And hopefully at that time some posters will stop acting as a complete arse...
The expected parameters of the engine are actually well known. The main unknown was the pre-cooler, and this has been shown to work. The launch parameters and the options for orbital insertions are well understood.
Discussion of potential launch sites is now a viable concern, this beast will not be quiet compared to any other convientional aircraft. It may well be that it operates from outside the UK, other operators ( Virgin or others) may wish to operate from sites in the UK. Personally I can't see a case for it beyond polar orbital or sub-orbital launches, we're too far north.
The recent study was useful in outlining the limitations that Sabre and Skylon will have to fit into and shouldn't be pooh-poohed automatically because the hardware doesn't exist as yet.
I'm not poo-poohing the study because the hardware hasn't been built yet, but because it isn't actually a milestone in the building of the hardware.
Discussion of launch sites and limitations for the as-yet hypothetical Skylon doesn't actually tell us anything about whether Skylon is possible, feasible, viable, profitable, or in fact
any closer to being built than it was when this thread started.
Earlier I asked, "[w]hat's an ESA technical evaluation and what does it mean to pass one?"
What I meant was something like, does the ESA evaluation come with any obligations or commitments or opportunities?
When an engineer signs off on a piece of engineering work, they assume legal liability for the quality of the work. When a buyer signs a contract with a vendor, it often includes an enforceable commitment to buy a certain quantity at a certain price, or similar obligation. The contract often makes similar impositions on the vendor. Before a government makes a grant to fund a project, it might audit the project to determine whether it meets the necessary standards of feasibility and oversight to merit such an investment.
So. What's an ESA technical evaluation and what does it mean to pass one? Does this evaluation open the door to ESA funding for the project? Does it represent any sort of commitment or guarantee of quality on the part of the ESA? What was the scope of the evaluation? Was it a single subsystem or group of subsystems? Does passing the subsystem imply any endorsement by the ESA regarding the overall viability of the final integrated supersystem?
Does it imply any endorsement
at all by the ESA? If so, what exactly is the ESA endorsing, with this evaluation? What--if anything--does it tell us about how close SABRE is to its next real developmental milestone?
What's an ESA technical evaluation and what does it mean to pass one?
