Behind the X Prize

Photo courtesy Ansari X Prize

Human history is filled with tales of explorers who took a chance, put their lives on the line and plunged into the deep reaches of the unknown. Because of their efforts and ambition, it seems we now have access to even the most mysterious of places on Earth: the deepest rainforests, the darkest caverns, the highest mountains and the sky itself. Now, our incessant need to explore must be sated by yet another frontier: space.

But, unlike the days of the Wild West, when pioneers were free to set out for glory or gold with just a pack on their backs and a pair of good walking shoes, exploration of this new frontier requires quite a bit more money and has therefore been limited to elite government agencies -- until the Ansari X Prize.


In this article, we'll cover the origins and requirements of the "New Race to Space" for which SpaceShipOne took the $10 million prize on October 4, 2004 -- all without government funds, rocket parts from NASA or a special, cabinet-level position for private spaceflight. We'll also discuss some of the other teams and technology involved in the race and what the contest means for the future of space tourism.

Space Transport's Eric Meir with two-stage rocket
Space Transport's Eric Meir with two-stage rocket

So, just what is the Ansari X Prize? Simply put, it's a contest that promised a cash prize of $10 million to the first registered team to:

  • Build a spaceship able to carry three adults (height up to 188 centimeters [6 feet, 2 inches] and weight up to 90 kilograms [198 pounds] each).
  • Launch the spaceship with three soon-to-be astronauts to a height of 100 kilometers (62.5 miles), the internationally recognized altitude at which sub-orbital space begins.
  • Return the spaceship to Earth safely -- no broken bones on the astronaut, no severe damage to the ship, etc.
  • Repeat the flight within two weeks using the same ship, having replaced no more than 10 percent of the ship's parts (with the exception of fuel), thus classifying the spacecraft as a Reusable Launch Vehicle (RLV).

The feat had to be completed by January 1, 2005, so SpaceShipOne took the prize with lots of time to spare. In addition to the cash purse, the winner received a 5-foot-tall (152-cm), 200-pound (90.7-kg) bronze trophy. (See Ansari X Prize Trophy for a look at the design.)

No financial help could be accepted from any government -- this means no government grants, no government subsidies, no NASA ships and no NASA parts. There was no lack of private donors, however. The star-studded list of contributors include Microsoft co-founder Paul Allen (Scaled Composites' SpaceShipOne), the original space tourist and millionaire Dennis Tito, Charles Lindbergh's grandson Erik Lindbergh, former astronaut and U.S. Senator John Glenn, author Tom Clancy and actor Tom Hanks.

People from all countries of the world were able to compete for the X Prize, and more than 20 teams from seven countries were registered. Contestants had to submit a $1,000 registration fee along with a detailed description of the proposed vehicle and mission, and they had to agree to follow the rules and specifications above (for a look at the specific documents that were required, see Ansari X Prize: Register as a Team).

Testing the da Vinci Project rocket
Testing the da Vinci Project rocket
Photo courtesy da Vinci Project

After registration as an official X Prize contestant and all of the challenges of planning and building a spaceship that followed, a team ready for launch faced yet another roadblock: launch licensing. Most countries require a license to fly any vehicle into the air, and launching something into space and back definitely falls under that heading. In the United States, the Federal Aviation Administration (FAA) requires an Experimental Aircraft Certificate and a Space Launch License. The application form is fairly simple, but the process that follows is not: The FAA's Applicant Checklist is divided into four phases, which include frequent meetings with FAA officials and regular inspections of the project's progress.

Another thing to keep in mind: According to the FAA, you can't just build and launch a sub-orbital rocket in your backyard. Launches are allowed only at specific government-funded and privately funded sites (see FAA: Launch Sites); however, according to X Prize rules, a team could not use a government site unless it was open to all teams (including those from other countries).

Only two sub-orbital, manned rocket-launch licenses have ever been awarded in the United States, both of those within the last six months. Add the time it takes to get FAA approval to the 60-day notice required by the X Prise Foundation to launch, and time was of the essence.

Therefore, many teams came quite far in their development of spacecraft but could not get ready to launch before the January 1, 2005, deadline. Their ideas and technological innovations will live on, however. In the next section, we'll a look at some of the teams that were involved in the Ansari X Prize.

