
English: 
welcome to the introductory lecture of
the satellite
engineering course well let's kick off
with the introduction
from dreams to technical challenges
it's an outline of the different
lectures for the next months
you know that space make us dreams for
centuries
now we are able to put a lot of systems
into space and to change our
life to carry out this change the
engineers handled a lot of technical
challenges
for the next slides i will answer to
theses questions
what is a satellite why do we want to go
into the space
where is it possible to put a system
into space
when did everything start and who is
involved in the space domain
i will finish with a question how is
possible to manage the technical
challenges

English: 
Welcome to the introductory lecture of the
satellite engineering course
Well , let’s kick off with the introduction,
: From dreams to technical challenges. It’s
an outline of the different lectures for the
next months.
You know that space make us dreams for centuries.
Now we are able to put a lot of systems into
space and it changed our life.
To carry out this change, the engineers handled
a lot of technical challenges.
For the next slides, I will answer to theses
questions : what is a satellite ? Why do we
want to go into the space ? Where is it possible
to put a system into space ? When did everything
start ? And Who is involved in the space domain
?
I will finish with question : How is possible
to manage the technical challenges ?
As a teaser, I would like to share with you

English: 
some stunning pictures taken in space. Look
at the way,the american astronaut moving in
space.
This kind of activity is called an EVA as
know as extra vehiculary activity, because
you are out of the spaceship. The astronaut
is able to move/progress into space thanks
to a MMU, Manned maneuvering unit, a kind
of a chair with propulsion. This astronaut
is Bruce Mc Candless, first human being satellite
around the earth.
This picture shows 2 astronauts working on
the building of the ISS, International space
station. Can you imagine the same view from
your office?
It’s not only the USA or Europe and Russia
that are hands-on on the space. Our canadian
friends are also very involved in this domain.
For instance, they are the designers of the
Canadarm : it’s a robotic arm which is attached
either to the space shuttle or attached to

English: 
as a teaser i would like to share with
you some stunning pictures taken in
space
look at the way the american astronaut
moving in space
this kind of activity is called an eva
as known as
extravaticulary activity because you are
out of the spaceship
the astronaut is able to move progress
into space
thanks to mmu as know as man maneuvering
unit for kind of a chair with propulsion
this astronaut is bruce mccandless first
human being satellite around the earth
this picture shows two astronauts
working on the building of the iss
international space station can you
imagine the same view from your office
it's not only the usa or europe and
russia that are hands on on the space
our canadian friends are also very
involved in this domain
for instance they are the designers of
the canadarm
it's a robotic arm which is attached

English: 
either to the space shuttle or attached
to the international space station
speaking of the space shuttle here is
the huge cargo bay of the space shuttle
which delivered big satellites into the
orbit for example the hubble telescope
was deployed by the space shuttle
this same space shuttle from the united
states for america was
in the 90s the only way for the american
astronauts to get into the space and the
launch was
you can imagine such a spectacular
moment for the people who
had the chance to see that do you see
the blue circle there
does anyone have an idea of what it is
it's a water tank the purpose is that
just before the launch and the starting
of the engines a lot of water that comes
from the water tank is discharged
on the launch pad but why the noise
produced by the engines is
allowed that it could damage either the
launch pad or the rocket engines

English: 
the ISS.
Speaking of the space shuttle, HERE IS the
huge carbo bay of the space shuttle which
delivered big satellites into the orbit , for
example the hubble telescope was deployed
by the space shuttle.
This same space shuttle from the united states
for America was, in the 90’s the only way
for the American astronauts to get into the
space and the launch was, you can imagine,
such a spectacular moment for the people who
had the chance to see that.
Do you see the blue circle there. Does anyone
have an idea of what it is?
It’s a water tank. The purpose is that:
just before the launch and the starting of
the engines, a lot of water that comes from
the water tank is discharged on the launch
pad.
But why ?
The noise produced by the engines is so loud
that it could damage either the launch pad

English: 
or the rocket engines themselves. The water
is therefore used as a vibration damper to
reduce this noise. The white smoke you see
on the right side and the left side of the
picture is water steam and not the smoke of
the combustion in the engines.
As we move to this picture, do you notice
anything atypical ?
We have some sunspots.
It’s some colder area on the surface of
the sun but we have this black spot there.
With a zoom, it’s what we can see.
In the center of the picture it’s the ISS
, moving in front of the sun, and on the left,
it’s the space shuttle approaching the ISS.
Of course, you have to be quick to take this
kind of picture because the passage of the
two objects in front on the sun, seen from
the ground is a fraction of second. It’s
a snapshot.
sometimes things don't go as planned.

English: 
themselves
the water is therefore used as a
vibration damper to reduce this noise
the white smoke you see on the right
side and the left side of the picture is
water steam and not the smoke of the
combustion in the engines
as we move to this picture do you notice
anything atypical
we have some sunspots it's some colder
area on the surface of the sun but we
have this black spot there
with a zoom it's what we can see in the
center of the picture it's the iss
moving in front of the sun
and on the left it's the space shuttle
approaching the iss
of course you have to be quick to take
this kind of picture because the passage
of the two objects in front on the sun
seen from the ground is a fraction of
second
it's a snapshot

English: 
sometimes things don't go as planned
watch here the launch of a de lta
ii rocket with a gps satellite on board
from cape canaveral air station of the
air force delta
ii launch vehicle carrying the new gps
2r satellite
we have had an anomaly where
i just had an anomaly of the delta ii
launch vehicle from cape canaveral air
station
we need to secure the area
once again we had liftoff of delta ii
launch vehicle from cape canaveral air
station
and we just had a problem with the
vehicle on the pad

English: 
watch here the launch of a DELTA2 rocket with
a GPS satellite on board.
This one-meter resolution satellite image
of Manhattan, New York was collected at 11:43
a.m. EDT on Sept. 12, 2001 by Space Imaging's
IKONOS satellite.
Here, you will discover different satellites.
I emphasize on:
in green the technical challenges of the mission
of the satellite,
in red, the design interaction we have in
the satellite ,
and in blue to explain the kind of failures
we came across.
We begin with Sputnik: the first satellite
in space. Sputnik, launched in 57 by the russians,
For most of you, if you don’t know, it was
the cold war between USA and the CCCP, ex-russia.

English: 
we finish with this one meter resolution
satellite image of manhattan new york
was collected at 11
43 a.m on sept
12 2001 by space imaging's ikon
os satellite
here you will discover different
satellites
i emphasize on in green the technical
challenges of the mission of the
satellite
in red the design interaction we have in
the satellite
and in blue to explain the kind of
failures we came across
we begin with sputnik the first
satellite in space
sputnik launched in 57 by the russians
for most of you if you don't know it was
the cold war between usa
and the cccpx russia
the first major success was won by the

English: 
The first major success was won by the russians
with a successful launch into orbit of an
artificial satellite.
You see, Sputnik, is a sphere with 2 antennas
.
CCCP was trying to act smarter than the USA
but anyways, at the bottom of all, it had
a scientific goal. The idea was to identify
the different layers in the upper atmosphere
of the earth.
Sputnik performed an outstanding/disruptive
breakthrough, in spite of several failures
before the successful flight.
Let’s take a look at the technical datas
of the satellite.
Sputnik is a small sphere, kind of 0,6 m of
diameter and the weight is no more than 84
kgs.
The power of the signal emitted by Sputnik
is only 1 Watt . it’s the same for your
mobile phone.
Sputnik didn’t need propulsion a soon as
it was into orbit, it was not able to change
its orbit.

