Category Space Ship One

Nearly one full year since flight testing began, SpaceShipOne was on the verge of making a spaceflight. One critical piece of infor­mation was missing, though. “The object of that flight was to do a supersonic feathered reentry,” Mike Melvill said. “We needed that data before we could go beyond that.” Figure 8.7 shows SpaceShipOne mated up to White Knight in preparation for the third powered flight.

Ten seconds after releasing from White Knight at 46,000 feet (14,020 meters), Melvill lit off the rocket engine. Figure 8.8 shows a dramatic rearward view of the rocket engine’s fiery plume and exhaust.

“During the boost after he reached the vertical part of the trajec­tory, the avionics display started flickering and then went blank,” Doug Shane said. “We all had good displays in the ground station. And Mike said, T looked out the window, and we were going pretty much straight up. So, I stayed with her.’ Gotta love a guy like Mike. Of course it came back on as soon as the motor shut down.”

The rocket engine burn duration was set by a timer. As Melvill looked out the windows to navigate, SpaceShipOne boosted to 150,000 feet (45,720 meters) and Mach 2.5, and then its rocket engine shut down. SpaceShipOne

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Flight Test Log Excerpt for 14P

Date: 13 May 2004

Flight Number Pilot/Flight Engineer

SpaceShipOne 14P Mike Melvill

White Knight 56L Brian Binnie/Matt Stinemetze

Objective: The third powered flight of SpaceShipOne. 55 seconds motor burn time. Handling qualities during boost and performance verification. Reaction control system use for reorientation to entry attitude. Supersonic feather stability and control.

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Fig. 8.7. The photograph shows SpaceShipOne being prepared for its third rocket-powered test flight. SpaceShipOne had made its very first test flight just about a year earlier. The main goal of this test flight was to evaluate the performance of the feather at supersonic speed. Mojave Aerospace Ventures LLC, photograph by David M. Moore

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Fig. 8.9. SpaceShipOne reached an apogee of 211,400 feet (64,430 meters), and the video camera in the tail boom recorded the feather in the extended position. While high above Los Angeles, SpaceShipOne was technically not in space, even though the curvature of Earth can be clearly seen. However, the curvature is somewhat exaggerated due to the auto focus lens used. Mojave Aerospace Ventures LLC, video capture provided courtesy of Discovery Channel and Vulcan Productions, Inc.

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reentry just as expected. It actually descended more smoothly at supersonic speeds than it did at subsonic speeds. Figure 8.9 shows SpaceShipOne above Earth, with Los Angeles and the California coast­line in the background.

Back on the ground, engineers traced the avionics malfunction to a dimmer, a small electrical component. And since the thermal protection data looked good, Scaled Composites felt that SpaceShipOne performed well enough to continue forward.

The construction of SpaceShipOne really began with the building of the fuselage. Without its wings and tail attached to the fuselage, SpaceShipOne looks like a stubby little rocket. Figure 4.5 shows the crew compartment in the forward section of the fuselage, the oxidizer tank in the middle section, the rounded pressure bulkhead that separates the crew compartment from the oxidizer tank, and the rocket engine in the aft section. The maximum outer diameter of the cylindrical

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Fig. 4.5. The cutaway drawing shows the crew positions in the cockpit of SpaceShipOne. A pressure bulkhead separates the crew from the rest of the rocket engine. The oxidizer tank mounted at the center of the fuselage has the rocket engine CTN (case/throat/nozzle) attached directly to it. Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites

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Fig. 4.6. A first step in the assembly was to build the carbon fiber/epoxy composite subassemblies that made up the fuselage. The subassemblies were bonded together, except for the nose cone, which was a detachable emergency escape hatch. Mojave Aerospace Ventures LLC, photograph by Scaled Composites

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fuselage is 60 inches (152 centimeters). It is a monocoque design, which means that the fuselage hull provides most of the structural support and load bearing for the spacecraft. However, the rocket engine obviously exerts a tremendous amount of force. So, the oxidizer tank is actually a very important structural member as well.

SpaceShipOne was put together much the same way a small plastic model airplane is put together. Beginning with a bunch of individual parts, they are assembled piece by piece. Woven layers, also called plies, of carbon fiber and epoxy were the primary materials used to make most of the lightweight composite parts of SpaceShipOne. These parts were used to build the fuselage, the wings, and the tail booms.

The whole process began by designing the parts using three – dimensional computer-aided design (CAD). The designs were then fed into an automated computer numerical control (CNC) machine to carefully shape the parts by whittling down foam blocks. Even though these foam parts precisely resembled the actual composite parts, they did not share the same strength, durability, resilience, and imperviousness to temperature. The foam parts were used to create molds that would then be used to create the actual composite parts to build SpaceShipOne.

After the molds were created, lay-up began. Here the composite material was built up layer by layer. Once enough material was added and the layers were to the proper thickness, the parts were vacuum-bagged and oven-cured. The vacuum-bagging process is basically what it sounds like. A part is covered with an airtight bag, which is evacuated by a pump. What this does is remove air from in between the layers and volatile compounds that are in the epoxy, which have become unwanted byproducts. The more thoroughly they are removed, the stronger the composite will be. The oven-curing enables the epoxy to properly set and achieve the desired properties. After the parts for SpaceShipOne were cured, assembly began.

Although the materials may have changed, the building technique was not unlike that used to build European sailplanes over the past forty or fifty years.

The primary structure of the fuselage is made up of only a few very large subassemblies. Figure 4.6 shows the nose cone and cabin section. The subassemblies have edges that fit to one another. They are then fastened with a jig and chemically bonded together. The subassemblies

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Fig. 4.7. Piece by piece, the exterior of SpaceShipOne took shape, like the building of a plastic model airplane. As construction proceeded, the wings were attached to the fuselage, and all the wiring, plumbing, linkages, and other components were installed inside. Mojave Aerospace Ventures LLC, photograph by David M. Moore

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Fig. 4.8. Because the cockpit was pressurized and SpaceShipOne faced extreme conditions in space, the walls of the fuselage provided double containment. In between the "shell within a shell" was an insulating layer that also improved the structural strength of the fuselage. Mojave Aerospace Ventures LLC, photograph by David M. Moore

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Fig. 4.9. This photograph shows the early stages of construction for the aft section of SpaceShipOne. A pressure bulkhead will be put in place at about the location of the opening in the fuselage to separate the oxidizer tank from the cockpit. Mojave Aerospace Ventures LLC, photograph by David M. Moore

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together form the inner hull or shell of SpaceShipOne. This inner shell is still not strong enough to support the spacecraft.

The nose cone is attached to the rest of the fuselage a little differ­ently. The nose cone is the primary escape hatch. Its edge is keyed so that it can lock and unlock from the fuselage with a quick little turn.

