10 ms·

Skylon ‘spaceplane economics stack up’

75 points by timthorn 12y ago

iwwr 12y ago
So is it just a suborbital plane that can launch something high enough where an additional small booster can put the payload in orbit?
- filipncs 12y ago
  No, it's single stage to orbit; it's a poorly written article. It goes to mach 5.4 with atmospheric air before switching to liquid oxygen. The article makes it sound like it only ever reaches mach 5.4. http://en.wikipedia.org/wiki/Skylon_(spacecraft) http://en.wikipedia.org/wiki/Skylon_(spacecraft)
  - trhway 12y ago
    it is lost on me why Skylon would be noticeably better than a Mach 5-6 plane boosting a second stage. Such 2 stage system would have obviously less trade-offs and thus would be easier/cheaper to design and build.
    - icegreentea 12y ago
      Staging isn't free. While true that the second stage vehicle will be simpler, the combined second and first stage together could be more complicated/heavier than the Skylon. Noticeably, the point of the Skylon and SABRE is that it's possible to use a common engine core in airbreathing and pure rocket mode, thus potentially generating weight savings. I'm sure someone sat down and did the calculations. I have this feeling that a lot of the times when you actually sit down and work out the math for a range of assumptions, you generally come down to 'eh, maybe A, maybe B, so may as well try A'.
  - blueskin_ 12y ago
    >it's a poorly written article. It's the BBC, so I'd say it's an averagely written article in their context.
    - ris 12y ago
      It's by Jonathan Amos, who generally knows his stuff and whose articles are usually well above most bbc tech articles in quality. It's an unfortunately worded paragraph I'd say.
      - blueskin_ 12y ago
        Well, I suppose 'poor' is above 'awful'.
- Someone 12y ago
  No. It's a plane that can go into low orbit. You need an additional booster to bring stuff into high orbits. For smaller satellites, this study concludes that it is economical to recover that booster. "power units that work like jet engines at low altitudes and slow speeds, but then transition to full rocket mode at high altitudes" and "Skylon itself is designed only to go a few hundred km above the Earth, so it would need an additional "upper-stage" module to push the satellite into its final, 36,000km-high orbit."
panduwana 12y ago
So it needs taxpayer subsidy just to be on par with fully-private Falcon 9? Seems like it loses before the match even begins.
- noir_lord 12y ago
  What a narrow world view. A fully reusable single stage to orbit "plane" completely changes the dynamics of putting stuff in orbit both on cost and turn around time. The Falcon 9 is privately funded as is the Merlin engine it uses however pretty much all the materials science, initial engineering etc required to design and build a merlin was publicly funded. There are times when a public/private partnership makes sense and this is one of them.
- outworlder 12y ago
  The 'subsidy' is less than a non-SpaceX launch would cost and peanuts for a R&D project, specially one with this potential. And it's about the same amount the US military is currently spending to certify SpaceX for military launches. What about the NASA contracts? These are done with taxpayer money too.
  - Fuxy 12y ago
    I find it fascinating that Elon Musk hasn't chipped in since even though it's a competitor to SpaceX it is ultimately a step in the right direction for his goal of putting people on Mars and into space. Hell he could take the engine and build a new spacecraft based on it.
    - ceejayoz 12y ago
      I think he's happy with the engines he has, as well as the ability to say "here's what we're doing" without someone else having the final say.
      - goodcanadian 12y ago
        Also, as rich as he is, he is not made of money. His wealth is tied up in SpaceX and Tesla.
outworlder 12y ago
Forget about 'spaceplane economics'. Just get the SABRE engine out of the door already, then people can start talking about economics. Apparently the engine design has been complete for years and they just need additional funding. Should a production SABRE engine prove to be low maintenance enough, it won't just be a matter of "stacking up", this will be huge. However, if the maintenance is costly, then it's the Space Shuttle all over again. In contrast to the shuttle, tho, there's no costly thermal protection system, the skin and some water cooling should be enough. Also, no astronauts, Skylon is supposed to be fully automated. A fully reusable spaceplane for small payloads and a big dumb booster (SpaceX) should complement each other very well.
- JulianMorrison 12y ago
  Skylon isn't only for small payloads. It's closer to "Thunderbird Two" in the size of payload pods.
  - outworlder 12y ago
    I stand corrected. Wikipedia says 15000kg (doesn't say at what altitude however).
    - throwaway_yy2Di 12y ago
      Says 15 000 kg to 300 km LEO, or 11 000 kg to 800 km, out of 350 000 kg launch mass: https://en.wikipedia.org/wiki/Skylon_%28spacecraft%29#Overview https://en.wikipedia.org/wiki/Skylon_%28spacecraft%29#Overvi... So similar sized as the two-stage Delta IV Medium, with exactly the same mass fraction (23.3 - 23.5): http://www.spaceflight101.com/delta-iv-medium-42.html http://www.spaceflight101.com/delta-iv-medium-42.html
- mrfusion 12y ago
  Why wouldn't it need a costly thermal protection system?
