Four things SpaceX can do in 2017

[john smith 19]

If you use RP1, maybe. Not industrial methane and oxygen in bulk.

RP1 is not cheap relative to other hydrocarbons. I've no feel for bulk Methane pricing or what sort of mass we're talking about, although obviously in the 10s to 100s of tonnes.

[Robotbeat]

If you use RP1, maybe. Not industrial methane and oxygen in bulk.

RP1 is not cheap relative to other hydrocarbons. I've no feel for bulk Methane pricing or what sort of mass we're talking about, although obviously in the 10s to 100s of tonnes.

On the order of 100 tons of methane per person, 400 tons of O2.

[envy887]

If you use RP1, maybe. Not industrial methane and oxygen in bulk.

RP1 is not cheap relative to other hydrocarbons. I've no feel for bulk Methane pricing or what sort of mass we're talking about, although obviously in the 10s to 100s of tonnes.

Landing 1 loaded ITS on Mars will require roughly 50,000 tonnes of methalox. Methalox bulk cost is about $0.20 per kg, so that's $10M. Each passenger would have to contribute roughly $100k to pay for fuel if there are 100 per flight.

[meekGee]

I recognise that comsats are less exciting than Mars, uh, occupation.  But there is no business case for occupation.  Without profit it cannot scale.

Comsats have been shown to be profitable.  A LEO last-mile constellation addresses a growing trillion-dollar market, but has, so far, cost too much to deploy.

If SpaceX can drop the cost of a LEO constellation enough to make last-mile internet service cost effective, that will change them and the world utterly.  Apple is a nearly $200B/year company.  SpaceX can be a > $500B/year company.  The available profit will force them to hire hundreds of thousands of people.  They will end up in very high stakes negotiations with most countries.  The real estate of space will become vastly more valuable, and therefore there will be more struggle to control it, both commercially and militarily.  Huge numbers of people who currently do not care at all about space stuff because it does not affect them will become interested.

Therefore, the most important thing SpaceX can do in 2017 is make progress on the constellation.  Launch a couple demo satellites.

Absolutely agreed on the constellation. It may be a "detour", but it is potentially a huge revenue source.

But here's something they need to do IMO.  The constellation will require constant launches.  Tens per year.  All to similar LEO orbits.  Launch cost will be a significant part of the total constellation cost.

They also have competition from oneWeb.

SpaceX has an opportunity to reduce launch costs through full reusability.  For several reasons outlined in other threads, full reusability of S2 has been deferred for now.  A lot of it had to do with the fact that the S2 is really optimized for delivery to GTO.

But launching the BFC satellites with a generic S2 and a fairing system is really sub-optimal.

What SpaceX needs, to be competitive, is a reusable all-in-one S2 dispenser combo.

Consider:

- BFC launches are pretty much "all the same"
- BFC launches are volume limited, since they are to LEO, and F9 has a LOT of performance now.
- BFC launches are to LEO, which makes reentry and recovery easier. (e.g. air capture over the ocean near the launch site)
- BFC satellites are small. This means there's no need for a large fairing the encompasses the whole thing. You can integrate the fairing with the structure, and still allow the satellites to be deployed.
- If you try to carry too many satellites, you become inefficient because they won't all go into the same orbital plane.

- A fully reusable system is going to be cheaper, and that's the SpaceX way - optimize for cost.  Make a launch system that puts enough satellites per orbital plane, and then comes back and is fully reusable - giving them a unique edge over the competition that will be launching using expendables.

But I don't know if we'll see this in 2017 already...  I think they certainly need to start working on it.

[john smith 19]

Landing 1 loaded ITS on Mars will require roughly 50,000 tonnes of methalox. Methalox bulk cost is about $0.20 per kg, so that's $10M. Each passenger would have to contribute roughly $100k to pay for fuel if there are 100 per flight.

Thanks for that. Can you split out the bulk Methane cost alone?

So $400k/passenger left to cover other consumables, and all development and launch costs.
I'm using a round trip time of 2 years to Mars & back so maybe 15 flights in 30 years? That's about $750m revenue per vehicle over it's lifetime, less 150m for the propellant that's $650m for everything. That suggests 2 could recover a $1Bn development cost over their lifetimes.

It's pretty obvious they will be building more than one hull. I think once you send more than one vehicle at a time the risks of catastrophic failure in one of them drops a lot, like having engine out capability during launch. Likewise more hulls means less overhead per hull to allocate to the contingency of taking on passengers from other hulls. To keep it reasonable I think you need to have at least 4 hulls at a time in transit. 

