Author Topic: The Reaction Engines Skylon Master Thread (1)  (Read 566399 times)

Offline tnphysics

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Re: Skylon
« Reply #300 on: 06/24/2011 01:28 am »
Does SKYLON support emergency opening/jettison of the payload bay doors? I am wondering because this could become an issue on a manned mission if an abort was required.

Offline Hempsell

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Re: Skylon
« Reply #301 on: 06/24/2011 11:53 am »
Does SKYLON support emergency opening/jettison of the payload bay doors? I am wondering because this could become an issue on a manned mission if an abort was required.

This was considered during a previous incarnation of the passenger module for ejection seats but it did not look good.  The SPLM assumes that it is the safe haven; it will not leave the SKYLON and passengers would stay inside until any incident is over then they would exit through the side doors.  But this not cast in concrete and may change as discussions with the certifying authorities progress over the development programme.

Offline mr. mark

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Re: Skylon
« Reply #302 on: 06/24/2011 01:13 pm »
Not sure if this will effect the Skylon effort or not as money was thought to come from private sources. But, ESA will not be funding independent manned spaceflight.

http://online.wsj.com/article/SB10001424052702304569504576403810498723484.html?mod=WSJ_DefenseandAerospace_leftHeadlines

Offline Hermit

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Re: Skylon
« Reply #303 on: 06/24/2011 01:26 pm »
thanks Hempsell.

@Hermit: sorry pal. Wont do it again. But anyway, A2 is kinda related to Skylon... not only it looks similar (but larger and white :)) as
"The Scimitar engines use related technology to the company's earlier SABRE engine, which is intended for space launch, but here adapted for very long distance, very high speed travel."

Actually your question was not the target of my comment- it was the tide of discussion on nozzle theory I was hoping to stem. Please carry on with A2 related questions!

@mr.mark
I doubt it will effect funding for Skylon, most money in space is made from military and communications satellites at the moment, human passengers represent a very small market for the near-term. And as has been mentioned, the SPLM is not an integral part of the Skylon architecture and infrastructure

Offline aceshigh

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Re: Skylon
« Reply #304 on: 06/24/2011 02:01 pm »
Does SKYLON support emergency opening/jettison of the payload bay doors? I am wondering because this could become an issue on a manned mission if an abort was required.

This was considered during a previous incarnation of the passenger module for ejection seats but it did not look good.  The SPLM assumes that it is the safe haven; it will not leave the SKYLON and passengers would stay inside until any incident is over then they would exit through the side doors.  But this not cast in concrete and may change as discussions with the certifying authorities progress over the development programme.

??

how can it be a safe haven if Skylon falls?

Offline jee_c2

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Re: Skylon
« Reply #305 on: 06/24/2011 04:14 pm »
May be SPLM will protect the passengers in case of an accident (explosion), and then provides safe landing (big parachute?), and so the passengers inside the SPLM would stay safe? I'm guessing only.
So it depends on the aimed safety level (when the abort of mission is needed). I.e. a 0-0 catapult works even when the vehicle is standing on the runway.  A parachute in itself only works, when having enough altitude, and also, it must be ensured not to be damaged by the accident's fire, and other effects.

For a 0-0 solution (including the phase of flight at low altitude)  there should be some way to open/jettison the payload doors, having some propulsion for the payload itself, so it could be sent high enough for it's parachute to work properly, and to leave the path of the accident, so the parachute would not be damaged/destroyed.

I don't know much about these solutions, just the problem is interesting.

Offline Downix

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Re: Skylon
« Reply #306 on: 06/24/2011 04:22 pm »
Does SKYLON support emergency opening/jettison of the payload bay doors? I am wondering because this could become an issue on a manned mission if an abort was required.

This was considered during a previous incarnation of the passenger module for ejection seats but it did not look good.  The SPLM assumes that it is the safe haven; it will not leave the SKYLON and passengers would stay inside until any incident is over then they would exit through the side doors.  But this not cast in concrete and may change as discussions with the certifying authorities progress over the development programme.

