Australian Science Illustrated — Issue 54 2017

scienceillustrated.com.au | 55

Rockets "Blow" in the Wind

The rockets of WW2 fly almost haphazardly. If the Nazis are to hit the

enemy accurately, they must develop a brand new control system.

I

n the 1930s and 1940s, rocket control was more or less

about pointing a rocket in the right direction and

hoping for the best. That is of no use to the Nazis, who

would like their terror missile to strike specific cities such

as London and Paris hundreds of kilometres away.

The solution is an automatic control system, by which

two gyroscopes continuously ensure the correct course of

the rocket, whereas an accelerometer monitors the

speed, so the rocket can deactivate its engine at the

very right time to reach the specified target.

The system, which is the most accurate so far, allows

the V-2 rocket to strike within a 5 km radius of the target

area after a 200 km journey – when things go well.

Incorrect settings and design faults reduce the reliability

of the rocket, and only 517 of nearly 1,200 rockets

launched at London strike their target.

PROBLEM

#3

ROCKETS

LAND ON

A DIME.

In December 2015, the US

company SpaceX sensationally

took rockets into a new era with

the successful test of the reusable

Falcon 9. The rocket’s booster

stages can lift off and land again,

paving the way for much cheaper

space missions. A conventional

rocket costs over $100 million,

whereas a SpaceX reusable rocket

may one day be able to offer

commercial clients access to

space at 1/10th of this price.

Reuse ushers

in new era

1 The Falcon 9 is launched

from Cape Canaver-

al, in Florida.

3 With its landing legs

unfolded, the rock-

et lands 10 minutes

after lift-off in

the planned site.

2

The rocket's

first stage

makes a U turn at

an altitude of 200

km, heading back

towards Earth.

SPACEX HEADING

FOR MARS

The success of Falcon9

has made SpaceX devise

a shuttle route to Mars.

The company's Inter-

planetary Transport

System (ITS) is meant

to carry passengers

to and from the Red

Planet from 2024.

WING FINS PROVIDE

FLYING START

Fins on each of the four

rocket wings counteract rolling

and vertical turns – particularly

right after lift-off. The wing fins

work along with the fins of the

rocket's exhaust.

NOZZLE FINS

TAKE OVER IN THE ATMOSPHERE

Four graphite fins located by the end of the

exhaust control the rocket via the propellants.

This is convenient at high altitude, where wing

fins do not work due to falling pressure.

3 PROBLEMS FOR THE NAZIS

CONTROL BOX HOLDS

STEADY COURSE

Two gyroscopes monitor

deviations from the planned tilt

and course. Corrections are sent to

two electric motors which

communicate course

changes to the eight

guide fins.

STEFAN KÜHN

CLAUS LUNAU

SPACEX