WhiteKnightTwo Flight Test Summaries
The following list includes summaries of the flight test activity of the WhiteKnightTwo (WK2) aircraft. WhiteKnightTwo is the mothership/launch aircraft for SpaceShipTwo (SS2) and potentially other large payloads. It is equipped with many common system components to SS2 (cabin, ECS, speed-brake actuators, avionics, trim servos, air data, test data, video & TM). Thus, the flight test program of WK2 includes many tests that focus on SS2 systems qualification and maturity.
Objectives:
SS2 GF01 mission practice
SS2 approach practice
Crew proficiency and training
Results:
All objectives achieved. Multiple SS2 approaches flown.
Objectives:
Payload ECS heat characterization
SS2 release dry run
SS2 GF01 mission practice
SS2 approach practice
Crew proficiency and training
Results:
All objectives achieved. Multiple SS2 approaches flown to touchdown.
Objectives:
SS2 approach simulations
GF01 glide card practice
Crew proficiency and training
Results:
All objectives achieved. Multiple SS2 approaches flown to touchdown.
Objectives:
SS2 release dry run
SS2 GF01 mission practice
SS2 approach practice
Crew proficiency and training
Results:
All objectives achieved. Multiple SS2 approaches flown to touchdown.
Objectives:
SS2 mission practice
ECS evaluation
Control evaluation
Low fuel evaluation
Window fog evaluation
Results:
All objectives achieved. Climed to 51,500 ft and the ECS performed flawlessly. Flew cross-country to descend over the Pacific to evaluate window fogging. Upon return to the desert, performed controls evaluation which showed good positive control with power loss. Performed "roller coasters" (45° climb, low g pushover followed by 30° nose low dive) to evaluate low fuel states. Touch and goes were uneventful. Full stop landing on Rwy 26.
Objectives:
New hydraulic speedbrake evaluation
Pylon on altitude envelope expansion
SS2 mission practice
Pilot qualitative evaluation
Results:
All objectives achieved. New hydraulically actuated speedbrakes performed as designed. Expanded envelope with pylon installed to 51,000 ft. SS2 approaches flown to RWY 30. For the first time on the program, crew landed on the shorter, narrower 26 RWY.
Objectives:
Nosegear mod evaluation
Pylon evaluation
ECS evaluation
Results:
Objectives met. Successful evaluation of launch pylon effect on aircraft performance, handling and controls. Fired pylon mechanism in flight for first time.
Objectives:
Launch pylon envelope expansion and performance effects
Landing gear door evaluation
SpaceShipTwo approach guidance evaluation
Pilot proficiency
Results:
Launch pylon and gear doors performed well. Multiple SpaceShipTwo approaches flown.
Objectives:
Spoilflap loads data
Continued ECS testing
GPS airspeed calibration
Return from Edwards Air Show
Results:
Objectives achieved. Airborne pickup and unrestricted climb departure from Edwards Open House with WK.
Objectives:
Spoilflap loads data
ECS evaluation
GPS airspeed calibration
Roll effects of angle of attack
Edwards Air Show practice
Results:
GPS airspeed cal and approaches scrubbed for time. Other objectives achieved. Demo performed on arrival to Edwards Air Force Base "Flight Test Nation" Open House/Air Show.
Objectives:
Modified spoilflap envelope expansion
Pressurization/ECS functionality with SS2 valves to 50,000 ft
Landing gear/spoilflap cold soak extension retraction
Fuel system temperature evaluation
Avionics and instrument approach checkout
Aircrew proficiency
Edwards Air Show practice
Results:
Objectives achieved.
Objectives:
Return to Mojave
Results:
Evaluated systems functionality and performance on return trip to Mojave.
Objectives:
Oshkosh demo flight
Results:
Demo flight performed.
Objectives:
Oshkosh demo flight
Results:
Demo flight performed.
Objectives:
Cross country to Oshkosh AirVenture
Results:
Evaluated systems functionality and performance on trip to Oshkosh. Arrived at KOSH and performed short demo flight.
Objectives:
Oshkosh dress rehersal
Results:
Objectives achieved. Practiced all procedures and plans in preparation for our long cross country to the Oshkosh AirVenture Convention. Practiced demo flight after simulated mission profile.
Objectives:
Evaluate new DAS build
Instrument approach practice
FAA monitored flight for pilot "Type Rating"
Results:
All objectives completed. Rating Issued.
