
Skylon ‘spaceplane economics stack up’ - timthorn
http://www.bbc.co.uk/news/science-environment-27591432
======
outworlder
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
Skylon isn't only for small payloads. It's closer to "Thunderbird Two" in the
size of payload pods.

~~~
outworlder
I stand corrected. Wikipedia says 15000kg (doesn't say at what altitude
however).

~~~
throwaway_yy2Di
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#Overvi...](https://en.wikipedia.org/wiki/Skylon_%28spacecraft%29#Overview)

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)

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JimmyM
In true BBC-style: other brands of spaceplane are available.
[http://bristolspaceplanes.com/company/](http://bristolspaceplanes.com/company/)

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vilhelm_s
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...

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DonHopkins
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_televis...](https://en.wikipedia.org/wiki/Land_of_the_Lost_\(1974_television_series\)_geography_and_technology#Skylons)

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bbwonder
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!

------
iwwr
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
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_\(spacecraft\))

~~~
blueskin_
>it's a poorly written article.

It's the BBC, so I'd say it's an averagely written article in their context.

~~~
ris
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_
Well, I suppose 'poor' is above 'awful'.

------
kashkhan
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.

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al2o3cr
BRB, building one in Kerbal Space Program. :)

~~~
pjc50
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
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-Ferra...](http://forum.kerbalspaceprogram.com/threads/20451-0-22-Ferram-
Aerospace-Research-v0-9-7-Aerodynamics-Fixes-For-Planes-Rockets)

[2]
[http://forum.kerbalspaceprogram.com/threads/25823-0-23-TAC-F...](http://forum.kerbalspaceprogram.com/threads/25823-0-23-TAC-
Fuel-Balancer-v2-3-22Dec)

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

~~~
rayiner
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
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?

~~~
sparkman55
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...

~~~
rayiner
> Most engineering is not like software!

Not just that, but original R&D is much more expensive than implementation of
proven designs. Not knowing which designs will work, or whether the overall
idea will even work at all, greatly increases the number of
design/build/test/debug cycles needed to build a product.

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

~~~
leoedin
SpaceX received a subsidy from Elon Musk. The financial case for the company
wasn't clear at the start - it was only because they had significant financial
backing for the initial development period that they could get to where they
are now. They may now be profitable, but if you'd tried to make a case a
decade ago for funding you'd get nowhere. There are all sorts of high-capital
technology developments that simply aren't immediately profitable or low risk
enough for VC funding. Why should we as a society rely on the whims of a few
wealthy people? This kind of technology, should it be realised, has a value to
everyone.

~~~
maxerickson
Why not call it a risky investment? He ended up with a big ownership stake, he
wasn't just supporting them for the hell of it.

~~~
ceejayoz
The UK isn't supporting Skylon "for the hell of it", either. Their taxpayers
would likely be pretty happy to have the next Boeing/Airbus live on their
soil.

~~~
maxerickson
I guess it's just a pet peeve of mine when people call a private, profitable
financial arrangement a subsidy.

I complain about the usage for cell phones too.

~~~
ceejayoz
Both situations involve someone with money taking a bet on a currently non-
profitable venture hoping it'll pay off in the future. SpaceX wasn't
profitable when Musk put money in.