  - JulianMorrison 12y ago
kashkhan 12y ago
The technical risk has to be factored in. Nobody has ever done such heat exchangers and how to keep them free of ice is a secret sauce they are not sharing. Without peer review or open discussion the engine might as well not exist.
mrfusion 12y ago
They should consider a kickstarter for funding. Does anyone know if they've considered it?
- rayiner 12y ago
  You need real money to develop aerospace technology. The SABRE engine is in its final stage of development, and according to the articles linked from the main article, just finishing the final stage will cost about 200 million pounds ($330 million dollars). That's about thirty times what the largest project in Kickstarter history has ever raised. The article pegs the total development cost of the plane at the cost of developing an Airbus plane. That's about $10-15 billion, or more than an order of magnitude more than all of the money that has ever been raised in Kickstarter history. Probably more than all the money that has ever been raised by crowd funding period.
  - mrfusion 12y ago
    Wow, I had no idea it was that much. Sorry for the naive question, but any ideas on why it costs so much? Wouldn't putting 100-200 top engineers on it for a few years be enough? What do they need 300 million for?
    - arethuza 12y ago
      $300 million to cover "a few years" arguably isn't that much - even basic stuff as the loaded costs of staff is going to be a significant proportion of that. To maybe put that in perspective, $100 million a year is the budget of one of the smaller F1 teams.
    - sparkman55 12y ago
      You don't merely need engineers to design the thing. You also have to actually build what you design, custom manufactured out of exotic materials in small batches, and then test those components (often to destruction) before building a slightly-more ambitious prototype. A test or launch also involves a large land area for safety, significant support staff handling hazardous material, and miles of red tape to secure the firing range and airspace. This build-test-debug loop costs millions and may take months or years, and a single spectacular failure can sink the entire project (e.g. DC-X). Most engineering is not like software! For example, most of the cost of a bridge is not the civil engineering to design the structure...
al2o3cr 12y ago
BRB, building one in Kerbal Space Program. :)
- twic 12y ago
  You Must Construct Additional Skylons!
- pjc50 12y ago
  Spaceplanes are ludicrously hard to get right in KSP. The aerodynamics model is not very good and the process whereby fuel is taken from the frontmost tank first tends to make the plane flip halfway through the ascent. I've occasionally considered writing something with a better aerodynamics sim in ...
  - gerbal 12y ago
    There are a number of mods which add much finer control over fuel management and better aerodynamics to KSP. Ferram Aerospace[1] adds much more realistic aerodynamics and TAC fuel balancer[2] adds a fuel balancer. [1] http://forum.kerbalspaceprogram.com/threads/20451-0-22-Ferram-Aerospace-Research-v0-9-7-Aerodynamics-Fixes-For-Planes-Rockets http://forum.kerbalspaceprogram.com/threads/20451-0-22-Ferra... [2] http://forum.kerbalspaceprogram.com/threads/25823-0-23-TAC-Fuel-Balancer-v2-3-22Dec http://forum.kerbalspaceprogram.com/threads/25823-0-23-TAC-F...
JimmyM 12y ago
In true BBC-style: other brands of spaceplane are available. http://bristolspaceplanes.com/company/ http://bristolspaceplanes.com/company/
DonHopkins 12y ago
I guess that's what happens when you go playing around with things you don't know anything about... http://youtu.be/4-HOvQUL2zI?t=21m20s http://youtu.be/4-HOvQUL2zI?t=21m20s https://en.wikipedia.org/wiki/Land_of_the_Lost_(1974_television_series)_geography_and_technology#Skylons https://en.wikipedia.org/wiki/Land_of_the_Lost_(1974_televis...
vilhelm_s 12y ago
I'm currently reading "The Space Shuttle Decision" by T.A. Heppenheimer, which discusses the planning in the late 1960s for a reusable successor to the Saturn rockets. One interesting thing is that they then envisioned this to happen in phases: a "type I" partially reusable vehicle (with expendable fuel tanks and maybe expendable boosters), then a type II fully-reusable rocket-propelled vehicle (probably two winged stages which both fly back), and finally a type III air-breathing vehicle (Skylon-style air liquefaction was talked about already then). The more advanced concepts cost a lot of money to develop, but reduce the per-launch cost. So the hope was to start with a type I vehicle (the eventual Space Shuttle) to reduce launch cost and grow the market, until there are plans for so many launches that it makes sense to fund the advanced types. In hindsight, the Space Shuttle unfortunately kind of botched the reuseablity. But with SpaceX we finally seem to be on track to having a working partially resuable launch vehicle. Maybe this will "unfreeze the future"---with a bigger launch market and commercial pressure people might be tempted to go for something like Skylon rather than more of the same in follow-up Arianes...
bbwonder 12y ago
You can imagine Virgin Galactic are wll positioned to accelerate this project. They have the airframe building technology, and the commercial vision for affordable space access. Come on Branson, bring this British invention to life!