Objectives:
Eval control surface mods
Eval pitot probe relocation
Instrument approach practice
Pilot LOA practice
Results:
All objectives completed. Peak altitude for flight 51,000 ft. Instrument approaches practiced. LOA maneuvers practiced.
Objectives:
ECS evaluation
Third seat evaluation
Performance
Landing gear envelope expansion
Results:
All objectives completed. ECS shows exceptional cabin heating and cooling capability. Third seat adequate for test engineer duties. Gear extended out to 160 KEAS. Peak altitude for flight 51,000 ft. Instrument approach and touch and go at Victorville.
Objectives:
Flyby at Los Cruses, NM in support of Spaceport America event
Instrument approaches
Results:
Despite mechanical issues the day before, the Scaled team was able to turn the jet around for a Saturday morning demo at Los Cruses. Several flybys and approaches were performed for spectators in support of the Spaceport America groundbreaking. Systems were evaluated on the high altitude return leg to Mojave. One simulated approach was made to runway 26 before landing on 30.
Objectives:
To evaluate performance, stability and control, and cold soak effects on first long cross country
Flyby at Spaceport America as able
Results:
En route testing above 40,000 ft was uneventful. During the descent toward the Spaceport America groundbreaking we experienced a failure of a speedbrake actuator. Based on facilities available and logistics for our ground crew, the pilots elected to make a precautionary landing at Williams Gateway airport near Phoenix. Our ground crew is on site and we hope to return to Mojave either this afternoon or tomorrow morning.
Objectives:
Weight expansion at mid cg
Further pressurization/ECS functionality checks to 51,000 ft
Speed envelope expansion
Airborne engine relights
Results:
All objectives completed. Pressurization and ECS worked as designed. Speed envelope expanded with the gear up to 370 KTAS. Peak altitudes increased to 52,400 ft. Performance, stability and handling evaluation performed at altitude. Engines were shut down and restarted per plan. Practiced instrument approaches.
Objectives:
FAA monitored flight for issuance of pilot letter of authorization
Results:
Letter of authorization issued
Objectives:
Weight expansion at mid cg
Further pressurization/ECS functionality checks to 45,000 ft
Speed envelope expansion
G envelope expansion
Airborne engine relights
Results:
All objectives completed. Pressurization and ECS worked as designed. Speed envelope expanded with the gear up and down to 340 KTAS. Peak altitude increased to 45,000 ft. Wind-up turns were performed to 2.5 g's. Engines were shut down and restarted per plan.
Objectives:
Weight expansion at mid cg
Further pressurization/ECS functionality checks to 35,000 ft
Gear-down speed envelope expansion
Results:
All objectives completed. Pressurization and ECS worked as designed. Speed envelope expanded to 250 KTAS with the gear down. Peak altitude increased to 35,000 ft. Starship was onboard for video and safety chase. Two low approaches were followed by a full stop landing.
Objectives:
Aft center of gravity handling qualities evaluation
Initial evaluation of pressurization and environmental control systems (ECS)
Results:
All objectives completed. Pressurization and ECS worked as designed. Airspeed increased to 188 KTAS. Max altitude 20,000 ft. After landing, conducted an emergency response drill, including both Scaled and Mojave Air and Space Port resources.
Objectives:
New pilot integration
Envelope expansion
Landing gear evaluation
Results:
Objectives achieved. Stability and controls, performance and speed brakes evaluated to 140 KTAS, max 2 g's and altitude of 18,000 ft. Landing gear cycled at 100 KTAS. Asymmetric thrust on go-around resulted in large pitch and yaw excursions including tail contact with ground.
Objectives:
Envelope expansion
Landing gear evaluation
Engine in-flight restarts
Results:
Objectives achieved. Stability and controls, performance and speed brakes evaluated to 135 KTAS. Max altitude 20,000 ft. Engine in-flight restarts were cooler than planned.
Objectives:
Envelope expansion
Results:
Objectives achieved. Gear down speed expansion to 130 KTAS, max 1.5 g, and max altitude of 18,000 ft.
Objectives:
First flight
Qualitative assessment of stability and controls to facilitate a safe landing.
Results:
Objective achieved. Gear down envelope to 110 KTAS. Max altitude 18,000 ft. "Beautiful airplane to fly."