Figure 4.7 shows the cabin section that is forward of the pressure bulkhead in various stages of construction. Figure 4.8 shows the top of the cabin section after even more assembly, and figure 4.9 shows the aft section where the wings mount.

The next step in building the fuselage was to add a core of honey­comb material on top of the inner shell. Nomex, made by DuPont, was used as the honeycomb core. Not only is the honeycomb core lightweight, it offers high strength and it is heat and fire resistant. The honeycomb core, however, cannot serve as the outer layer. It needs further covering. So, panels called skins, manufactured using this composites process, were attached to the honeycomb core. The fuselage is a shell within a shell. The process of adding succes­sive layers creates what is known as a sandwich structure, as the fuselage hull is viewed in cross-section. Figure 4.10 shows an example of a sandwich structure. Another way to look at this is that the fuselage hull is a thick composite made up of several thin composites.

Honeycomb Sandwich Structure

After the assembly of the composite parts, SpaceShipOne resembled a spacecraft, but the job was far from over. “The hard part is stuffing all the systems in it and making sure that they are mounted properly,” Rutan said.

Initially the fuselage ended at the throat of the rocket-engine nozzle. During the flight tests, a fairing was added to extend the fuselage to the rim of the nozzle in order to improve aerodynamics.

Inside the cockpit, mixed between the circular windows, ports, door, and escape hatch, the pilot had all the instruments and controls he needed for all the various phases of flight. Figures 6.15 to 6.17 show views of the instruments and controls at the front of the cock­pit, to the left side of the pilot, and to the right side of the pilot, respectively. The instruments and controls are identified by their numbered callouts given from these figures.

The pilot used the control stick (33) and the rudder pedals (7 and 12) to fly subsonically and to maneuver using the RCS (15,38, and 41).

But for supersonic flight, trims (31,35, and 36) and backups (55) were used. The controls for the rocket engine included switches and a timer (34, 42, and 49—52).The feather was operated using valves and levers (1, 3, 39, 40, 43, and 44).

Cameras on the tail, on the fuselage, and in the cockpit (56) provid­ed video that was also an important source of data during flight testing. Mission Control used one of the cameras to monitor the feather and rocket engine in real-time. Two of the more unexpected things found in the cockpit were the ping-pong ball (8), which was used to provide a good visual during weightlessness, and the “Q-tip” (63), which the pilot used to wipe down excess moisture from the windows.

The controls for the ECS (13, 16, 17, and 64-69), battery (18—22), landing gear (45 and 53), radios (30), and other systems were also close at hand. However, important instruments like the air­speed indicator, Machmeter, altimeter, and energy altitude predictor were all displayed on the FDD of theTONU (11), and airspeed and altitude were also backed up on the Dynon (10).

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Fig. 6.11. One of the components of the Tier One navigation unit (TONU) was the flight director display (FDD). Like the glass cockpit of an airliner, the FDD showed many of the important instruments and readouts used by the pilot to fly SpaceShipOne. An initialize mode of the FDD is shown with SpaceShipOne lined up on Runway 30 of Mojave Airport. Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites

Fig. 6.12. As SpaceShipOne rockets to space, a boost mode is shown on the FDD. By closing together the red circle and green circle, the pilot achieved optimum trajectory. The pilot could also view the status of the rocket engine and oxidizer tank. Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites

Fig. 6.13. The FDD shows a reentry mode before SpaceShipOne returns to Earth’s atmosphere. The position of the feather, the operation of the reaction control system (RCS), and the condition of their pressurization sources are displayed. Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites

Fig. 6.14. After reentry and the feather is retracted, SpaceShipOne glides back to Mojave Airport. The test pilot used a glide mode on the FDD to help ensure SpaceShipOne reached the runway at correct position and speed. Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites

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Feather bottle low: A and В

Wing against stops and wing ТЕ locked

down indicators

Feather position

Launch separation controller

Spaceship “Armed” indicator

Mothership “Armed” indicator

Left rudder pedal

Ping-pong ball

Backup GPS navigation display Dynon backup altitude indicator FDD (flight director display) of theTONU (Tier One navigation unit)

Right rudder pedal Cabin altitude gauge

Landing pattern attitudes: normal and emergency (gear down)

RCS bottle pressure warning lights: A and В ECS bottle pressure warning lights: A and В Cabin pressure low warning light Battery voltage Bus tie A battery Selector switches В battery

Video transmit power TONU power

Trim circuit breakers: left stabilizer, right stabilizer, yaw, and backup trim Backup rate display

Stabilizer boost Damper heat

Circuit breaker panel indicators Communication/navigation panel: two radios, transponder, and intercom selector panel Pitch trim

Red button not used Pilot roll /pitch control stick Rocket motor fire Roll trim Yaw trim

FDD page control switches

RCS A enable switches Feather actuator Feather unlock RCS В enable switches Rocket motor arm

Feather lock pressure valves: A and В (the yellow feather lock valve also doubles as gear down emergency assist)

Feather actuator pressure valves: A and В

Landing gear handle

Nose cone release handle

Nitrous oxide dump valve

Backup dump (through main valve)

Rocket motor controller power: A and В buses Rocket motor controller reset

Motor armed indicator, main oxidizer valve commanded open indicator, and nitrogen pressure low indicator Rocket motor burn time controller Landing gear down indicators: left, nose, and right Lamp test

Backup trim (stabilizer) panel

Lipstick camera, forward cabin (focused on pilot)

Dry air feed line (vents between window panes to prevent fogging) GPS antenna (attached to window)

4-inch opening for fine cabin pressure relief valve

Fine cabin pressure relief valve (this is the storage location)

Emergency cabin pressure dump port (this is the storage location)

Oxygen control panel

“Q-tip”

Secondary cabin pressure bottle valve

Primary cabin pressure bottle valve

Pressure regulator and gauge

Defog control valve (for between window panes)

Cabin make-up air

Dehumidifier fans and CO2 scrubber fan switches 4-inch opening for emergency cabin pressure dump port

photo by Eric Long and Mark Avion, National Air and Space Museum, Smithsonian Institution

At 6:47 a. m. PST on June 21, 2004, White Knight lifted off from Mojave’s Runway 30, as shown in figure 8.10, to the cheers of twelve thousand spectators. Several days earlier, Mojave Airport officially became Mojave Air and Space Port after receiving its launch site operator license. It would have been another typical windy desert early morning with the Sun still not fully awake, except for a gangly looking airplane toting a stout little rocket plane on the first part of its journey to the hopeful reaches of space. Figure 8.11 shows the mated pair spiraling up to the launch altitude.

At an altitude of 47,000 feet (14,330 meters), White Knight could no longer guide SpaceShipOne any further and cut the rocket craft free to continue the quest on its own.

“You release the back pressure, and then the airplane starts to climb,” Mike Melvill said. “And at that point you must have the motor running. You unguard the switch that turns the elec – trons on to the ignition system, and you unguard the switch that fires it.

