Spaceplanes that are suborbital are mostly supersonic and feature H-tail or rather large wingtips. This looks to be similar to a H-tail configuration but I'm unsure abut how it works, which is why I say large wing tips. They focus on a delta wing and elevon for the pitch and roll and yaw seems to be controlled using this. For example look at the following spaceplanes. vss unitydream chaser NASA(Cancelled) XCOR Lynx

1. https://www.virgingalactic.com/articles/VSS-Unity-First-Powered-Flight/
2. https://www.sncorp.com/what-we-do/dream-chaser-space-vehicle/
3. https://www.flyfighterjet.com/xcor-lynx-space-flight


At extreme speed, the more symmetry you have, the better your chances are of staying straight. This is especially of concern at very high altitudes, where aerodynamic forces (indicated airspeed) are small. X15 is good example of this. Also, H type tail helps keep control surfaces away from the rocket nozzle.

Shuttle type vehicles also emphasize roll and pitch stability in re-entry. Very interesting to note the humble capsule has 360 degrees of roll stability (there for also pitch). The Soviets liked the ball, with the weight set a little low, for the same reason.

Space ship 2 has the (shuttle cock) feathered configuration. Dream Chaser (and the Air Force) has strong dihedral. These just want to come in upright and land safely.


Dreamchaser isn't intended to be suborbital. Don't know about your 3rd picture, but the Spaceship 1 & 2 were designed by the same person/company, so it's not surprising they use the same design elements.

The designs of Dreamchaser vs Spaceship N address two different problems. An orbital vehicle has to decelerate from ~17,000 mph, while a suborbital vehicle on a ballistic trajectory (simplistically straight up and straight down) starts from zero speed at its high point, and needs to keep from gaining too much speed. So if I'm not mistaken, a main function of the H-tail is to allow the entire vehicle to act as a drag device. That wouldn't be practical for an orbital reentry vehicle due to heating & aerodynamic forces.

  • $\begingroup$ Dream Chaser worries about gaining too much speed too, especially during re-entry. Both it and Space Ship 2 want to stably slow down from space to atmosphere and glide home. The third plane is concept only, it's company went out of business. $\endgroup$ – Robert DiGiovanni Sep 26 '18 at 2:23
  • $\begingroup$ In other words, after deorbit burn, Dream Chaser, now suborbital, but with much more potential and kinetic energy, must slow down and glide as well. So needs heat shield, Space Ship 2, not as much. $\endgroup$ – Robert DiGiovanni Sep 26 '18 at 15:38
  • $\begingroup$ @Robert DiGiovanni: As I said, suborbital flights start from essentially zero speed at the top of their arc, and want to keep from gaining speed (think parachute). Any orbital reentry vehicle starts from orbital speed (otherwise it wouldn't be in orbit, of course) and slows down. The problem there is to manage the slowing in a controlled way. $\endgroup$ – jamesqf Sep 26 '18 at 18:07
  • $\begingroup$ Here's where it gets good. An object in orbit starts with 0 vertical speed as well. It's all potential energy. It does have horizontal speed, and so does sub-orb (think Redstone). The task of returning to around 200 knot glide through the air is the same, why separate them? There for Dream Chaser is qualified for sub-orb flight. Imagine how much smaller the Space Shuttle's fuel tanks would be if it were sub orb as well. $\endgroup$ – Robert DiGiovanni Sep 26 '18 at 18:24
  • $\begingroup$ When Spaceship 2 feathers in vacuum, it will accelerate quite a bit before entering denser atmosphere. Not enough for significant heating, so I agree the strategy is more "parachute". Both want to be stable, hence the heartfelt efforts at weight low, drag high. $\endgroup$ – Robert DiGiovanni Sep 26 '18 at 18:30

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