75 points by timthorn 12y ago

iwwr 12y ago

So is it just a suborbital plane that can launch something high enough where an additional small booster can put the payload in orbit?

filipncs 12y ago
No, it's single stage to orbit; it's a poorly written article. It goes to mach 5.4 with atmospheric air before switching to liquid oxygen. The article makes it sound like it only ever reaches mach 5.4. http://en.wikipedia.org/wiki/Skylon_(spacecraft) http://en.wikipedia.org/wiki/Skylon_(spacecraft)
- trhway 12y ago
  it is lost on me why Skylon would be noticeably better than a Mach 5-6 plane boosting a second stage. Such 2 stage system would have obviously less trade-offs and thus would be easier/cheaper to design and build.
  - icegreentea 12y ago
    Staging isn't free. While true that the second stage vehicle will be simpler, the combined second and first stage together could be more complicated/heavier than the Skylon. Noticeably, the point of the Skylon and SABRE is that it's possible to use a common engine core in airbreathing and pure rocket mode, thus potentially generating weight savings. I'm sure someone sat down and did the calculations. I have this feeling that a lot of the times when you actually sit down and work out the math for a range of assumptions, you generally come down to 'eh, maybe A, maybe B, so may as well try A'.
- blueskin_ 12y ago
  >it's a poorly written article. It's the BBC, so I'd say it's an averagely written article in their context.
  - ris 12y ago
    It's by Jonathan Amos, who generally knows his stuff and whose articles are usually well above most bbc tech articles in quality. It's an unfortunately worded paragraph I'd say.
    - blueskin_ 12y ago
      Well, I suppose 'poor' is above 'awful'.
Someone 12y ago
No. It's a plane that can go into low orbit. You need an additional booster to bring stuff into high orbits. For smaller satellites, this study concludes that it is economical to recover that booster. "power units that work like jet engines at low altitudes and slow speeds, but then transition to full rocket mode at high altitudes" and "Skylon itself is designed only to go a few hundred km above the Earth, so it would need an additional "upper-stage" module to push the satellite into its final, 36,000km-high orbit."

