Discussion Earth: Space colonization a myth - ESA director.

[Urwumpe]

That's not the only factor. There's a reason we don't have supersonic passenger planes (anymore), for example: building and maintaining them is too expensive, an expense their advantages cannot justify, no matter how many of them we build. If these costs were significantly reduced, we would have supersonic passenger planes.

In comparison to other planes, thats the important difference. Today, the oil price is getting slowly back to the prime time of SSTs - but other planes still do the job better (despite the Concord being not that much a lossy product... just the combination of age with poor profitability made them deprecated)

You can't talk about markets by looking at a single product - without the alternatives, we would be loving nuclear power.

 

[Andy44]

IIRC the cost of propellant was not one of the major cost factors of STS, was it? I think it was the enormous cost of operating and servicing the vehicles between flights that drove the costs up, and the large employee payroll that came with it. Replacement parts for a space shuttle-type vehicle are expensive, too.

 

[Urwumpe]

IIRC the cost of propellant was not one of the major cost factors of STS, was it? I think it was the enormous cost of operating and servicing the vehicles between flights that drove the costs up, and the large employee payroll that came with it. Replacement parts for a space shuttle-type vehicle are expensive, too.

Exactly - it was a prototype, nothing was improved after gathering the first experiences with reuse, and so, the costs can only rise.

 

[C3PO]

That's not the only factor. There's a reason we don't have supersonic passenger planes (anymore), for example: building and maintaining them is too expensive, an expense their advantages cannot justify, no matter how many of them we build. If these costs were significantly reduced, we would have supersonic passenger planes. Any kind of reusable spacecraft is essentially facing the same conundrum. This problem could potentially be fixed by new manufacturing and material technologies (I kinda group them together, because new material technologies always require new manufacturing technologies if they are to be produced economically).

I don't completely agree with you on the demise of supersonic transport. IMHO it failed because the expected demand never materialized. There were only a few routes in regular service, and it was quicker to travel direct in a private/corporate jet if the departure or destination wasn't on a Concorde route and they can fly on their own schedule. Tourists chose cheap flights over quick flights because they could afford to travel longer or more often. This boosted volume and in turn opened more routes making it easier to get a direct flight to you destination. SST never generated enough business to fund new development and when the original design became uncompetitive there was no new design to pick up the baton.

Reusability is a way to lower costs, but so far it hasn't been very successful. SpaceX is having a stab at it but we have yet to see anything being reused in anything like a commercial aircraft manner. New materials and manufacturing will be required to get better efficiency. The key to low cost is efficiency and reusability may or may not be a part of that.

---------- Post added at 01:57 AM ---------- Previous post was at 01:35 AM ----------

IIRC the cost of propellant was not one of the major cost factors of STS, was it? I think it was the enormous cost of operating and servicing the vehicles between flights that drove the costs up, and the large employee payroll that came with it. Replacement parts for a space shuttle-type vehicle are expensive, too.

When STS was canned NASA looked at the possibility to extend flights by letting a private company continue running the programme. Ironically one of the measures to cut costs was to stop reusing the SRBs and make new ones for each flight. It was cheaper than to retrieve, refurbish and recertify them for flight. I guess that's one thing that KSP got spot on. :lol:

 

[n72.75]

breathable atmosphere

Have you been to LA?

 

[Unstung]

When STS was canned NASA looked at the possibility to extend flights by letting a private company continue running the programme. Ironically one of the measures to cut costs was to stop reusing the SRBs and make new ones for each flight. It was cheaper than to retrieve, refurbish and recertify them for flight. I guess that's one thing that KSP got spot on. :lol:

Huh, I didn't know this. IIRC, the SRBs on the SLS are designed to be expendable. That's confused me, but this must be the reason why. Surely there must be some rocket stages that must be worth saving instead of dumping them into the ocean. Hopefully we'll see how beneficial this is to SpaceX soon. Unlike the shuttle's rocket boosters, the Falcon 9's first stage is not split into several different parts that are reused in different combinations.

 

[jedidia]

that's pretty much the problem. Rocket parts are under so much stress that there is no easy reusability. They have a out the reusability of a cellphone you dumped in the river: Sure you can make them work again, but buying a new one is probably cheaper.