I'm not sure how much they can do in 2017 toward this. Musk has said they've done full size tanks and 1/4 scale Raptors already.  Finish the ground tests on the 1/4 Raptor and move to the full size one?
Start on a full size ground dummy of the ITS?

[Lar]

Musk has said they've done full size tanks and 1/4 scale Raptors already.

1/4 scale raptors? [[citation needed]]  I think you're thinking about power levels.

[john smith 19]

Musk has said they've done full size tanks and 1/4 scale Raptors already.

1/4 scale raptors? [[citation needed]]  I think you're thinking about power levels.

No. It struck in my mind because it was odd. It was IIRC during the ITS reveal. The first Raptor run was long enough to give steady state readings but then he mentioned it was 1/4 size, not quarter power.

[envy887]

Per this article the test raptor is a 1000 kN sub scale version, with the goal of reaching 3050 in with the production version: https://www.nasaspaceflight.com/2016/10/its-propulsion-evolution-raptor-engine/

There's some debate to whether that means the test engine is full size hardware at lower pressures, or smaller hardware at full pressures. Personally I think it's the latter, as it's much easier to scale hardware to 3x area (1.73x diameter) than to 3x chamber pressure.

[Robotbeat]

That's not true. Scaling size changes the physics a lot. It also would actually be smaller than Merlin 1D. That means it's need different tooling. Changing operating pressure means no change in tooling, because after all:

They already need Raptor to throttle down, i.e. Operate at lower pressure.

Operating at lower pressure is much easier, since the challenge of Raptor isn't the size (it's the same size as Merlin) but the extreme pressure.

Operating a smaller version of Raptor but at the same pressure would still require the insane double-stage turbo pump, which is one of the most challenging parts. It'd also require the crazy alloys for the oxygen side.

It makes far more sense to me that it was operated at lower pressure than a separate smaller scale design but at the crazy high pressure. Frankly, I don't understand the obsession here about sub scale Raptor. The challenge of Raptor isn't it's scale but the high pressure and the ox-rich side of the turbopump, neither of which are really easier at smaller scale. But operating at lower pressure definitely does help.

[douglas100]

...What SpaceX needs, to be competitive, is a reusable all-in-one S2 dispenser combo.

Consider:

- BFC launches are pretty much "all the same"
- BFC launches are volume limited, since they are to LEO, and F9 has a LOT of performance now.
- BFC launches are to LEO, which makes reentry and recovery easier. (e.g. air capture over the ocean near the launch site)
- BFC satellites are small. This means there's no need for a large fairing the encompasses the whole thing. You can integrate the fairing with the structure, and still allow the satellites to be deployed.
- If you try to carry too many satellites, you become inefficient because they won't all go into the same orbital plane.

- A fully reusable system is going to be cheaper, and that's the SpaceX way - optimize for cost.  Make a launch system that puts enough satellites per orbital plane, and then comes back and is fully reusable - giving them a unique edge over the competition that will be launching using expendables.

But I don't know if we'll see this in 2017 already...  I think they certainly need to start working on it.

A fully reusable system will probably be cheaper. But bear in mind that there has been no re-use of the recovered stages yet. That comes before any serious work on recovering the second stage. They were right to defer it. There are too many other things to do.

And the first thing is a no-brainer: returning the F9 successfully to flight. Everything else, including the constellation, is secondary. So I don't think you will see a reusable second stage fly in 2017. It doesn't mean they won't be working on it, though.

[envy887]

That's not true. Scaling size changes the physics a lot. It also would actually be smaller than Merlin 1D. That means it's need different tooling. Changing operating pressure means no change in tooling, because after all:

They already need Raptor to throttle down, i.e. Operate at lower pressure.

Operating at lower pressure is much easier, since the challenge of Raptor isn't the size (it's the same size as Merlin) but the extreme pressure.

Operating a smaller version of Raptor but at the same pressure would still require the insane double-stage turbo pump, which is one of the most challenging parts. It'd also require the crazy alloys for the oxygen side.

It makes far more sense to me that it was operated at lower pressure than a separate smaller scale design but at the crazy high pressure. Frankly, I don't understand the obsession here about sub scale Raptor. The challenge of Raptor isn't it's scale but the high pressure and the ox-rich side of the turbopump, neither of which are really easier at smaller scale. But operating at lower pressure definitely does help.

