VORSat_Madeira2010_.printfrdpptx

8/9/2019 VORSat_Madeira2010_.printfrdpptx

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Measuring a CubeSat attitude from the ground

and atmospheric re-entry

2nd June 2010 Madeira, Portugal

[email protected] | twitter.com/vorsat | facebook.com/vorsat

C. Capela, J. Gomes, R. Pinho, S. Cunha


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Mission GoalsMission Goals



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3 (patch) antennas/face

1 pair at a time

2.45 GHz

Attitude determination from the ground using RF signalsMissionMission



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A1

d

D

A1

A2

{ fffff

fff

=

=

+=

032

02

01

1

A

A

KHzf

GHzf

1

45,20

=

=

321 ,, Phases of the 3frequencies as received atGS, in cycles

)(

)()( 3221Dsend

==




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A1

A2

A1

.1 Phase difference between

one pair of antennasprovides one angle of

attitude




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A3

A2

A1



attitude.2 Other phase difference

gives the second angle




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attitude.2 Other phase difference

gives is the secondangle

.3 Third angle given by the

change of angle of sight




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UoP - Faculty of Engineering

3 m parabolic dish antenna

Yagi antennas (1.2GHz; 433MHz;

145MHz) with circular polarization;

Ground StationGround Station



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Adjust drag coefficient regardless VORSat attitude

Drag adjustment using control loop with feedback from GPS

Capsule release soon before significant deceleration (1/10 g)

De-OrbitDe-Orbit



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De-OrbitDe-Orbit


100 120 140 160 180 200 220 240 260 280 30010

-3

10

-2

10-1

100

101

102

103

Altitude (Km)

Orb

itvariation(orbits,

blueandred)andETA

(hours,green)

Along track landing distance variation due to +/-50% density (blue) and +/-20% drag (red) variations

Spoilers actuationCapsule Release


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Re-entryRe-entry



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Re-entryRe-entry


Oscillation dumping system

433 MHz Tx (ARGOS)

Flash memory with detailed mission log

Battery

Power generation mechanism TBD


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Combination of solar panels with antennas in order to maximize

the exposure area and power provided

Multiple face GPS antenna array

Structure made of CFRP

Re-entry of a CubeSat

ChallengesChallenges



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VORSat principle for attitude determination has been proved

viable with lab tests;

First draft of hardware requirements and layout for the VORSat

defined;

Capsule hardware layout - Design Review soon;

Capsule release mechanism TBD;

Structural simulation (FEMA) at an initial stage;

Work in progressWork in progress



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FacilitiesFacilities



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DEEC

DEMec


PartnersPartners


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2nd June 2010 Madeira, Portugal


Thank You!

Documents

VORSat_Madeira2010_.printfrdpptx