the (probably catastrophic) possibility that only one side moves to the other position as it should?
- If something significant like the above happens, do they have any secondary safety/escape systems eg BRS chute? I know a BRS won't be much use in the outer regions but if the tail doesn't feather for the glide portion it could be a lifesaver there.
- The feathering tail is a great idea in many respects. What happens if the feathering mechanism doesn't work at either stage? Does each side work independently of the other as well leaving the (probably catastrophic) possibility that only one side moves to the other position as it should?
- If something significant like the above happens, do they have any secondary safety/escape systems eg BRS chute? I know a BRS won't be much use in the outer regions but if the tail doesn't feather for the glide portion it could be a lifesaver there.
I think that it's possible for it to land without - the speeds involved are much lower than for the shuttle, so the extreme heat is not encountered and therefore it's not so critical which bit of the ship is used to do the braking. I would guess it would pitch up a bit to increase drag, which would be rather uncomfortable for those involved.
Just as an aside I found this article from the tinfoil hat brigade which is rather amusing.
http://www.ghostnasa.com/posts2/073spacetourism.ht...
Just as an aside I found this article from the tinfoil hat brigade which is rather amusing.
http://www.ghostnasa.com/posts2/073spacetourism.ht...
davepoth said:
Just as an aside I found this article from the tinfoil hat brigade which is rather amusing.
http://www.ghostnasa.com/posts2/073spacetourism.ht...
Just - Wow! I admit I have only a basic understanding of the engineering problems involved in designing spacecraft, but even I can see the flaws in that article. He really has no idea what he is talking about, but points out the danger of problems that he thinks could exist, in a design not yet finalised, based on a few photos and mock-up publicity graphics. http://www.ghostnasa.com/posts2/073spacetourism.ht...
Have a look at the super safe roll-bar he has designed for another good example.
jmorgan said:
Careful, tinfoil hatters have the power of google.
I'd love for him to come onto this thread and explain how a handrail either side of the cockpit would have saved Felipe Massa from his injuries...eta - He could avoid a lot of "that was my idea" whining, if he took out a few patents.
OP - Sorry for the jack!
Edited by Silver Smudger on Saturday 26th February 16:45
It is a bit mad, isn't it?
Still, back on subject. They wouldn't build something that fancy onto the airframe unless it was fail safe - it'll have multiple redundancies. On the assumption that the ship can re-enter in the normal position, I imagine that there's a facility to disengage the hydraulics (or electrics or whatever) and let the force of the air put the wings back into position if they get stuck up.
Still, back on subject. They wouldn't build something that fancy onto the airframe unless it was fail safe - it'll have multiple redundancies. On the assumption that the ship can re-enter in the normal position, I imagine that there's a facility to disengage the hydraulics (or electrics or whatever) and let the force of the air put the wings back into position if they get stuck up.
Rantings of an paranoid idiot who doesn't understand the subject they are discussing.
1. On the subject of money, many of these huge aerospace companies are highly inefficient and waste huge sums, just because one companies budget is less than another's doesn't necessarily result in poorer work or less effort.
If you know the history of scaled composites, one of the key things they've attempted to promote to the US's that there isn't always a need to invest so much cash.
2. Pressure suits is a good argument, but a full space suit is not required, they are not doing space walks and I believe that is what is provided. All commercial airlines don't offer this method of safety, and most of the problems exist here at these altitudes, how is this any different?
3. They do receive training before taking the trip.
4. The flight crews for orbital craft undergo much higher stresses on the body than SS2, there will be limits of course, but this guys paranoia knows no bounds.
5. Yes Hybrid rocket motors can explode, but the context of his arguments are irrelevant, the challenger disaster was caused by gases escaping from a sectional solid rocket motor, cutting a hole in a hydrogen tank and igniting the contents, none of which are present on the SS2. A lot of testing occurs before the engine will ever see a ship.
6. Emergency systems and Failure Mode Event Analysis will have been covered, the FAA would never grant flight authorisation without this.
7. They are performing flight tests as we speak and there will be a gradual build up to commercial flight certification.
1. On the subject of money, many of these huge aerospace companies are highly inefficient and waste huge sums, just because one companies budget is less than another's doesn't necessarily result in poorer work or less effort.
If you know the history of scaled composites, one of the key things they've attempted to promote to the US's that there isn't always a need to invest so much cash.
2. Pressure suits is a good argument, but a full space suit is not required, they are not doing space walks and I believe that is what is provided. All commercial airlines don't offer this method of safety, and most of the problems exist here at these altitudes, how is this any different?
3. They do receive training before taking the trip.
4. The flight crews for orbital craft undergo much higher stresses on the body than SS2, there will be limits of course, but this guys paranoia knows no bounds.
5. Yes Hybrid rocket motors can explode, but the context of his arguments are irrelevant, the challenger disaster was caused by gases escaping from a sectional solid rocket motor, cutting a hole in a hydrogen tank and igniting the contents, none of which are present on the SS2. A lot of testing occurs before the engine will ever see a ship.
6. Emergency systems and Failure Mode Event Analysis will have been covered, the FAA would never grant flight authorisation without this.
7. They are performing flight tests as we speak and there will be a gradual build up to commercial flight certification.
Eric Mc said:
It doesn't "re-enter" in the same type of way as an orbiting spacecraft would, In reality, it just "falls down". from a great height. Because the speeds are under 4,000 mph, the heating on re-entry will be minimal.
