BBC Focus

(Marcin) #1

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

1
Free download pdf