Project XSR - eXperimental Shuttle Replacement WIP

[CarlKinder]

This is a project that I'm developing for X-Plane 10.51, and I'm thinking about porting it over to Orbiter once it's finished. I can convert most of the objects used into blender files. I'm looking to refine this system as much as possible before it's released, so any input is appreciated...

Vehicle Summary:

Launch Profile: VTHL (Vertical Takeoff / Horizontal Landing) Triamese 1st stage with crossflow - parallel main engine burn.

Wingspan: 125ft

Height (gear to tail): 43.5ft

Length: 171ft

Tailspan: 80ft

Empty Weight: 200,000lb (manned orbiter), 195,000lb (unmanned orbiter), 190,000lb (unmanned booster)

Fuel weight: 1,100,000lb (manned/unmanned orbiter), 1,222,500lb (unmanned booster)

RCS/OMS (ethane+N2O): 20,000lb (manned/unmanned orbiter), 2,000lb (each unmanned booster)

Engine: RS-25 SSME Space Shuttle Main Engine (5 per vehicle) 418,000lb sea level thrust each

Stack total thrust at liftoff: 6,270,000 lb (15 RS-25 engines @104% throttle)

Payload weight: 50,000lb + 10,000lb discarding payload shroud with mounting hardware (load frame) and cross-flow plumbing

Stack total liftoff weight (Triamese launch – 1 orbiter + 2 boosters): 4,204,000lb

Liftoff thrust to weight: 1.49 : 1

Cross range capability estimate: ~ 800 – 900 miles

Delta-V Performance Estimates:



1st Stage (ISP estimated by average altitude during ascent):

9.81m/s^2*(370s)*ln(4,204,000lb/1,919,000lb) = 2,846.5 m/s

2nd Stage: (Orbiter Thrust to weight – 1.8 : 1)

9.81m/s^2*(420s)*ln(1,375,000lb/275,000lb) = 6,631.2 m/s

Orbiter total = 9,477.7 m/s – 1,850 m/s (Estimated aero & gravity losses)

= 7,627.7 m/s for polar orbit (military payload)



+ 250 m/s boost to ISS inclination = 7,877.7 m/s



+ 400 m/s boost to low inclination eastern orbit = 8,027.7 m/s



Post 2nd Stage booster Delta-V Brake (using reserve fuel – RCS depleted during attitude reverse):

9.81s*(400s)*ln(270,000lb/194,000lb) = 1,297.1 m/s

Orbiter RCS / OMS available Delta-V for orbital maneuvers & inclination changes:

9.81s*(310s)*ln(275,000lb/255,000lb) = 230 m/s (with 50,000lb payload)

The XSR is intended to be a follow on to the space shuttle with a number of design changes intended to eliminate deficiencies with the shuttle program. Areas of design emphasis are:

· Improved safety.

· Reduced operating costs.

· Increased performance.

· Reduced maintenance, recovery, and launch prep effort and time.

· Reduced development costs.

· Reduced environmental impact.

· Increased utility.

Improved safety:

Crews are housed in a module in the nose during manned missions, which is capable of stack separation with a safe parachute descent back to earth during a launch pad fire, ascent emergency, or orbital mishap. Such a system may have saved the crews of Challenger and Columbia (14 fatalities). Fuel tanks are housed within the insulated vehicle fuselages, reducing the chance for ice formation, and ice debris collision with heat shield tiles. Heat shield tiles are durable metallic thermal protection developed for the Venture Star program in place of the brittle ceramic tiles of the Shuttle.

Solid boosters are eliminated. Although cheap, they’re impossible to shut down or throttle once ignited, are difficult and expensive to recover and refurbish, and are environmentally unfriendly. Typical solid booster exhaust components are hydrochloric acid, aluminum oxide, chlorine, carbon dioxide, and nitrogen oxide. The RS-25 engines used as the Space Shuttle Main Engine (and for all engines on the XSR) burn hydrogen (H2) and oxygen (O2) creating water (steam) as the major combustion byproduct (2h2 + 02 -> 2h2O). In addition, the toxic hypergolic RCS / OMS fuel system used in the shuttle for orbital maneuvering is replaced with a non-toxic ethane fuel with nitrous oxide as the oxidizer.

XSR is designed for automated glide landing recovery of the boosters downrange of the launch site, and unpowered glide landing of the orbiter. Boosters are towed back to the launch site by C-17. Launches would take place in south Texas (Houston) with booster recovery in an arc from Florida to North Dakota (depending on final orbit inclination). Quick recovery, refit and refueling of orbiters and boosters allow for reduced operating costs, and faster launch turnaround times.

Identical components, and aerodynamic shapes used in the boosters and orbiter allow for reduced design, testing, and manufacturing time and costs, reducing total development costs. As an added bonus, the entire system can be scaled up or down to fit multiple missions. A single booster can be launched with a disposable 2nd stage attached to a small payload for lower payload weight missions. The triamese launch configuration is used for larger payloads, and for ferrying crews in and out of orbit. Two or three XSR unmanned boosters can even be attached for augment liftoff thrust in place of solid rocket boosters on a large SLS, or Saturn V style rocket for very heavy payloads bound for the moon or beyond. By contrast, the massive budget needs, and limited performance of the shuttle is blamed for stifling human space exploration outside of low earth orbit since its entry into service.

Engineering challenges: At launch the XSR requires 15 x RS-25 engines to operate simultaneously without failure. In addition, the fuel tanks would need to be able to survive numerous pressurization / depressurization + re-entry heating without failure. An affordable way to refurbish and service the RS-25 would need to be established (which was never realized by the shuttle program)