Two Canadian teams vying in separate competitions to test equipment for use in space elevators at this year's X-Prize became embroiled in disputes with organizers over the contest rules. 

Team Snowstar, a group of undergraduate science students from the University of British Columbia, came up half a millimetre short of a chance to compete in a $200,000 contest to test the strength of tethers for use in space elevators.

Meanwhile, a team from the University of Saskatchewan thought they won the $150,000 top prize in the Power Beam Challenge when their robot climber beat all other competitors. But their climber was deemed not fast enough after organizers measured the ribbon track on which it climbed.

"They were by far the strongest competitor," the event's organizer Ben Shelef told CBC.ca on Monday. Shelef co-founded the Spaceward Foundation on Space Elevator Development.

Weighing controversy

Three of four teams in the NASA-funded Tether Challenge — including Team Snowstar — were disqualified for winding their fibres into too narrow a loop.

"All three teams screwed up," Shelef said. "They tried to get greedy and got too close."

Undeterred, the teams decided to compete among themselves, while the big prize went unawarded.

In the competition, teams are required to use tethers that weigh no more than two grams and are able to carry more weight before breaking than a NASA-built tether that weighs three grams.

Each tether is made of a single fibre wound into a loop. A special machine then stretches the loop to the breaking point.

The rules state the circumference of the loop must measure at least two metres. Snowstar’s tether was measured and deemed half a millimetre short of the mark.

"There was just a little miscommunication about the rules," Team Snowstar member Steve Jones told CBC.ca on Monday as he was driving back to Vancouver from Las Cruces, N.M., where the competition was held.

But Shelef defended the decision, saying the rules were "very precise and very clear."

"The decision was made that they were just a little too short," Shelef told CBC.ca Monday.

Jones used his father's truck to drive the tether down to the Space Elevator Games, which were part of the Wirefly X-Prize Cup, a festival mounted by the X-Prize Foundation.

In 2004, the foundation awarded a $10-million US prize to the first private team to launch a manned vehicle into space twice in as many weeks.

NASA began sponsoring the event in 2005 to spur breakthroughs in building cables for the elevators.

Similar to an elevator in a highrise building, a space elevator would convey people or cargo along a 100,000-kilometre-long cable or ribbon anchored to the ground at one end and an orbiting space station at the other. The process would be a much safer and cost-effective method of reaching space than launching a rocket, experts say.

Jones said the Snowstar tether was misaligned on the test stand and was twisted in the pre-test weigh-in, which could have created a narrower loop. The team launched a heated protest, arguing the rules weren’t specific enough to warrant disqualification, but the contest organizers held fast to the rules' wording.

"You could imagine it as like when you twist a bunch of string or a rope," the 23-year-old UBC student said. "It gets a bit bunched up. … We would have liked to see it weighed after the test."

But Shelef said the weighing-in before the competition rule was necessary to protect the integrity of the measurements.

"Weighing after is a bad habit," he said, noting that the tethers often explode after failing, causing the remnants to expand. "That was made very clear in the procedural rules that we weigh in, not weigh out."

The tethers are only as good as their weakest point. Some teams used glue to secure the two ends together, while others tied the ends into knots, twisted the fibres together or created defects in the material that would then create more friction when the loop was being pulled apart.

Team Snowstar's tether snapped at 403 kilograms of force.

"Our tethers are good," Jones said. "We definitely want to compete again."

Another challenge, another controversy

The University of Saskatchewan team was competing in the Power Beam Challenge, in which competitors build a machine that can climb at a rate of at least one metre a second up a ribbon suspended from a crane. The climber must be powered by a light source.

But organizers soon realized they did not know whether the ribbon used in the competition was 50 metres or 60 metres long.

The USST robot ascended the ribbon in 57 seconds — which was fast enough to qualify for the $150,000 top prize if the ribbon is 60 metres long, but not if it is 50 metres.

The ribbon was more than 50 metres when it was erected, but the effects of wind and load caused it to stretch, Shelef said. Upon measuring the ribbon after the event, organizers ruled the USST robot's time was two seconds short of qualifying for the prize.  

The other competitors argued the USST climber didn’t qualify for the prize regardless of the ribbon's length because it became stuck at the top of the ribbon and was unable to descend.

"They probably would have been disqualified for that," Shelef said.

'Huge success' despite disputes: Organizer

The events were designed to generate innovation and competition in solar system exploration and other areas of relevance to NASA's missions.

The space agency has funded a prize purse of $200,000 US this year for the tether competition. The amount will rise every year until 2010's purse of $600,000.

Shelef said he hoped the teams would come back to the competition next year, despite the disputes.

"This is a huge success," Shelef said, noting that an aerospace designer expressed interest in the teams.

"These are future aerospace engineers getting interested in going into the field of building space elevators."