PSC IONSAT

23/08/2023
Ricardo Colpari

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Agenda
14:00 - 14:10 Team Introductions

14:10 - 15:30 Slides presentation

15:30 - 17:30 Work in groups

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SMALLSATS
…and IonSat

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What is a smallsat ?

Usually:

SmallSat < 500 Kg

Micro-Satellite < 100 Kg

Nano-Satellite < 10 Kg CubeSat

Pico-Satellite < 1 Kg

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The CubeSat Standard

Developed in 1999 by:

■ Prof. Robert Twiggs (Stanford University)
■ Prof. Jordi Puig-Suari (CalPoly State U)

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Complexity trends:
example

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Forecasts

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Summary of differences

“Big” Satellites SmallSats

 High Complexity, thousands of parts,  Low Complexity, few parts, no redundancies
redundancies, safety mechanisms. little or no mechanisms.
 Lifetime: 5 to 15 years.  Lifetime from a few months to < 5 years.

 Long development times.  Shorter development times.

 High cost: hundreds of millions.  Reduced costs by ~2 orders of magnitude.

 Build by large companies or consortiums.  Build by students, start-ups, emerging

companies, experimental labs.
 Evolutionary innovation (slow).  Revolutionary innovation (fast).

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Problématique scientifique
Very Low Earth Orbits (VLEO) : de 200 à 450km d’altitude
 Moins de latence  Coûts de lancement réduits
 Pas de problème avec la LOS  Meilleure résolution

Mais une zone encore peu connue : contrainte liée à la forte traînée
atmosphérique (durée de vie de quelques semaines à 300km d’altitude)

L’objectif d’IonSat : démontrer la faisabilité des missions en VLEO, en

concevant un nanosatellite propulsé capable de réaliser un maintien à poste à une
altitude inférieure à 300km.

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Planification Mission
Mission Overview: IonSat
Deploy-
altitude >400
≈
400
Descent phase
Mean altitude (km)

350

Orbit control Planned Trajectory

(10 km levels) Mission extension

300
290 Real Trajectory
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Passive
270
de-orbitation
260 (*)
Time
Deploy t0 Mission Success (*) t0+6 (months)
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INTRODUCTION TO
ORBITAL
MECHANICS

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Kepler Laws (1605)

1. The orbit of every planet is an ellipse with the sun at a focus.

2. A line joining a planet and the sun sweeps out equal areas
during equal intervals of time.
3. The square of the orbital period of a planet is directly
proportional to the cube of the semi major axis of its orbit.

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Elliptic motion (e<1)

With:

Periapsis:

Apoapsis:

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Conservation equations
■ Conservation of angular momentum:

 The trajectory lies in a single plane

■ Conservation of specific mechanical energy

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Specific mechanical energy
■ Depending on the value of the eccentricity “e” the orbit is:

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Orbit description
■ How to describe an orbit?

Orbital Orbital
State vectors elements

Drawbacks: Orbital Mechanics - orbital elements visualizer

o Limited physical interpretation and launch simulator
o Mathematical simplification impossible

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Orbital elements
Keplerian elements = Classical orbit elements.
The orbital elements defines :
• Shape of the orbit: and
• Position of the orbital plane: and Ω
• Position of the orbit in the plane:
• Position of the satellite on the orbit: the anomaly ()

■ Also used :
– Orbital element adapted to near circular orbit
– Orbital element adapted to near circular orbit near equatorial
– Others

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Relating orbital position and time
■ The elliptic motion is a periodic motion as per Kepler’s third law:

■ The motion can be described using :

– mean motion
– mean anomaly
■ The position of a fictitious point given by:

■ The 3 anomalies:
– True anomalies ()
– The eccentric anomaly (E)
– The mean anomaly (M)

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Perturbations
The order of importance of
these forces depends on
altitude and shape of the
satellite (here Low Earth
Orbit)

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Questions
 Orbital elements units?

 Which orbit has faster speed at perigee/apogee?

 Orbit A: apogee alt. 1000 km, perigee alt. 400km.
 Orbit B: apogee alt. 1200 km, perigee alt. 200km.
 Orbit C: circular alt. 700km.
 Orbit C: circular alt. 1000km.

 Altitude of a Geo-Synchronous satellite?

 What orbital perturbations shall be considered for IonSat?