English: 
russians with a successful launch into
orbit of an artificial satellite
you see sputnik is a sphere with two
antennas
ccp was trying to act smarter than the
usa but anyways at the bottom of all it
had a scientific goal
the idea was to identify the different
layers in the upper atmosphere of the
earth
sputnik performed an outstanding
disruptive breakthrough in spite of
several failures before the successful
flight
let's take a look at the technical data
of the satellite
sputnik is a small sphere kind of zero
six meters of diameter and the weight is
no more than 84 kgs
the power of the signal emitted by
sputnik is only one w
it's the same for your mobile phone
sputnik didn't need propulsion as soon
as it was into orbit it was not able to
change its orbit
no adcsi adcs is the acronym

English: 
No ADCS either, ADCS is the acronym of Attitude
determination and control system, you will
have a lecture on it in the next weeks.
But, don’t get confused by these two terms:
Propulsion is for changing your orbit.
ADCS is to change your attitude into orbit.
For rotating your satellite or stabilize the
rotation of the satellite , for example to
place the antenna of the satellite towards
the ground.
To communicate, Sputnik has two antennas with
a spherical radiation pattern, don’t forget
this course in just an introduction. You will
be followed by plenty of details in the next
lectures,
For the orbit, it’s the same, next week
you will received all the knowledges related
to orbit.
For sputnik, the orbit was a LEO, low earth
orbit, with the different features.
950 is the apogee, highest altitude of the
orbit,
220 is the perigee , lowest altitude ,

English: 
of attitude determination and control
system you'll have a lecture on it in
the next weeks
but don't get confused by these two
terms
propulsion is for changing your orbit
adcs
is to change your attitude into orbit
for rotating your satellite or stabilize
the rotation of the satellite
for example to place the antenna of the
satellite towards the ground
to communicate sputnik has two antennas
with a spherical radiation pattern don't
forget this course in just an
introduction
you'll be followed by plenty of details
in the next lectures
for the orbit it's the same next week
you will receive
all the knowledges related to orbit for
sputnik the orbit was a leo
low earth orbit with the different
features
950 is the apogee highest altitude of
the orbit

English: 
220 is the perigee lowest altitude
and 65 is the inclination of the orbit
sputnik was a very small satellite but
on the other hand we have the
international space station or yss
the iss is made of an international
cooperation
except china the objective is to perform
scientific experiments
the iss is massive 470 tons
the sizes are huge 58 by 73 by 28
the size of a football field currently
we have some astronauts doing
experiments and need a lot of power
at peak you collect up to 110 000 what
thanks to the solar panels the iss has a
propulsion
two svester engines or the thrusters
from the cargo which resupply the iss
with food water experiments astronauts
and many more
what is the use of these thrusters to

English: 
And 65 is the inclination of the orbit
Sputnik was a very small satellite but on
the other hand we have the international space
station or ISS. The ISS is made of an international
cooperation,except china. The objective is
to perform scientific experiments.
The ISS is massive, 470 tons, the size is
so huge : 58 by 73 by28 : the size of a football
field.
Currently we have some astronauts doing experiments
and need a lot of power : at peak, you collect
up to 110000 watt thanks to the solar panels.
The ISS has a propulsion: 2 Zvezda engines
or the thrusters from the cargo which resupply
the ISS , with food, water, experiments, astronauts
, and many more. What is the use of these
thrusters ?

English: 
To answer this question, take a look first
at the orbit, The orbit of the ISS is quite
circular because you have the apogee which
is nearer than the perigee. But mainly, the
altitude is very low.
The limit of the space is established at 100
km, but 350 km is very low anyway. So what
?
In low orbit, the atmosphere is very thin
but you are not in a full vacuum, so you still
have a atmospheric drag that decrease slowly
the speed of the ISS and then the altitude,
Therefore, we need to rise up periodically
the orbit of the ISS , thanks to the thrusters.
You can see here others technical datas. The
ISS has of course attitude determination & control
system, It works with gyroscope, small thrusters,
star trackers , sun sensors, GPS and many
more.

English: 
answer this question
take a look first at the orbit the orbit
of the iss
is quite circular because you have the
apogee which is nearer than the perigee
but mainly the altitude is very low
the limit of the space is established at
100 kilometers but
350 kilometers is very low anyway
so what in low orbit the atmosphere is
very thin but you are not in a full
vacuum
so you still have an atmospheric drag
the decrease slowly the speed of the iss
and then the altitude therefore we need
to rise up periodically the orbit of the
iss
thanks to the thrusters you can see here
others technical datas
the iss has of course attitude
determination and control system
it works with gyroscope small thrusters
star trackers sun sensors gps and many
more

English: 
the hst this is the hubble space
telescope the famous one
it was the origin of the revolution of
the astronomy with beautiful pictures of
stars
constellations nebula and galaxies
it was launched with the space shuttle
in 1990
as you can see the pointing accuracy of
the optics is very less than one arc
second
but at the beginning the telescope just
sent fuzzy pictures
because there was a defect on the
primary mirror
the nasa sent two missions with the
space shuttle
to make a hardware upgrade of the
telescope
it's still in orbit and sending
beautiful pictures
and creating sciences to understand the
universe
in 2021 or 2022 the usa will launch with
a european rocket the successor of this
telescope
it will be the james webb telescope the
technical challenge in this case was to

English: 
The HST.
This is the Hubble space telescope, the famous
one.
It was the origin of the revolution of the
astronomy, with beautiful pictures of stars,
constellations, nebula, and galaxies.
It was launched with the space shuttle in
1990.
As you can see, the pointing accuracy of the
optics is very less than 1 arc second.
But, at the beginning, the telescope just
sent fuzzy pictures,because there was a defect
on the primary mirror.
The NASA sent two missions, with the space
shuttle, to make a hardware upgrade of the
telescope.
It’s still in orbit and sending beautiful
pictures… and creating sciences to understand
the universe.
In 2021 or 2022 , the USA will launch with
a European rocket the successor of this telescope
: it will be the James Webb telescope.
The technical challenge in this case was to
put 11 tons in orbit.

English: 
put 11 tonnes in orbit
the only solution at that time was the
space shuttle with its cargo bay
the weight is heavy as the size is large
you need more than four kilowatt to use
the telescope and you can imagine the
complexity of the adcs as the
requirements of the pointing accuracy
reach less than one arc second
to communicate you have to center the
ground pictures
so the rate of the communication has to
be higher that why you need to have big
antennas
here is illustration of the next space
telescope
the james webb space telescope
do you know the difference between a
probe and a satellite
as satellite orbits the earth and a
probe is made to travel in the solar
system to visit the difference planets
or the sun or the asteroids
let's go far beyond with the voyager
probe

English: 
The only solution at that time was the Space
Shuttle with its cargo bay.
The weight is heavy as the size is large.
You need more than 4 kilowatt to use the telescope
and you can imagine the complexity of the
ADCS as the requirements of the pointing accuracy
reach less than 1 arc second.
To communicate, you have to send to the ground,
pictures , so the rate of the communication
has to be higher , that’ why you need to
have big antennas.
Here is a illustration of the next space telescope
: the James Webb space telescope.
Do you know the difference between a probe
an a satellite?
A satellite orbits the earth, and a probe
is made to travel in the solar system to visit
the differents planets, or the sun, or the
asteroids,
Let’s go far beyond with the Voyager probe,
This probe was launched far before your birth,

English: 
in 1977, Voyager travelled to Jupiter, then
Saturn, and Uranus and then Neptune, It was
the first human object reaching Uranus and
Neptune . So it was the first time we received
some pictures of theses two planets.
As you can see on this picture, it needed
12 years in between the launch and the arrival
near Neptune. The planetary alignment occurs
only every 176 years. So you have to be ready
for launch as planned.
This distance in this case is about 10 exponent
9 kilometers that means 10 billions km, and
you have just a 23 watt for your transceiver,
just as much as an old radio.
Do you have any idea of the size of the ground
antenna which is able to decode the signals
coming from the probe?
Concerning the technical datas, take a look
at the power needed to perform the mission.