The point is to prove they can do the hard parts, not try to build a less capable but easier to make engine. Once they solve the pressure and ox-rich issues, scaling is fairly easy.

Testing a sub-scale full pressure engine means they are a lot closer to flying Raptor than testing a full scale low pressure version.

[meekGee]

...What SpaceX needs, to be competitive, is a reusable all-in-one S2 dispenser combo.

Consider:

- BFC launches are pretty much "all the same"
- BFC launches are volume limited, since they are to LEO, and F9 has a LOT of performance now.
- BFC launches are to LEO, which makes reentry and recovery easier. (e.g. air capture over the ocean near the launch site)
- BFC satellites are small. This means there's no need for a large fairing the encompasses the whole thing. You can integrate the fairing with the structure, and still allow the satellites to be deployed.
- If you try to carry too many satellites, you become inefficient because they won't all go into the same orbital plane.

- A fully reusable system is going to be cheaper, and that's the SpaceX way - optimize for cost.  Make a launch system that puts enough satellites per orbital plane, and then comes back and is fully reusable - giving them a unique edge over the competition that will be launching using expendables.

But I don't know if we'll see this in 2017 already...  I think they certainly need to start working on it.

A fully reusable system will probably be cheaper. But bear in mind that there has been no re-use of the recovered stages yet. That comes before any serious work on recovering the second stage. They were right to defer it. There are too many other things to do.

And the first thing is a no-brainer: returning the F9 successfully to flight. Everything else, including the constellation, is secondary. So I don't think you will see a reusable second stage fly in 2017. It doesn't mean they won't be working on it, though.

There hasn't been, but from a development standpoint, they are pretty advanced there.

Unlike conventional satellites, with BFC, they have a chance to simply price competitors out of the market, since they can be running a fully reusable launcher.

Reusing a second stage is in many ways easier than reusing a first stage. The only problem is that it eats up payload mass.

But with BFC, it actually plays out that there's inherently a lot of unused lifting capacity...  So they can use that capacity for a heatshield and parachute, and maybe some structural enhancements, which is all it really takes.  Remember they know how to re-enter already.

[DigitalMan]

Landing 1 loaded ITS on Mars will require roughly 50,000 tonnes of methalox. Methalox bulk cost is about $0.20 per kg, so that's $10M. Each passenger would have to contribute roughly $100k to pay for fuel if there are 100 per flight.

Thanks for that. Can you split out the bulk Methane cost alone?

So $400k/passenger left to cover other consumables, and all development and launch costs.
I'm using a round trip time of 2 years to Mars & back so maybe 15 flights in 30 years? That's about $750m revenue per vehicle over it's lifetime, less 150m for the propellant that's $650m for everything. That suggests 2 could recover a $1Bn development cost over their lifetimes.

It's pretty obvious they will be building more than one hull. I think once you send more than one vehicle at a time the risks of catastrophic failure in one of them drops a lot, like having engine out capability during launch. Likewise more hulls means less overhead per hull to allocate to the contingency of taking on passengers from other hulls. To keep it reasonable I think you need to have at least 4 hulls at a time in transit. 

I'm not sure how much they can do in 2017 toward this. Musk has said they've done full size tanks and 1/4 scale Raptors already.  Finish the ground tests on the 1/4 Raptor and move to the full size one?
Start on a full size ground dummy of the ITS?

The ITS slides show methane cost of $168/ton

[Robotbeat]

Landing 1 loaded ITS on Mars will require roughly 50,000 tonnes of methalox. Methalox bulk cost is about $0.20 per kg, so that's $10M. Each passenger would have to contribute roughly $100k to pay for fuel if there are 100 per flight.

Thanks for that. Can you split out the bulk Methane cost alone?

So $400k/passenger left to cover other consumables, and all development and launch costs.
I'm using a round trip time of 2 years to Mars & back so maybe 15 flights in 30 years? That's about $750m revenue per vehicle over it's lifetime, less 150m for the propellant that's $650m for everything. That suggests 2 could recover a $1Bn development cost over their lifetimes.

It's pretty obvious they will be building more than one hull. I think once you send more than one vehicle at a time the risks of catastrophic failure in one of them drops a lot, like having engine out capability during launch. Likewise more hulls means less overhead per hull to allocate to the contingency of taking on passengers from other hulls. To keep it reasonable I think you need to have at least 4 hulls at a time in transit. 

I'm not sure how much they can do in 2017 toward this. Musk has said they've done full size tanks and 1/4 scale Raptors already.  Finish the ground tests on the 1/4 Raptor and move to the full size one?
Start on a full size ground dummy of the ITS?

