NEAR SPACE
■ FIGURE 8. The torture chamber of
tethers. A pair of two meter long
tether loops are tested against each
other in this jig. Ouch!
collaboration with the MIT team.
Stephen Steiner from MIT told me
that the carbon in their CNT tether is
not that expensive. It’s the cost of
running a cutting edge company like
Nanocomp Technologies that makes
it expensive. I foresee the day though
when the use of CNT is ubiquitous in
our society that CNT tethers like
Team Delta-X’s will be as affordable
as twine (Figure 9).
At the tether pull, two tethers
are loaded into the jig and pulled
simultaneously. The tether that fails
first is eliminated and the winner then
WANT TO KNOW MORE?
Here are the websites where you
can read more about the light
racers and super strong tethers:
Team Astroaraneae
www.astroaraneae.com
Team Delta-X
www.teamdeltax.com
Nanocomp Technologies
www.nanocomptech.com
The Light Racer Competition
www.spaceward.org/lightRacers
goes on to face the house tether. The
MIT tether wasn’t a woven loop of
CNT; there was too little time for
them to do that. So instead, MIT
made the CNT tether into a loop by
tying its ends together with a knot.
However, CNT is too slick to
hold knots. So very early in the test,
the knot in the CNT tether pulled
apart. The test ended at a force of
only 200 pounds. Team Astroaraneae
decided not to test the house tether
■ FIGURE 9. Dr. Edwards holding the
first CNT tether. Until this day, the
public only saw CNTs from under a
microscope. It looks like a glossy
black plastic twine.
since it required that their tether
stand up to a punishing 1,800 pounds
of force on the jig. Team Astroaraneae
has tested their tether to 1,336
pounds of force, which is pretty darn
good for a two gram cord.
Onwards and Upwards,
Your Near Space Guide NV
May 2008 87