English: 
this preb was launched far before your
birth in 1977
voyager traveled to jupiter then saturn
and uranus and then
neptune it was the first human object
reaching uranus and neptune
so it was the first time we received
some pictures of theses two planets
as you can see on this picture it needed
12 years in between the launch and the
arrival near neptune
the planetary alignment occurs only
every 176 years
so you have to be ready for launch as
planned
this distance in this case is about an
exponent
9 kilometers that means 10 billion
kilometer
and you have just a 23 watt for your
transceiver just as much as an old radio
do you have any idea of the size of the
ground antenna which is able to decode
the signals coming from the probe
concerning the technical data take a
look at the power needed to perform the

English: 
mission
we need 470 watt but we are very far
from the sun
so it's impossible to collect enough
energy with solar's panels
the only possibility even today is to
use rtg
as known as radioisotopic generator
it's not a nuclear reactor because you
don't e
have any fission or fusion but we still
have nuclear elements producing
electricity with the heating of
thermocouples
no real orbit in this case we are flying
towards the outer planets
more recently the european probe mars
express was launched in 2003 with as
objective to explore mars with a 40
meters resolution radar
the idea was to measure the distribution
of water into the ground of mars you had
two parts in mars express
the first one is the orbiter and the
second one is the beagle two lander
as soon as the probe is in orbit of mars

English: 
We need 470 watt, but, we are very far from
the sun. So it’s impossible to collect enough
energy with solars panels.
The only possibility, even today, is to use
a RTG, as know as, Radio isotopic generator.
It’s not a nuclear reactor because you don
’t have any fission or fusion. but we still
have nuclear elements producing electricity
with the heating of thermocouples.
No real orbit in this case. We are flying
towards the outer planets.
More recently, the European probe Mars Express
was launched in 2003 with, as objective, to
explore mars with a 40 meters resolution radar.
The idea was to measure the distribution of
water into the ground of mars.
You had two parts in Mars Express. The first
one is the orbiter, and the second one is
the Beagle 2 lander.

English: 
As soon as the probe is in orbit of Mars,
the lander was jettisonned on to the orbit.
doing the atmospheric reentry and land.
but there was a defect in the parachute and
Beagle crashed into the ground.
At this time, only the USA achieved to land
something properly on Mars because it’s
very difficult.
First you have to reach the mars orbit and
than , at 50 millions kilometers away to manage
the reentry.
Lot of attempts, but few successes.
Here the parameters of the orbit, 259 km for
perigee and 11560 for the apogee, so your
orbit is an ellipse with a big eccentricity.
Even it is an European probe, it was launched
with a russian rocket : Soyuz.
Next satellite I want to share with you it
SOHO.

English: 
the lander was jettisoned onto the orbit
doing the atmospheric re-entry and land
but there was a defect in the parachute
and beagle crashed into the ground
at this time only the usa achieved to
land something properly on mars because
it's very
difficult. first you have to reach the
mars orbit and then at 50 millions
kilometers away to manage the re-entry
lot of attempts but few successes
here are the parameters of the orbit 259
kilometers for perigee and 11560 for the
apogee
so your orbit is an ellipse with a big
eccentricity
even it is an european probe it was
launched with the russian rocket
soyuz
next satellite i want to share with you
at soho

English: 
so who is solar probe it means that it's
in orbit around the sun
the scientific goal of the mission is to
observe the sun and make space weather
predictions because the sun emits lot of
particles and radiation
which change with time
here is a look at the images coming from
soho with a huge solar flare
over
over here you can see the technical
data's of Soho but we will skip it
there is a big story behind this probe we
lost the contact for a month with the
probe
we used a radio telescope to diagnose
the satellite
we sent a huge power thanks to the radio
telescope to have an echo from soho
it confirmed that soho was in the good

English: 
Soho is solar probe. It means that it’s
in orbit around the sun.
The scientific goal of the mission is to observe
the sun and make space weather predictions,because
the sun emits lot of particles and radiation,
which change with time.
Here is a look at the images coming from Soho
with a huge solar flare.
Over here, you can see the technical datas
of Soho , but we will skip it.
There is a big story behing this probe.
We lost the contact for a month with the probe.
We used a radiotelescope to diagnose the satellite.
We sent a huge power thanks to the radiotelescope
to have an echo from Soho .
It confirmed that Soho was in the good location,
but it was spinning with a rate of 1 round

English: 
per minut.
The recovery team began by allocating the
limited electrical power.
Thawing the frozen hydrazine fuel tank using
SOHO's thermal control heaters began Thawing
pipes and the thrusters was next, and SOHO
was re-oriented towards the Sun.
After nearly a week the spacecraft recovers
its activities.
Now, we are down to Liège, with OUFTI-1 , first
100% belgian satellite.
OUFTI is a nanosatellite. It’s a cube with
a volume of 1 liter.
The objective of OUFTI was to test a brand
new digital radio protocol.
The second objective was to test news solars
cells.
OUFTI was entirely designed by students and
launch from Kourou in French Guyana thanks
to a Soyuz rocket in 2016.
Sadly, we lost the contact with the satellite
after three weeks.

English: 
location but it was spinning with a rate
of one round per minute
the recovery team began by allocating
the limited electrical power
throwing the frozen hydrazine fuel tank
using
soho's thermal control heaters began
thawing pipes and the thrusters was next
and soho was reoriented towards the sun
after nearly a week the spacecraft
recovers its activities
now we are down to liege with oufdi one
first 100 percent belgian satellite
oufdi is a nanosatellite
it's a cube with a volume of one liter
the objective of a ufdi was to test a
brand new digital radio protocol
the second objective was to test news
solas cells
oufdi was entirely designed by students
and launched from koru in french guyana
thanks to a soyuz rocket in 2016.
sadly we lost the contact with the
satellite after three weeks

English: 
Here is some pictures of the integration of
the satellite in the Liege Space Center.
Juste before the launch, you have the integration
of the satellite into a P-POD which will be
attached to the last stage of the rocket.
Here you can see the fourth stage of the rocket.
Here is the main payload , and there the P-POD
with OUFTI inside.
The picture on the right shows you the liftoff
of the rocket.
As you can see, the datas are in opposite
way of the datas of the ISS. The weight of
OUFTI id only 1 kilogramm and the power is
only 1 watt.
No propulsion on board and a simple ADCS made
of permanent magnets with hysteric materials.
To summarize the 7 examples I showed you : all
the satellite are different.
The heaviest satellite is several tons while
the smallest weighs only a few kilograms.

English: 
here is some pictures of the integration
of the satellite in the liege space
center
just before the launch view have the
integration of the satellite into ap
pod which will be attached to the last
stage of the rocket
here you can see the fourth stage of the
rocket
here is the main payload and there the p
pod with ou fdi
inside the picture on the right shows
you the liftoff of the rocket
as you can see the data's are in
opposite way of the datas of the iss
the weight of oufdi is only one kilogram
and the power is only one watt no
propulsion on board and a simple adcs
made of permanent magnets with hysteric
materials to summarize the seven
examples i
showed you all the satellite are
different
the heaviest satellite is several tons
while the smallest way is only a few
kilograms

English: 
As you have seen, OUFTI-1 was a small cube
with a edge of 10 cm and we can see satellite
with a size more than 10 meters.
Of course, a small satellite works with a
fraction of watt than a bigger satellite for
the telecommunications can use several thousands
of watts.
You can see a lot of different frequency bands
used for the telecommunication, a lot of options
for the ADCS , many styles of orbits , all
with specific features and a lot of choice
of rockets to send your satellite in space.
I hope you will have a quite clear view of
all ,at the end of the different lectures.
I want to come back to the failures and explain
to you one of the most well known.
It’s was for the Mars climate orbiter.
There was a navigation error for the atmospheric
reentry.

English: 
as you have seen oufdi1 was a small cube
with edge of 10 centimeters and we can
see satellite with a size more than
10 meters of course a small
satellite works with a fraction of what
than a bigger satellite for the
telecommunications can use several
thousands of watts you can see a lot of
different frequency bands used for the
telecommunication
a lot of options for the adcs many
styles of orbits
are always specify features and a lot of
choice of rockets to send your satellite
in space
i hope you will have a quite clear view
of all at the end of the different
lectures
i want to come back to the failures and
explain to you one of the most
well-known
it's was for the mars climate orbiter
there was a navigation error for the
atmospheric
the nasa did all the specifications in

English: 
The NASA did all the specifications in metric
units, as meter, kg.
Lockheed Martin used the imperial units as
miles abs so on.
So there was an error between the electronics
and the software because both of them didn’t
use the same units.
The results came to a later opening of the
parachute and then to a landcrash on Mars.
Maybe, you are overconfident of the design
of your satellite, but the rocketry is an
art.
. With some success and some failures.
Look at this chart. in blue the success launch
and in red the failures.
Even now, you have disasters.
One example in 2019 happened with a Vega rocket
designed in Europe.
One of the stages of the rocket didn’t work
well and the satellite burnt in the atmosphere.
The first question at this time is :
What is a satellite ?
A satellite is just an element within a large
system.

