Very Low Earth Orbits are orbits in altitudes lower than 450 km. The interaction between the atmosphere particles and the surfaces of the spacecraft is responsible for the aerodynamic torques and forces. Simulating several aspects of the performance of a satellite flying in VLEO is very important to make decisions about the design of the spacecraft and the mission.

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Scilab and Xcos for VLEO satellites modelling
David González, Deimos Satellite Systems
Scilab Conference 2019

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Discoverer
This project has received funding from the European
Union’s Horizon 2020 research and innovation programme
under grant agreement No 737183.
Web page: https://discoverer.space/

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Enabling technologies and developments
Discoverer
Low drag, atomic
oxygen resistant
materials
Aerodynamic attitude
and orbit control
Atmosphere breathing
electric propulsion
Modelling of
aerodynamic surfaces
Very Low Earth Orbit
Satellite Concepts

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VLEO
Benefits
• Improved payload performance
• Improved launch vehicle payload mass
• Reduced space debris collision risk
• End-of-life disposal
Challenges
• Increased atmospheric drag
• Increased atomic oxygen erosion
• Shorter communications windows with ground stations
• Free molecular flow
Very Low Earth Orbit
O
He
N2 O2

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Feather and shuttlecock
Geometries
FeatherShuttlecock

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Xcos model

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Attitude stabilization (Feather)
VLEO Orbit: altitude 350km, inclination 50°, agument of perigee 90°, mltan 12h, eccentricity 0.001

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Yaw and pitch
Pointing maneuvers (Feather)
Accommodation
coefficient
Settling time (s) Overshoot (%)
0 4281 32.73
0.2 5426 32.86
0.4 9022 33.01
0.6 22513 33.13
0.8 68319 36.06
0.95 - -
• Accommodation coefficient (σ)

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Attitude stabilization Shuttlecock

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Feather and shuttlecock comparison
Pointing maneuvers
Feather Shuttlecock
Pointing Angle Settling Time Overshoot(%) Settling Time Overshoot(%)
5 3523 37.8 253 79.3
10 3271 35.7 261 77.8
15 4116 29.5 272 73.7
20 - - 279 69.1
25 - - 312 62.1
30 - - 433 51.5
35 - - 673 42.1
40 - - - -

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Toolbox

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Comparison LEO – VLEO (DTM2013)
Toolbox examples

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