Pilot Mike Melville atop SpaceShipOne
Pilot Mike Melville atop SpaceShipOne
Photo courtesy Ansari X Prize

The Ansari X Prize garnered teams from countries as varied as Russia, Canada, Romania, Israel, England, Argentina and the United States. Contrary to the expectation that big aerospace companies would jump to get involved, many of the teams' companies were founded after the announcement of the contest, and teams often consisted of their founders. When Scaled Composites' SpaceShipOne took the prize, more than 20 teams were registered. Most only managed to complete the design or build the spacecraft, but a few did have test flights with demonstrator rockets -- some successful, others not so successful. Here's a breakdown of the successful ones:

WINNER: Scaled Composites LLC

Mojave, California

Vehicle: SpaceShipOne, a 16.4-foot (~5-meter) rocket launched mid-air from carrier aircraft White Knight

Team Leader: Burt Rutan

Web Site:

The Ship

Design: Two-stage rocket based on the German V-2

Length: 82 feet (25 meters) first stage, 16.4 feet (5 meters) second stage

Cabin: Pressurized to the point that you could be comfortable in a short-sleeved shirt

Number of Engines: Two turbojets (first stage), one rocket (second stage)

Propulsion System: Afterburning engine (first stage), hybrid engine (second stage)

Thrust: 7,700 pounds (first stage)

Reaction Control System: Cold pressurized CO2 gas

The Flight

Launch Site: Mojave, California

Ascent Method: Carrier aircraft

Ascent Duration: 60 minutes

Altitude at Ignition: 53,000 feet (~16,000 meters)

Maximum Acceleration Force on Ascent: 3 to 4 g (the force of gravity)

Time of Engine Cut-off: 65 seconds

Maximum Speed: Mach 3.5

Maximum Altitude: 62 miles (~100 km)

Time in Weightless Conditions: 3.5 minutes

Re-entry Method: Ballistic

Acceleration Force on Descent: 5 g maximum; over 4 g for 20 seconds

Landing Method: Unpowered horizontal

Total Duration: 90 minutes

Landing Distance from Take-off: 0 miles

Photo courtesy Scaled Composites, LLC

To learn much more about SpaceShipOne and its flights, see How SpaceShipOne Works. Space Program

da Vinci Project

Toronto, Ontario, Canada

Vehicle: Wild Fire, a 16-foot (~9-meter) rocket launched mid-air from a huge helium balloon

Team Leader: Brian Feeney

Web Site:

The da Vinci rocket
The da Vinci rocket
Photo courtesy da Vinci Project
Beginning of construction on the da Vinci rocket
Beginning of construction on the da Vinci rocket
Photo courtesy da Vinci Project

The Flight

Ascent Method: Reusable helium balloon

Ascent Duration: 90-120 minutes

Altitude at Ignition: 70-80,000 feet (21,336-24,384 meters)

Orientation at Ignition: 75 degrees; 90 degrees after eight seconds

Maximum Acceleration Force on Ascent: 3.5 g

Altitude at Engine Cut-off: 206,000 feet (~62,800 meters)

Time at Engine Cut-off: 90 seconds

Maximum Speed: 2,670 miles per hour (~4,300 kph)

Maximum Altitude: 377,000 feet (115 km)

Time in Weightless Conditions: 3.5 minutes

Re-entry Method: Cabin capsule and propulsion section enter separately

Acceleration Force on Descent: Maximum of 6.75 g, more than 3 g for 20 seconds

Landing Method: Parachutes are released before landing on air bags

Total Duration: 90-110 minutes

Landing Distance from Take-off Location: 31-62 miles (50-100 kilometers) depending on the wind

the da Vinci Team
the da Vinci Team
Photo courtesy da Vinci Project

High Altitude Research Corporation (HARC)

Huntsville, Alabama

Vehicle: Liberator, a 40-foot-tall (~12-meter) rocket launched vertically from an ocean-going vessel

Team Leader: Tim Pickens

Web Site:

The Ship

Design: Two-stage rocket based on the German V-2

Length: 43 feet (~13 meters)

Diameter: 4 feet (~1.2 meters)

Take-off Weight: 10,000 pounds (~4,500 kg)

Cabin: Pressurized with suits

Engines: Two liquid, one hybrid in the escape tower

Propulsion System: Kerosene/LOX pressure-fed rocket engine

Fuel & Oxidizer: Liquid oxygen

Thrust: 24,000 pounds

Reaction Control System: Cold gas thrusters

The Flight

Launch Site: Ocean-going barge or ship

Ascent Method: Rocket fires for 57 seconds; cabin capsule coasts to 107 kilometers (~66 miles)

Ascent Duration: 189 seconds

Altitude at Ignition: 0 feet

Orientation at Ignition: Within two degrees of vertical

Maximum Acceleration Force on Ascent: 5 g

Altitude at Engine Cut-off: 29 kilometers (~18 miles)

Time at First-stage Engine Cut-off: T+57 seconds

Maximum Speed: 1,263 meters per second (~4,144 feet per second)

Maximum Altitude: 107 kilometers (~66 miles)

Time in Weightless Conditions: 4 minutes

Re-entry Method: Ballistic

Maximum Acceleration Force on Descent: 5 g

Landing Method: Parachute descent into the ocean

Total Duration: 10 minutes

Landing Distance from Take-off Location: 16 kilometers (~10 miles)

Aeronautics & Cosmonautics Romanian Association (ARCA)

