The SABRE engine is NOT a scramjet!

This is big - I can't overstate the importance of getting the SABRE engine off the drawing board and into production. This is a miracle engine in terms of routine travel outside the gravity well of Earth. It might very well be the first trillion dollar industry. It is very difficult to understand the amount of extraterrestrial resources that are ripe for the plucking, nor the importance of exporting humans from Earth and into space routinely. This vehicle enables vast extraterrestrial resources to be routinely exploited. Sad that countries aren't devoting vast resources to this project.

SABRE is a dual mode turbo-compressed ROCKET engine, not a jet.
It operates as a rocket at all times - in the atmosphere it compresses and cools external air for its oxidant, in space it uses liquid oxygen.

I've been following Skylon for a long time, waiting for the day SABRE became a reality. That day is finally coming, it's a very exciting technology.
I want to know though, while it is obviously great for small payloads and ferrying people. Will it be efficient enough to make heavy lifters obsolete? Also, is it scalable - for the same reasons?

DomainRider. It works as a jet engine, using atmospheric air,until the air becomes too thin, then it uses internal liquid oxygen like a rocket engine.It does not operate as a rocket at all times.

Wow. But who cares what BAE produces? They are developers and manufacturers of weapons of mass destruction aren't they? They should and WILL be criminalized for their activities. Period.

The day this craft gets off the ground is still at least a decade away, probably 15+. But I'm glad they are continuing to plug away at it.
Cuckoo - It won't ever replace heavy lifters, but it could put a dent in the small satellite market. But unfortunately for them, a LOT of companies are working hard on making that emerging market more affordable. Rocket tech is more straight forward...which means cheaper, and if a standard rocket is reusable...then it's possible that this thing will end up costing MORE then a standard rocket.

Message for Mr. Mark Golding... Be very, very grateful for arms manufacturers. Germany (and probably Japan) would have overwhelmed us in WW2, but for technologically superior arms. If you think either of these two countries would have been benign victors, you only have to look at the brutality and concentration camps to be disavowed of such a notion. Sat, securely and comfortably in the peace of your home, it's very easy to pontificate about war and "how it could otherwise have been prosecuted". - All very well if both combatants play by civilised rules. History has taught us otherwise. Learn from history, or risk becoming a forgotten statistic yourself. German murders - around 10 million. Russian murders - around 30 million. Factor in Cambodia, North Korea, Islam nations etc etc etc - you're talking about a lot of innocent human lives lost to evil despots. Despots love people like you. Lenin referred to people with your views as "Useful idiots". (his words, not mine). Pacifist views such as yours might sound honourable and decent, until you consider the alternatives.

I've been following the development of this crucial tech for years! So excited. though a little disapointed that BAE is getting its fingers in the pie.

Mutley is absolutely correct. The SABRE engine is NOT a scramjet. The SABRE engine is NOTHING LIKE a scramjet! Scramjets attempt to do the impossible: Supersonic Combustion, which is a contradiction of terms. While combustion can occur in a supersonic flow, assuming the ingredients are properly mixed, combustion itself can only progress at subsonic rates. When chemical reactions progress faster than sound, that is called "detonation", which is a completely different beast. What the SABRE engine is designed for is MUCH simpler and easier than scramjets.