 

[Urwumpe]

that's pretty much the problem. Rocket parts are under so much stress that there is no easy reusability. They have a out the reusability of a cellphone you dumped in the river: Sure you can make them work again, but buying a new one is probably cheaper.

Exactly that, but thats an engineering problem - lower performance requirements would make it easier to create parts that can fly multiple times. If a rocket engine can for example be allowed to be two times heavier for the same thrust, you could have around 4-8 times the MTBT, simply because the high-stress components could be left away. A rocket chamber is not as much the problem as for example turbo-pump bearings, which wear out quickly and which are hard to replace.

The only real problem is: A few things in spaceflight are constant. You can't reduce gravity. Atmosphere does not just go away. You need to find new ways to deal with those old problems. Getting into LEO is the hardest part sadly, otherwise we would have a lot of other options available. If we could put the rocket into high atmosphere at high speed before leaving the launch infrastructure, a lot of the problems would be much simpler...

---------- Post added at 12:29 PM ---------- Previous post was at 12:22 PM ----------

Maybe one reason for colonizing Mars... we could move our spaceflight industry there and get rid of a few many problems related to Earth...

 

[fsci123]

If we wanted to get rid of the problems related to earth based launches, we could move our space flight industry to Leo or the moon or some nea.

 

[C3PO]

Maybe one reason for colonizing Mars... we could move our spaceflight industry there and get rid of a few many problems related to Earth...

That is IMHO exactly why high volumes in space travel could be possible in the future. The main problem is the price of launching heavy loads into LEO from Earth. If we could move manufacturing to another planetary body, getting it into LEO is actually much easier. Remember that although a thick atmosphere can bring all sorts of problems, it's actually a very good brake. Sure aerodynamic losses are a , but imagine if we had to land from LEO using only propulsion. The problem with Mars is that it has a competitor that's much closer to Earth, the Moon. It doesn't have a pesky thin atmosphere that actually makes real life Mars landings very difficult. And you are only 3 days away in an emergency.

The easiest thing to manufacture off-Earth is probably fuel because that's not that hard to automate. Now we can really talk reusability. It's much easier to build a reusable space craft if it doesn't have to launch or land on Earth. Sure space is a hostile environment, but not as hostile as launch or reentry. Once that is in place colonization of space doesn't look quite as impossible.

When I first went to sea good drinking water was a real problem on long trips. Now water purification systems are so common that you almost don't have to think about it. "Prediction is very difficult, especially if it's about the future." - Niels Bohr -

 

[Urwumpe]

And you are only 3 days away in an emergency.

Well - I believe that leaving the safety net behind is one important step in spaceflight. You can't always remain tethered to Earth.

 

[C3PO]

Well - I believe that leaving the safety net behind is one important step in spaceflight. You can't always remain tethered to Earth.

It sure is! But during the initial phase of constructing space infrastructure Earth will be the place you head for in an emergency. Eventually we will have "safe havens" off-Earth with the necessary equipment etc. to make a dash for the blue marble the 2'nd option.

 

[Andy44]

The problem with moving the space launch industry off the Earth is...that you have to move it OFF the Earth!

In order for it to get started you need to swallow a big fat bitter money pill and hope it works.

 

[Urwumpe]

The problem with moving the space launch industry off the Earth is...that you have to move it OFF the Earth!

In order for it to get started you need to swallow a big fat bitter money pill and hope it works.

Could still be cheaper than moving democracy to Iraq, don't you think?

 

[Andy44]

Could still be cheaper than moving democracy to Iraq, don't you think?

But to be serious, yes, you are correct. Trying to get the public to favor space exploration over killing foreign people they have never met is unfortunately very difficult, and takes us back to the beginning of the argument re. how to pay for it.

 

[Urwumpe]

Ba Dum Tss! - YouTube

But to be serious, yes, you are correct. Trying to get the public to favor space exploration over killing foreign people they have never met is unfortunately very difficult, and takes us back to the beginning of the argument re. how to pay for it.