“A rocket motor doesn’t start off like a jet engine. It starts off as hard as it is ever going

Flight Test Log Excerpt for 15P

Date: 21 June 2004

Flight Number Pilot/Flight Engineer

SpaceShipOne 15P Mike Melvill

White Knight 60L Brian Binnie/Matt Stinemetze

Objective: First commercial astronaut flight by exceeding 100 kilometers (328,000 ft).

to be right there. The first time it lights, it is going as strong as it will ever be. In fact, it gets weaker as you go along. The initial kick on your back is very strong—more than 3 g’s. Your eyeballs go in at 3 g’s. And then you make about a 4-g turn. And you do that by just pulling back on the stick. In only 9 or 10 seconds, you are supersonic. You are supersonic about two-thirds of the way through that turn. And then you can’t use the stick anymore. You have to use the trim. So, that transition is something you have to learn in the simulator.”

But before completion of the pull-up, severe wind shear rolled SpaceShipOne to the left. As Melvill tried to regain wings level, SpaceShipOne rolled 95 degrees to the right and then 90 degrees to the left. He soon got control and had SpaceShipOne flying vertical, as in figure 8.12. But he ended up far off course.

A minute into the burn, as the oxidizer ran low in the tank, it began to transition from a liquid to a gas. The roar of the rocket engine made a drastic change. “As it starts sucking gas, it chugs,” Melvill explained. “And it goes boom, boom, boom, boom, boom, boom, boom, boom, boom, like that as it is going up. It really rattles your head. It doesn’t do that for too long. But it is disconcerting the first time it happens. I didn’t know what the heck that was all about.”

But the rocket engine wasn’t finished with its mischief. “The rubber that is on the inside of that thing has got ports in it, pie­shaped ports that run the whole length of the rubber fuel. So, as you are burning all the surfaces of the inside of each of these pie-shaped ports, they are coming together. You end up with a plus – sign—shaped piece of rubber that is very thin that runs the whole length of the machine. It will break off eventually and go out the back. That must have broken off and got sideways in the nozzle or something because it made a tremendous bang. It really rattled the airplane. I thought the whole tail had fallen off the airplane.”

To improve the airflow around the rocket engine for this flight, a fairing was added, which extended from the back of the fuselage over the sides of the nozzle. But heat from the rocket engine caused it to buckle. It was necessary to modify the design slightly for the next flight. It was unlikely the source of the sound Melvill heard.

Melvill seriously wondered if he’d be able to make it back, but Mission Control could see that the tail booms were just fine from the live video feed of the onboard camera. Unfortunately, Melvill didn’t have the capability to view this imagery. A failure of the primary pitch trim control, which Melvill needed while moving at supersonic speed, also occurred while the rocket engine blasted away. This only

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Fig. 8.10. As White Knight fired up its engines and began taxiing to the runway, it rounded the corner, around the control tower, to find a crowd of twelve thousand well-wishers lined up along the flightline. At 6:47 a. m. on June 21,2004, SpaceShipOne began its first journey into space. Tyson V. Rininger

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Fig. 8.12. Mike Melvill ignited the rocket engine, "turned the corner," and blasted nearly straight up. The rocket engine burned for 76 seconds and shut down at 180,000 feet (54,860 meters). After reaching a maximum speed of Mach 2.9, SpaceShipOne coasted the rest of the way up to space. Tyson V. Rininger

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minutes of weightlessness, he released two handfuls of M&Ms into the cockpit to float around in zero gravity. Mojave Aerospace Ventures LLC, video capture provided courtesy of Discovery Channel and Vulcan Productions, Inc.

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deepened his worry. However, he was able to get pitch trim control back by switching to the backup.

Melvill obviously had his hands full, and he wasn’t finished battling the rocket engine. He said, “The thrust is supposed to be right down the centerline. The nozzle is an ablative nozzle. It would burn away, and if it burns away a little bit on one side compared to the other side, you can end up with a yaw going on or a pitch. It burned like about a half a degree from being straight.

“Full rudder would only just deal with a half a degree from asym­metry in the thrust. I put the rudder on the floor, but it still went sideways across the ground. It is just amazing how quickly you go from one place to another if that happens.”

By this point, the good-luck horseshoe pin that Sally Melvill pinned to her husband’s flight suit just before the flight must have weighed five pounds.

“Poor trajectory control drew the airplane way far downrange. It spent an awful lot of energy going downrange rather than straight up where you want it to go,” Doug Shane said.

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seconds. The shadow of the feather on SpaceShipOne quickly moved position as SpaceShipOne’s orientation to the Sun rapidly changed. Mojave Aerospace Ventures LLC, screen captures provided courtesy of Discovery Channel and Vulcan Productions, Inc.

Boosting SpaceShipOne to Mach 2.9 (2,150 mile per hour or 3,460 kilometers per hour), the rocket engine cut off at 180,000 feet (54,860 meters) after firing for 76 seconds. SpaceShipOne coasted toward space, but concern rapidly grew whether or not it would reach the Ansari X Prize goal of 328,000 feet (100,000 meters).

Paul Allen could only watch and wait as the Mission Control staff tracked SpaceShipOne’s progress. “You’ve got a human being in a very small projectile that is going straight up at Mach 3,”Allen said, “and me pacing around behind the scenes going, ‘I just want Mike to get back on the ground safely.’ And you got an altimeter that just zips around as SpaceShipOne accelerates upward during the engine burn. And then it starts coasting. The altimeter is just wrapping itself around itself as fast
as it can, and then it starts slowing. You are wondering if SpaceShipOne is going to get high enough, and then it did but barely.”

Before reaching apogee, Melvill raised the feather in preparation for reentry. Gravity was calling SpaceShipOne back, and the spacecraft crept up slower and slower until it finally stopped. Measurements of the altitude were being taken from several different sources, and for a moment, there was nothing but uncertainty. SpaceShipOne did beat the mark by just a fraction, making it to 328,491 feet (100,124 meters), but substantially short of its targeted 360,000 feet (109,700 meters).

Despite the problems Melvill faced in the cockpit, he had a few moments to enjoy the 3.5 minutes of weightlessness. While in zero-g, he wanted to give a good demonstration of the weightless

experience. From a zipped pocket on the left arm of his flight suit, Melvill grabbed two handfuls of M&Ms, which he had bought on the way to the airport earlier that morning, and cast the multicolored candies out into the cockpit. Figure 8.13 shows Melvill in the cockpit with M&Ms floating about.

“The sky was jet black above, and it gets very light blue along the horizon. And the Earth is so beautiful, the colors of the Earth, the colors of the high desert, and along the coastline. And all that fog or low stratus that’s over L. A. looked exactly like snow. The glinting and the gleaming of the Sun on that low cloud looked to me exactly like snow,” recounted Melvill at a press conference after the spaceflight.