panduwana 12y ago

So it needs taxpayer subsidy just to be on par with fully-private Falcon 9? Seems like it loses before the match even begins.

noir_lord 12y ago
What a narrow world view. A fully reusable single stage to orbit "plane" completely changes the dynamics of putting stuff in orbit both on cost and turn around time. The Falcon 9 is privately funded as is the Merlin engine it uses however pretty much all the materials science, initial engineering etc required to design and build a merlin was publicly funded. There are times when a public/private partnership makes sense and this is one of them.
outworlder 12y ago
The 'subsidy' is less than a non-SpaceX launch would cost and peanuts for a R&D project, specially one with this potential. And it's about the same amount the US military is currently spending to certify SpaceX for military launches. What about the NASA contracts? These are done with taxpayer money too.
- Fuxy 12y ago
  I find it fascinating that Elon Musk hasn't chipped in since even though it's a competitor to SpaceX it is ultimately a step in the right direction for his goal of putting people on Mars and into space. Hell he could take the engine and build a new spacecraft based on it.
  - ceejayoz 12y ago
    I think he's happy with the engines he has, as well as the ability to say "here's what we're doing" without someone else having the final say.
    - goodcanadian 12y ago
      Also, as rich as he is, he is not made of money. His wealth is tied up in SpaceX and Tesla.

outworlder 12y ago

Forget about 'spaceplane economics'. Just get the SABRE engine out of the door already, then people can start talking about economics. Apparently the engine design has been complete for years and they just need additional funding. Should a production SABRE engine prove to be low maintenance enough, it won't just be a matter of "stacking up", this will be huge. However, if the maintenance is costly, then it's the Space Shuttle all over again. In contrast to the shuttle, tho, there's no costly thermal protection system, the skin and some water cooling should be enough. Also, no astronauts, Skylon is supposed to be fully automated. A fully reusable spaceplane for small payloads and a big dumb booster (SpaceX) should complement each other very well.

JulianMorrison 12y ago
Skylon isn't only for small payloads. It's closer to "Thunderbird Two" in the size of payload pods.
- outworlder 12y ago
  I stand corrected. Wikipedia says 15000kg (doesn't say at what altitude however).
  - throwaway_yy2Di 12y ago
    Says 15 000 kg to 300 km LEO, or 11 000 kg to 800 km, out of 350 000 kg launch mass: https://en.wikipedia.org/wiki/Skylon_%28spacecraft%29#Overview https://en.wikipedia.org/wiki/Skylon_%28spacecraft%29#Overvi... So similar sized as the two-stage Delta IV Medium, with exactly the same mass fraction (23.3 - 23.5): http://www.spaceflight101.com/delta-iv-medium-42.html http://www.spaceflight101.com/delta-iv-medium-42.html
mrfusion 12y ago
Why wouldn't it need a costly thermal protection system?
- JulianMorrison 12y ago

kashkhan 12y ago

The technical risk has to be factored in. Nobody has ever done such heat exchangers and how to keep them free of ice is a secret sauce they are not sharing. Without peer review or open discussion the engine might as well not exist.

mrfusion 12y ago

They should consider a kickstarter for funding. Does anyone know if they've considered it?

