Virgin choose hybrid engine as it is lot safer than liquid engine. Fuel is a solid in engine, remove LOX and it is inert. Adding small capsule with LAS would reduce viewing windows and space to experience 0g, whole point of flight. Sub orbital flights aren't going to be anywhere near as safe as aircraft flight. Its a risk customers need to be aware.
I don't think there is a need for an abort system. If something breaks on the flight maybe an airframe parachute could improve safety:https://cirrusaircraft.com/innovation/airframe-parachute/
This is the idea I had in mind, when I opened the thread:
Additionally, airplane crashes are so rare that having an ejectable cabin with parachutes isn't worth the cost in fuel it would require to fly it around.
Quote from: whitelancer64 on 03/19/2019 09:51 pmAdditionally, airplane crashes are so rare that having an ejectable cabin with parachutes isn't worth the cost in fuel it would require to fly it around. A not-completely-irrelevant comparison might be the crew escape capsules used in the F-111 (and other) supersonic aircraft. IIRC, not all ejections resulted in happy memories for the crew - sure some did, but many still died on impact or as a result of the capsule being compromised in some way - and general consensus appears divided over whether or not they're a good idea.https://en.wikipedia.org/wiki/Escape_crew_capsule
The question is if this system can handle the extra mass penalty to incorporate a LES and still meet it's performance requirements to make it to space... Would they then have redefine what a spaceflight altitude downward again from 62, 50... You get the idea...
Quote from: Rocket Science on 03/19/2019 11:30 pmThe question is if this system can handle the extra mass penalty to incorporate a LES and still meet it's performance requirements to make it to space... Would they then have redefine what a spaceflight altitude downward again from 62, 50... You get the idea...The NASA / USAF definition of space has always been 50 miles, VG lowered their target altitude, they didn't change a definition. Also there's a fair argument to be made on lowering the definition of "space" to 80 km based on the lowest observed perigee of satellite orbits.
Quote from: whitelancer64 on 03/20/2019 06:55 pmQuote from: Rocket Science on 03/19/2019 11:30 pmThe question is if this system can handle the extra mass penalty to incorporate a LES and still meet it's performance requirements to make it to space... Would they then have redefine what a spaceflight altitude downward again from 62, 50... You get the idea...The NASA / USAF definition of space has always been 50 miles, VG lowered their target altitude, they didn't change a definition. Also there's a fair argument to be made on lowering the definition of "space" to 80 km based on the lowest observed perigee of satellite orbits.You are misinterpreting what I'm saying... The system does not have the excessive performance required to incur a mass penalty and make it to space FAI or USAF/NASA... This is a hypothetical query of a system with a LES and based on existing performance parameters, what would VG sell as a ride to space then 40mi 30mi...?
Quote from: Rocket Science on 03/20/2019 07:23 pmQuote from: whitelancer64 on 03/20/2019 06:55 pmQuote from: Rocket Science on 03/19/2019 11:30 pmThe question is if this system can handle the extra mass penalty to incorporate a LES and still meet it's performance requirements to make it to space... Would they then have redefine what a spaceflight altitude downward again from 62, 50... You get the idea...The NASA / USAF definition of space has always been 50 miles, VG lowered their target altitude, they didn't change a definition. Also there's a fair argument to be made on lowering the definition of "space" to 80 km based on the lowest observed perigee of satellite orbits.You are misinterpreting what I'm saying... The system does not have the excessive performance required to incur a mass penalty and make it to space FAI or USAF/NASA... This is a hypothetical query of a system with a LES and based on existing performance parameters, what would VG sell as a ride to space then 40mi 30mi...?VG isn't going to add a LAS into SS2, so it's pretty irrelevant. Even 30 miles is still higher than manned balloons can go, so there's that.
If it is too risky for the crew to bail out of SpaceShipTwo or SpaceShipThree at high altitude in the event of a mishap with the rocket motor, then the best option for the crew would be for SS3 to carry out a sustained glide down to a distant airport in the eastern US, Europe, or Japan at Mach 2.7.
Quote from: CameronD on 03/19/2019 10:01 pmQuote from: whitelancer64 on 03/19/2019 09:51 pmAdditionally, airplane crashes are so rare that having an ejectable cabin with parachutes isn't worth the cost in fuel it would require to fly it around. A not-completely-irrelevant comparison might be the crew escape capsules used in the F-111 (and other) supersonic aircraft. IIRC, not all ejections resulted in happy memories for the crew - sure some did, but many still died on impact or as a result of the capsule being compromised in some way - and general consensus appears divided over whether or not they're a good idea.https://en.wikipedia.org/wiki/Escape_crew_capsuleF-111 was designed for crew survival from combat damage, real possibility given that it is warplane. The SS2 will be flying in perfect conditions, any failures are likely to be from poor design or pilot error. Adding LAS means they have very little confidence in the design and crew, its like placing ambulance at base of the cliff.