9/29 2017 IAC - Elon: Interplanetary Plans Pt. 2

[e-FTW]

I'm wondering about sound and I don't see a solution in the context of going point to point on the earth. I love the idea and I wish we could find something. The problem as I see it is that if the rocket is only as loud as F9 (I expect it to be a lot louder), where exactly will the spaceports be sited. The toy video showed people hopping on a boat and riding out to sea to a platform. Is 20 miles far enough out to sea from New York, or are you really going more like 50 to 100 miles?

If an early network included something like:
- LA
- New York (somewhere eastern seaboard)
- Tokyo
- China
- Europe western seaboard (France / Germany)
- Australia
- India

Easy enough to think of more, but start with these, with a flight leaving from each to the others 1/day. That means that wherever you site the US eastern seaboard spaceport, you've got a big racket being made over a big area 2x per departure, and 1x per arrival. Space coast launches are a big deal and a big hit when they happen 1-4 times/month. Make it 10-20 times per day, and it'll stop being sexy and cool really fast, and instead be a constant source of noise pollution.

How far out to sea do you need to move to lower the sonic booms plus engine noise to at most "distant thunder"? Up thread, somebody said launches are audible in Orlando - google maps tells me it's 55 miles from Cape Canaveral to Orlando.

Oh - and some of those flights will need to depart after dark, or arrive after dark. I just assume that's a snap for the software - that'll be a problem for people trying to sleep.


Anyway - the physics of the sonic booms going and coming, the sound of the rocket taking off and the lesser sound of the rocket slowing down to land. Does a slower take off lower the sound and help keep the neighbors happy to have a spaceport in their back yard?

Anyway - I can see how this works for lots of other reasons already mentioned. I remain dubious (today) that anything serious / commercial will come of this until I hear how at least 2 sites can be situated that mitigates the noise pollution adequately and results in neighbors that want a spaceport nearby.

I figure that LA / New York run is popular enough for a back and forth each day, and maybe 2 (morning and night), creating the ability for some people to day trip back and forth.

Until the sound problem is solved in a clear way, I don't yet see this as a serious source of revenue to fund BFR development and building.

Agreed on sound pollution. See Concorde over continental US (never happened, which helped kill that business).
Also, you have current limitations around rockets flying over populated areas: we don't allow it, or at least rarely do.

 

[ecarfan]

To add to the city-to-city drawbacks, I’ll say that the 30 minutes travel time is solely time in flight. It wouldn’t include the ferry ride, boarding, the inevitable (and potentially very long) launch delays, etc. Still I imagine a huge time savings but not “I’m headed to Shanghai, I’ll be back for dinner.”

Agreed that there is of course much more to long distance travel times than the actual flight, but that is true for planes as well. And planes can also be delayed: 6 days ago coming back from Honolulu my flight was delayed for 6 hours for no reason I could determine. It certainly wasn't weather-related.

As @dhanson865 noted, boarding the BFR may in fact be easier in some ways! There certainly will not be any time spent fighting for space in the overhead bins.

More seriously, there will be some medical requirements involved in taking the BFR. Due to the G forces involved, I would think that the very elderly and the very young would not be qualified for the trip. And that will also reduce boarding times!

 

[e-FTW]

Loved the way Elon tried pulling a Steve Jobs and presented city-to-city as "one more thing". Shorter city-to-city travel times are touted as the primary benefit of flying BFR versus the airlines, but there are other, notable selling points:

1. No weather (other than space weather, a potential roadblock at times) at suborbital altitudes. Therefore, no turbulence. Even during the ascent and descent phases through the atmosphere, I'm guessing that passenger comfort will be less affected by weather conditions than on airplane flights.

2. Killer views. Who needs suborbital "space tourist" flights when you can travel with SpaceX on your next overseas trip? I wonder what Sir Richard Branson (Virgin Galactic) is thinking right now. Views will depend on seating configuration, but I'm guessing that every passenger will have at least a sliver of a view.