“And it was really an awesome sight. I mean, it was like nothing I’ve ever seen before. And it blew me away. It really did.”

Figure 8.14 shows video frames, at three-second intervals, of SpaceShipOne, with its feather extended, as it races through space over

Earth. In just a matter of seconds, it moves from one side of Earth to the other. Notice how the shadows change position as the orientation of SpaceShipOne rapidly changes with respect to the Sun. By the last frame, the Sun is behind the portside tail boom.

With the pitch trim control anomaly resolved, all Melvill had to do was let SpaceShipOne’s feather handle the “carefree” return into the atmosphere. SpaceShipOne hit 5.0 g’s while reaching Mach 2.9 during reentry.

“We started out over Boron and wound up directly over the top of the Palmdale VOR [VHF omnidirectional radio beacon]. That is a long way south, right out of the restricted area,” Melvill said. In fact, SpaceShipOne reentered over Palmdale Airport at 65,000 feet (19,810 meters), some 30 miles (48 kilometers) south of Mojave Air and Space Port.

“It was perfectly safe to be flying as an airplane or glider out there,” Doug Shane said.

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Fig. 8.17. In a surprise presentation, Patti Grace Smith, the FAA’s associate administrator for Commercial Space Transportation, awarded Mike Melvill the first-ever commercial astronaut wings. In flying SpaceShipOne above 328,000 feet (100,000 meters), Melvill satisfied the primary Tier One goal of getting to space. Now it was time to set the sights on the prize. Mojave Aerospace Ventures LLC, photograph by David M. Moore

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SpaceShipOne had better than a 60-mile (97-kilometer) glide range. It defeathered at 57,000 feet (17,370 meters) and started to glide back to Mojave.

“I got back to Mojave at 40,000 to 50,000 feet [12,190 to 15,240 meters]. I think we could make it from L. A., LAX probably, if we ended up really off course,” Melvill said.

Doug Shane would eventually get a call from the FAA for a meeting. Palmdale was the location of the air traffic control center responsible for all of Southern California. When Shane met with the FAA, an official enthusiastically said Scaled Composites could have all of LA Center’s airspace, no questions asked. All it would cost is one ride.

Figure 8.15 shows SpaceShipOne coming in for a perfect landing after a tumultuous spaceflight. As the spacecraft came to rest, completing only its fourth powered flight, Melvill, who had worked for Burt Rutan since 1978 and been Rutan’s first employee, became the first commercial pilot of a vehicle to and from space. The Scaled Composites team became the first nongovernment space program to
successfully send a human to space. And figure 8.16 shows Burt Rutan and Paul Allen congratulating Melvill on accomplishing a true milestone of flight. Also waiting to congratulate Melvill was Apollo astronaut Buzz Aldrin, who welcomed him to the club. Melvill became only the 433rd person in space since Cosmonaut Yuri Gagarin was the first to reach space in 1961. This works out to an average of ten new people to reach space per year since the very start of human spaceflight.

During a presentation shortly after the spaceflight, the FAA had a surprise for Melvill. “I am very pleased and honored to present, for the very first time, these FAA commercial astronaut wings to Mike Melvill in recognition of this tremendous achievement,” said Patricia “Patti” Grace Smith, associate administrator for the Office of Commercial Space Transportation.

Figure 8.17 shows Melvill with his astronaut wings standing next to Paul Allen and Patti Grace Smith. “I wasn’t expecting anything like that,” said Melvill. “It was really a thrill.”

The FAA now issues astronaut wings to any member of a crew, including passengers, on a spacecraft that exceeds an altitude of 50 miles (80.5 kilometers) during a spaceflight. The 50 miles (80.5 kilometers) was an arbitrary boundary traditionally used by the U. S. military. Internationally, the bar is higher, and the accepted boundary of space, which was used for the Ansari X Prize, is set by the scientifically based Karman Line of 100 kilometers (62.1 miles).

The primary goal of the Tier One space program set by Burt Rutan and Paul Allen had been achieved once SpaceShipOne returned safely to Mojave after reaching space. To that end, SpaceShipOne was optimized for altitude, not payload. Any unnecessary weight would have adverse­ly impacted performance. So, even though SpaceShipOne made it past the Ansari X Prize altitude goal, the passenger requirement wasn’t met.

Scaled Composites had much to think about now that the focus of Tier One was ready to change. Their first spaceflight had not gone entirely as planned, but the Ansari X Prize was now legitimately within reach. Yes, SpaceShipOne had made it to the altitude required by the Ansari X Prize—with only a few hundred feet to spare. Serious problems were encountered, however, and SpaceShipOne wasn’t even hauling the extra weight of a payload. It was necessary to review the spaceflight data and evaluate and repair the damage to SpaceShipOne. Corrective action was required to ensure these mishaps would not repeat and that the performance was improved to meet the demands of the Ansari X Prize.

The Ansari X Prize was to expire in half a year. Within that time, Scaled Composites had to fly two qualifying flights. Six months sounds like a lot of time, but margins of error for spaceflight are razor thin. For the challenges they faced—risking a test pilot’s life and possibly derailing the drive for private spaceflight for many years if something catastrophic occurred—six months were more like six weeks. The need for an additional powered flight before making an attempt at the Ansari X Prize had to be considered.

SpaceShipOne has a space-qualified environmental control system (ECS). Its pressurized cabin has room to fit three people. The pilot sits up front in the nose, and behind him and up against the pressure bulkhead is a row of two seats for the passengers.

The pilot and the passengers sit upright but slightly reclined, as shown previously in figure 4.5. This helps them tolerate the g-forces they face during the boost and reentry phases of the mission. They do not have to wear spacesuits or g-suits, but SpaceShipOne has an oxygen system with oxygen masks for them to wear.

The backseat row is less than 2 feet from the oxidizer tank, but the pressure bulkhead separates the cabin from the oxidizer tank and the rest of the rocket engine. The dome shape of the pressure bulkhead is necessary. “These shapes are real important as pressure vessels,” Rutan said. “And it is pressurized all the way to the nose. There is not another bulkhead up in front.”

For test flights, the pilot pressurized the cabin to 4,000—6,000 feet (1,220—1,830 meters). An airliner sets the pressure inside its cabin to about 8,000 feet (2,440 meters). This means that no matter how high or low it flies, the passengers inside will always feel a pressure equal to what they would feel if they were standing on a mountain with a height above sea level of 6,000 feet (1,830 meters).

The cabin was sealed but did have a small amount of leakage. The pilot watched the cabin altimeter, which was used to measure the cabin pressure, and manually adjusted it as necessary.

SpaceShipOne does not have its own heating or cooling system. During captive carry, however, the vehicle was heated by bleed air from White Knight’s engines, which pumped the hot air to the pressure bulkhead. The cabin temperature did not change by more than 15 to 20 degrees Fahrenheit from the time the door was closed on the ground. Again, the short duration of the mission really played to Rutan’s design principles of simplicity and low construction cost.