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 SATELLITE
ARCHITECTURE
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ATTITUDE CONTROL
- Orientation of the spacecraft (not the motion itself)
- Momentum management system
- Angular momentum can be acquired, disposed or stored

Constraints
• Precision
• Stability
• Knowledge

Mains solutions:
• Reaction wheels
• Magnetorquers
• Thrusters
• Solar sailing…

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TELEMETRY, COMMAND, DATA
HANDLING
- Telemetry : downlink to the ground station(s)
- Telecommand : uplink and commands for the satellite
- Data Handling and processing : avionics and data management and formatting
- Highly connected to other subsystem (diagnosis, information, …)

Constraints
• Mainly driven by the mission subject, orbit, type of payload and selected ground
control station(s)
• Large missions : different on-board computer for all these functions
• Small satellites : all-in-one solution
• Encodage of data, protocols and frequency depends on the type of mission

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ELECTRICAL POWER
SYSTEM
- One of the most critical subsystem : Power failure -> Mission loss
- Solar panels is the most common, but lots of existing technologies

Constraints
• Depends on the allocated size / mass
• Driven by the mission duration
• Distance to the sun (solar panels or not)

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PROPULSION
- Final orbit acquisition
- Station keeping and orbit control
- Attitude control

Constraints
• Fuel consumption (linked to ISP)
• Allocated size
• Thrust

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STRUCTURES AND
CONFIGURATION
- Transversal sizing, encompasses all the spacecraft.
- Needs to support all the loads (launch, shocks, vibrations…)
- Important to look at previous successful design concepts
- Configuration ensures all the subsystems are coherently dispatched
Constraints
• Mechanical interfaces: Launcher/Spacecraft, equipment mounting, mass
• Thermal interfaces : Environmental protection, thermal and electrical conductivity
• Material selection : Properties, characteristics, applications (metal, composite, …)
• Configuration : Subsystems characteristics (thermal constraints, sizes) and
structure forms

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Mechanisms
- Use only if necessarily and critical design
- Two types:
- one-shot (deployment, separation…) or
- continuous / intermittent (reaction wheel, pointing…)
Constraints
• Mechanical interfaces: Launcher/Spacecraft, equipment mounting, mass
• Thermal interfaces : Environmental protection, thermal and electrical conductivity
• Material selection : Properties, characteristics, applications (metal, composite, …)
• Configuration : Subsystems characteristics (thermal constraints, sizes) and
structure forms

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THERMAL CONTROL
- Control of spacecraft equipment and structural temperatures
- Make sure the equipment operate within their definite temperature range
- Prevent thermal distortions
- Heat is generated both within the spacecraft and by the environment

Constraints
• Structural stability (pointing accuracy / mechanisms …) and subsystems
temperature ranges

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Subsystem interaction

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GENERAL INFO

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Calendar of activities
■ Week 1: Introduction, 1st meeting
■ Week 2: Discuss “Proposition initial”
■ September: Week 3, 4, 5 & 6 CSEP formation with Ariane
■ October: 4 Journee du PA ESDS (maison de la
chimie)
Differences PSC IonSat vs Mission IonSat?
• Evaluated by Polytechnique professors • Evaluated by reviewers: CNES, TAS, etc
• Reports by groups (Proposition, • Project documents: requirements,
intermediate report, etc) definition justifications, budgets.
• Scientific objective, 1 academic year • Multi-year Project execution
project • Reviews: The satellite project is evaluated
• Student evaluation: Demonstrate • Multiple short or long reviews scheduled
collective problem solving abilities by the IonSat team
• One final evaluation with jury at the end
of the year
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Proposed Organigram X22 IonSat Mission
Telecommunicatio
Thermal Control Power Luca Bucciantini
ns CSEP DIRECTOR
Responsible COM Responsible TCS Responsible EPS
PROJECT
CONTROLLER
STUDENT PROJECT Ricardo Colpari
Attitude Control MANAGER Structure
STUDENT CSEP MONITOR
Resp. ADCS & SYSTEMS Responsible STR Nicolas Lequette
Thruster ENGINEER

On-Board SOFTWARE ENGINEER

Structure MGSE In recruitment
Computer
Resp. EGSE &
Responsible STR Responsible MGSE
OBC BUDGET & COMMS
Sylvie Pottier
Responsible Operations
Responsible AIT Planning
Etat de l’avancement d’IonSat
Idée du projet
2017, 1st PSC
2017-2018 REP RDP Δ RDP RCD RQ ROps RAV

PHASE D

PHASE C

PHASE B

PHASE A

05/2018 05/2019 11/2021 11/2023 05/2024 01/2025 06/2025 09/2025

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FOLLOW THE REAL WORLD
OUTSIDE

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Reference & Bibliography
■ Swartout’s CubeSat Database
https://sites.google.com/a/slu.edu/swartwout/cubesat-database
■ Guide des projets du CNES : site-gns.cnes.fr
■ « Spacecraft System Engineering » 4th edition, 2011 – Fortescue, Swinerd, Stark
■ « Je comprends enfin… fusée, satellites et vols spatiaux non habités » Jeau Daniel
Touly.

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Contact

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Shared folder OneDrive

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Office location CSEP

T-shirts:
specify
your size!

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BACK UP SLIDES

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General aerospace industry response to the CubeSat concept

■ Dumbest idea we have seen!

■ Too small for any practical purposes!
■ Stupid naive educators
■ They don’t have a clue what it takes to make something work in space!
■ Ignore them, maybe they will go away!
■ There are no parts that can be used to make a satellite that small!

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Satellogic

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