Is Space Exploration an Ego Trip or a Scientific Investment?

[sophiecentaur]

It only cares how much carbon it puts out.

As long as "puts out" includes all manufacturing, servicing and transport contributions. Choosing what and what not to include is advertisers' technique and not good Engineering.

FYI, we'll probably split this talk of the carbon footprint of space travel to its own thread...

That could be a good idea; go for it. However, along the same lines as Health and Safety matters, environment should at least have a presence in any discussion involving large amounts of energy.

 

[russ_watters]

As long as "puts out" includes all manufacturing, servicing and transport contributions. Choosing what and what not to include is advertisers' technique and not good Engineering.

I agree, lifecycle emissions include manufacturing/servicing, but with a really, really big caveat: most of those indirect (not from the fuel) lifecycle emissions are pass-through from other sectors; energy and transportation. So if you fix those sectors, the indirect emissions go way, way down.

And while I too would like to see the numbers, since a rocket by empty mass is mostly a flying fuel tank I would find it hard to believe manufacturing carbon emissions is a significant fraction like it is for a car. Cars are even unusual amongst vehicles in that they have a very low utilization rate, which makes the manufacturing emissions a larger fraction than other vehicle types.

 

[sophiecentaur]

Cars are even unusual amongst vehicles in that they have a very low utilization rate, which makes the manufacturing emissions a larger fraction than other vehicle types.

Indeed. Public transport is often a far more economical solution to people getting to work than driving themselves in a year old family car.

 

[Frabjous]

Indeed. Public transport is often a far more economical solution to people getting to work than driving themselves in a year old family car.

Depends on whether you include the value of time.

 

[russ_watters]

Indeed. Public transport is often a far more economical solution to people getting to work than driving themselves in a year old family car.

I don't mean [emissions] cost per passenger or ton-mile (yes, cars are the worst at that too), I mean hours of use per year or lifetime. Truck, ships, planes, and yes trains all are operated much more than a car. Google tells me a truck gets 2-3x the distance lifespan of a car. So, for example if manufacturing emissions is 20% of a car's lifecycle emissions it might be 7% of a truck's. I'd have to do some research (a quick google doesn't find this info), but I suspect that the manufacturing emissions are only very significant for a car, and aren't for any other major form of transportation - including a hypothetical re-usable rocket.

 

[sophiecentaur]

Depends on whether you include the value of time.

I lived a long time in Brighton UK. So much quicker to go almost anywhere there by bus and parking charges and delays were heavy. Quite the opposite where we live now in Essex. One bus per hour to get into Brentwood. So, as usual, the actual figures and circumstances count.

“Value of time” is worth discussing. The present situation in which people travel many miles to work is doing no one any favours. Lifestyle choice and the ability of society to change seem to be off the menu unfortunately.
I went from one hour + drive each way (plus holdups) to twenty minutes walking maximum, a local park and tree lined quiet roads. Lower pay though. No contest.