And with that in mind I guess that they haven't had to massively shield the craft on one side to take all of that heat, making it able to survive (although at the expense of an uncomfortable ride) regardless of attitude when it hits the thick air.UVB said:
As much as I admire Burt Rutan and his design for the Virgin spacecraft, I almost equally admire Virgin's ambition of truly pushing the boundaries for commercial travel. I can't help but wonder about the safety aspects though...I'm not an engineer in any way, and although they appear to have removed significant areas of risk there's still a couple of things that I'm curious about and wondered if anyone had any insight/more detailed knowledge on the topic.
- The feathering tail is a great idea in many respects. What happens if the feathering mechanism doesn't work at either stage? Does each side work independently of the other as well leaving the (probably catastrophic) possibility that only one side moves to the other position as it should?
- If something significant like the above happens, do they have any secondary safety/escape systems eg BRS chute? I know a BRS won't be much use in the outer regions but if the tail doesn't feather for the glide portion it could be a lifesaver there.
If something doesn't work, you're dead - The feathering tail is a great idea in many respects. What happens if the feathering mechanism doesn't work at either stage? Does each side work independently of the other as well leaving the (probably catastrophic) possibility that only one side moves to the other position as it should?
- If something significant like the above happens, do they have any secondary safety/escape systems eg BRS chute? I know a BRS won't be much use in the outer regions but if the tail doesn't feather for the glide portion it could be a lifesaver there.
It's a spacecraft.
davepoth said:
Eric Mc said:
It doesn't "re-enter" in the same type of way as an orbiting spacecraft would, In reality, it just "falls down". from a great height. Because the speeds are under 4,000 mph, the heating on re-entry will be minimal.
And with that in mind I guess that they haven't had to massively shield the craft on one side to take all of that heat, making it able to survive (although at the expense of an uncomfortable ride) regardless of attitude when it hits the thick air.It is allowed to more or less fall back at it's own terminal velocity until denser air is encountered and the wings can start to work properly.
A de-orbiting spacecraft, such as a Shuttle or Soyuz hits the upper atmosphere at 17.500 mph.
The Apollo Command Module re-entered at 25,000 mph.
In those cases heating is a major issue and some sort of heat shield system is essential.
Eric Mc said:
Yes.
It is allowed to more or less fall back at it's own terminal velocity until denser air is encountered and the wings can start to work properly.
A de-orbiting spacecraft, such as a Shuttle or Soyuz hits the upper atmosphere at 17.500 mph.
The Apollo Command Module re-entered at 25,000 mph.
In those cases heating is a major issue and some sort of heat shield system is essential.
Safety is designed in. I'll put the tinfoil back in the cupboard. It is allowed to more or less fall back at it's own terminal velocity until denser air is encountered and the wings can start to work properly.
A de-orbiting spacecraft, such as a Shuttle or Soyuz hits the upper atmosphere at 17.500 mph.
The Apollo Command Module re-entered at 25,000 mph.
In those cases heating is a major issue and some sort of heat shield system is essential.
17.500 mph......... 
Apollo 10 holds the record I think from the moon shots? And a man has parachuted from a great height, a certain Mr Kittenger. A model plane has been flown to earth from a drop up hi. So, not wanting to be blasé about the risks, I think the drama that people associate with a full blown rocket launch and full blown disaster cloud the reality here?
It is a business venture so I would imagine that a bit of care has been taken or its a waste of money. I would also think that many engineers are alo looking at this and either blowing the whistle or silently thinking "damn, wish I had thought of that".
Edit, actually those engineers are probably thinking "damn, wish I had the backing"
Apollo 10 holds the record I think from the moon shots? And a man has parachuted from a great height, a certain Mr Kittenger. A model plane has been flown to earth from a drop up hi. So, not wanting to be blasé about the risks, I think the drama that people associate with a full blown rocket launch and full blown disaster cloud the reality here?
It is a business venture so I would imagine that a bit of care has been taken or its a waste of money. I would also think that many engineers are alo looking at this and either blowing the whistle or silently thinking "damn, wish I had thought of that".
Edit, actually those engineers are probably thinking "damn, wish I had the backing"
davepoth said:
I tried reading that article but the bold and colour made it read like having an argument with someone shouting very loudly and incoherently.
t how safe it is?Personally Im wondering what standards its been designed to.
Which alloys they are using.
Testing.
And all manner of other dull stuff.
Having just done the last of 3 prelim design reivews in a month for a spacecraft, unfortunately the really dull but important questions for lodged in my head...and my in-box as actions. Perhaps I should ring old Branson and ask him when his next Materials Parts Control Board is
Which alloys they are using.
Testing.
And all manner of other dull stuff.
Having just done the last of 3 prelim design reivews in a month for a spacecraft, unfortunately the really dull but important questions for lodged in my head...and my in-box as actions. Perhaps I should ring old Branson and ask him when his next Materials Parts Control Board is
annodomini2 said:
They have pictures from the future!Date error under pictures I assume? Taken in 2010
No point in in calling Branson, the IP in the SS1 & SS2 designs is jointly owned by Paul Allen's Vulcan Ventures & Scaled Composites. Virgin Galactic is paying royalties to Vulcan for the use of its intellectual property. The Microsoft founder bankrolled the Scaled Composites SS1 / X-Prize effort. I believe Jeff Bezos (Amazon) has a space programme of his own which is fairly interesting.
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