ceres – atelier vol en formation pour l’astrophysique et la physique solaire 17 octobre 2005 1 -...

CERES – Atelier Vol en formation pour l’astrophysique et la physique solaire 17 Octobre 2005 1

- ASPICS 2 -Formation Flying for Solar Physics

- ASPICS 2 -Formation Flying for Solar Physics

100 m +/- 0.5m Study Leader :P. Duchon, CIC Team Leader :E. Hinglais,System : R. Clédassou,Schedule : September 5th 2005 to October 4th 2005

Main conclusion :The satellites are different and specialized. The Coronagraph mass is around 265 kg (including 30 kg payload). The Occulter mass is roughly 125 kg (with 20% system margin). Feasible in less than 5 years. Low level redundancy philosophy (ie. Myriade). Currently developed FF Flying techniques & technologies are well fitted. Numerous equipments from CNES Micro & Mini Sat.Science mission : 6 months mini

Study context and objectives

ASPICS 2 is part of a joint activity between CNES/DCT & ESA/ESTEC in the frame of PROBA-3 programme . The study objective was the operational validation of CNES concurrent Engineering Facility (named CIC).

ASPICS 2 : A Solar Physics Mission to observe the solar corona between 1.02 and 3.2 solar radius, both continuum & emission lines thanks to an interferometer. Formation Flying allows to observe the corona down to the solar limb and at a very low level of scattered light thanks to the distance between the 2 S/C of the formation ( around 100m).

CORONAGRAPH SPACECRAFT Attitude

: +/-30 arc sec

OCCULTING SPACECRAFT

Attitude : +/- 1 deg

RELATIVE LATERAL POSITION :

+/-7 mm


- ASPICS 2 – (With CIC)Spacecrafts & Launch : Final configuration

Satellites Launch capability : Dnepr ST-2, Soyuz 2.1.a or 2.1.b in lower place together with a co-passenger

The 2 S/C on the launcher

440 Kg

Spacecraft parameters

• High Elliptic Orbit ~ 400 Km / 71000 / 65 or 93 deg

• RF Metrology for localization and collision avoidance.

• Optical Metrology for accurate lateral relative position measurement: 0.15mm (transversal)

• Coronagraph S/C : Cold gas (FF) & Hydrazine (orbit)

• Occulter S/C: hydrazine & Wheels


Strong points: Small satellites class mission (125 Kg + 265 kg) leading to a cheap launch Feasible in less than 5 years, Simple operations, No technological gap with respect to currently developed FF techniques & technologies, Numerous of-the-shelf equipment.

… AND therefore a minimized mission cost

Weak points study results need consolidation, Attitude stability study & payload design, risk due to low redundancy philosophy with regard to costs.

Dedicated to the payload Coronagraph Interferometer optimization Attitude stability study and test (< 1 arc sec during 1 s)

Formation Flying: in line with current work :

RF metrology development. Lateral sensor Detail study 6 d.o.f. by cold gas… gyro stellar filter performances

Conclusion

R & D Links

- ASPICS 2 –Synthesis


- ASPICS II -Parameters & Scenarios

Satellites : 100 – 250kg

Common for each scenario :

• Maximal heritage on other PFs

• off the shelf harware

• asymmetrical Formation Flying

• FF on Coronagraph

• Occulter on natural orbit

• payload on Coronagraph

• design to cost

Open :

• Recurrence of the satellites

• “Only Cold Gas or with Hydrazine

• Payload uncoupled with respect to the PFs or embedded into the PFs’

Science

Solar Corona :

min = 1.01 to 1.03 Rs

Max = 2.5 to 3.2 Rs

Observation

6 h to 12 h / orbit

~6 images / 15 mn

Visible :

1 Fabry-Perot interferometer

ISL Distance :

~100 m

Passenger

LAUNCHER

Ariane 5

GTO

ONE DAY

300 / 71 000 km

ORBITMISSION SPACECRAFTs & FF

Soyuz

2.1.a

2.1.b

Dnepr

ceres – atelier vol en formation pour l’astrophysique et la physique solaire 17 octobre 2005 1 -...

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