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Space Policy Online's report on IAC2014 Day Three: Stratolaunch and Sierra Nevada Courting on Dream Chaser mentions that:

... Stratolaunch would be used to launch a 75 percent version of Dream Chaser into low Earth orbit (LEO).

And goes on to somewhat elaborate:

A Stratolaunch-Dream Chaser system envisions using Stratolaunch to launch a 75 percent version of Dream Chaser into space with cargo or two-three crew. It could launch and return to the launch site within 24 hours in a “responsive space” mode. It could take off from anywhere in the world and deliver cargo or people to any inclination orbit and, with its cross-range capability, land anywhere there is a runway that can handle a 747 or A320 aircraft.

But I didn't find any further information on what exactly is meant with these "75%". 75 percent of / by what? Of its size? Carrying capacity? By volume? Time supporting orbital activities?

So, failing to find further info on this so-called 75 percent version of Dream Chaser, short of what the linked article mentions about the differences with the full-scale Dream Chaser that Sierra Nevada competed with for NASA's CCDev / CCtCap, i.e. that the smaller scale version will support a two to three crew flights only, how else will it differ from current Dream Chaser design?

Wouldn't that mean, for example, it's basically going back to the HL-20 Personnel Launch System design and using Launch Escape System (LES) adapter instead of integrating LES into its body? 75% also can't refer to supported crew size since the HL-20 was meant to service up to ten astronauts, the version of Dream Chaser that SNC competed for NASA's CCDev / CCtCap would have serviced seven, and this new version is supposed to service up to three astronauts. That's more than half the reduction in crew size.

So which new design features would this "75% version" keep from its bigger brethren (Dream Chaser / HL-20), and which of its systems would go back to the drawing boards or have already undergone change?

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    $\begingroup$ Stratolaunch and Dream Chaser? Holy cow, there's nothing stopping them! $\endgroup$ – HDE 226868 Oct 3 '14 at 15:03
  • $\begingroup$ "- I like this car! Can you make me a 75% sized version of it? You know, with a three cylinder engine, three wheels and a back seat for only one." $\endgroup$ – LocalFluff Oct 21 '14 at 10:29
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Your linked article says the 75% version would carry cargo or 2-3 crew; the Wikipedia article on Dream Chaser says it could carry 7 crew. From that, my guess would be that they're talking about a 75%-scale version of the ship.

This article seems to back that interpretation: http://www.sncorp.com/press_more_info.php?id=636

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  • $\begingroup$ OK yes that's a given, the article I linked to mentions that, but I'm still not sure what all this 75%-scale involves and what systems will be changed. $\endgroup$ – TildalWave Oct 2 '14 at 17:44
  • $\begingroup$ Dream Chaser and HL-20 are basically the same size. To build a scaled-down version, I assume a great many hardware/airframe components would have to be redesigned, using lessons-learned from the full size system. Presumably avionics wouldn't change much. $\endgroup$ – Russell Borogove Oct 2 '14 at 17:49
  • $\begingroup$ One of the lessons I learned here about the differences between HL-20 and Dream Chaser is that Sierra Nevada Corp. integrated LES into the Dream Chaser body, something that HL-20 used an adapter for. Would, for example, a smaller scale Dream Chaser still integrate LES, or would they revert back to using a separate unit with a new adapter? And I do apologize for my ninja-edit of the question, I kinda wrote it in a hurry and forgot to mention that I did read the linked to article in full. That it's gonna support smaller crew only is already mentioned there, but what else changes? $\endgroup$ – TildalWave Oct 2 '14 at 17:54

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