Aeronautics & Cosmonautics Romanian Association (ARCA)

Ramnicu Valcea, Romania

Vehicle: Orizont, a 55.7-foot (17-meter) rocket launched vertically from the ground

Team Leader: Dumitru Popescu

Web Site:

The Ship

Design: One-stage, vertically launched rocket

Length: 55.7 feet (17 meters)

Width (Span): 4.3 feet (1.3 meters)

Take-off Weight: 15,430 pounds (7,000 kilograms)

Cabin: Pressurized to 1 atm

Number of Engines: 4

Propulsion System: Uncooled, pump-fed

Fuel & Oxidizer: HTPB, hydrogen peroxide

Thrust: 27,000 pounds

Reaction Control System: Hydrogen-peroxide, low-thrust engines

The Flight

Ascent Method: Vertical lift-off

Maximum Acceleration Force on Ascent: 5 g

Altitude at Engine Cut-off: Over 130,000 feet (~40,000 meters)

Time at Engine Cut-off: T+220 seconds

Maximum Speed: 2,900 miles per hour (1,300 meters per second)

Maximum Altitude: Over 62 miles (100 kilometers)

Time in Weightless Conditions: 2 minutes

Re-entry Method: Parachutes released at 2.5 miles (4 kilometers)

Acceleration Force on Descent: 4 g

Landing Method: Parachute recovery

Landing Distance from Take-off Location: 31.3 miles (50 kilometers)

Space Transport Corporation

Forks, Washington

Vehicle: Rubicon, a 22-foot (~6.7 meter), 7-engine rocket launched from a movable platform

Team Leaders: Phillip Storm and Eric Meier (co-founders)

Web Site:

See MSNBC: Space-race rocket blows up.

Armadillo Aerospace

Mesquite, Texas

Vehicle: Black Armadillo, a 24-foot (~7-meter) rocket launched vertically from the ground

Team Leader: John Carmack, creator of the popular first-person shooter video games Wolfenstein 3D (1992), DOOM (1993) and Quake (1996)

Web Site:

See Armadillo Aerospace’s X Prize Prototype Crashes.

The da Vinci team's final prototype preparations
The da Vinci team's final prototype preparations
Photo courtesy da Vinci Project

To understand the challenges the X PRIZE teams faced and the individual solutions they engineered to conquer them, you may need to brush up on some basic rocket science. (If you're up for a more extended course in rocket science, be sure to check out How Rocket Engines Work.)

When creating a space-bound rocket, you need to know about two main things:

  • Orbital Mechanics - These are the basic principals behind the behavior of any moving object that is affected by gravity, including people (within the Earth's atmosphere), the satellites orbiting the Earth that make the GPS system in your car work and even things as big as a planet or as small as a atom.
  • Propulsion Systems - In a word, these make the rocket go. To combat the gravity on the Earth's surface, the propulsion system of a spacecraft has to create considerable force in the opposite direction. This force is called thrust. Thrust is created by the often-explosive combustion of the propellant (or fuel), which can consist of things as everyday as gasoline or tire rubber. The more the rocket weighs, the more propellant is required; however, the more propellant is required, the more the rocket weighs, so the rocket's design must be planned carefully.

These two basic elements affect the complex Ansari X Prize spacecraft similar to the way they'd affect something as simple as a golf ball. When a golfer takes a swing, the golf club functions as the propulsion system and thrusts the golf ball high into the air, flying in the direction of the swing. Because it is hit from the side, it forms a long, wide arc before returning to the ground. If the ball could be hit from the bottom, it would go straight up -- which is pointless for golfers but great for rocket scientists.

The traditional way of propelling a rocket or a spacecraft into sub-orbit is to fire up the propulsion system directly beneath the vehicle to thrust it straight up. Upon reaching burnout (the point at which all of the fuel is used up), the rocket continues to ascend for a short time. As it slows down from lack of propellant, it begins to make an arc -- this is where it reaches its highest point (or altitude), known as apogee. It then begins to descend, completing the arc until it falls in a straight line back to the Earth's surface. To prevent the destruction of the rocket on impact, many are equipped with parachutes to slow the fall.

There are plenty of resources for the at-home rocketeer. Do-it-yourself, beginner rocket kits -- complete with engines -- can be purchased for as little as $5 to as much as $150 at hobby stores nationwide. For the serious hobbyist or budding rocket scientist, high-powered versions can be purchased that fly as high as a commercial jet -- more than 30,000 feet (9,144 meters). A word to the wise: Use of these and H-class rockets require National Association of Rocketry approval for a reason -- these launches can be dangerous. FAA approval may be required as well.

In the next section, we'll describe some of the technology used in the X Prize competition and take a detailed look at the top teams' flight plans.