English: 
metric units as meter kilogram
lockheed martin used the imperial units
as miles and so on
so there was an error between the
electronics and the software because
both of them didn't use the same units
the results came to a later opening of
the parachute and then to a land crash
on mars
maybe you are overconfident of the
design of your satellite but the
rocketry is a nod
with some success and some failures look
at this chart
in blue the success launch and in red
the failures
even now you have disasters one example
in 2019
happened with the vega rocket designed
in europe
one of the stages of the rocket didn't
work well and the satellite burnt in the
atmosphere
the first question at this time is what
is a satellite
a satellite is just an element within a
large system

English: 
First, you need to launch your satellite .
And a lot of constraints and requirements
comes from the launch vehicles.
By instance, the size of your satellite, the
weight of course, the launch site , the orbit
and the vibration your satellite must bear.
After the launch, your satellite is working
on its orbit and you have to get in touch
with it.
So you need an antenna on the ground . we
call it the ground station .
You can send telecommand , TC, and receive
the datas from the satellite.
We speak of TC/TM .
According to the types of communications needed,
you must use the right ground stations. Let
me show you two different examples.
First , in Redu in Belgium , we use small
antennas for the Galileo constellation.
Another example, here we have the DSN : deep
space network.

English: 
first you need to launch your satellite
and a lot of constraints and
requirements comes from the launch
vehicles by instance
the size of your satellite the weight of
course the launch site the orbit and the
vibration your satellite must bear
after the launch your satellite is
working on its orbit and you have to get
in touch with it
so you need an antenna on the ground we
call it the ground
station you can send telecom and tc and
receive the data's from the satellite
we speak of tctm according to the types
of communications needed you must use
the right ground
stations let me show you two different
examples
first in redo in belgium we use small
antennas for the galileo constellation
another example here we have the dsn
deep space network it uses three huge
antennas of 70 meters of diameters

English: 
located in goldstone madrid and canberra
each antennas covers an angle of 120
degrees
thus any probes anywhere in space can be
in the linear side of one of the three
antennas
what is in a satellite you have two
mains parts
the payload in violet is the part of the
satellite which is the motivation of the
mission
for example this probe is voyager 1 or
two and the main scientific objective
was to measure the magnetic field in
space with this part
another scientific goal was to take some
pictures
so here use some scientific instruments
to perform this you need some parts for
the power
a main computer a transceiver with an
antenna and a pointing system
all of these subsystems is called the
bus or the platform
take a look at these instruments of
voyager 1 and 2.

English: 
It uses 3 huge antennas of 70 meters of diameters
located in Goldstone, Madrid and Canberra.
Each antennas covers an angle of 120 degrees.
.Thus any probes , anywhere in space, can
be in the linesight of one of the 3 antennas.
What is in a satellite?
You have two mains parts:
The payload ,in violet, is the part of the
satellite which is the motivation of the mission.
For example, this probe is Voyager 1 or 2
and the main scientific objective was to measure
the magnetic field in space with this part
.
Another scientific goal was to take some pictures,
so here you some scientific instruments.
To perform this, you need, some parts for
the power, a main computer, a transceiver
with an antenna and a pointing system.
All of this subsystems is called the BUS or
the platform.
Take a look at these instruments of Voyager
1 and 2.

English: 
We have , for the payloads, different cameras,
magnetometers, cosmic ray detector, plasma
detector, photopolarimeter and UV and infrared
spectrometers.
So, as I said the bus or platform is a complex
assembly of different subsystems :
• Structure and mechanism to withstand the
launch and to maybe deploy or run mechanisms.
• A propulsion for maneuvers and trajectory
• A thermal control to survive to the harsh
space environment
• Telecommunications to exchange with the
ground
• Attitude control system to ensure a correct
orientation in space
• Power subsystem to manage the power, solars
panels and batteries
• And last but not least, the on board computer
which is the brain of the satellite.
Take a look at the Voyager probe.
For the telecommunication subsystem, you have
two antennas.

English: 
we have for the payloads different
cameras magnetometers
cosmic ray detector plasma detector
photo perimeter and uv
and infrared spectrometers
so as i said the basal platform is a
complex assembly of different subsystems
structure and mechanism to withstand the
launch and to maybe deploy or run
mechanisms
a proportion for maneuvers and
trajectory
a thermal control to survive to the
harsh space
environment telecommunications to
exchange with the ground
attitude control system to ensure a
correct orientation in space
power subsystem to manage the power
solar's panels and batteries
and last but not least the onboard
computer which is the brain of the
satellite
take a look at the voyager probe for the
telecommunication subsystem

English: 
One with a high gain, for the higher data
rate. And one with a lower gain , for the
low data rate.
One part of the ADCS subsystem is the sun
sensor.
You can see it on the dish of the antenna
here.
ON the very top of the probe, you can find
the RTG, radio isotopic thermal generator
, which provide the power to the satellite.
The RTG is outside the frame of the satellite
to be as far as possible of the different
parts. The idea is to avoid the perturbations
coming from the RTG.
The structure of the satellite is right here
and is made of a decagon of about 1.8 m of
diameter.
here are the thrusters, powered by N2H4 , hydrazine.
For the thermal control, you have some louvers
to control the temperature inside the satellite.
Of course, you can find some mechanism.
This one is for the deployment of the magnetometer.

English: 
you have two antennas one with a high
again for the higher data rate
and one with a low again for the low
data rate
one part of the adcs subsystem is the
sun sensor
you can see it on the dish of the
antenna here
on the very top of the probe you can
find the rtg
radioisotopic thermal generator which
provide the power to the satellite
the rtg is outside the frame of the
satellite to be as far as possible of
the other parts
the idea is to avoid the perturbations
coming from the rtg
the structure of the satellite is right
here and is made of a decagon of about
1.8 meters of diameter
here are the thrusters powered by n2h4
hydrazine
for the thermal control you have some
louvers to control the temperature
inside the satellite of course you can
find some mechanism
this one is for the deployment of the
magnetometer

English: 
on the frame of the satellite you can
find the star tracker which is a part of
the adcs subsystem
here is a very important picture which
summarizes
all we said before for a space mission
we have three parts first the satellite
called the space segment the ground
segment on the left
is the ground station which is on earth
and which performs the dc
tm and the launch vehicle to place the
spaceship into orbit
within the space segment here is a
simplified block diagram
of a satellite with the two main spots
the payload and the bus for the bus
you'll have all the subsystems i listed
before
the next question that we want to answer
is
when starts the space race on the next
lecture you will receive mr theo perad

English: 
On the frame of the satellite, you can find
the star tracker which is a part of the ADCS
subsystem.
Here is a very important picture which summarizes
all we said before.
For a space mission, we have 3 parts :
• First, the satellite, called the space
segment.
• The ground segment on the left, is the
ground station which is on earth , and which
performs the TC/T M.
• And the launch vehicle to place the spaceship
into orbit.
Within the space segment, here is a simplified
block diagram of a satellite. with the two
maints parts.
The payload and the bus.
For the bus, you will have all the subsystems
I listed before .
The next question that we want to answer is
:
When starts the space race ?

English: 
will tell you with all
his passion of the history of the
astronautics
imagine that you have your satellite
where can you or should you place it
we see here a representation of the
solar system
you can of course put your satellite
around the earth
and moreover the majority of satellites
are in earth orbit
however there are many other planets
where your spaceship can go
the constraints that the satellite will
undergo depend on the place where it
will be and these constraints can vary
extremely
for example the magnetic field undergone
by the satellite can be huge if you are
close to jupiter or almost
zero if you are close to mars which does
not have a magnetic field
if you are near to the sun the heat
received by your satellite is huge and
you must therefore develop a very
complex thermal design
if you are far from the sun you have
problems because you have less energy

English: 
On the next lecture, you will receive Mr Théo
Pirard will tell you, with all his passion
of the history of the astronautics.
Imagine that you have your satellite, where
can you or should you place it?
We see here a representation of the solar
system.
You can,, of course put your satellite around
the earth, and moreover the majority of satellites
are in Earth orbit.
However, there are many other planets where
your spaceship can go.
The constraints that the satellite will undergo
depend on the place where it will be, and
these constraints can vary extremely.
For example, the magnetic field undergone
by the satellite can be huge if you are close
to Jupiter or almost zero if you are close
to Mars,which does not have a magnetic field.
If you are near to the sun, the heat received
by your satellite is huge and you must therefore
develop a very complex thermal design.
If you are far from the sun, you have problems
because you have less energy from the sun.