rayiner 12y ago
You need real money to develop aerospace technology. The SABRE engine is in its final stage of development, and according to the articles linked from the main article, just finishing the final stage will cost about 200 million pounds ($330 million dollars). That's about thirty times what the largest project in Kickstarter history has ever raised. The article pegs the total development cost of the plane at the cost of developing an Airbus plane. That's about $10-15 billion, or more than an order of magnitude more than all of the money that has ever been raised in Kickstarter history. Probably more than all the money that has ever been raised by crowd funding period.
- mrfusion 12y ago
  Wow, I had no idea it was that much. Sorry for the naive question, but any ideas on why it costs so much? Wouldn't putting 100-200 top engineers on it for a few years be enough? What do they need 300 million for?
  - arethuza 12y ago
    $300 million to cover "a few years" arguably isn't that much - even basic stuff as the loaded costs of staff is going to be a significant proportion of that. To maybe put that in perspective, $100 million a year is the budget of one of the smaller F1 teams.
  - sparkman55 12y ago
    You don't merely need engineers to design the thing. You also have to actually build what you design, custom manufactured out of exotic materials in small batches, and then test those components (often to destruction) before building a slightly-more ambitious prototype. A test or launch also involves a large land area for safety, significant support staff handling hazardous material, and miles of red tape to secure the firing range and airspace. This build-test-debug loop costs millions and may take months or years, and a single spectacular failure can sink the entire project (e.g. DC-X). Most engineering is not like software! For example, most of the cost of a bridge is not the civil engineering to design the structure...

al2o3cr 12y ago

BRB, building one in Kerbal Space Program. :)

twic 12y ago
You Must Construct Additional Skylons!
pjc50 12y ago
Spaceplanes are ludicrously hard to get right in KSP. The aerodynamics model is not very good and the process whereby fuel is taken from the frontmost tank first tends to make the plane flip halfway through the ascent. I've occasionally considered writing something with a better aerodynamics sim in ...
- gerbal 12y ago
  There are a number of mods which add much finer control over fuel management and better aerodynamics to KSP. Ferram Aerospace[1] adds much more realistic aerodynamics and TAC fuel balancer[2] adds a fuel balancer. [1] http://forum.kerbalspaceprogram.com/threads/20451-0-22-Ferram-Aerospace-Research-v0-9-7-Aerodynamics-Fixes-For-Planes-Rockets http://forum.kerbalspaceprogram.com/threads/20451-0-22-Ferra... [2] http://forum.kerbalspaceprogram.com/threads/25823-0-23-TAC-Fuel-Balancer-v2-3-22Dec http://forum.kerbalspaceprogram.com/threads/25823-0-23-TAC-F...

JimmyM 12y ago

In true BBC-style: other brands of spaceplane are available. http://bristolspaceplanes.com/company/ http://bristolspaceplanes.com/company/

DonHopkins 12y ago

I guess that's what happens when you go playing around with things you don't know anything about... http://youtu.be/4-HOvQUL2zI?t=21m20s http://youtu.be/4-HOvQUL2zI?t=21m20s https://en.wikipedia.org/wiki/Land_of_the_Lost_(1974_television_series)_geography_and_technology#Skylons https://en.wikipedia.org/wiki/Land_of_the_Lost_(1974_televis...

vilhelm_s 12y ago

I'm currently reading "The Space Shuttle Decision" by T.A. Heppenheimer, which discusses the planning in the late 1960s for a reusable successor to the Saturn rockets. One interesting thing is that they then envisioned this to happen in phases: a "type I" partially reusable vehicle (with expendable fuel tanks and maybe expendable boosters), then a type II fully-reusable rocket-propelled vehicle (probably two winged stages which both fly back), and finally a type III air-breathing vehicle (Skylon-style air liquefaction was talked about already then). The more advanced concepts cost a lot of money to develop, but reduce the per-launch cost. So the hope was to start with a type I vehicle (the eventual Space Shuttle) to reduce launch cost and grow the market, until there are plans for so many launches that it makes sense to fund the advanced types. In hindsight, the Space Shuttle unfortunately kind of botched the reuseablity. But with SpaceX we finally seem to be on track to having a working partially resuable launch vehicle. Maybe this will "unfreeze the future"---with a bigger launch market and commercial pressure people might be tempted to go for something like Skylon rather than more of the same in follow-up Arianes...

bbwonder 12y ago

You can imagine Virgin Galactic are wll positioned to accelerate this project. They have the airframe building technology, and the commercial vision for affordable space access. Come on Branson, bring this British invention to life!