74 Science & technology The EconomistOctober 5th 2019
2 with planetary colonisation in mind.
When paired with a Falcon Super Heavy
booster, which is also being developed, the
result should be capable of lifting around
150 tonnes into orbit. That would make it
the most powerful rocket ever built,
squeaking ahead of the Saturn V, which
propelled astronauts to the Moon in the
1960s and 1970s. And unlike the Saturn,
whose three stages were abandoned to the
sea or to space as their fuel was used up, the
Starship and its booster will be reusable,
which should keep costs down.
It is a bold plan. Mr Musk’s shorter-term
plans are bold too. Besides designing a new
spaceship and booster, SpaceX’s engineers
are busy working on a new, more efficient
engine to power them. Called Raptor, it is
designed to burn super-cold methane rath-
er than the kerosene that fuels the com-
pany’s current Merlin engines. The Star-
ship will sport six Raptor engines. But each
Super Heavy booster will need somewhere
between 24 and 37. The result will be a
plumber’s nightmare.
Mr Musk has said, perhaps optimisti-
cally, that a Starship prototype might be
ready for a test flight all the way to orbit (al-
beit without its booster stage) within six
months. That would be of a piece with its
frenetic development schedule. The rock-
et-building industry is used to generous
government contracts that are about job
creation as much as rocket creation. Spa-
ceX has brought a different sensibility,
closer to the rapid-fire development prac-
tices of the software industry.
The Starship prototype, for instance,
was welded together in a matter of months.
It was built out in the open, rather than in a
carefully controlled factory environment.
The firm has two teams competing against
each other to produce the best design.Ideas are tested quickly, taken forward if
they work, and scrapped if they do not. The
Starship was originally to be made of a car-
bon-fibre composite. But the company
soon abandoned that idea, destroying its
production tools. Steel, noted Mr Musk,
has a higher melting point than carbon fi-
bre, making re-entry easier. It is also an or-
der of magnitude cheaper.
To see the contrast, look at the Space
Launch System (sls), another super-heavy
rocket designed to ferry astronauts to theMoon and Mars, but which is being built by
nasa, America’s space agency. The slshas
had around $14bn of taxpayers’ money
since it was authorised in 2011—and that
understates the true cost, since the slsin-
corporates technology from old, aban-
doned rocket projects. It is due to make its
first flight in 2020, though nasahas hinted
that date may slip. Mr Musk claims that less
than 5% of SpaceX’s resources are dedicat-
ed to Starship. Yet it stands a good chance
of beating the slsinto orbit. 7The world of todayI
naccessible islandis well named. It
is an uninhabited rock in the South
Atlantic ocean that belongs to Tristan da
Cunha, a British dependency which itself
vies with Easter Island for the honour of
being the most remote inhabited place
on the planet. Go there, though, and you
will find its coast is covered with litter.
That, at least, has been the experience
of Peter Ryan of the University of Cape
Town, in South Africa. Since 1984 Dr
Ryan, an ornithologist, has been visiting
Inaccessible and, along with his other
studies, recording the litter stranded on
the island’s beaches. This week, in the
Proceedings of the National Academy of
Sciences, he has published the results.
Though Inaccessible is indeed re-
mote, being near the South Atlantic’s
midpoint, the nature of oceanic circula-
tion means that this is exactly the sort of
place where floating rubbish tends to
accumulate—at the centre of whirlpools
thousands of kilometres across, called
gyres. Dr Ryan’s particular interest was
where all the litter came from before itwas swept into the gyre. And he found
that this has changed a lot over the de-
cades he has been visiting the island.
To impose some order on the ques-
tion, he and his colleagues focused on
one particular class of litter: bottles.
Their definition of a bottle included jars
and aerosol containers, and encom-
passed things made of metal, glass or
polymer. Most, though, were of polyeth-
ylene terephthalate, a light plastic, and
had once held drinks.
A particular advantage of picking
bottles to investigate is that they are
often stamped with their country of
manufacture. That enabled Dr Ryan to
analyse the history of oceanic littering.
As the chart shows, he picked three
recording points, corresponding to field
trips to the island, and analysed the
proportions of bottles from various
geographical sources. In 1989 the prepon-
derance of them (67%) was South Ameri-
can. Twenty years later, in 2009, bottles
made in Asia contributed more or less
equally (44%) with South American ones
(41%). By 2018 the overwhelming major-
ity (74%) were Asian.
This geographical shift speaks vol-
umes. The first sample suggests most
litter arriving on Inaccessible had been
washed off the land or dropped from
coastal shipping—South America being a
relatively nearby continent. The other
two, with their rising proportions of
trash from Asia, which is too far from the
island for it to have floated there, strong-
ly suggest it was crews’ empties being
flung from ocean-going vessels.
Such littering is banned by Annex V of
the International Convention for the
Prevention of Pollution from Ships—
which, ironically, came into force in
1989, the year of Dr Ryan’s first survey. But
evidently a lot of ships’ captains do not
care. They permit the dumping of rub-
bish over the side, regardless.A message in some bottles
Marine pollutionPlease take your litter home...Washed up
Origin of plastic
bottles found on
InaccessibleIsland
%oftotalSource:PNASInaccessible
IslandInaccessible
IslandOtherregionsAfricaEuropeAsiaSouth
America1989 2009 201810080604020067941442074