English: 
from the sun
other variable criteria can also come
from the type of vehicle
the type of communication required and
many more
all this kind of different features are
a guide for the design
of the satellite next week you will
receive a lecture on the different types
of orbit
but i would like to show you a very
particular example
these are the lagranges point maybe you
have already seen
this in physics there are five points in
space where there is a gravitational
balance in the earth's sun
system that means an object place there
does not move relative to the earth
it is for example at point l two that we
place the big space telescope at one
million
five hundred thousand kilometers but why
because at this point we do not have the
infrared radiation coming from the earth

English: 
Other variable criteria can also come from
the type of vehicle, the type of communication
required, and many more.
All this kind of different features are a
guide for the design of the satellite.
Next week, you will receive a lecture on the
different types of orbit.
but I would like to show you a very particular
example.
These are the Lagrange’s point.
Maybe you have already seen this in Physics.
There are 5 points in space where there is
a gravitational balance in the earth-sun-
system.
That means an object placed there does not
move relative to the earth.
It is for example at point L2 that we place
the big space telescope at 1500000 km.
but Why?
Because at this point, we do not have the
infrared radiation coming from the earth which
risks to parasitize your payload.

English: 
which risks to parasitize your payload
let's go back near to the earth we have
families for the orbits
first we begin with the leo orbits
it means low earth orbit from 100
kilometers
which is the official limit for space to
2000 kilometers
for the moment we can found the majority
of satellites within this range
you will find after the mayo orbits
medium earth orbit from 2000 kilometers
to 20
000 kilometers this area fits well for
the constellation of satellites
for example for the gps or galileo
constellation
a constellation is an orbit or several
orbits with several satellites placed on
it and all the satellites are working
for the same system
for example for the gps you have more
than 30 satellites
just above we can find the geo orbit
geostationary orbit
at 36 000 kilometers that means that a

English: 
Let’s go back near to the earth. We have
families for the orbits.
First we begin with the LEO orbits.
It means low earth orbit, from 100 km ,which
is the official limit for space, to 2000 km.
For the moment we can found the majority of
satellites within this range.
You will find after the MEO orbits. Medium
earth orbit. from 2000 km to 20000 km.
This area fits well for the constellation
of satellites . for example for the GPS or
Galileo constellation.
A constellation is an orbit or several orbits
with several satellites placed on it and all
the satellites are working for the same system.
For example ,for the GPS, you have more than
30 satellites.

English: 
satellite on this kind of orbit takes 24
hours to make a round
thus as seen from the ground the
satellite appears to be fixed
that's why we place all the big
satellites for telecommunications
above 36 000 kilometers it's the heo
orbit
high earth orbit all the examples on
this slide in black
iss spot 5 have quite circular orbits
but we can find elliptic orbits as well
for example the first version of the
orbit of o ufdi1 was higgly elliptic
but as you can see we have a gap here
few satellites are in this era but why
because in this area we have the van
allen belts dot the physicist not the

English: 
Just above, we can find the GEO orbit .geostationnary
orbit. at 36000 km. That means that a satellite
on this kind of orbit takes 24 hours to make
a round.
Thus , as seen from the ground, the satellite
appears to be fixed. That’s why we place
all the big satellites for telecommunications.
Above 36000 km , it’s the HEO orbit . high
earth orbit. .
All the examples on this slide, in black,
ISS, SPOT-5 have quite circular orbits .
but we can find elliptic orbits as well. for
example the first version of the orbit of
OUFTI-1 , was higly elliptic.
But, as you can see, we have a gap here. few
satellites are in this aera. but why ?
Because in this area , we have the Van Allen
Belts .the physicist, not the musician.

English: 
The van allen belts are a zone where you can
find a lot of charged particles that could
damage your spacecraft.
The root cause comes from the radiation and
particles ejected by the sun, they are deflected
by the magnetic field and trapped into the
Van allen belts.
You can find some electrons or protons.
The graph on the right show you measurements
of the energy of the particles you can find.
There is a maximum for the energy of the proton
for the radiation belt in pink .
and above you can find another radiation belt,
in blue, for the electrons.
So, it’s a very bad idea because these particles
can damage, even destroy your spacecraft electronics.
In the case you have to cross the radiations
belts. it’s highly recommended to turn off
your electronics or try to be in that area
as brief as possible.

English: 
musician
the van allen belts are zone where you
can find a lot of charged particles that
could damage your spacecraft
the root cause comes from the radiation
and particles ejected by the sun
they are deflected by the magnetic field
and trapped into the van allen belts
you can find some electrons or protons
the graph on the right show you
measurements of the energy of the
particles you can find
there is a maximum for the energy of the
proton for the radiation built in pink
and above you can find another radiation
belt
in bloop for the electrons so it's a
very bad idea because these particles
can damage even destroy your spacecraft
electronics
in the case you have to cross the
radiations belts
it's highly recommended to turn off your
electronics or try to be in that area as
brief as possible
the big question is why do we want to go

English: 
into the space why do we want to put
some satellites on orbit
there are a lot of reasons mainly the
objectives of the satellites are either
scientifical or for telecommunications
purposes
the most classical example is the
satellite dedicated for the weather
observation
today if we know well the weather you
will have five days in the future
it's thanks to the weather satellites
they are able to see more than the
clouds of course it's possible to see
the fire
sometimes the pollution or the sand
storms
and they work sometimes in different
wavelengths to collect different
information
others satellites used for the earth
observation here
the satellite json measures the surface
of the ocean with an accuracy of three
to three centimeters
envy set one of the biggest satellite

English: 
The big question is : Why do we want to go
into the space, Why do we want to put some
satellites on orbit ?
There are a lot of reasons. Mainly, the objectives
of the satellites are either scientifical
or for telecommunications purposes.
The most classical example is the satellite
dedicated for the weather observation.
Today, if we know well the weather you will
have 5 days in the future, it’s thanks to
the weather satellites.
They are able to see more than the clouds
of course, it’s possible to see the fire,
sometimes the pollution or the sand storms.
and they work sometimes in different wavelengths
to collect different information.
Others satellites used for the earth observation
are here. The satellite Jason measures the
surface of the ocean with an accuracy of 3.3
cm.

English: 
size of a bus
26 by 10 by 5 meter has a lot of senses
to measures a lot of parameters of the
earth
land water ice atmosphere of course you
are not always in the civilian sector
the militaries have also their
satellites
they are looking the earth but not the
same things as the civilian satellites
do
the satellite kh13 has an accuracy of
one centimeter in the visible domain
you can't hide anywhere for the
communication
we have all the geostationary satellites
as utilsat
is it can emit more than 2500
televisions channels and
up to 1 000 radio stations
a very well known name is iridium it's a
constellations of 66 satellites
dedicated for the communications
if you have an iridium phone you can
call
anywhere on earth even if you are lost

English: 
Envisat, one of the biggest satellite, size
of a bus, 26 by 10 by 5 meter has a lot of
sensors to measures a lot of parameters of
the earth : land , water, ice , atmosphere.
Of course, you are not always in the civilian
sector, the militaries have also their satellites.
They are looking the earth, but not the same
things as the civilian satellites do.
The satellite KH-13 has an accuracy of 1 cm
in the visible domain. You can’t hide anywhere.
For the communication, we have all the geostationary
satellites as Eutelsat is. It can emit more
than 2500 televisions channels and up to 1000
radio stations.
A very well know name is Iridium.
it’s a constellations of 66 satellites dedicated
for the communications.
If you have an iridium phone. you can call
anywhere on earth. even if you are lost in
the pacific ocean.

