The NASA Centennial Challenges

In 2003, NASA started a new program known as “The Centennial Challenges” based on a recom­mendation of the National Academy of Engineering in 1999. This recommendation was that Congress should encourage federal agencies to experiment more extensively with inducement prize contests in science and technology. The NASA Centen­nial Challenges were named in recognition of the Wright brothers’ first flight 100 years before.

The “Challenges” set up a monetary prize format similar to that discussed above, and which actually relates back to the British prize of

20,0 pounds sterling offered in 1714 for a reli­able method of determining longitude on a ship at sea. (See Chapter 1.)

The NASA Challenges typically coordinate the competitions with private foundations, like the X Prize Foundation, the Spaceward Foundation, or others, which actually mn the events. The Chal­lenges are announced annually and range over a wide spectrum of scientific and technical issues. Examples from past competitions include the Astro­naut Glove Challenge (to devise the best performing glove for space use), the Moon Regolith Oxygen Challenge (the extraction of oxygen from lunar soil), and the Suborbital Payload Challenge (to achieve suborbital altitudes that provide enough linger time for the kind of microgravity research NASA needs).

The Strong Tether Challenge and the Power Beaming Challenge are designed to produce

FIGURE 41-11 Hybrid rocket engine used by SSI.

technology that will put humans and objects into space without the use of rocket propulsion. These Challenges are subparts of the larger “space elevator” concept that was first mentioned by Konstantin Tsiolkovsky in the late 19th century, and then more specifically proposed by a Rus­sian engineer (Yuri Artsutanov) in the 1960s. The basic idea is to anchor a tether (a ribbon with a diameter half that of a pencil) at a point on earth that will extend into outer space, to a point beyond the geosynchronous orbit. A counterweight positioned at the space end of the tether would provide enough inertia through the rotation of the earth (centripetal force) to keep the length of the tether taut. Payloads would be attached to the tether for delivery into space.

When first proposed, and even in 1960, the idea was assigned to science fiction because there existed no material strong enough to construct a workable tether. In 1991, science discovered a new class of molecule known as the carbon nano­tube, which possesses over twice the strength necessary to make the tether work.

The Strong Tether Challenge is held at the Space Elevator Conference sponsored by Microsoft, The Leeward Space Foundation, and the International Space Elevator Consortium. Although as of 2011 there has been no win­ner, the strength of the tethers has continued to increase for the five years of the competition. The prize purse has continued to increase over the years and is now at $2 million.

The Power Beaming Challenge is a competi­tion to build a wireless lifting mechanism, called a climber system, powered by electricity from a ground electrical outlet that is “beamed” (wire­lessly) to the climber apparatus. The beam is a high-power low-intensity laser. The lifting mecha­nism must lift a payload a prescribed height within a prescribed time. Beamed power competitions held since 2005 finally resulted in a winner in 2009. LaserMotive LLC was awarded $900,000 that year for successfully driving the climber up a cable one kilometer high, suspended from a helicopter.