??

how can it be a safe haven if Skylon falls?
Same thing can be said of your standard airliner.
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

Offline Archibald

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Re: Skylon
« Reply #307 on: 06/24/2011 05:51 pm »
Not sure if this will effect the Skylon effort or not as money was thought to come from private sources. But, ESA will not be funding independent manned spaceflight.

http://online.wsj.com/article/SB10001424052702304569504576403810498723484.html?mod=WSJ_DefenseandAerospace_leftHeadlines

Skylon is unpiloted, and will not carry passengers imediately. It is a satellite launcher before a manned ship - so it might find a small niche along Ariane, but REL said they don't want government to be involved in their funding.
Perhaps Bond still resent the way the Tatcher government stopped HOTOL funding 25 years ago...

About safety: good point about the airliner. Skylon theorically has a small advantage, in the sense the passenger pods might be ejected in orbit, and wait for rescue - try that with an airliner passenger section !
« Last Edit: 06/24/2011 05:54 pm by Archibald »
...you have been found guilty by the elders of the forum of a (imaginary) vendetta against Saint Elon - BLAAASPHEMER !

Offline simonbp

Re: Skylon
« Reply #308 on: 06/24/2011 07:02 pm »
Some more skylon snippets here:

http://www.rocketeers.co.uk/node/1595

Apparently there are plans for ten X-37 sized nacelle test vehicles to be constructed...

Another very interesting tidbit:

Quote
Reaction Engines designing propulsion systems for Martian atmospheric ISRU. LOX/carbon monoxide, LOX/cyanogen, N2O4/cyanogen. LOX/CO has sufficient performance for SSTO from Mars surface.

LOX/CO seems to have fallen out of favor, with most Mars mission proposals using LOX/CH4. CH4 needs water to be produced, which is available on Mars, assuming you dig deep enough. N2O4 and cyanogen both need nitrogen, which is in much shorter supply on Mars and realistically would have to be shipped to the planet (but are a great idea for Titan).

LOX/CO is intriguing, on the other hand, as it can be produced from the Martian atmosphere without needing to touch the surface at all...
« Last Edit: 06/24/2011 07:05 pm by simonbp »

Offline aceshigh

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Re: Skylon
« Reply #309 on: 06/24/2011 08:00 pm »
Does SKYLON support emergency opening/jettison of the payload bay doors? I am wondering because this could become an issue on a manned mission if an abort was required.

This was considered during a previous incarnation of the passenger module for ejection seats but it did not look good.  The SPLM assumes that it is the safe haven; it will not leave the SKYLON and passengers would stay inside until any incident is over then they would exit through the side doors.  But this not cast in concrete and may change as discussions with the certifying authorities progress over the development programme.

??

how can it be a safe haven if Skylon falls?
Same thing can be said of your standard airliner.


my airlines isnt a safehaven in case of an explosion. I suppose to compensate the lack of such safety features, Skylon intends to be much less prone to accidents than the Space Shuttle or common rockets?
« Last Edit: 06/24/2011 08:00 pm by aceshigh »

Offline Hempsell

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Re: Skylon
« Reply #310 on: 06/26/2011 01:38 pm »
Some key points on passenger safety issue

Most aircraft incidents happen at takeoff and landing and in aircraft incidences most causalities occur after the aircraft has come to a stop on the ground (hence the emphasis on rapid evacuation in safety briefings).  In our case we expect the outside environment to be more dangerous because of the cryogen propellants and the presence of an oxidiser; so evacuation maybe a more dangerous procedure than staying put.

There are two points that help us with this stay put approach. First; with aircraft the passengers are contained in the primary airframe we are not and so can consider the passenger module as protective structure and the airframe primary structure as an impact absorber. Second we have a sealed cabin with a full environmental support system again unlike an aircraft.

With a mid air-break up again the independent passenger structure puts us more into the Shuttle territory where the cabin structure survived the Challenger accident and we can learn lessons from this. It is possible that parachutes and airbags may give a substantial increase in survival probability from that type of incident.  However an active ejection system does not look feasible we rely on the module free falling from the break up.

An in orbit stranding is handed by a second SKYLON performing a rescue mission which is why the docking port is set 15 degrees off axis; it enables two SPLM equipped SKYLONs to dock without the airframes hitting each other.

Offline A_M_Swallow

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Re: Skylon
« Reply #311 on: 06/26/2011 02:29 pm »
According to the video the passenger pod is lowered into the Skylon.  A mobile crane could be used to extract the pod from a crashed Skylon.  The crane's wheels/tracks will need protecting against the cryogenic cold.