English: 
It’s the ultimate way to communicate. but
it’s very expensive and you have a lag of
the communications because you have the time
of flight of the radio wave from ground to
space.from satellite to others satellites
maybe, plus from satellite to ground and then
to you.
It’s not necessary to introduce the GPS
: global positioning system. 31 satellites
placed on 6 orbitals planes equally spaced
in their ascending node location. the next
lecture will provide to you the meaning of
the ascending node signification.
But there is a representation of the different
orbital planes of the GPS constellation.
…you can see here what it means with a picture.
You can see there an orbital plane with some
satellites. and there another one. So anywhere
you are on earth. you can see more than one

English: 
in the pacific ocean
it's the ultimate way to communicate but
it's very
expensive and you have a lag of the
communications because you have the time
of flight of the radio wave from ground
to space
from satellite to others satellites
maybe plus
from satellite to ground and then to you
it's not necessary to introduce the gps
global positioning system 31 satellites
placed on six orbitals planes equally
spaced in their ascending node location
on of the next lecture chen will provide
to you the meaning of the ascending node
signification
but there is a representation of the
different orbital planes of the gps
constellation
you can see here what it means with the
picture you can see there an orbital
plane with some
satellites and there another one
so anywhere you are on earth you can see
more than one

English: 
satellite it's what we mean by
constellation
i spoke about gps but w in europe have
our constellation
pretty operational it's the galileo
system
we have more than thousands of probes
and satellites launched into the space
since sputnik
some examples here cassini high guns
around saturn
soho looking for the sun galileo around
jupiter and also
asteroid encounters with near shoemaker
probe
the different payloads are always
different and depend on the wavelength
you need
it's not always an optic payload in the
visible domain the xmm newton
satellite works for example in the
x-rayed oh my
so the payload design is totally
different
on the same satellite there is more than
one payload or sensor
for the mission galileo we have more
than 10 different instruments
each instruments designed by a different
team

English: 
satellite. it’s what we mean by constellation.
I spoke about GPS, but w., in Europe, have
our constellation, pretty operational. its
the Galileo system.
We have more than thousands of probes and
satellites launched into the space since Sputnik,
.
Some examples here : Cassini-Huygens around
Saturn . Soho looking for the sun. Galileo
around Jupiter and also asteroid encounters
with NEAR Shoemaker probe.
The different payloads are always different
and depend on the wavelength you need. It’s
not always an optic payload in the visible
domain, the XMM Newton satellite works , for
example, in the X-ray domai. so the payload
design is totally different.
On the same satellite, there is more than
one payload or sensor. For the mission Galileo
, we have more than 10 different instruments.
Each instruments designed by a different team.

English: 
you can imagine the work of the system
engineers
for the bravest we have space stations
the mere space station was the first
real space station
and designed by the russians the
objective was to perform science with
microgravity
mir was orbited in 2001.
now we have the iss and we have all the
time
some astronauts five or six
working on it here is a stunning project
from bigelow aerospace
you know that it's complicated and
expensive to design a space laboratory
you need to have a very safe design and
the weight is so
important that you need a lot of money
to send it into the space
big low want to change this paradigm in
building some inflated structure as you
can see on the pictures
now in 2019 bigelow has already sent a
prototype
attached to the iss and already inflated

English: 
you can imagine the work of the system engineers.
For the bravest, we have space stations. The
MIR space station was the first real space
station and designed by the russians.
The objective was to perform science with
microgravity. Mir was de-orbited in 2001.
Now we have the ISS and we have all the time
some astronauts . 5 or 6 . working on it.
Here is a stunning project from Bigelow Aerospace.
You know that it’s complicated and expensive
to design a space laboratory.
You need to have a very safe design and the
weight is so important that you need a lot
of money to send it into the space.
Bigelow want to change this paradigm in building
some inflated structure as you can see on
the pictures.
Now, in 2019, Bigelow has already sent a prototype.
attached to the ISS and already inflated.

English: 
It was just a prototype to check if the kind
of structures presents some leaks for a long
time. For now, the test is successful and
we can hope that , in a near future, we can
see the kind of giantic with light structure.
And why not for an inflatable hotel… the
sky is the limit.
Who is involved in the space activities ?
You know that we have 2 major key players
for space . Russia . and America.
You have a list of the companies working for
the space as NASA of course or the JPL, jet
propulsion laboratory, designers of the American
probes . Lockedd Martin. also know for the
design of the F-35 . Northrop Grumman and
Boeing , for the most known companies.
Russia has 2 big companies : Roscosmos for
satellites. and Energia for the rockets.

English: 
it was just a prototype to check if the
kind of structures present
some leaks for a long time for now the
test is successful and we can hope that
in the near future we can see the kind
of jantic with light structure
and why not for an inflatable hotel the
sky is the limit
who is involved in the space activities
you know that we have two major key
players for space
russia and america you have a list of
the companies working for the space as
nasa of course or the jpl
jet propulsion laboratory designers of
the american probes
lockheed martin also know for the design
of the f-35
northrop grumman and boeing for the most
known companies
russia has two big companies ross cosmos
for satellites

English: 
and energia for the rockets the third
key player in space race is the europe
maybe you already know this name of
companies
cn is in france dlr for the germany
asi for the italy eads aryan spaced
sales and so on
we have two emerging countries for the
space race
first the india very active for the
moment around the moon for example with
their probe chadran
and of course china is on the track and
maybe you don't know but in 2018
china launched more rockets than usa and
russia
and what is going on in belgium if you
want to work in space-related fields
after you studies and stay in belgium
you have the choice
amos kegeleck csl
liege space center euroheat pipes
gilliman liege ionic software
lambda x sabka sam tech

English: 
The third key player in space race is the
Europe. Maybe you already know this name of
companies : Cnes in France. DLR for the Germany.
A S I for the Italy. E A D S. Arianespace.Thales
and so on.
We have two emerging countries for the space
race. First the India , very active for the
moment around the moon for example with their
probe Chadrayan.
And of course, China is on the track. and
maybe you don’t know, but in 2018 . China
launched more rockets than USA and Russia.
And what is going on in Belgium? If you want
to work in space related fields after you
studies and stay in Belgium, you have the
choice :
• Amos
• Cegelec
• CSL, Liege space center
• Euro heat pipes,
• Gillam in Liège,
• Ionic Software
• Lambda-X
• Sabca
• Samtech
• Sonaca

English: 
• Spacebel
• Safran Aerobooster
• ETCA in Charleroi
• Verhaert,
• Vitrocisset
• And many more
Some companies listed here are at less then
1 km from the place we are. Liege is a pole
for the space.
Here you can find the url of the Wallonie-espace
website.
We have a lot of Belgian equipment into the
space. One of the famous project in which
the Belgium was involved is the ATV Jules
Verne. The ATV is the European cargo ship
which re-supply the ISS.
Many parts of the cargo were designed by Belgian
companies : Euro Heat Pipes for the heat pipes
.
Etca for the EPS, electrical power system.
Spacebel for the software.
Rhea for the software as well.
The ground station in Redu was the backup
ground station of the project.

English: 
sanaka space bull saffron area booster
etc in shalawah verhart
vitra sisit and many more some companies
listed here
are at less than one kilometer from the
place we are
liege is a pole for the space here you
can find the url of the wall only aspes
website
we have a lot of belgian equipment into
the space
one of the famous project in which the
belgium was involved is the atv jules
verne
the atv is the european cargo ship which
resupply the iss
many parts of the cargo were designed by
belgian companies
euroheat pipes for the heat pipes
egca for the eps electrical power system
spaceable for the software rear for the
software as well
the ground station in redo was the
backup ground station of the project

English: 
and saffron aero booster for the valves
of the eastest engine of the cargo ship
how is it possible to make all these
things
what are the technical challenges the
first objective is always the same in
engineering
you must satisfy the customer the
customer
is the one who pays at first you have to
make the design of the payload which is
the ultimate goal of the mission
just after you have to do the mission
analysis
which will determine the orbit in the
space environment
which will put the constraints on your
satellite
it gives you many requirements that you
use now to design the bus
it shows you the workflow that you'll
find for a mission
as you know now each satellite is
different because many missions are one
shot
and the design of the satellite is
therefore the sum of unique technical
challenges

English: 
And Safran Aerobooster for the valves of the
Aestus engine of the cargo ship.
How is it possible to make all these things.
What are the technical challenges ?
the first objective is always the same in
engineering : You must satisfy the customer
. The customer is the one who pays.
At first you have to make the design of the
payload which is the ultimate goal of the
mission.
Just after, you have to do the mission analysis.
which will determine the orbit and the space
environment. which will put the constraints
on your satellite.
It gives you many requirements that you use
now to design the bus.
It shows you the workflow that you’ll find
for a mission. As you know now. each satellite
is different because many missions are one
shot. and the design of the satellite is therefore
the sum of unique technical challenges.