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| Flight: | 32 | Date: | 1 Jul 10 |
| Flight Time: | 5.3 hr | ||
| Pilot: | Siebold | CoPilot: | Stucky |
| FTE: | Harvey | ||
Objectives:
SS2 GF01 mission practice
SS2 approach practice
Crew proficiency and training
Results:
All objectives achieved. Multiple SS2 approaches flown.
| Flight: | 31 | Date: | 30 Jun 10 |
| Flight Time: | 5.3 hr | ||
| Pilot: | Stucky | CoPilot: | Siebold |
| FTE: | Agold | ||
Objectives:
Payload ECS heat characterization
SS2 release dry run
SS2 GF01 mission practice
SS2 approach practice
Crew proficiency and training
Results:
All objectives achieved. Multiple SS2 approaches flown to touchdown.
| Flight: | 30 | Date: | 24 Jun 10 |
| Flight Time: | 2 hr | ||
| Pilot: | Siebold | CoPilot: | Alsbury |
| FTE: | Reeder | ||
Objectives:
SS2 approach simulations
GF01 glide card practice
Crew proficiency and training
Results:
All objectives achieved. Multiple SS2 approaches flown to touchdown.
| Flight: | 29 | Date: | 24 Jun 10 |
| Flight Time: | 3.4 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | Persall | ||
Objectives:
SS2 release dry run
SS2 GF01 mission practice
SS2 approach practice
Crew proficiency and training
Results:
All objectives achieved. Multiple SS2 approaches flown to touchdown.
| Flight: | 28 | Date: | 15 Jun 10 |
| Flight Time: | 5.3 hr | ||
| Pilot: | Siebold | CoPilot: | Stucky |
| FTE: | Stinemetze | ||
Objectives:
SS2 mission practice
ECS evaluation
Control evaluation
Low fuel evaluation
Window fog evaluation
Results:
All objectives achieved. Climed to 51,500 ft and the ECS performed flawlessly. Flew cross-country to descend over the Pacific to evaluate window fogging. Upon return to the desert, performed controls evaluation which showed good positive control with power loss. Performed "roller coasters" (45° climb, low g pushover followed by 30° nose low dive) to evaluate low fuel states. Touch and goes were uneventful. Full stop landing on Rwy 26.
| Flight: | 26 | Date: | 1 May 10 |
| Flight Time: | 5.5 hr | ||
| Pilot: | Stucky | CoPilot: | Shane |
| FTE: | Maisler | ||
Objectives:
New hydraulic speedbrake evaluation
Pylon on altitude envelope expansion
SS2 mission practice
Pilot qualitative evaluation
Results:
All objectives achieved. New hydraulically actuated speedbrakes performed as designed. Expanded envelope with pylon installed to 51,000 ft. SS2 approaches flown to RWY 30. For the first time on the program, crew landed on the shorter, narrower 26 RWY.
| Flight: | 24 | Date: | 4 Mar 10 |
| Flight Time: | 3.7 hr | ||
| Pilot: | Stucky | CoPilot: | Nichols |
| FTE: | Kalogiannis | ||
Objectives:
Nosegear mod evaluation
Pylon evaluation
ECS evaluation
Results:
Objectives met. Successful evaluation of launch pylon effect on aircraft performance, handling and controls. Fired pylon mechanism in flight for first time.
| Flight: | 23 | Date: | 28 Jan 10 |
| Flight Time: | 3.1 hr | ||
| Pilot: | Stucky | CoPilot: | Binnie |
| FTE: | Kalogiannis | ||
Objectives:
Launch pylon envelope expansion and performance effects
Landing gear door evaluation
SpaceShipTwo approach guidance evaluation
Pilot proficiency
Results:
Launch pylon and gear doors performed well. Multiple SpaceShipTwo approaches flown.
| Flight: | 22 | Date: | 17 Oct 09 |
| Flight Time: | 1.2 hr | ||
| Pilot: | Stucky | CoPilot: | Kalogiannis |
| FTE: | Stinemetze | ||
Objectives:
Spoilflap loads data
Continued ECS testing
GPS airspeed calibration
Return from Edwards Air Show
Results:
Objectives achieved. Airborne pickup and unrestricted climb departure from Edwards Open House with WK.
| Flight: | 21 | Date: | 17 Oct 09 |
| Flight Time: | 1.3 hr | ||
| Pilot: | Stucky | CoPilot: | Kalogiannis |
| FTE: | Stinemetze | ||
Objectives:
Spoilflap loads data
ECS evaluation
GPS airspeed calibration
Roll effects of angle of attack
Edwards Air Show practice
Results:
GPS airspeed cal and approaches scrubbed for time. Other objectives achieved. Demo performed on arrival to Edwards Air Force Base "Flight Test Nation" Open House/Air Show.
