Science_Illustrated_Australia_-_Issue70_2019

By Andreas Ebbesen Jensen

The Perlan II glider beat the world record, gliding through the air 23km

above Earth’s surface. Scientists aim to use the engineless plane to unveil

the stratosphere’s influence on weather phenomena and climate change.

To the edge of space...

in an engineless glider

Glider to explore

the ozone layer

The stratosphere includes the ozone

layer that protects Earth against UV

radiation, but decades of emissions of

hazardous chemicals have cut holes in

the layer, contributing to global

warming. In 2016, new research showed

that the holes are healing in several

places, but to be certain of this scientists

aim to measure the exact percentage of

ozone in the air. Perlan II will make

measurements at an altitude of 20km,

where 90% of the air is ozone.

O

n 2 September 2018, 13km above

the Andes Mountains, pilots Jim

Payne and Tim Gardner are

flying the Perlan II glider. A

propeller aircraft has lifted the

500kg glider from the ground, but has now

disengaged, leaving Perlan II to climb higher

on the wind alone.

Perlan II has a wing span of 25 metres,

and is designed for maximum lift when

surfing on warm air currents from the

mountains. The warm currents lift the plane

past the Armstrong line at 19.2km. The

atmosphere is now so thin that the blood in

the pilots’ bodies would boil were they not

protected by the plane’s pressure chamber.

Five hours after take-off, Perlan II is

gliding 23km above Earth, almost 4km

higher than any other engineless plane has

reached. Only spy planes and air balloons

have achieved similar altitudes.

Perlan II can glide at the edge of space

and measure speeds, temperatures and

chemical make-up of the winds without

pollution from a petrol-powered plane

engine. The measurements will teach

scientists about phenomena in the strato-

sphere and so about weather and climate

change – and perhaps even help mankind

conquer the airspace of Mars.

Mountain waves paved the way

For many years, plane engineers believed

that gliders could not possibly climb any

higher than 15km above the Earth, because

warm air normally stops rising at this

point. NASA test pilot Einar Enevoldson

proved them wrong. In the 1990s, he was

determined to study the mountain ‘waves’

that occur when high temperatures close to

Earth heat the air above mountain-sides.

The waves produce a particularly forceful

Airliner

Perlan II

STRATOSPHERE

(15-50km)

TROPOSPHERE

(0-15km)

OZONE LAYER

UV radiation

KEN

IKE

DA^

MA

DSE

N^ &

SH

UTT

ERS

TOC

K

scienceillustrated.com.au | 53