3. Experience zero gravity. This won't be a selling point for everyone, but many will enjoy being weightless for long enough to savor the experience, and not long enough to have to worry about going to the bathroom or trying to eat.

You do have to account for the G-load that passenger will experience on the way up and down. Not sure this will be comfortable for everyone. People get car-sick today, not to mention when they’re flying. We don't take 5G's like astronauts can...
Then we get to zero-G, where even astronauts get, um, uncomfortable. Even for a short period of time, like in those zero-G experience flights you can get on today, things can get dicey for your breakfast.
I still want in though! Where can I get in line?

 

[ItsNotAboutTheMoney]

To add to the city-to-city drawbacks, I’ll say that the 30 minutes travel time is solely time in flight. It wouldn’t include the ferry ride, boarding, the inevitable (and potentially very long) launch delays, etc. Still I imagine a huge time savings but not “I’m headed to Shanghai, I’ll be back for dinner.”

Right. However, there are two _really_ unpleasant bits to flying:
(1) Security
(2) Airplane seats

But again, this is Elon Musk selling a dream to generate excitement, when the real meat is in the "mundane" benefits of the technology that would dramatically improve access to space.

 

[ecarfan]

No weather (other than space weather, a potential roadblock at times) at suborbital altitudes. Therefore, no turbulence. Even during the ascent and descent phases through the atmosphere, I'm guessing that passenger comfort will be less affected by weather conditions than on airplane flights.

While Elon was obviously technically correct, I think he was skirting the issue of launch and landing stresses on the human body. Very few people (including me) have ever experienced more than 2Gs. BFR liftoff and landing Gs will be significantly greater than that, and the vibration of the rocket engines will be very noticeable I would assume. It will be unlike any commercial jet experience.

Killer views. Who needs suborbital "space tourist" flights when you can travel with SpaceX on your next overseas trip? I wonder what Sir Richard Branson (Virgin Galactic) is thinking right now. Views will depend on seating configuration, but I'm guessing that every passenger will have at least a sliver of a view.

I agree. What Virgin and Blue Origin are planning for space tourism seems pathetic compared to the experience of taking a BFR from say San Francisco to Hong Kong and, if Elon is to be believe, the BFR will be well over an order of magnitude less expensive

Experience zero gravity.

Considering that all BFR flights that Elon described are under an hour, and many no more than half an hour, passengers will not be allowed to float around the cabin. It would be impossible to ensure that they were all securely buckled into their seats for the landing.

I can imagine a seat design where the belts would automatically loosen slightly for several minutes mid-flight so that one could experience zero-G in a limited way. Which would be super cool.

Although I was thrilled to learn from Elon's presentation that the Mars mission remains on track, that he has no plans to use SpaceX resources to go to the moon, and that the "aspirational" goal is first Mars landing in 2022 and first humans on Mars in 2024, I honestly was just as thrilled to learn that in my lifetime I might be able to buy a ticket on the BFR and fly to space myself!

Realistically (if that word can be used here) I doubt that the Earth-to-Earth BFR flights will start happening before 2027: building the ships, testing repeatedly for high reliability and reusability, building the "spaceports", overcoming regulatory hurdles, that is all going to take many years while SpaceX has to stay focused on the Mars missions. But I think there is a significant chance that they will in fact happen and be successfull.

In fact I can envision a few years from now that a "SpaceX Commercial" division being formed, with private funding, just to do Earth-to-Earth BFR flights. I think there are a lot of investors who would want to be part of that. The clear potential is there to revolutionize the long distance commercial flight business.

 

[ecarfan]

Imagining how the "spaceport" ASDS platforms will be designed is an interesting theoretical exercise.

I don't see how the launching and landing rocket exhaust is going to be handled. It will have to be vented away from the platform and into the air. The forces exerted on the platform will be huge. The exhaust can't destabilize or move the platform around.