English: 
take a look at this picture a spacecraft
is totally different according your
technical background
and each engineer in each domain must be
inventive to reach the technical
requirements needed
now i want to show you some examples of
challenges encountered by the engineers
and then the solutions
used let's start with the voyager
mission
as i already said the voyager probe was
designed to make some fly be over
jupiter
satin uranus and neptune
so we are into the deep space far from
the sun dot and thus without
energy coming from it the only
possibility we have to generate power is
to use nuclear materials
but the electronics must survive to the
radiation emitted by the nuclear
materials so the engineers had to design
an adequate configuration of the bus
and this design is completely different
over classical satellite flying over the

English: 
Take a look at this picture. A spacecraft
is totally different according your technical
background. and each engineer, in each domain
must be inventive to reach the technical requirements
needed .
Now, I want to show you some examples of challenges
encountered by the engineers and then the
solutions used.
Let’s start with the Voyager mission. As
I already said, the Voyager probe was designed
to make some flyby over Jupiter. Saturn. Uranus.
and Neptune.
So we are into the deep space, far from the
sun .and thus without energy coming from it.
The only possibility we have to generate power
is to use nuclear materials.
But,the electronics must survive to the radiation
emitted by the nuclear materials .so the engineers
had to design an adequate configuration of
the bus. And this design is completely different
of a classical satellite flying over the earth.

English: 
earth
the use of nuclear material could lead
to political problems as well
even it's not technical the solution of
these problems is to make a
multi-disciplinary design
the objective of the course is that to
understand systems
engineering and to have a
multi-disciplinary overview of a problem
look for the optimal solution for the
entire
spacecraft do not look for the optimal
solution for your subsystem it's the
kind of way of thinking used in esa
the picture shows a cdf concurrent
design facility
in estec in netherlands
where engineers from all domains can
work together
we have a cdf in esa ready for the
cubesat activities

English: 
The use of nuclear material could lead to
political problems as well. even it’s not
technical.
The solution of these problems is to make
a multidisciplinary design. THe objective
of the course is that : to understand systems
engineering and. To have a multidisciplinary
overview of a problem.
Look . for the optimal solution . for the
Entire spacecraft . do not look for the optimal
solution for your subsystem.
It’s the kind of way of thinking used in
ESA. The picture shows a CDF . concurrent
design facility. in ESTEC in Netherlands.
where engineers from all domains can work
together. We have a CDF in Esa Redu for the
cubesat activities.
Second challenge : Each mission is unique.
you know now !

English: 
second challenge each mission is unique
you know now where is the satellite
going
and what is the mission so which kind of
wavelengths do we deal with
radio x-ray visible so you need to
fulfill the requirements that it lead to
totally different design
to fit the requirements you must be
inventive and sometimes you must design
totally new things or concept
for example for the hubble space
telescope
the engineers had to design a way to
roll out the solar panels for the launch
the prep stardust was designed to meet
the he1p comet
the preb was following the comet and
sometimes went into the queue of the
comet
made of billions of small particles the
difference of velocity between these
particles and the spaceship is up to 18
kilometers per second
so you can imagine the energy received
by an impact of the particles even its

English: 
Where is the satellite going ?
And what is the mission ?
So which kind of wavelengths do we deal with
. radio? , X-ray ? Visible ?
So you need to fullfill the requirements,
that it lead to totally different design
To fit the requirements. you must be inventive
and sometimes you must design totally new
things or concept.
For example, for the Hubble space telescope.
the engineers had to design a way to roll-out
the solar panels for the launch.
The probe Stardust was designed to meet the
81P Comet. The probe was following the comet
and sometimes went into the queue of the comet.
made of billions of small particles.
The difference of velocity between theses
particles and the spaceship is up to 18 km
per second. so you can imagine the energy
received by an impact of a particles even

English: 
it’s small.
In that case, engineers designed a whipple
shield . it’s a kind of several multi layers
shield .
Let’s finish with solar orbiter . as its
name recalls, this probe is designed to observe
the sun. So you need, to perform it, to design
some new equipments to observe the sun while
surviving to the heat produced by it.
I just have spoken about the heat of the sun
for the solar orbiter, but what is the orders
of magnitude of the different physical quantities
?
This picture show you a test performed in
the CSL .here is Liège.
You know that in space, it’s cold . very
cold. It’s obligatory to test your satellite
before launch to check if everything is ok.
So we have facilities to do it. You put the
satellite in a TVAC . thermal vacuum chamber.
which recreate the same conditions as you
have in space : vacuum and coldness.

English: 
small
in that case engineers designed a
whipple shield
it's a kind of several multi-layers
shield
let's finish with solar orbiter as its
name recalls
this probe is designed to observe the
sun
so you need to perform it to design some
new equipments to
observe the sun while surviving to the
heat produced by it
i just have spoken about the heat of the
sun for the solar orbiter but what is
the orders of magnitude of the different
physical quantities
this picture show you a test performed
in the csl
here is liege you know that in space
it's cold
very cold it's obligatory to test your
satellite before launch to check if
everything is okay
so we have facilities to do it you put
the satellite in a tvac
thermal vacuum chamber which recreate
the same conditions as you have in space

English: 
the vacuum and coldness take a look at
the engineers working the diameter of
the tv ac is 5 meters
the planck satellite was qualified in
liege
but what was the lowest temperature for
this nest
it was 0 1 k another order of magnitude
was the power of the signal received on
earth by the voyager probe
10 exponent in minus 16 watt
because the probe is at more than 15
billions of kilometers
another example is the pointing accuracy
of the optics of the hubble space
telescope
0.07 arc second hubble received in orbit
some hardware upgrade one of them was
the replacements of the solar panels
because they produced some vibrations
during the passage from sun to shadow
and these vibrations reduce the pointing
accuracy

English: 
Take a look at the engineers working, the
diameter of the TVAC is 5 meters.
The Planck satellite was qualified in Liege.
But what was the lowest temperature for this
test ?
It was 0,1 K …
Another order of magnitude was the power of
the signal received, on earth, by the Voyager
probe. Ten exponent minus 16 Watt. because
the probe is at more than 15 billions of kilometers.
Another example is the pointing accuracy of
the optics of the Hubble space telescope : 0.007
arc-second. Hubble received, in orbit, some
hardware upgrade.
One of them was the replacements of the solar
panels because they produced some vibrations
during the passage from sun to shadow and
these vibrations reduced the pointing accuracy.

English: 
for the next challenge let's speak about
their jupiter probe called galileo
it had to perform an atmospheric
re-entry in jupiter
in less than two minutes the probe drops
its speed from 171
000 kilometers per hour to 1600
kilometers per hour
the friction of the atmosphere of
jupiter on the spacecraft leads to a
shoot of the temperature
almost reaching 3900 degrees
no materials can reach this temperature
while keeping its mechanicals parameters
so the engineers had to design something
out of the box
and it's an ablative heat shield this is
the simulation of the thickness of the
heat shield
on the left where i am pinpointing the
thickness
is 14 6 centimeters before re-entry
and on the right the illustration shows
that the thickness is only 10

English: 
For the next challenge . let’s speak about
the Jupiter probe called Galileo. It had to
perform an atmospheric re-entry in Jupiter.
In less than two minutes, the probe drops
its speed from 171000 km/h to 1600 km/h. The
friction of the atmosphere of Jupiter on the
spacecraft leads to a shoot of the temperature.
Almost reaching 3900 degrees.
No materials can reach this temperature while
keeping its mechanicals parameters. So the
engineers had to designed something “out
of the box”.
And it’s an ablative heat shield.
This is the simulation of the thickness of
the heat shield.
On the left, where I am pinpointing. the thickness
is 14,6 cm before reentry.
And on the right, the illustration shows that
the thickness is only 10 cm after reentry.

