BBC Focus

SPACE

ANTIMATTER

R OCKETS

Antimatter is the staple fuel source inStar
Trekk– and perhaps the reason why Scotty
alwayslookssoworried.This notoriously
volatilesubstance is the perfectfuelin one
sensebecause it converts matter into energy
with100 per cent efficiency. In other words,
itcanrelease vast amounts ofoomph.
In 2006,theNASAInstituteforAdvanced
Concepts funded the study of apossible
antimatterspacecraft.LedbyGeraldSmith
of Positronics Research, the work concluded
that a ship could be propelled to Mars in just
45 days, using a minuscule one-hundredthof
agramme of antimatter. Withpotency like
that, whystopatMars?
In 2003,physicist GeraldJackson and
nuclear engineer Steven Howe,bothof
US company Hbar Technologies, LLC,
publishedtheir own study. It showedthat
with17g ofantimatter, a spacecraftcould
cross onelight-year ofspace in just adecade.
This wouldmean that the nearest star
system, Alpha Centauri, could be reached in
about 40 years.
But there’sacatch.Antimatteristhemost
expensive substance on Earth.Backin 1999,
NASA estimatedthat to create a singlegram
ofit wouldcost $62.5tn. Even today, thecost
ishoveringaroundatrilliondollars. This is
because tiny quantities ofantimatter are
createdas aby-product in particle
accelerators, whichare super-expensive to
start with.Ofalltheparticleaccelerators in
theworld,including theLargeHadron
Collider at CERN,less than 20 nanograms of
antimatterhave beenmade.
Storage is another problem. Antimatter is
theopposite ofmatter. The antimatter
equivalent ofan electron is calleda positron.
Althoughit contains thesamemass,its
electricalcharge is opposite. When a
positron andan electron meet, they
annihilate eachotherbackinto energy. So
tryingtostoreantimatterinsomething made
from matter is doomed to explosive failure

• hence Scotty’sperpetualanxiety.
  However,since antimatter carries an
  electricalcharge it canbedeflectedbya
  magneticfield.This means antimatter could
  bestoredin someform ofbottlethat creates a
  magneticlining insidetopreventittouching
  thesides. Despite thedifficulties, the
  promise ofsuchapowerkeeps researchers
  coming back to studying antimatter. Earlier
  this year, Jackson andHowe startedtolook
  forfunding tobuild laboratory prototypes of
  an‘antimattersail’that theyhope could
  make this theoretical idea a reality.

The capsules are

shot from their storage

areas into the nozzle

compartment many

times a second

The lead casing

produces X-rays that

gradually vaporise the

nozzle’s lining, producing

an exhaust that pushed

the spacecraft forwards

The nozzle is kept

well away from the

crew compartment and

instruments, because

of the high-energy

radiation it produces

2

Inside the

compartment, a

capsule’s magnetic field

turns off and the

antimatter annihilates

with the lead casing

3

4

5

Antimat ter is kept

in a multitude of lead

capsules, each equipped

with an internal magnetic

field to contain the

volatile substance

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