If 400 test flights are planned then it would be a crying shame to haul 6,000 mt of dummy payloads to orbit. After say a dozen successes you might as well start using all that capacity and stimulating the market with a low cost to orbit so that your potential vehicle customers actually SEE the huge demand bubbling up that would be necessary to justify purchasing a vehicle.
1. I expect launch control to be much smaller given the higher structural margins and the underlying assumption that Skylon will work, rather than something that's a hairs breadth away from falling apart. 2. I would expect Range Safety to be autonomous on the vehicle. with engine shut down and propellant dumping ( no self destruct charges) to be SOP.3. Mission Control? Isn't that what happens in an airport Control Tower? Shared across all vehicles using the runway. Quote from: Jim on 12/04/2015 04:36 pmSo look at Spacex pad but without the erector.4. The word you're looking for is "runway."
So look at Spacex pad but without the erector.
Quote from: Spaceflight vol 58, p26[reporting on IAC 2015]... the new head of Arianspace, Stephane Israel, said he had not heard of Reaction Engines or the Skylon concept.
[reporting on IAC 2015]... the new head of Arianspace, Stephane Israel, said he had not heard of Reaction Engines or the Skylon concept.
I thought the 400 flights info comes from before they planned the boilerplate prototype?
The qualification flight test programme has two production prototypes (there are also two earlier full scale development vehicles which are probably not orbital).
1. Would that be covered by ATC?2. Do you think the prop storage and fueling area are likely to be a spaceport facility? does the decoupling of fueling from launch give any benefits in terms of reducing the complexity of the launch process. Any benefits in terms of the size of the range control staff?
Quote from: Impaler on 12/06/2015 05:25 amIf 400 test flights are planned then it would be a crying shame to haul 6,000 mt of dummy payloads to orbit. After say a dozen successes you might as well start using all that capacity and stimulating the market with a low cost to orbit so that your potential vehicle customers actually SEE the huge demand bubbling up that would be necessary to justify purchasing a vehicle.Good point.I'd expect dummy payloads for the first couple of Skylon test flights, and then deeply discounted commercial payloads for each subsequent flight, with the price discount ever reducing as the vehicle is proven and risk of loss is reduced. Then once the 200+ flight testing period draws to a close, the final operator of the now fully tested vehicles will look in vain for anything remaining on the ground still left to be launched.What then? Launch what exactly into LEO? Rocks?That's the achilles heel of both the Skylon commercial proposition and also SpaceX: without a Mars or Lunar program or some other pressing *need* to launch lots and lots of stuff into orbit, then both systems are going to be spending most of their time on the ground. Granted SpaceX has a Mars program on the drawing board (but I'm sceptical that even Elon and his friends have deep enough pockets to pay for it) so they're at least on paper providing their own pressing need for a reusable launch system. But Skylon's first operator? What's the pressing need for them? And can they cover the huge opportunity costs whilst a Skylon or two sit on the ground with nothing to launch?This is where the infamous airliner comparison quickly falls apart: any airliner spends a large proportion of its time in the air... it'd better at those capital costs. And if not, it's soon returned to the leasing company after the airline goes bankrupt.I personally would *love* Skylon to fly, but I greatly fear for the first commercial operator. "Build it, and they will come" is a fallacy that engineering-first companies fall for time and again. The Brits have a rich history of that, but I deleted the long list of examples that spring to my mind because I don't want to distract anyone from my point. But there is one sector with deep pockets where Skylon has a hope: first they'll need to paint it olive green; and then they'll have to weaponise it.Cue the rush of SpaceX amazing peoples, Skylon amazing peoples and anti-military establishment types. (Yawn) Sticks and stones...Ric
By decoupling the choreography of disconnections and releases, and by slowing the actual launch do you think the horizontal take-off concept have the potential to drastically simplify the launch sequence, or would it be only marginal, or make no significance difference? In addition by being dynamically stable and having a variety of intact abort options, does the Skylon concept have the potential to allow the launch control centre be scaled down? by how much?
Changing up the angle a bit, why don't airliners require the same level of ground control attention as rockets, and how can (or why can't) Skylon move in that direction?
I don't understand how your reference to a VTOL would help me to understand your answer -
Because:A. Airliners have multiple back systems and also have the ability to have multiple abort modes. Also, they have the ability to operate in a degraded mode.
b. Jet engines are not working at the edge and they can contain a destructive failure or even fall off.
c. An airliner fully fueled and ready to fly can sit on the ramp almost indefinitely. A vehicle that uses cryogenics and hygols has to be monitored.
1. Agreed, cryogenic fuels require much more careful handling than AV fuels. There shouldn't be any major issues with Skylon having to wait on the runway while problems are resolved - after all standard rockets have to do this fairly frequently, even ones using cryogenics.2. However Skylon is won't be using hygols - the OMS and RCS systems will use LH2/LO2.3.However it is intended to operate in a way which is much closer to normal airport operations than any other launch vehicle.
Skylon's test flight schedule is designed to test the limits of the engines so they can be operated within safe limits. I doubt they'll be operating at the edge without any safety margin.
That's useful insight, thank you. I've never dealt with anything scarier than LPG, what are the problems with cryogenic fuel handling that make you think the design has missed?
I thought a fair amount of consideration had been put into the ground support equipmentPages 26-28 of the concept manual outlines the Ground Operations Sequence and Timing (pages34-36 of the PDF)