English: 
To continue with the order or magnitude. let
focus on the rocket now and especially on
the Saturn V rocket. that one which sent the
astronauts to the moon.
Saturn V is more powerful than 160000000 horsepower.
About 120000000000 of watts.
It’s a question of power over here. Let
compare the Saturn V rocket with some quantities.
The challenges are everywhere in the space
domain. The VAB . vehicle assembly building
. in the KSC . Kennedy space center . has
a volume higher than 3.5 times the volume
of the empire state building.
The picture on the right show you the Crawler.
It’s a motorized vehicle designed to carry
the Space Shuttle.
with the central core and boosters from the
VAB to the launch pad : it’s the largest
self powered land vehicle in the world.

English: 
centimeters after re-entry
to continue with the order or magnitude
let focus on the rocket now and
especially on the saturn v
rocket that one which sent the
astronauts to the moon
saturn v is more powerful than 160
million horsepower
about 120 billion of watts
it's a question of power over here let's
compare the saturn v rocket with some
quantities
the challenges are everywhere in the
space domain
the vab vehicle assembly building
in the ksc kennedy space center
has a volume higher than 3.5 times the
volume of the empire state building
the picture on the right show you the
crawler
it's a motorized vehicle designed to
carry the space
shuttle with the central core and
boosters from the vab to the launch pad
it's the largest self-powered land
vehicle in the world

English: 
355 liters per kilometer….
When you see the orders of magnitude. you
have only one solution : You must be creative
!
You have just only a small fraction of Watt
for the telecommunications ?
Just design bigger antennas . 70 m for that
one.
You only have 15Watt/m² of power from your
solar panels because you are far from the
sun . in earth orbit. you have 1356Watt/m²
. you have to design an RTG with nuclear materials.
Take a look at the next challenge. you have
others severe constraints.
1. The planning. for the Voyager probe, you
just have one alignment of the planets Jupiter

English: 
355 liters per kilometer when you see
the orders of magnitude
you have only one solution you must be
creative
you have just only a small fraction of
what for the telecommunications
just design bigger antennas 70 meters
for that one
you only have 15 watt per square meter
of power from your solar panels because
you are far from the sun
in earth orbit you have 1356
watt per square meter you have to design
an
rtg with nuclear materials
take a look at the next challenge you
have others severe constraints
one the planning for the voyager probe
you just have one alignment of the
planets jupiter
saturn uranus and neptune

English: 
, Saturn, Uranus and Neptune. every 176 years.
So you have a tight window to launch your
probe. if not. You have to come 176 years
later.
2. Another challenge is the weight of your
satellite. It costs about 25000 euros per
kg to send. So you need to reduce the weight
of your spaceship while keeping the requirements
.
3. You don’t have fuel or a lot of power,
even with solar panels, so your spaceship
has to save the energy and minimize the consumption.
Again. for all these reasons. the engineers
must to be creative.
If the volume is limited for the launch ,because
the size of the fairing. you must design some
deployable elements. as we have within the
Voyager probe .
Let me show you the deployable boom. which
is rolled up into to the spaceship for the
launch and deployed in orbit.

English: 
every 176 years
so you have a tight window to launch
your probe
if not you have to come 176 years later
2. another challenge is the weight of
your satellite
it costs about 25 000 euros per kilogram
to send
so you need to reduce the weight of your
spaceship while keeping the requirements
3. you don't have fuel or a lot of power
even with solar panels so your spaceship
has to save the energy and minimize the
consumption
again for all these reasons the
engineers must to be creative
if the volume is limited for the launch
because the size of the fairing
you must design some deployable elements
as we have within the voyager probe let
me show you the deployable boom
which is rolled up into to the spaceship
for the launch and deployed in orbit
not enough fuel to reach the right speed

English: 
Not enough fuel to reach the right speed ? It’s
always possible to play with the physics and
to rise your speed. thanks to a gravitational
assistance.
In two words, thanks to the conservation of
the angular momentum, your probe catch a small
quantities of the energy of a massive planet
and increases its speed.
Fifth challenge : as I said before, the environment
is harsch.
You will find :
• cold temperature
• hot temperature if you are near of the
sun
• if you want to reach the outers planet.,
you have to go through the meteroids fields
• you can receive some cosmic ray able to
damage your electronics
• all your spaceship is in the vacuum and
thus, you don’t have convection ,
• you can be exposed to huge magnetic field.
• And so on
So , now you know, it’s not the easiest
environment to place an equipment but you
don’t have other choices.
The solution is to be inventive again and
you must develop new technologies as the whipple

English: 
it's always possible to play with the
physics and to rise your speed
thanks to a gravitational assistance in
two words
thanks to the conservation of the
angular momentum your probe catches
small quantities of the energy of a
massive planet and increases its speed
fifth challenge as i said before the
environment is harsh
you will find cold temperature hot
temperature if you are near of the sun
if you want to reach the outers planet
you have to go through the metroids
fields
you can receive some cosmic ray able to
damage your electronics
all your spaceship is in the vacuum and
thus you don't have convection
you can be exposed to huge magnetic
field
and so on so now you know it's not the
easiest environment to place an
equipment but you don't have other
choices
the solution is to be inventive again

English: 
shield I mentioned before. or thermal blanket
to protect your spaceship from severe cold.
And the next. last and worst challenge. is
that in space. it’s impossible to do maintenance.
except for unusual examples.
As soon the spaceship is in the rocket. It’s
to late. And I repeat you will be in a harsch
environment. and you have severe constraints.
So you can be sure that one part of your equipment
can have troubles during your mission.
The only way to succeed is to have redundancy.
For the voyager probe : not only one RTG,
but 3 , 2 by 8 thrusters, 2 transceivers,
2 on board computer and 2 magnetometers.
And the ultimate redundancy is to send two
identical probes instead of only one. as NASA

English: 
and you must develop new technologies as
the whipple shield i mentioned before
or thermal blanket to protect your
spaceship from severe cold
and the next last and worst challenge
is that in space it's impossible to do
maintenance
except for unusual examples as soon the
spaceship is in the rocket
it's too late and i repeat you'll be in
a harsh environment
and you have severe constraints so you
can be sure that one part of your
equipment can have troubles during your
mission
the only way to succeed is to have
redundancy
for the voyager probe not only one rtg
but
three two by eight thrusters two
transceivers two
on-board computer and two magnetometers
and the ultimate redundancy is to send
two identical probes instead of only one

English: 
as nasa had done with the voyager probe
so even there was a disaster with one
the second could do the job it's a
philosophy sometimes practiced by
nasa and they did it again with the
vikings marsha landers in the 70s and
with the opportunity martian rovers
to summarize this introduction operative
you can find the paradigm in the box
your spaceship is a harsh environment
and you have to be creative
but it's so expensive that maybe you
need to use proven technologies
a good way to prevent failures is to
make some redundancies
but the weight is very crucial factor
due to financial constraints
some paradoxes and technical conflicts
are the order of the day
the resolution of such conflict in a
productive manner is precisely the goal
of systems engineering

English: 
had done with the Voyager probe. So even there
was a disaster with one. the second could
do the job.
It’s a philosophy sometimes practiced by
NASA. and they did it again with the Vikings
martia landers in the seventies and with the
opportunity martian rovers.
To summarize this introduction/aperitive,
you can find the paradigm in the box.
Your spaceship is in a harsh environment.
and you have to be creative. but it’s so
expensive that maybe you need to use proven
technologies.
A good way to prevent failures is to make
some redundancies . but the weight is very
crucial factor due to financial constraints
.
Some paradoxes and technical conflicts are
the order of the day …The resolution of
such conflict, in a productive manner is precisely
the goal of systems engineering.