 

[N5329K]

Thousands of people fly on trans-oceanic flights every single day.
True. Though the operating costs and characteristics of ultra-large capacity aircraft have proven to be less than popular with airlines. Airbus is struggling to keep the A 380 line going as mid-sized, point-to-point twin jets take up more and more market share...even on long haul routes. This indicates a very strong sensitivity to operating expenses, and it's difficult to imagine how any BFR would not have BF Operating Expenses, Elon's rosy scenarios notwithstanding. And are major cities (some of which are planning to ban diesels soon) really going to be OK with plumes of smoke from multiple launches?
The demand for long distance air travel is enormous.
Also true. So long as it's cheap, people will fly. The BFR, though, would carry what? 100 passengers? Say they are asked to pay Business Class (forget Economy...the BFR is not the cheap seats) from New York to Shanghai. That's about $10,000 right now. So $10 million revenue per full-cabin flight. Can the BFR really fuel, launch, fly, land, and turnaround for less than that? Remember, the Falcon 9 costs $65 million per launch.
It will only increase if the flight time is decreased by over an order of magnitude.
That's an opinion and one worth arguing, but I think it might be wishful thinking. Load factors on jets depend on a fuzzy Venn diagram made up of convenience, price and safety (perceived and real). There may (may) be a case for providing ultra-fast point to point travel for a select and very wealthy few (and for those who want to join the 50-Mile-High Club while weightless), but if you don't own a megayacht I don't see an intercontinental BFR flight in your future.
Despite the internet and advances in virtual reality, the fact remains that humans like to go places and directly experience other environments and directly interact with other people. That isn't going to change any time soon.
Also true. But the economics will dictate how you choose to get there. There are always a few aerospace innovators working on a supersonic business jet (intended for the Masters of the Universe who now float around in their Gulfstreams, not the masses). Not one has made it far from paper airplane status.
Robin

 

[RubberToe]

 

[Chet]

And how many homeless and disadvantaged could be helped and/or rescued with the billions of dollars frittered away in space?

 

[RubberToe]

And how many homeless and disadvantaged could be helped and/or rescued with the billions of dollars frittered away in space?

Good point Chet...

1. Useless weather satellites, for example, Hurricane is going to hit anyway, right?
2. Useless GPS satellites, maps worked fine for centuries, good enough for Grandpa, eh?
3. Military communications, no need for rapid global satcom, wars going to drag on no matter what, right?
4. I don't believe that Elon or anyone else in the world was ever inspired by seeing men walking on the moon, I sure wasn't.

Lets see, am I missing any other ways all that space investment is useless?

RT

 

[AudubonB]

"...and ends..."

 

[Mike1080i]

And how many homeless and disadvantaged could be helped and/or rescued with the billions of dollars frittered away in space?

Currently there's nobody in space to take that money. So far, every dollar spent on spaceflight has been right here on Earth keeping people gainfully employed and supporting their families.

 

[ecarfan]

Hmm...when you quote me, I suggest you use the "QUOTE" function so that readers will know who you are quoting.

Thousands of people fly on trans-oceanic flights every single day.
True. Though the operating costs and characteristics of ultra-large capacity aircraft have proven to be less than popular with airlines. Airbus is struggling to keep the A 380 line going as mid-sized, point-to-point twin jets take up more and more market share...even on long haul routes. This indicates a very strong sensitivity to operating expenses, and it's difficult to imagine how any BFR would not have BF Operating Expenses, Elon's rosy scenarios notwithstanding. And are major cities (some of which are planning to ban diesels soon) really going to be OK with plumes of smoke from multiple launches?
The demand for long distance air travel is enormous.
Also true. So long as it's cheap, people will fly. The BFR, though, would carry what? 100 passengers? Say they are asked to pay Business Class (forget Economy...the BFR is not the cheap seats) from New York to Shanghai. That's about $10,000 right now. So $10 million revenue per full-cabin flight. Can the BFR really fuel, launch, fly, land, and turnaround for less than that? Remember, the Falcon 9 costs $65 million per launch.
It will only increase if the flight time is decreased by over an order of magnitude.
That's an opinion and one worth arguing, but I think it might be wishful thinking. Load factors on jets depend on a fuzzy Venn diagram made up of convenience, price and safety (perceived and real). There may (may) be a case for providing ultra-fast point to point travel for a select and very wealthy few (and for those who want to join the 50-Mile-High Club while weightless), but if you don't own a megayacht I don't see an intercontinental BFR flight in your future.
Despite the internet and advances in virtual reality, the fact remains that humans like to go places and directly experience other environments and directly interact with other people. That isn't going to change any time soon.
Also true. But the economics will dictate how you choose to get there. There are always a few aerospace innovators working on a supersonic business jet (intended for the Masters of the Universe who now float around in their Gulfstreams, not the masses). Not one has made it far from paper airplane status.
Robin