| Flight: | 20 | Date: | 15 Oct 09 |
| Flight Time: | 3.5 hr | ||
| Pilot: | Stucky | CoPilot: | Kalogiannis |
| FTE: | Stinemetze | ||
Objectives:
Modified spoilflap envelope expansion
Pressurization/ECS functionality with SS2 valves to 50,000 ft
Landing gear/spoilflap cold soak extension retraction
Fuel system temperature evaluation
Avionics and instrument approach checkout
Aircrew proficiency
Edwards Air Show practice
Results:
Objectives achieved.
| Flight: | 19 | Date: | 1 August 09 |
| Flight Time: | 5.1 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | Morgan | ||
Objectives:
Return to Mojave
Results:
Evaluated systems functionality and performance on return trip to Mojave.
| Flight: | 18 | Date: | 31 July 09 |
| Flight Time: | 0.2 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | Morgan | ||
Objectives:
Oshkosh demo flight
Results:
Demo flight performed.
| Flight: | 17 | Date: | 25 July 09 |
| Flight Time: | 0.2 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | Branson | ||
Objectives:
Oshkosh demo flight
Results:
Demo flight performed.
| Flight: | 16 | Date: | 27 July 09 |
| Flight Time: | 5.5 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | Morgan | ||
Objectives:
Cross country to Oshkosh AirVenture
Results:
Evaluated systems functionality and performance on trip to Oshkosh. Arrived at KOSH and performed short demo flight.
| Flight: | 15 | Date: | 21 July 09 |
| Flight Time: | 5.7 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | Morgan | ||
Objectives:
Oshkosh dress rehersal
Results:
Objectives achieved. Practiced all procedures and plans in preparation for our long cross country to the Oshkosh AirVenture Convention. Practiced demo flight after simulated mission profile.
| Flight: | 14 | Date: | 17 July 09 |
| Flight Time: | 0.9 hr | ||
| Pilot: | Stucky | CoPilot: | Siebold |
| FTE: | None | ||
Objectives:
Evaluate new DAS build
Instrument approach practice
FAA monitored flight for pilot "Type Rating"
Results:
All objectives completed. Rating Issued.
| Flight: | 13 | Date: | 14 July 09 |
| Flight Time: | 5 hr | ||
| Pilot: | Stucky | CoPilot: | Siebold |
| FTE: | None | ||
Objectives:
Eval control surface mods
Eval pitot probe relocation
Instrument approach practice
Pilot LOA practice
Results:
All objectives completed. Peak altitude for flight 51,000 ft. Instrument approaches practiced. LOA maneuvers practiced.
| Flight: | 12 | Date: | 9 July 09 |
| Flight Time: | 4.5 hr | ||
| Pilot: | Stucky | CoPilot: | Siebold |
| FTE: | None | ||
Objectives:
ECS evaluation
Third seat evaluation
Performance
Landing gear envelope expansion
Results:
All objectives completed. ECS shows exceptional cabin heating and cooling capability. Third seat adequate for test engineer duties. Gear extended out to 160 KEAS. Peak altitude for flight 51,000 ft. Instrument approach and touch and go at Victorville.
| Flight: | 11 | Date: | 20 June 09 |
| Flight Time: | 3 hr (planned) | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | None | ||
Objectives:
Flyby at Los Cruses, NM in support of Spaceport America event
Instrument approaches
Results:
Despite mechanical issues the day before, the Scaled team was able to turn the jet around for a Saturday morning demo at Los Cruses. Several flybys and approaches were performed for spectators in support of the Spaceport America groundbreaking. Systems were evaluated on the high altitude return leg to Mojave. One simulated approach was made to runway 26 before landing on 30.
| Flight: | 10 | Date: | 19 June 09 |
| Flight Time: | 6 hr (planned) | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | None | ||
Objectives:
To evaluate performance, stability and control, and cold soak effects on first long cross country
Flyby at Spaceport America as able
Results:
En route testing above 40,000 ft was uneventful. During the descent toward the Spaceport America groundbreaking we experienced a failure of a speedbrake actuator. Based on facilities available and logistics for our ground crew, the pilots elected to make a precautionary landing at Williams Gateway airport near Phoenix. Our ground crew is on site and we hope to return to Mojave either this afternoon or tomorrow morning.