The ITS slides show methane cost of $168/ton

That's the spot price at the time of the presentation, roughly. So cheap that the liquid oxygen actually costs more, I believe (partly because you need more of it).

Optimistically, triple that price if you want to synthesize it from electricity. (triple the methane cost. the oxygen cost stays basically the same)

[john smith 19]

The ITS slides show methane cost of $168/ton

Thanks for that. Yes that's less than 8c/lb

That's the spot price at the time of the presentation, roughly. So cheap that the liquid oxygen actually costs more, I believe (partly because you need more of it).

Optimistically, triple that price if you want to synthesize it from electricity. (triple the methane cost. the oxygen cost stays basically the same)

That's uncharacteristically down beat of  you.

Unlike Hydrogen Methane can be produced by biology

[Robotbeat]

Not down-beat at all. Methane straight from the ground is ridiculously cheap right now in the US.

And a ton of methane is about 15 MWh of energy though takes almost twice that in electricity to produce it, say 25MWh. Even with, like 2 cents per kWh, you're still looking at $500. But you also have capital cost of the electrolysis, etc.

Biomethane wouldn't be cheaper than that.

But each passenger only needs like 100 tons of methane. So even at $500/ton, that's not so bad. (need about 400 tons of liquid oxygen, which is like $110/ton, maybe less if you make it yourself)

(Side note: hydrogen can also be made biologically.)

[MP99]

Not down-beat at all. Methane straight from the ground is ridiculously cheap right now in the US.

And a ton of methane is about 15 MWh of energy though takes almost twice that in electricity to produce it, say 25MWh. Even with, like 2 cents per kWh, you're still looking at $500. But you also have capital cost of the electrolysis, etc.

Biomethane wouldn't be cheaper than that.

But each passenger only needs like 100 tons of methane. So even at $500/ton, that's not so bad. (need about 400 tons of liquid oxygen, which is like $110/ton, maybe less if you make it yourself)

(Side note: hydrogen can also be made biologically.)

One question re biomethane - how pure is it? Would it need a lot of purification before being used as fuel?

Cheers, Martin

[Torbjorn Larsson, OM]

Not down-beat at all. Methane straight from the ground is ridiculously cheap right now in the US.

And a ton of methane is about 15 MWh of energy though takes almost twice that in electricity to produce it, say 25MWh. Even with, like 2 cents per kWh, you're still looking at $500. But you also have capital cost of the electrolysis, etc.

Biomethane wouldn't be cheaper than that.

But each passenger only needs like 100 tons of methane. So even at $500/ton, that's not so bad. (need about 400 tons of liquid oxygen, which is like $110/ton, maybe less if you make it yourself)

(Side note: hydrogen can also be made biologically.)

One question re biomethane - how pure is it? Would it need a lot of purification before being used as fuel?

Cheers, Martin

It must be the New Year - this made me chuckle.  You know what the local lingo calls that which a rocket need to get to orbit? You know, purely that and nothing else, as SpaceX likes to tell us - velocity?

It is called "fart".   

[john smith 19]

There's some debate to whether that means the test engine is full size hardware at lower pressures, or smaller hardware at full pressures. Personally I think it's the latter, as it's much easier to scale hardware to 3x area (1.73x diameter) than to 3x chamber pressure.

The article you cited certainly makes it sound like a smaller engine has been built. That gives you smaller pressure vessels to mfg which are better able to cope with high pressures. IIRC Cost models for engines scale at around Pc^3 and swallowing the hard work of high pressure up front (along with all the issues around the tight coupling of the start sequence. SSME was a nightmare. The much improved engine modelling should help, but now you've got 2 pre burners to start up in which order, or both together? If together how far out of synch can you let their startups get before an abort? And so on) in a smaller engine is the sensible option. Smaller parts to build, smaller parts to rebuild if they fail.

[john smith 19]

Not down-beat at all. Methane straight from the ground is ridiculously cheap right now in the US.

And a ton of methane is about 15 MWh of energy though takes almost twice that in electricity to produce it, say 25MWh. Even with, like 2 cents per kWh, you're still looking at $500. But you also have capital cost of the electrolysis, etc.

Biomethane wouldn't be cheaper than that.

Perhaps not but that's on Earth. On Mars energy of any kind is going to be expensive.

Even assuming the hulls can come back completely empty as an RPV/autopilot system they're still going to need a lot of propellant to get them back to Earth orbit.