Yes, the economics certainly determine how you travel. Note that Elon claimed in a post-conference tweet that the BFR price of the New York to Shanghai trip will be about the same as "full fare Economy class". If that is true, demand will be huge. If he is off by even 100%, demand will be huge. If he is off by an order of magnitude, demand will be more modest.

As for how many passengers the BFR will carry in "Earth transport" configuration, you need to pay more attention to what Elon said in his presentation. He stated that in Mars transport configuration it will carry about 100 passengers and conceivably up to about 250. In an Earth transport configuration, given that the BFR pressurized volume is roughly equal to an Airbus A380 which can carry over 500 passengers in full Economy configuration, the BFR will carry even more than that because it likely won't have bathroom, galleys, or overhead luggage bins. So you might want to recalculate your predictions...

 

[Ben W]

And are major cities (some of which are planning to ban diesels soon) really going to be OK with plumes of smoke from multiple launches?

Methalox does not generate smoke or particulates, just CO2 and water vapor. So it is far cleaner than jet exhaust or car exhaust. And as pointed out, it can be generated renewably using nothing but air, water and electricity.

The BFR, though, would carry what? 100 passengers? Say they are asked to pay Business Class (forget Economy...the BFR is not the cheap seats) from New York to Shanghai. That's about $10,000 right now. So $10 million revenue per full-cabin flight. Can the BFR really fuel, launch, fly, land, and turnaround for less than that? Remember, the Falcon 9 costs $65 million per launch.

This math is off; 100 people at $10k each would be $1 million, not $10 million. But as pointed out, the cabin will be able to hold more like 500 people, so at $10k each that would still be $5 million revenue per launch. The cost of fuel per launch is only about $200k, and if the ~ $100 million to build each rocket is amortized across 100 launches ($1m / launch), there's plenty of room for profit.[/QUOTE]

 

[Ben W]

Imagining how the "spaceport" ASDS platforms will be designed is an interesting theoretical exercise.

I don't see how the launching and landing rocket exhaust is going to be handled. It will have to be vented away from the platform and into the air. The forces exerted on the platform will be huge. The exhaust can't destabilize or move the platform around.

I would imagine that the ocean-based launch/landing platforms might be fixed in place, like an oil rig, and have Hyperloop-like tunnels connecting them to the mainland for quick access (much faster than ferries). That would also allow them to be further away, to alleviate noise / safety concerns. Note that the force of the rocket exhaust at launch is only about 125% the weight of the rocket, so it's not much more force than just the rocket sitting there. And the landing thrust is only a tiny fraction of the launch thrust.

 

[N5329K]

Thanks for the math correction. This is what happens when you try to give up coffee. As for the rest, it will be very interesting to see how, or if, it all pans out. As for predictions, I don't mean to make them. Just voice concerns and doubts.
Speaking of doubts, the operational requirements for a scheduled "air" service are extensive:
Air Carrier and Air Agency Certification
Here's one prediction, though: BFR flights to Mars will seem routine before the FAA approves regularly scheduled, passenger revenue generating BFR sub-orbital flights.
We ought to make bets.
Robin

 

[evp]

MMmmmmm......the miner in me says that when choosing between a deposit that is between 70,000 and 1 million or so times richer than the other deposit (polar solids vs. atmospheric gases), you have to do better - an awful lot better - than the above to convince me not to use the former.