At low altitudes, the pilot could get fresh air by opening two 4-inch (10-centimeter) plugs located on either side of the fuse­lage. Similar to the design of airliner doors, the plugs open inward and are beveled, like corks, so that the high pressure inside the cabin helps keep them closed tight and prevents opening at high altitudes. “You didn’t need cooling,” Doug Shane said. “You could keep the airplane cool on the ground with the [external] air con­ditioner. Once you took off, you could wait to put the plugs in until you were at 10,000 to 12,000 feet [3,050 to 3,660 meters], where it is pretty cool.”

The plug on the pilot’s right-hand side has a safety pressure relief valve that could be capped in case it failed. The other plug has a manual ball valve that opens to dump the pressure in the cabin if necessary. This plug also has a big tab riveted to it. In an emergency situation where the crew would have to bail out, they would have to wait for the cabin to depressurize through a small valve. The tab provided the leverage so the pilot could peel off the plug fast, allowing the cabin to rapidly depressurize. Once SpaceShipOne was all sealed up, it was essentially a trapped volume of air. “There’s no exchange of air. So you’ve got to be concerned about humidity and carbon dioxide,” Shane said.

A second hose coming off each oxygen mask collected the exhaled air in order to control the carbon dioxide (C02) levels and humidity. The exhaled air was dried, and a scrubber using an absorbent material was used to remove excess C02. But because of the mission’s short duration and the fact that the cabin was sealed off from the atmosphere

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Fig. 4.11. Looking from underneath into the engine bay, these are the two main spars running perpendicular through the fuselage, one in front of the oxidizer tank and one behind it. These provided the structure to support the fixed and movable sections of the wings. Mojave Aerospace Ventures LLC, photograph by David M. Moore

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Fig. 4.12. SpaceShipOne’s wings had to be very rigid and strong because they not only supported the tail booms and feather mechanism, they also had to withstand the very high forces encountered during boost and reentry. This photograph shows how thick the ribs inside had to be. Mojave Aerospace Ventures LLC, photograph by David M. Moore

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“We actually demonstrated on White Knight that we had adequate control with three people on board for a three – or four-hour flight,” Shane said. “We knew it would be fine for one hour.”

s soon as SpaceShipOne was able to fly, flight testing began. This didn’t mean it was fully operational—not by a long shot. But the only way to learn more about the spacecraft was to get it up in the air and see how things worked.

The purpose of flight testing was to understand how the parts of SpaceShipOne operated individually and collectively while in flight. Only so much can be eval­uated by ground tests and computer models. SpaceShipOne was, after all, designed to fly, not to take up idle space inside a hangar.

SpaceShipOne’s flight test program proceeded incrementally, as with most flight test programs. After each step, Scaled Composites knew a little bit more how SpaceShipOne flew. Resolving problems, expected and unexpected, by making modifications or procedural changes is a normal part of any flight test program. And this one was no different.

SpaceShipOne completed fifteen test flights before attempting to capture the Ansari X Prize: three captive carries, eight glides, and four powered flights. These test flights, beginning on May 20, 2003, enabled the team to qualify the instruments, controls, systems, and test pilots as well as expand the flight envelope of SpaceShipOne.

Flight testing of SpaceShipOne actually began in White Knight. Since the cockpits were virtually identical, as were many of the controls and compo­nents, SpaceShipOne had a tremendous head start by the time it finally reached the sky.

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Fig. 7.1. White Knight flew more than four times the number of flights as did SpaceShipOne because it was also used to shake-out the components that were common to SpaceShipOne. Because they shared very similar cockpits and some similar flight characteristics, White Knight was also an effective flight trainer for SpaceShipOne. When White Knight and SpaceShipOne did fly together, a "cave painting" was added to the fuselage of White Knight to acknowledge each mission. Mojave Aerospace Ventures LLC, photograph by Scaled Composites

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In this chapter and the following chapters, excerpts taken from the flight log of Scaled Composites are given for all the flights made by SpaceShipOne during the flight test program, including the Ansari X Prize attempts. The key information given for each includes the date, the flight numbers for both SpaceShipOne and White Knight, the crew members, and the test flight objective. From the photographs, the sequence of modifications to the tail booms, engine fairing, thermal protection system, and paint scheme becomes apparent.

For both SpaceShipOne and White Knight, the flight numbers were sequential, representing each time the vehicle flew. White Knight flew many more times because it was flown first and also used as a trainer for SpaceShipOne. For captive-carry test flights, a C was added to the end. For a glide or powered test flight, a G or P was added, respec­tively, while L denoted a launch for White Knight. Appendix A lists important data about each of the flights.

Piloting rotated between Pete Siebold, Mike Melvill, and Brian Binnie. But while one of these test pilots flew SpaceShipOne during a test flight, one of the others always flew White Knight. The remain­ing of the three test pilots typically flew a chase plane to closely observe the test flight. Appendix В gives details about the chase planes for the flights.

To commemorate the completion of each SpaceShipOne flight, a “cave painting” was added to the side of White Knight, as shown in figure 7.1.

Being a test pilot is a risky occupation, as history has continually proven. Anytime a new aircraft is flown, there are many unknowns. The test pilot has to be prepared for the worst case, though. The nose cone of SpaceShipOne was specially designed to detach from the fuse­lage, so, in an emergency, the test pilot could make a quick escape and parachute to safety. The job of the test pilots was to fly SpaceShipOne and, with the help of the entire test flight team, turn those unknowns into knowns.

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Flight Test Log Excerpt for 1C

Date: 20 May 2003

Flight Number Pilot/Flight Engineer

SpaceShipOne 1C none

White Knight 24C Pete Siebold/Brian Binnie

Objective: First captive-carry flight with mated White Knight and SpaceShipOne. Vibration and aerodynamic interface assessment. Mated handling qualities evaluation. Envelope expansion to 130 knots/Mach 0.5 above 45,000 feet [13,720 meters]. Stalls and 2/3-rudder sideslips. SpaceShipOne systems inactive, controls locked, and cabin unmanned. Launch system was qualified and functional for this flight.

(source: Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites)

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ime was running out. Scaled Composites announced that they would be making their attempt at the Ansari X Prize on September 29, 2004. To win, SpaceShipOne would have to fly not just on that day, but would have to fly once more by October 13th, leaving less than three months before the Ansari X Prize would expire. A major setback would take SpaceShipOne out of contention.

Brian Feeney’s team scheduled to launch their spacecraft Wild Fire on October 2, 2004. But there was a concern as to whether or not they would be ready to launch. What would happen if the January 1,2005, expiration rolled by without a winner?

“We had a contingency plan that whoever won it would get a trophy but not ten million bucks,” Erik Lindbergh said. “But whether or not it would have been as effective was a question. Whether or not it would have gained as much media attention was a question. And also whether or not we would have been able to keep the doors open was a question.”

