Virgin Galactic spaceship crash

[ollypenrice]

But what is 'nonsensical' to one person is fun for another.

My work colleagues think I am nuts because I sit freezing my behind off for hour after hour in the dark gathering data that I could improve on by a thousand fold in 10 mins off the internet!!!! 

Surely it's about perception ??

No, I think my point was about reality. Some ideas are naive. Bryson describes architectural plans for skyscraper rooftop airports and airship mooring masts, for instance. These ignored the simple fact of risk which cannot be eliminated. It is not a good idea to have aircraft approaching skyscrapers at all, ever, let alone trying to land on them. It can be done. But is it ever going to be a good idea? I think that one thing we have learned is that things go wrong and always will go wrong.  It's worth considering how severe are the losses in military fast jet flying. They are very severe. Can Richard Branson seriously expect to transform the military fast jet casualty rate into something acceptable in a commercial 'airline?' A friend was a fast jet pilot. He tells me he went to many funerals...

Olly

[stash_old]

I don't  know why there is all this "dislike" towards Branson/Virgin. As a businessman/business he/it is no worse than many and better then a lot.

As an adventurer he has some balls  - remember his balloon trip that nearly ended in disaster.

Maybe its jealousy -  I guess some here are jealous of others here with lots of very expensive kit which they will never afford but that is just how the cookie crumbles.

Give the guy a break he has earned it .

Hope his project goes from strength to strength as it seems there are some here are willing him to fail.

I remember the Comet it was hailed as safe but square windows killed that one - All other plane makers learned from that at the Comet's (and the UK air industry's) expense.

As for people who don't like risk - don't take any (like me  ) but I am glad there are some who push boundaries.

[ollypenrice]

Personally I don't dislike either Virgin in general or Branson. Rather the opposite. I generally like both, but this project is different and I can't say I like it.

Ollyu

[Zakalwe]

 It's worth considering how severe are the losses in military fast jet flying. They are very severe. Can Richard Branson seriously expect to transform the military fast jet casualty rate into something acceptable in a commercial 'airline?' A friend was a fast jet pilot. He tells me he went to many funerals...

Olly

I'm not sure that analogy would stand too much inspection, to be honest. Military fast jet flying is very different to a high altitude sub-orbital slingshot.

Plus, the fatal causality numbers, caused by accident, are remarkably low (49 deaths in the RAF for the whole 1990s). It's a fairly small community though, so any death or accident will be known to pretty much anyone in the Service.

Your point about the environmental impact is very valid though, especially as the commercial gains seem limited to space tourism (I'm aware of some small-beer contracts that exist between NASA and Virgin. These are small enough to be ignored though). VG states that they are pretty low (here). I suppose, there's a heck of a lot more CO2 pumped out by a handful of billionaire's yachts in a month than VG will use in a year. Abramovich's yacht burns fuel at a rate of $3000 per hour..... :eek:

[Kropster]

Sounds like another layer of 'fail-safe' is needed on the feathering mechanism to stop it being unlocked at inappropriate times...or leave it to a computer....as in modern airliners.

[jamespels]

Sounds like another layer of 'fail-safe' is needed on the feathering mechanism to stop it being unlocked at inappropriate times...or leave it to a computer....as in modern airliners.

Indeed - least I was more right than the "experts" rolled out by the weekend press blethering on about safety warnings being ignored and how a rocket explosion was inevitable... I have no idea what control mechanisms are in place but it was clearly a control issue of some description.

Olly: not sure the analogy with fast jet pilots really holds out, tbh - the flight envelope is very different and the fighter jocks spend a lot of their time at high speed and low level "evading the enemy" - this is a scenario that gives you very little time when things go wrong and I think the RAF do well to keep the accident rate as low as it is. SS2 is pushing boundaries but it is not operating at pressure or stress regimes that are particularly high - a fighter manoeuvring at Mach 1 near sea level will potentially be under much higher stress - and it has a very limited flight profile so the number of different ways it can fail are also fewer. I am definitely not saying it is low risk - it clearly is not - but the risks can be fairly well understood and mitigated.

