Did anybody watch the SpaceX launch today?

[Bozo]

Waste of money and aload of bollox.

What a very boring response.

 

[SWP's back]

It isn't cheaper in fuel terms, full stop, end of discussion.

I never said it was cheaper (in terms of fuel costs alone) no wonder you want to end the discussion.

I said it’s cheaper using a rocket than plane and rocket.

Musk has famously stated at the National Press Club that the cost of propellant is only 0.3% the cost of the rocket, which yields about $200,000 for a $60m launch

So in reality, who really cares about saving 1/3 to 1/2 of the cost of fuel when it accounts for 0.3% of th cost of a launch?

 

[Chippy_boy]

I never said it was cheaper (in terms of fuel costs alone) no wonder you want to end the discussion.
I said it’s cheaper using a rocket than plane and rocket.

Well you shouldn't have corrected my original post with irrelevant commentary then.

May I remind you, Silver Surfer said:

"Unfortunately it will never be possible for a plane to do such a thing. It takes a massive amount of power and fuel to take something into space and straight up is the most efficient option. A plane strapped onto a rocket is a rocket so there is no point really in having a plane attached to it."

To which I replied saying that straight up is not the most efficient option, which is correct.

If you want to start talking about relative costs, then fine, but please don't try to tell me I was wrong about something which (a) I didn't say, (b) you know fuck all about and (c) is not wrong.

 

[el blue]

Well you shouldn't have corrected my original post with irrelevant commentary then.

May I remind you, Silver Surfer said:

"Unfortunately it will never be possible for a plane to do such a thing. It takes a massive amount of power and fuel to take something into space and straight up is the most efficient option. A plane strapped onto a rocket is a rocket so there is no point really in having a plane attached to it."

To which I replied saying that straight up is not the most efficient option, which is correct.

If you want to start talking about relative costs, then fine, but please don't try to tell me I was wrong about something which (a) I didn't say, (b) you know fuck all about and (c) is not wrong.

Haha quality.
"No further questions Your Honor"

 

[SWP's back]

Well you shouldn't have corrected my original post with irrelevant commentary then.

May I remind you, Silver Surfer said:

"Unfortunately it will never be possible for a plane to do such a thing. It takes a massive amount of power and fuel to take something into space and straight up is the most efficient option. A plane strapped onto a rocket is a rocket so there is no point really in having a plane attached to it."

To which I replied saying that straight up is not the most efficient option, which is correct.

If you want to start talking about relative costs, then fine, but please don't try to tell me I was wrong about something which (a) I didn't say, (b) you know fuck all about and (c) is not wrong.

Straight up is the most efficient option.

It may not be the most fuel efficient option but it is the most cost efficient option.

Seeing as the subject (that you commented on) was on the relative costs involved when comparing Space X vs the Shuttle then cost efficiency was what everyone else was discussing. You are the only one referring to fuel efficiency alone and as stated several times, the fuel costs account for around 0.3% of launch costs.

You also stated "Shoving a rocket up in the air is technically a lot more simple than flying half the way up and then taking off from there. I suspect that has something to do with it." - when it most likely hasn't. If it was cheaper then it would be the preferred option. The organisations involved aren't put off by technical difficulty are they, but by cost. Landing booster rockets back on the ground for re-use isn't simple technically but it saves a lot of money, hence Space X doing it. That's kind of the point.

So perhaps admit that a) you did say, b) don't assume that because of my job I am an idiot savant and incapable of understanding several fields, especially as I've not said anything factually incorrect and you know nothing of my understanding of the subject matter, the fact that you used to be a physicist has no bearing on that and c) it was wrong in the context as no one else was referring to fuel efficiency alone.

 

[idahoblues]

Being an old fart remember watching the moon landing at school as a kid and that yesterday got me just as excited thinking about the possibilities of what mankind will achieve in the future only question is whether I will be around to see it

Hey, you got to see City win the league...be content :)

 

[inbetween]

Well you shouldn't have corrected my original post with irrelevant commentary then.