Exactly - or much different: Who should pay this? Because obviously, we can afford it, if we just would be motivated for it.

 

[C3PO]

The problem with moving the space launch industry off the Earth is...that you have to move it OFF the Earth!

In order for it to get started you need to swallow a big fat bitter money pill and hope it works.

Cheap is relative. Is christmas cheap? NASA costs fewer $ than valentines day. Funding will be one of the biggest hurdles but it's not impossible.
Rocket science: Difficult
Rocket engineering: Harder
Rocket economics: Mayday!

We moved explorers all around the solar system without breaking the bank. Those explorers are different to the ones used to explore this planet, and I'm sure that an off-Earth fuel factory will be vastly different to the ones we use now. IIRC Mars society are doing experiments on making methane on Mars, and JPL on making LH/LO2 on the Moon.

We know quite a bit about LEO assembly already. We can launch the parts on unmanned launches, and send the crews up later. An added safety feature is that the craft the crew launched in can be used as a life boat. We could even use robotics to do most of the work. That's what the offshore oil industry has done for years now.

 

[BruceJohnJennerLawso]

That's not the only factor. There's a reason we don't have supersonic passenger planes (anymore), for example: building and maintaining them is too expensive, an expense their advantages cannot justify, no matter how many of them we build. If these costs were significantly reduced, we would have supersonic passenger planes. Any kind of reusable spacecraft is essentially facing the same conundrum. This problem could potentially be fixed by new manufacturing and material technologies (I kinda group them together, because new material technologies always require new manufacturing technologies if they are to be produced economically).

IIRC, the other issue with supersonic jet liners was that their original expected gains in fuel economy over subsonic evaporated once high-bypass turbofan jet engines entered service.

Damn those plucky engineers, going and finding a more-efficient, but less cool way of doing things :facts:

 

[statickid]

That's not the only factor. There's a reason we don't have supersonic passenger planes (anymore), for example: building and maintaining them is too expensive, an expense their advantages cannot justify, no matter how many of them we build. If these costs were significantly reduced, we would have supersonic passenger planes. Any kind of reusable spacecraft is essentially facing the same conundrum. This problem could potentially be fixed by new manufacturing and material technologies (I kinda group them together, because new material technologies always require new manufacturing technologies if they are to be produced economically).

An aircraft historian at uni once told me that in the main reason we don't have super sonic passenger flights are because sonic booms are pesky and cause property damage. This makes them illegal in many above land airspaces so it leaves supersonic flight to trans ocean flught. That's unfortunate though, because trans ocean flights typically carry more passengers, but super sonic jets aren't good at carrying lots of people since they are designed for speed and not capacity, similar to the way F-1 racers aren't shaped like school buses. It makes the seat cost higher, and the luxury you are buying is a shorter trip, but given the choice passengers prefer a roomy first class treatment to shaving hours off the flight. This limits the market further to people who are on a tight schedule (travel for business), but from a business standpoint teleconference easily trumps personnel travel. In short, sonic booms kill the market.

There are no doubt other contributing factors too, but I find this explanation definitely has strong legs to stand on.

 

[Urwumpe]

An aircraft historian at uni once told me that in the main reason we don't have super sonic passenger flights are because sonic booms are pesky and cause property damage. This makes them illegal in many above land airspaces so it leaves supersonic flight to trans ocean flught. That's unfortunate though, because trans ocean flights typically carry more passengers, but super sonic jets aren't good at carrying lots of people since they are designed for speed and not capacity, similar to the way F-1 racers aren't shaped like school buses. It makes the seat cost higher, and the luxury you are buying is a shorter trip, but given the choice passengers prefer a roomy first class treatment to shaving hours off the flight. This limits the market further to people who are on a tight schedule (travel for business), but from a business standpoint teleconference easily trumps personnel travel. In short, sonic booms kill the market.

There are no doubt other contributing factors too, but I find this explanation definitely has strong legs to stand on.

If you know how loud a sonic boom can be if a fighter near the netherlands, 250 km away passes the speed of sound... yeah... understandable.

(Story archived here, in German: http://archiv.raid-rush.ws/t-62032.html)