SpaceShipOne attached to the underbelly of its launch vehicle (followed by another aircraft)
SpaceShipOne attached to the underbelly of its launch vehicle (followed by another aircraft)
Photo courtesy Scaled Composites, LLC

The spaceship designs are as varied as the origins of the teams, making use of established as well as innovative technology.

Traditional Tactics

Several teams took the "oldie but goodie" tack, basing their sub-orbital rockets on technology developed as early as the 1940s. A popular design to copy was the German V-2, a World War II rocket that launched vertically from the ground into the Earth's stratosphere so as not to be detected and destroyed by enemy aircraft -- the world's first guided ballistic missile. Teams that chose this model for their spacecraft, such as Canadian Arrow, were forced to make some serious adjustments to fulfill the contest's requirements: Primarily, the rocket had to be large enough to carry three people, and the passengers couldn't explode when the rocket touched back down. To tackle this, some teams divided the rocket from the launch vehicle, turning the launch into a two-stage affair. The first stage involved lift-off from the ground, the craft propelled by the main rocket engine. During the second stage, the cabin of the spacecraft disengaged from the bottom portion, propelled by its own engines into sub-orbit. In the case of the Canadian Arrow, the two portions were equipped with parachutes to ease the landing.

High Ambitions

The most successful teams in the contest took a slightly different tack. Using the rationale that launching from the Earth's surface is twice as difficult as launching from high altitudes, Scaled Composites and the da Vinci Project developed spacecraft that actually launched from the sky care of a carrier plane and a gigantic helium balloon, respectively. These high-altitude launches reduce the amount of rocket fuel required (a major factor in keeping down weight and cost) because the rocket has a shorter distance to travel to get to sub-orbit, and the thin air provides less resistance than that on the Earth's surface. Scaled Composites' SpaceShipOne released from its carrier plane White Knight at about 45,000 feet (~13,700 meters), boosted itself into sub-orbit, cut its engines for a three-minute view of the Earth in weightless conditions and then fell back down to Earth, slowing its decent by creating aerodynamic drag (see How SpaceShipOne Works for detailed information of the flight).

The da Vinci Project used a slightly different approach, dangling its spaceship from a reusable helium balloon until reaching 80,000 feet (~24,400 meters), at which time the engines were fired. Since propelling the rocket straight up would destroy the balloon (disqualifying the entry), the GPS-guided vessel first shot out at a 75-degree angle to clear the balloon and then changed to a 90-degree trajectory to go straight up to sub-orbit. The cabin then separated from the bottom portion and, after three minutes of weightlessness and an awe-inspiring view, plummeted back to the Earth while using parachutes on both sections to break the fall.

The da Vinci launch balloon
The da Vinci launch balloon
Photo courtesy Ansari X-Prize

Innovative Effort

Some of the more unique designs did not make it to the flight-testing stage, but certainly deserve an "E" for effort. American Discraft of Portland, Oregon, had the inspired idea to create a 100-foot-diameter (~30.5-meter) "hypersonic wave rider aerospace craft" -- a flying saucer. In theory, the ship (called the Space Tourist) would take off horizontally from a runway at 60 miles per hour (~97 kph) by creating suction along the top surface and would then thrust the air through the ship's exhaust to create propulsion and steering.

In the next section, we'll discuss future developments and what is expected to arise from the efforts of the Ansari X Prize contestants.

So what does all this rocket science mean for the average person? Well, for starters, it means that space tourism could be widely available before we even lay eyes on those flying cars we thought we'd be driving by now.

The developments and efforts of the X Prize contestants have both sped up the time-table for such an adventure and potentially driven down the cost. According to market studies cited by X Prize founder Diamandis, as many as 10,000 Americans would be willing to pay up to $100,000 for the opportunity to ride in a sub-orbital spacecraft -- the question, of course, is whether that fee is a realistic one to cover costs and profit. The X PRIZE chairman and CEO equates the near future of space tourism with the "barnstorming" of the 1920s, when people flocked to freelance pilots and paid them a fee for riding along. According to Diamandis, the X Prize contest is the first of three phases in the development of a privatized space-flight industry:

  1. Research and development - Spacecraft are conceptualized, designed, created and then tested. This stage has occurred during the Ansari X Prize.
  2. Trained participation - Passengers undergo training, understand the possible risks involved in flying in an experimental spacecraft and sign a liability waiver before the trip. Between 2,000 and 3,000 flights will have to occur before the safety of the process is approved for the general public, making the next step possible.
  3. Government certification - The spacecraft and manufacturers undergo a rigorous FAA approval process, which could end up costing up to 100 times more than the development of the vehicle before its final certification of public safety.

In addition to space tourism, it is anticipated that Ansari X Prize vehicles will provide cheap satellite launches, faster point-to-point passenger travel and same-day international mail delivery. The sky is truly the limit.

For more information on the X Prize, private spaceflight, space tourism and related topics, check out the links on the next page.

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