It's all about mass and energy - how much to mine it, to transport it, to thaw it, separate out tailings. The mass of mining and transport equipment needs to be balanced against the mass of an air compressor. The mining equipment will have to be powered by something compact and mobile, or recharged at the fuel generator periodically. It will also need to have a human operator or high-grade A.I. to run it. An air compressor can be awfully stupid and still work. Granted, all these problems also apply to mining ice too.

Also - the other resource needed to create the rocket fuel is H2O, and the richest source on Mars for that also is going to be the polar deposits.

True. But then there's this recent discovery: A Fresh Look at Older Data Yields a Surprise Near the Martian Equator - SpaceRef
There are places near the equator that seem to have 10% ice by weight. Of course near the poles you can find 70% pure ice. http://phoenix.lpl.arizona.edu/images/Mars_Full_Planet_Water_Map.jpg

• the two other inputs also needed - TIME & ENERGY - are of sufficient quantity to permit the inefficient resource base to be utilized:
  • TIME: are recycle trip times more a function of Earth<-->Mars locations, OR are they a function of the time needed to create Mars-based fuels? The answer to that weighs heavily on choosing which of these diametrically different fuel-factory locations.

Agreed. Those are large fuel tanks to fill. Robert Zubrin proposes planting a self-contained 100kW nuclear reactor on the surface to keep the production rate high enough.

A 100kW solar facility would be massive. The four arrays on the ISS generate a little over 100kW in optimal conditions; Mars surface is less than optimal: 40% less irradiance, wind storms, dust obscuring the surfaces. The ISS panels are light-weight because they would only be unfurled in zero-gee, and never subject to wind loading. Even so, each of the four panels took a dedicated launch to orbit.

And, of course, solar powered mining in the Martian arctic circle would not work out -- complete darkness for half a Martian year (one earth year), and you go back in the spring to find CO2 ice coating everything.

• Is there a difference in Martian launching/landing as f(latitude)?
• If so, by how much and do the above factors counter those differences sufficiently to outweigh them?

Yes, it's a significant advantage to launch from the equator. Martian escape velocity is about 5 km/s, and rotational velocity at the equator is close to 10% of that.

By the by, "...need to be gaseous anyway..." is a non-issue. There's never a problem turning CO2 or H20 into the appropriate state.

Every bit of energy helps. The reactants need to be at 300-400C for the Sabatier reaction. Might as well let the sun warm your CO2 ice from -109C to maybe 0C at the equator.

 

[Ben W]

Yes, it's a significant advantage to launch from the equator. Martian escape velocity is about 5 km/s, and rotational velocity at the equator is close to 10% of that.

So you'd weigh about 1% less at the Martian equator than at its poles? Cool.

 

[SmartElectric]

Solar makes the most sense.
Send the infrastructure that you already know works in space, Solar.
Make sure it has the fewest moving parts, meaning, not a steam based turbine system.
There is no one there to fix stuck valves or plumbing, etc.
Weight of solar panel mounts can be dramatically reduced on Mars compared to hurricane force wind resistant structures used on Earth.

 

[abasile]

Solar makes the most sense.
Send the infrastructure that you already know works in space, Solar.
Make sure it has the fewest moving parts, meaning, not a steam based turbine system.
There is no one there to fix stuck valves or plumbing, etc.
Weight of solar panel mounts can be dramatically reduced on Mars compared to hurricane force wind resistant structures used on Earth.

Solar will be a part of the energy solution on Mars. However, solar PV isn't without issues there, as stated by evp. Because of gigantic dust storms and seasonal variation in insolation, plus the fact that peak insolation on Mars is about 590 watts per square meter versus about 1000 on Earth, PV will need to be supplemented with other energy sources. It may well be adequate for the production of fuel, however, since fuel can be produced as PV production allows and stored for later use.

It's widely assumed that nuclear reactors will be important on Mars. Even the Curiosity rover is nuclear powered!