Offline tnphysics

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Re: Skylon
« Reply #312 on: 06/26/2011 09:41 pm »
Some key points on passenger safety issue

Most aircraft incidents happen at takeoff and landing and in aircraft incidences most causalities occur after the aircraft has come to a stop on the ground (hence the emphasis on rapid evacuation in safety briefings).  In our case we expect the outside environment to be more dangerous because of the cryogen propellants and the presence of an oxidiser; so evacuation maybe a more dangerous procedure than staying put.

There are two points that help us with this stay put approach. First; with aircraft the passengers are contained in the primary airframe we are not and so can consider the passenger module as protective structure and the airframe primary structure as an impact absorber. Second we have a sealed cabin with a full environmental support system again unlike an aircraft.

With a mid air-break up again the independent passenger structure puts us more into the Shuttle territory where the cabin structure survived the Challenger accident and we can learn lessons from this. It is possible that parachutes and airbags may give a substantial increase in survival probability from that type of incident.  However an active ejection system does not look feasible we rely on the module free falling from the break up.

An in orbit stranding is handed by a second SKYLON performing a rescue mission which is why the docking port is set 15 degrees off axis; it enables two SPLM equipped SKYLONs to dock without the airframes hitting each other.


I would be worried about a breakup in which some structure did not separate from the crew cabin and prevented parachute/airbag deployment.

Offline tnphysics

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Re: Skylon
« Reply #313 on: 06/27/2011 03:48 am »
Also, what about turning the nacelle ramjets (hmm...look alot like the warp nacelles from Star Trek!) into dual-mode scramjets that can provide airbreathing propulsion up to Mach 10 and beyond?

Offline Hempsell

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Re: Skylon
« Reply #314 on: 06/27/2011 02:19 pm »
According to the video the passenger pod is lowered into the Skylon.  A mobile crane could be used to extract the pod from a crashed Skylon.  The crane's wheels/tracks will need protecting against the cryogenic cold.

The cunning plan is to wait until everything is over rather than a Thunderbirds style rescue mid-disaster. To do this would require both the payload bay doors and the attachment mechanism to be working - which I think is a very unlikely eventuality after a crash.

Offline Hempsell

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Re: Skylon
« Reply #315 on: 06/27/2011 02:23 pm »

I would be worried about a breakup in which some structure did not separate from the crew cabin and prevented parachute/airbag deployment.

Yes I agree, but you are in a better position after a mid-air break up than in a conventional airliner.  We will have to see what comes out of the certification process when the passenger module development gets underway.

Offline Hempsell

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Re: Skylon
« Reply #316 on: 06/27/2011 02:32 pm »
Also, what about turning the nacelle ramjets (hmm...look alot like the warp nacelles from Star Trek!) into dual-mode scramjets that can provide airbreathing propulsion up to Mach 10 and beyond?

Ramjets we know and can design.

Scramjets we don't. Only the most basic of very simple and relatively low speed Scramjets have been experimentally proven, and no accelerating Scramjet is even in the serious offing. We need technologies at TRL 4 or above and this definately does not include Scramjets.

If we do have a scramjet, the intake would need to much larger and longer and the nacelle structure much stronger to the dry mass would start shotting up.  It is not obvious the performance gains would break even over the mass ratio.

Offline tnphysics

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Re: Skylon
« Reply #317 on: 06/27/2011 08:46 pm »
I did not mean to use the scramjets faster than the X-43 did, but I agree that it is too risky

Offline tnphysics

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Re: Skylon
« Reply #318 on: 07/02/2011 05:03 am »
One question: What about using the Skylon as a booster for spacecraft that already have their own engines, and thus can be their own upper stages?

Offline Archibald

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Re: Skylon
« Reply #319 on: 07/02/2011 08:44 am »
Similarly, does suborbital release of the upper stage augment payload to orbit?
I can't see, however, a Skylon carrying a smaller spaceplane, piggyback-style. I suppose the structure would need to be reinforced, plus the usual D-21/M-21 separation risk...

A different question. Could Skylon carry existing upper stages, cryogenic or not? for example a russian Breez-M or Block D?
« Last Edit: 07/02/2011 08:45 am by Archibald »
...you have been found guilty by the elders of the forum of a (imaginary) vendetta against Saint Elon - BLAAASPHEMER !

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