The X Prize Foundation wanted desperately to award the Ansari X Prize. To them, this wasn’t a one-shot deal. Winning the Ansari X Prize meant jumping the first, but highest by far, hurdle on the path to public space access. But having the prize unclaimed was not their only fear. They knew that progress would only come from the successes and the failures of flying over and over again.

“It was very tense the night before and in the morning as we were gathering in the cold in Mojave to watch the launch,”Anousheh Ansari said. “We were very anxious. We had to prepare ourselves for all sorts of possibilities.”

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Fig. 9.1. When Mike Melvill made it to space in SpaceShipOne, it was like a great awakening. Scaled Composites gave proof to the world that commercial spaceflight was for real. Millions of people seemed to catch the space craziness as the Ansari X Prize attempts were made and broadcasted

live on television and over the Web. Dan Linehan

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There was no doubt of the risks involved with spaceflight. And although SpaceShipOne s first spaceflight earlier that June had some unexpected difficulties, the spacecraft and the pilot made it back safely. This was no guarantee for subsequent missions, which would continually stretch the flight envelope. After all, SpaceShipOne was still a research vehicle.

Everyone felt the enormity of the events. “To watch how the wives said goodbye to their husbands before they went up and wished them well was certainly a moment when you felt the respon­sibility of being involved in a project like this,” Paul Allen said, “and them being worried for their husbands and you being worried, too.” The attempts at the Ansari X Prize would have unprecedented media coverage as well. Tens of thousands of people gathered to
watch the launches in person (refer to figure 9.1 and figure 9.2). And the launches were broadcast live over television and the World Wide Web in a way like none other.

“The whole world was watching,” said Gregg Maryniak, the executive director of the X Prize Foundation. “Most people don’t appreciate that this was the first spaceflight ever that had video coming down that people—regular people—were watching in real time from a manned spaceship. It has never happened before. It has happened where in flight you could see snippets but never during ascent. When was the last time you saw NASA showing footage from inside the shuttle?”

The Ansari X Prize received upwards of six billion media impressions over its course, with a large percentage of them focused

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Fig. 9.2. A giant screen gave crowds a live, up-close view of SpaceShipOne from inside and outside the cockpit as it made its way to and from space.

These same images were being seen on televisions and computers all over the world.

Dan Linehan

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on the small company from the Mojave Desert that was ready to prove that its first spaceflight wasn’t a novelty.

“The entire Tier One team that was taking this vehicle through flight testing had been working really, really hard for the last six weeks or so to where there was almost always someone at Scaled doing something with the vehicle or preparing for the flights or in the simulator,” Brain Binnie said.

“We had a lot of anxiety between our first flight to space with Mike with the lightweight vehicle and trying to decide how we were going to make the adjustment to carrying 600 pounds [270 kilograms] of pay – load for the X Prize flights and still get to those same altitudes. There was concern that the

Flight Test Log Excerpt for 16P

Date: 29 September 2004

Flight Number Pilot/Flight Engineer

SpaceShipOne 16P Mike Melvill

White Knight 65L Brian Binnie/Matt Stinemetze

Objective: First X Prize flight: ballasted to simulate 3 place and to exceed 100 kilometers (328,000 ft).

(source: Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites)

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rocket motor didn’t have enough energy or impulse for us to get there. We had spent a lot of time worrying about that, wondering whether we needed to augment the motor with some other boosters. We eventually settled on a scheme that was really quite clever, but it took a while to work out the details.”

The design of the wings had to take into consideration more factors than most other winged aircraft must consider. The wings of SpaceShipOne had to perform from subsonic to supersonic, withstand reentry into Earth’s atmosphere, and incorporate the mechanism of movable wings. No other winged vehicle has had to tackle all these at the same time.

Swept wings, which look like delta wings with the wingtips cut off, are attached high on the fuselage. This shape was required for supersonic flight. A tail boom with an outboard horizontal stabilizer is mounted to each wingtip.

The wings have an airfoil shape, but a hinge runs along the full length of the wingspan. The hinge allows the aft section of the wings to pivot up for the feather maneuver and back down after reentry. The forward wing sections, which are roughly the front two-thirds of each wing, do not move.

The wing area is approximately 160 square feet (15 square meters) and the wingspan is 16.4 feet (5.0 meters). However, since the horizontal stabilizers of the tail booms extend out farther than the wings, the width is 27 feet (8.2 meters).

The aspect ratio of the wing is 1.7, which is very low compared to the high aspect ratios of the long, thin wings of sailplanes. For traditional gliders, the lift characteristics are a key design factor. But for SpaceShipOne, it requires only enough lift to be able to point its nose upward during rocket-powered ascent in the atmosphere and to be able to glide back after reentry to the landing site for a safe touchdown.

There are two main spars that each run through the wing from tip to tip. One spar goes in front of the oxidizer tank, and one goes behind it, which can be seen in figure 4.11.

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Fig. 4.13. NASA had designed the Ames-Dryden-1 (AD-1) to explore the use of an oblique wing that could pivot during flight. During takeoff, the AD-1’s wing was perpendicular to the fuselage, like a traditional aircraft. In order to evaluate fuel efficiency, it was possible to pivot the wing to a maximum of 60 degrees, as shown in this photograph. NASA contracted Burt Rutan’s RAF to analyze design and loading characteristics. NASA-Dryden Flight Research Center

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“The wing is not tapered in total thickness,” Rutan said. “It is as thick at the tip as it is at the root. It has to do with meeting the stiffness to support the boom. And of course for the hinge line of the boom, it has to be a perfectly straight line or it would bind.”

There are no control surfaces on the leading or trailing edges of the wings like other aircraft. Wings on most aircraft also store fuel. But since fuel is stored in the rocket engine itself, which runs through the fuselage, and the oxidizer is in a large tank behind the cockpit, the wings have plenty of room to fit other components and systems, as shown in figure 4.12.

Thirty-two days after Scaled Composites revealed its space program to the world, SpaceShipOne was about to take to the air for the first time. “Here we are about to embark on a flight test program with a spaceship,” said Doug Shane, the director of the flight test program. “And we started off with an unmanned captive-carry flight just to make sure the interactions between the two airplanes were fine.” The first test flights off the ground were captive carries, where White Knight and SpaceShipOne took off attached together in the mated configuration and did not separate during the flight. This was just like a giant wind tunnel, but instead of an enormous fan blowing air on SpaceShipOne, White Knight moved SpaceShipOne through the

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Fig. 7.2. SpaceShipOne took to the air for the first time on May 20, 2003, for an unmanned captive carry. A primary goal of the flight was to ensure that the two vehicles could safely fly while mated. Mojave Aerospace Ventures LLC, photograph by Scaled Composites

air. Figure 7.2 shows SpaceShipOne and White Knight during the first captive carry.

