LITTLE SISTER

SOPHIE THE FAITHFUL ORBITER

Our previous post examined a blended wing body aircraft designed to be a booster stage for horizontal launch to orbit.  A reusable booster can be a step to reduced launch costs and it can also offer some comfort and safety advantages.  Today we look at an upper stage vehicle to reach orbit and return to earth.

 S1

 This vehicle is a low aspect ratio flying wing or lifting body.  It has more length and less wingspan which serves to enhance lift on takeoff and reduce mass for orbital flight.  A lifting body has lots of internal volume and structure for fuel tanks and cargo.  When attached to the front of the first stage it serves as a leading edge strake to create a vortex in high angle of attack flight.  The Concorde wing was optimized to use this vortex, allowing it to operate without mechanical flaps on takeoff.

The swept wings position the tails far to the rear, allowing stability without oversized vertical surfaces.  For safety a third stage vehicle is blended into the upper surface for emergency escape.  Crew and passengers are always able to separate from the two booster stages at any time in the flight.  The Crew Rescue Vehicle (CRV) is based on the form of the operational X-37 space plane.  A thin skin covering blends the CRV to the main second stage vehicle.

Stage separation from the booster can use methods in use in vertical launch for decades.  It is possible that pyrotechnic  or mechanical devices may join the craft.  A boost at staging may be provided by compressed gas or small rockets.  Separating the orbiter to the front avoids the potential of collision that challenges stacked stages.

F6

JOINED LAUNCH

 S2

 The aft cowl over the engines provides some vertical walls that aid the structural attachment to the first stage.  Other aircraft have operated with in-line staging so this is not new or impossible.  These two aircraft are designed to blend the wings for better lift and reduced drag.

 S3

 Propulsion to orbit uses both liquid and hybrid rockets.  The hybrids are single use, but unlike solids they can be shut down if needed.  The liquids can be throttled, shut down, and re-started as required.  They can provide reverse thrust to de-orbit, and throttled for powered landing if needed.

 S5

CROSS SECTION

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 In an emergency the covers can be ejected for CRV separation.  The covers may also be hinged to allow the CRV to perform activities on orbit.  The smaller vehicle is better suited to station docking.

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When preparing for reentry the vehicle may use a “jack-knife” design similar to Scaled Composite suborbital vehicles.  Heat and speed may be bled off by combined high drag turns and high angle of attack flight.

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 The CRV is entirely shielded by the large delta wing during reentry.

 S14

 During reentry the body flap deploys rearward to shield the engines from reentry heat.

 S16

 With the elevator sections raised, the vehicle presents only a basic flat bottom as a reentry heat shield.  Aggressive surfaces maintain control as atmosphere begins to flow again.

 S17

 The CRV nose protrudes slightly to launch a slight shock wave in front of the wind screen glass.  Our crew and passengers can enjoy the view without over stressing the thermal properties of the cabin glass.

 S18

 The pressure hull and inner glass are some secondary backing against thermal or impact failures.

 S20

Lunar construction crews, asteroid miners, and tourists are ready to go home to earth.    A runway landing allows family to meet them, and eliminates waiting for water recovery and transportation.

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WHEELS DOWN!

 S24

On final approach the elevators enhance the high angle of attack and minimize the chance of a tail strike.

 S25

 The vortex formation at high angle of attack will increase lift for an easy landing.  Please remain seated until the aircraft is fully stopped at the terminal!

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