| Flight: | 09 | Date: | 15 June 09 |
| Flight Time: | 7.5 hr | ||
| Pilot: | Siebold | CoPilot: | Stucky |
| FTE: | None | ||
Objectives:
Weight expansion at mid cg
Further pressurization/ECS functionality checks to 51,000 ft
Speed envelope expansion
Airborne engine relights
Results:
All objectives completed. Pressurization and ECS worked as designed. Speed envelope expanded with the gear up to 370 KTAS. Peak altitudes increased to 52,400 ft. Performance, stability and handling evaluation performed at altitude. Engines were shut down and restarted per plan. Practiced instrument approaches.
| Flight: | 08 | Date: | 11 June 09 |
| Flight Time: | 1 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | None | ||
Objectives:
FAA monitored flight for issuance of pilot letter of authorization
Results:
Letter of authorization issued
| Flight: | 07 | Date: | 8 June 09 |
| Flight Time: | 6.1 hr | ||
| Pilot: | Siebold | CoPilot: | Alsbury |
| FTE: | None | ||
Objectives:
Weight expansion at mid cg
Further pressurization/ECS functionality checks to 45,000 ft
Speed envelope expansion
G envelope expansion
Airborne engine relights
Results:
All objectives completed. Pressurization and ECS worked as designed. Speed envelope expanded with the gear up and down to 340 KTAS. Peak altitude increased to 45,000 ft. Wind-up turns were performed to 2.5 g's. Engines were shut down and restarted per plan.
| Flight: | 06 | Date: | 2 June 09 |
| Flight Time: | 3.1 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | None | ||
Objectives:
Weight expansion at mid cg
Further pressurization/ECS functionality checks to 35,000 ft
Gear-down speed envelope expansion
Results:
All objectives completed. Pressurization and ECS worked as designed. Speed envelope expanded to 250 KTAS with the gear down. Peak altitude increased to 35,000 ft. Starship was onboard for video and safety chase. Two low approaches were followed by a full stop landing.
| Flight: | 05 | Date: | 20 May 09 |
| Flight Time: | Approx. 3 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | None | ||
Objectives:
Aft center of gravity handling qualities evaluation
Initial evaluation of pressurization and environmental control systems (ECS)
Results:
All objectives completed. Pressurization and ECS worked as designed. Airspeed increased to 188 KTAS. Max altitude 20,000 ft. After landing, conducted an emergency response drill, including both Scaled and Mojave Air and Space Port resources.
| Flight: | 04 | Date: | 20 Apr 09 |
| Flight Time: | 4 min | ||
| Pilot: | Siebold | CoPilot: | Binnie |
| FTE: | None | ||
Objectives:
New pilot integration
Envelope expansion
Landing gear evaluation
Results:
Objectives achieved. Stability and controls, performance and speed brakes evaluated to 140 KTAS, max 2 g's and altitude of 18,000 ft. Landing gear cycled at 100 KTAS. Asymmetric thrust on go-around resulted in large pitch and yaw excursions including tail contact with ground.
| Flight: | 03 | Date: | 25 Mar 09 |
| Flight Time: | 2 hr 20 min | ||
| Pilot: | Siebold | CoPilot: | Morgan |
| FTE: | None | ||
Objectives:
Envelope expansion
Landing gear evaluation
Engine in-flight restarts
Results:
Objectives achieved. Stability and controls, performance and speed brakes evaluated to 135 KTAS. Max altitude 20,000 ft. Engine in-flight restarts were cooler than planned.
| Flight: | 02 | Date: | 4 Feb 09 |
| Flight Time: | 1.5 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | None | ||
Objectives:
Envelope expansion
Results:
Objectives achieved. Gear down speed expansion to 130 KTAS, max 1.5 g, and max altitude of 18,000 ft.
| Flight: | 01 | Date: | 21 Dec 08 |
| Flight Time: | 1 hr | ||
| Pilot: | Siebold | CoPilot: | Nichols |
| FTE: | None | ||
Objectives:
First flight
Qualitative assessment of stability and controls to facilitate a safe landing.
Results:
Objective achieved. Gear down envelope to 110 KTAS. Max altitude 18,000 ft. "Beautiful airplane to fly."
Back to WhiteKnightTwo Information

Founded in 1982 by Burt Rutan, Scaled has broad experience in air vehicle design, tooling and manufacturing, specialty composite structure design, analysis and fabrication, and developmental flight tests of air and space vehicles.
Founder, 





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