May I remind you, Silver Surfer said:

"Unfortunately it will never be possible for a plane to do such a thing. It takes a massive amount of power and fuel to take something into space and straight up is the most efficient option. A plane strapped onto a rocket is a rocket so there is no point really in having a plane attached to it."

To which I replied saying that straight up is not the most efficient option, which is correct.

If you want to start talking about relative costs, then fine, but please don't try to tell me I was wrong about something which (a) I didn't say, (b) you know fuck all about and (c) is not wrong.

You are right - rockets are not at their most efficient going straight up nor can they even achieve orbit by doing so. If you go straight up then you are going straight against gravity which requires a greater amount of power for a given weight. So to move something straight up you need the most fuel burnt at the greatest rate and where you need more fuel you leave less room for chargeable weight like payload which makes things less cost efficient.

Food for thought on planes - Falcon Heavy can take up 64 tonnes into orbit with an apparent 5 million lbs of thrust. The best jet engine out there cannot even match 1% of that thrust plus it would stop functioning after getting 5% of the way there.

The quoted max payload for Falcon Heavy to get something to Mars despite its power is just shy of 17 tonnes..... The jet engine I quoted above weighs 8 tonnes alone...... Add the weight of a plane in and it kind of defeats the object of what is trying to be achieved because every single kg added seriously matters.

 

[bluethrunthru]

didn't watch but I have seen a number of Bond films so I guess I have it covered

 

[grunge]

the landing of the 2 side rockets... be warned its LOUD

 

[Chippy_boy]

You are right - rockets are not at their most efficient going straight up nor can they even achieve orbit by doing so. If you go straight up then you are going straight against gravity which requires a greater amount of power for a given weight. So to move something straight up you need the most fuel burnt at the greatest rate and where you need more fuel you leave less room for chargeable weight like payload which makes things less cost efficient.

Food for thought on planes - Falcon Heavy can take up 64 tonnes into orbit with an apparent 5 million lbs of thrust. The best jet engine out there cannot even match 1% of that thrust plus it would stop functioning after getting 5% of the way there.

The quoted max payload for Falcon Heavy to get something to Mars despite its power is just shy of 17 tonnes..... The jet engine I quoted above weighs 8 tonnes alone...... Add the weight of a plane in and it kind of defeats the object of what is trying to be achieved because every single kg added seriously matters.

In think perhaps you miss the point a bit?

With a conventional rocket, you need to accelerate not only the payload, but also the vehicle and the fuel. The fuel required to do this is enormous, and since you need an enormous amount of fuel, you need an even more enormous amount of fuel to accelerate all that fuel... if you get what I mean! Carrying the fuel is by far the biggest energy cost and the fuel makes up most of the weight of the rocket assembly.

But most of the fuel is needed to get up to half the required speed, since the rocket is heaviest at launch and as the fuel burns, it gets lighter and lighter. Nearing orbital velocity when most of the fuel has gone, the rocket is much much lighter and the final amount of fuel needed is not much at all.

So, if you were to fly the rocket half way up on the back of an aeroplane, you could eliminate the need for very much more than half the fuel. For example, the solid rocket boosters on the Shuttle carry 500 tons of fuel each, and yet get thrown away at (from memory) something like 120,000 feet. You could strap a rocket onto an aeroplane and carry it to 100,000 feet using a tiny fraction of that fuel. (Not that such an aeroplane exists, but we could build one.)

This is why horizontal take off and landing, reusable spacecraft is so appealing. Craft that can "fly" to perhaps 100,000 feet, and then engage the LO2 based rocket power from there. At that altitude, you don't need to carry much liquid oxygen (LOx) - only a tiny fraction of what you need if you start at ground level.

So why isn't everyone doing this? Simple. Because although engines that can run on air at low altitude and then switch to L0x at high altitude have been invented, not yet brought into commercial operation yet. There's still much work to be done. And the engineering required for such a vehicle is much more complex (read expensive) than the Elon Musk alternative, which to be honest, is not much more than a very big and fancy firework.

Today, the fuel cost is dwarfed by the enormous r&d and manufacturing costs of your typical unreusable rocket. Musk is bringing the cost down by making his rockets reusable. In future the fuel cost is going to be the biggest factor and vertical take off is not going to be how we do it.