NOVEMBER 2019
spectacles.
The rover itself also owes an
engineering debt to its predecessor
whilst boasting several improvements.
Largely based on the engineering
design for the Curiosity rover,
Perseverance is around 3 metres long, 2.7
metres wide, 2.2 metres tall and weighs
1025kg. Like Curiosity, it is powered
by a multi-mission radioisotope
thermoelectric generator that converts
heat from the natural radioactive decay
of plutonium into electricity. It also
boasts three communications antennas
for sending data directly back to Earth.
Key improvements over the earlier
system include larger diameter, and
more robust aluminium wheels, and
an advanced new software system
developed to help the rover manage its
daily activities more eff ectively, and to
operate with greater independence than
Curiosity.
But perhaps the biggest diff erence is
the system that will be used to gather
and cache samples that will be collected
and returned to Earth by subsequent
missions.
Described by the mission’s chief
engineer Adam Steltzner as “the most
complicated, most sophisticated
mechanism that we have ever built,
tested and readied for space fl ight,” this
system consists of what are eff ectively
three separate robots designed to work
in tandem.
The most visually striking element
is the rover’s two-metre-long robotic
arm, a fi ve jointed structure bolted to
NASA technicians and engineers place
sample tubes in the belly of the rover
Credit: NASA / JPL - Caltech
July 2020 / www.theengineer.co.uk 28
In addition to the sample caching system the rover is
equipped with a payload of various scientifi c instruments
for measuring the atmospheric characteristics of the planet,
assessing the mineralogy of the Martian surface, and probing
the subsurface.
A further instrument, the Mars Oxygen ISRU Experiment
(MOXIE) will even a empt to produce oxygen from Martian
atmospheric carbon dioxide, an eff ort that could pave the
way for technology able to produce oxygen for propellants for
future Mars Ascent Vehicle (MAV).
But Perseverance will save what is arguably its most eyecatching
party trick until around two months after it lands,
when a small helicopter will emerge from the rover’s belly to
perform what is hoped to be the fi rst powered fl ight on Mars,
or indeed any planet other than the Earth.
Dubbed Ingenuity, this solar powered autonomous
vehicle will perform a series of test fl ights
and help inform decisions relating to the
use of helicopters
on future Mars
missions, where
it’s thought they could be
used as robotic scouts
to survey terrain from
above and to carry out further
scientifi c experiments.
Powered fl ight on Mars presents some
signifi cant challenges: whilst the gravity is
around a third of that on Earth, the atmosphere
is around 1 per cent the density of Earth’s,
making it much harder to generate lift.
Developing an aircraft capable of fl ying these conditions
required miniaturisation of many of the key components so
that it is light enough to take off . Powered by solar energy, the
aircraft weighs just 1.8kg and is propelled by two 1.2-metrelong
rotors that spin at upto 2400 rpm.
The aircraft will operate autonomously and is equipped
with inertial sensors, a laser altimeter and two cameras to
help it make sense of its environment. Its fi rst fl ight will be
short hover lasting around 30 seconds, and it will then a empt
incrementally more challenging missions, culminating in
fl ights of around 300 metres at altitudes of 10 – 15 feet above
the ground.
space exploration
the front of the chassis. This carries a
large hand (or turret) which features
a percussive drill that will be used for
collecting and saving rock samples.
A robotic carousel provides drill bits
and empty sample tubes to the drill
and moves tubes containing samples
into the rover chassis, whilst a third
robotic system, a half metre long sample
handling arm - will move these samples
between the carousel and storage
stations
within the
rover.
Flight model of NASA’s
Ingenuity Mars helicopter
The helicopter was attached
to the belly of the rover
ahead of launch
Credit: NASA / JPL
- Caltech
/www.theengineer.co.uk