With Pete Siebold at the controls and Brian Binnie in its backseat as flight engineer, White Knight carried the unmanned SpaceShipOne to an altitude of 48,000 feet (14,630 meters), which would eventually be the approximate launch altitude. They reached a speed of Mach 0.53 after the 700 feet per minute (210 meters per minute) climb to this altitude. Siebold and Binnie flew for 1.8 hours and found that White Knight had excellent handling qualities and could perform the captive carry without any stability, interference, or vibration problems. SpaceShipOne was now ready for a pilot.

SpaceShipOne Now Manned (2C)

Within specifically designated airspace, Mike Melvill rode inside SpaceShipOne during a 2.1-hour-long captive-carry test flight. Aside

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Flight Test Log Excerpt for 2C

Date: 29 July 2003

Flight Number Pilot/Flight Engineer

SpaceShipOne 2C Mike Melvill

White Knight 29C Brian Binnie/Cory Bird

Objective: First manned captive-carry flight of SpaceShipOne. A man-in-loop launch rehearsal and inflight checkout of all ship systems, including flight controls and propulsion system plumbing.

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Fig. 7.3. Two months after SpaceShipOne’s first test flight, Mike Melvill became the first test pilot to get behind the stick of SpaceShipOne. This mission was a captive carry, though. The Starship, designed by Burt Rutan, flew as a chase plane. Mojave Aerospace Ventures LLC, photograph by Scaled Composites

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Flight Test Log Excerpt for 3G

Date: 7 August 2003

Flight Number Pilot/Flight Engineer

SpaceShipOne 3G Mike Melvill

White Knight 30L Brian Binnie/Cory Bird

Objective: First glide flight of SpaceShipOne.

(source: Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites)

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from checking systems, Melvill preformed a full rehearsal for the first glide-test flight with Brian Binnie and Cory Bird, who crewed White Knight.

Figure 7.3 shows this test flight and the Starship chase plane trailing behind. Several chase planes flew alongside SpaceShipOne and White Knight at various stages during the flight test program. They monitored how SpaceShipOne performed from an external standpoint, and, should SpaceShipOne or White Knight run into difficulties, they provided a valuable extra set of eyes.

During this rehearsal, SpaceShipOne also practiced the communi­cation that would take place, which included sending data and video down to Mission Control on the ground.

Although pilots trained to fly SpaceShipOne with the simulator and White Knight, this was the first time that a pilot could actually feel the forces on the controls during flight. After Melvill exercised all the different systems aboard SpaceShipOne, which included parts of the feather and propulsion systems, SpaceShipOne was ready for the big next step.

As White Knight came in for a landing, though, Melvill couldn’t help trying to land, even though SpaceShipOne still remained fixed to White Knight. From the chase plane video, SpaceShipOne7s elevons moved as White Knight flared for landing. Afterward, Melvill joked with Binnie by congratulating him on such a fine landing.

“Ladies and gentlemen, we are at the start of the personal spaceflight revolution, right here, right now. It begins in Mojave, today. What is happening here in Mojave today is not about technology. It is about a willingness to take risk, to dream, and possibly to fail,” said Peter Diamandis during the morning of September 29, 2004, as XI, the name of the first required flight of SpaceShipOne in the quest for the Ansari X Prize, prepared to launch.

Mojave was abuzz. A little more than three months earlier, Mike Melvill had earned his astronaut wings as he piloted SpaceShipOne on a history-making flight just past the 100- kilometer (62.1 miles or 328,000 feet) line demarking the start of space. Now Rutan’s team set their sights on the most exciting and influential prize of the new millennium.

Pete Siebold, who had already flown two glide flights and one powered fight in SpaceShipOne, was selected to pilot the flight. Siebold had been training for three years for this moment, but a health scare forced a very disappointing change.

“There were two other guys that were more than qualified to fly that flight,” Siebold said. “At the time, I didn’t feel as though I was doing the team any justice by putting myself in that situation and flying
the mission when I probably wasn’t in the right frame of mind and not to mention healthy enough.” Siebold made the tough decision, but very fortunately his health issues were eventually determined to be nowhere near as serious as first suspected.

Rutan then turned to the test pilot with the most experience flying SpaceShipOne. Mike Melvill would get his chance to become an astronaut a second time, but to do so, he’d have to get back into training again. Figure 9.3 shows Melvill at the controls in the cockpit of SpaceShipOne preparing for XI.

Like Spirit of St. Louis, SpaceShipOne was stripped of anything absolutely nonessential. The lighter the craft, the greater the margin SpaceShipOne had for clearing the 100 kilometers (62.1 miles or 328,000 feet) because the removal of each and every pound enabled the spacecraft to go an additional 150 feet (46 meters) higher. SpaceShipOne needed all the help it could get. Melvill’s earlier spaceflight had cleared the 100 kilometers by only the slimmest of
margins, less than 500 feet (150 meters). And during this spaceflight, SpaceShipOne was not even carrying the full payload required by the rules of the Ansari X Prize.

Ironically, as the Scaled Composites team scrimped for a pound here and a pound there, removing a total of about 45 pounds (20 kilograms), they would have to add weight to simulate two passen­gers. “We had to carry 400 pounds [180 kilograms] in the back seat, which was a heck of a lot more load in that thing than we ever had before. And I had to be ballasted,” Melvill said.

Since Melvill weighed only 160 pounds (73 kilograms), he had to be ballasted up to 200 pounds (90 kilograms).These were the rules. But keeping the gross weight as low as possible was still critical. Every pound that didn’t have to be carried was a pound that the force from the rocket engine didn’t have to lift.

Figure 9.4 shows Melvill gesturing “okay” from a removable port as final preparations were made. SpaceShipOne was carried

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Fig. 9.4. Mike Melvill gives the thumbs up from the cockpit of SpaceShipOne as last-minute preparations are made. For the Ansari X Prize,

SpaceShipOne had to carry enough weight to simulate three 198-pound (90-kilogram) people. SpaceShipOne just barely made it past 328,000 feet (100,000 meters) without the extra weight, so it was necessary to bump up the performance of the rocket engine. Mojave Aerospace Ventures LLC, photograph by David M. Moore

into the air at 7:12 a. m. PST by White Knight with Brian Binnie behind the controls.

Separation occurred at 8:10 a. m. PST when flight engineer Matt Stinemetze, who sat in the back seat of White Knight, released SpaceShipOne from an altitude of 46,500 feet (14,170 meters). Clear of White Knight and no longer pushing forward on the control stick, Melvill fired the rocket engine, which had been enhanced to provide greater performance by increasing the amount of propellant and burn time.

“You could sure hear it,” Melvill said. “It was very loud—it was extremely loud.

“But it is a fabulous ride going up. I think that people who go on the next one—the passengers—will get the most exciting thing they ever did. A lot of noise. They are going really fast. The acceleration is dramatic. You are accelerating at a huge rate. You just watch the speed going up.”