Coming back to what we get out of it, SS1 had proven a concept; SS2 is commercialising it. The step from SS2 to low orbit is not THAT great and, if they achieve that, they have got to orbit and can start commercialising true space. True exploration of space will need to be commercially viable to ever get anywhere beyond a handful of state-sponsored research probes (remarkable as Curiosity, Cassini, James Webb and others appear now). Coming back to an earlier point, if the uber-rich want to help find technological development, that's fine by me.

[Zakalwe]

The step from sub - orbital to orbit is massive. A sub - orbital flight only needs something like 4% of the energy that's needed to achieve orbital velocity.It really is an order of magnitude harder, which is why so few have achieved it.

Personally, I think that SpaceX are the ones to watch. Yes, they are getting access to a lot of NASA money AND skills, but what they are achieving is really impressive.

[Paul M]

I always thought it was a bit fantastical to call this a spacecraft.

It barely skiped through the top of the atmosphere and wasn't intended to atain orbit.

The temporary weightlessness is just as can be experienced onboard one of NASA's conventional training aicraft on parabolic flightpaths.

I just don't get it.

But then, I never "got" the spaceshuttle.

Just think what could have been done with the money that they wasted on the shuttle...

Sent from my HTC One using Tapatalk

[jamespels]

The step from sub - orbital to orbit is massive. A sub - orbital flight only needs something like 4% of the energy that's needed to achieve orbital velocity.It really is an order of magnitude harder, which is why so few have achieved it.

I always thought it was a bit fantastical to call this a spacecraft.

Agreed on both counts - it barely makes it into space. BUT, think about what this means:

1. There is a two-stage launch system capable of getting to the edge of space.

2. SS2 is space-rated, i.e. it operates in an effective vacuum and has a pressurised hull

3. SS2 is (will be) human rated, i.e. it has life support

From a technological point, this is a lot of the way there and is what I meant. Two obvious challenges remain:

1. The energy difference: over-simplifying, this is really just a case of "more fuel / bigger rocket". The rocket fundamentals appear to work well and I really, really, like the idea of a solid fuel motor that you pump oxidant into to make it burn - this all but prevents the fuel and oxidant mixing explosively - you can still get problems with the oxidant and pumps but the size of bang is much smaller than you get with a stack of liquid fuel and oxidant in the same hull. At a conceptual level, carry more fuel & oxidant, pump the oxidant faster and you can get SS3 / 4 / 5 into orbit. Think of SS2 as a proof of concept rather than the end product.

2. Re-entry: the one bit that is not covered by the SS2 design. As it is, SS2 effectively starts at zero speed so the feathering system is there to keep it stable rather than bleed of the energy of orbit. Not sure how this will be handled but I would bet good money that Branson and Scaled Composites have been working on this for some time, whatever they tell the press.

I say again, I think this system is a valuable contribution to space science. Virgin have also taken a very pragmatic baby-steps approach so they can cover one challenge at a time. To me, this is almost the ideal way to handle innovative engineering and the fact they have not gone all-out is hugely positive in my view. In all of this, I hugely respect Branson but am pretty neutral about him and Virgin in terms of like / dislike. What I am hugely in favour of is people trying something new and taking a pragmatic approach to achieving it. The fact they can cover some of their costs by giving rich people a taste of space on an intermediary step is just a sign of Branson's marketing genius and makes the overall venture even more viable.

Regarding Space-X: huge credit to them, too. They have substantially reduced the cost-to-orbit but lets not forget that conceptually Falcon is little different from Atlas / Apollo / Ariane / Soyuz and even the Shuttle launch system. As such, they have a relative wealth of experience and knowledge to draw on - Virgin, by comparison, are trying something very different and need to work it out as they go.

Think I am well over my 2p by now...