The cockpit shook as Melvill pulled the nose up, making a very sharp turn toward the sky above. “The straighter you flew it, the

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Fig. 9.5. A video-capture image shot from a chase plane shows SpaceShipOne spiraling up during its boost. Melvill struggled to control the rolls but still allowed SpaceShipOne’s rocket engine to fire so he would be sure to pass the 328,000-foot (100,000-meter) mark. SpaceShipOne rolled twenty-nine times. Mojave Aerospace Ventures LLC, video capture provided courtesy of Discovery Channel and Vulcan Productions, Inc.

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higher it would go in the same amount of time,” he said. “We didn’t need to burn the motor for its full length that it was capable of burning because it went up there quite easily.”

During his previous flight, though, he had battled wind shear, rocket asymmetries, and pitch control failure. These had prevented him from flying a very straight trajectory. Melvill was more than determined to nail the trajectory on this flight.

As SpaceShipOne blasted through the upper atmosphere, Melvill had closed up the two donuts on theTONU display, which meant he was doing a great job flying the planned trajectory, and he monitored the energy altitude predictor, an instrument that predicted how high SpaceShipOne would go once the rocket engine was shut down.

“You may be at 160,000 feet [48,770 meters],” Melvill said, “and it will say, if you turn it off right now, you’ll go all the way to 328,000 feet [100,000 kilometers]. So, you watch that instrument. That’s the primary instrument to know when to turn it off. Initially, we did it with a timer, and we just said you’re going to run 55 seconds. And at the end of 55 seconds, we’d shut it off.”

But only 60 seconds after lighting the rocket engine, traveling at Mach 2.7, SpaceShipOne was in trouble. The crowd hushed as the contrail from SpaceShipOne switched from a nice, smooth line to a wild corkscrew in the sky. Things happened fast. But from the angle of the shot displayed on the jumbo screen, it was hard to tell what was actually happening. Figure 9.5 shows SpaceShipOne rolling out of control, viewed from the cockpit of a chase plane.

“When he started doing the rolls, I thought he was dead,” recalled Erik Lindbergh. “I thought that was it—the craft was going to break up and he was done.”

Thousands of people were gripped in silence.

“I didn’t think he was doing rolls. I thought he was tumbling at that point,” Lindbergh recalled.

SpaceShipOne rolled right uncontrollably at an initial rate of 190 degrees per second, spiraling up toward space.

“I had one of the walkie-talkies, and I could hear Melvill talking to ground control,” Ansari said. “He said that everything is fine. It didn’t look fine. But because he was convinced that everything was fine, I felt comfortable.”

The rocket engine kept burning while SpaceShipOne still spun its way up, reaching a maximum speed of Mach 2.92 (2,110 miles per hour or 3,400 kilometers per hour). Melvill still kept his eye on the energy altitude predictor. As he explained, “Unless you see 328,000 feet [100,000 meters] in that window, you are not going to win the X Prize. So, you don’t want to turn it off until you read at least that much or more. And so that was why I didn’t turn it off when we were doing all those rolls, because it didn’t say 328,000 feet [100,000 meters] yet. I went to turn it off thinking, wow, something was wrong here. And when I looked at the energy height predictor, it was not predicting that we would go high enough. So, I just left the motor running and just ignored the rolling.”

At a total burn time of 77 seconds, Melvill finally shut off the rocket engine. His altitude was 180,000 feet (54,860 meters) at that point and only about halfway through its ascent. But as Melvill got higher and higher, the air became too thin for him to counteract the rolls with either the subsonic or supersonic flight controls. SpaceShipOne left the atmosphere still rolling at 140 degrees per second.

Melvill was able to keep from being disoriented by focusing on the Tier One navigation unit and not glancing out the windows. He acti­vated the feather and then focused on nulling-out the rolls with the reaction control system. “I just pushed it on, turned on both systems, and just left it on until it stopped it,” Melvill said.

By the time SpaceShipOne stopped rolling, it had completed twenty – nine rolls. The vehicle now continued to coast to an apogee of 337,700 feet (102,900 meters), but now Melvill could enjoy the 3.5 minutes of weightlessness and the view while still having time to take a few photos out the window.

On reentry, SpaceShipOne hit a top speed of Mach 3.0. Still in the feathered configuration, it decelerated from supersonic to subsonic,

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Fig. 9.6. By using the reaction control system (RCS), Mike Melvill stopped the rolls. He reached an apogee of 337,700 feet (102,900 meters), which gave him about 10,000 feet (3,000 meters) to spare.

Now, coming down was the easy part. Mojave Aerospace Ventures LLC, video capture provided courtesy of Discovery Channel and Vulcan Productions, Inc.

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Fig. 9.7. SpaceShipOne’s second spaceflight was nearly over as it approached Mojave’s runway. But before Melvill had gotten close to the airport, he did some early celebrating by rolling SpaceShipOne once more to make it an even thirty. Mojave Aerospace Ventures LLC, video capture provided courtesy of Discovery Channel and Vulcan Productions, Inc.

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Fig. 9.9. On October 4, 1957, Sputnik became the first man-made object to orbit Earth. The Soviet Union had launched the beach ball­sized satellite, which circled the planet for three months. Sputnik put the space race between the United States and Soviet Union into overdrive. Decades later, on this day, SpaceShipOne was ready to finish a race of its own. NASA

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while it reached a peak g-force of 5.1 g’s at 105,000 feet (32,000 meters).

At 61,000 feet (18,590 meters), Melvill retracted the feather to begin his glide back to Mojave. As SpaceShipOne descended, the chase planes caught up and tucked in behind. Figure 9.6 shows the view of SpaceShipOne from the Alpha Jet.

During the 18-minute glide to Mojave, SpaceShipOne suddenly rolled completely around, surprising the chase planes. But this roll wasn’t uncommanded. Melvill performed a victory roll, rounding out his total rolls for the flight at thirty.

Figure 9.7 shows SpaceShipOne coming in for a landing as the crowds lining the runway cheered.

“It was fabulous—it really was—knowing that we at least were halfway there. We went plenty high. And coming back and all the excitement, everybody was just thrilled to death,” Melvill said.

Melvill’s flight exceeded the altitude requirement by nearly 10,000 feet (3,050 meters) and satisfied the other rules set by the Ansari X Prize. To fulfill the remaining conditions, SpaceShipOne had to repeat the spaceflight within two weeks. Standing on SpaceShipOne, Melvill celebrated successfully completing the XI, as shown in figure 9.8.

“We knew what we had to do. My task was to not damage the air­plane. I wasn’t going to go for any altitude records but just plenty of margin and burn the engine as little as possible and land the airplane as smooth as possible so we didn’t have to fix anything. We didn’t even change the tires. We refueled it, and it was ready to go. We could have gone the next day,” Melvill said.