Controlled Deployment of Gossamer Spacecraft · 2016-12-23 · sail technology, Advances in Solar...

www.DLR.de • Chart 1 >ISSS2017 Patric Seefeldt • 20.01.2017

Controlled Deployment of Gossamer Spacecraft

DLR’s Gossamer-1 stowing and deployment strategy

www.DLR.de • Chart 2

Content

- Stowing and deployment strategies for deployable gossamer systems

- Selection considerations: controlling and automatization of the process

- Mathematical description of the deployment geometry

- Mathematical description of the deployment mechanism force

- Verification testing

ISSS2017 Patric Seefeldt • 20.01.2017


Stowing and deployment of gossamer systems

Examples see [1,3,4]



Considerations for the selection

- Constraint: crossed-boom configuration -> triangular membranes

- Constrain: photovoltaic -> required rectangular, not-folded areas

- Requirement controllable deployment

- Slow (30 min) deployment

- Stopping and resuming the deployment at any time (FDIR)

=> No free floating, unmentioned sail area during the deployment



Retrospection

- “The wrong choice for large membranes in a slow deployment”



Retrospection – the wrong choice

- Small sail highly dynamic deployment as demonstrated by the space

sailors is possible [8]

- But after deployment of the boom to length equal to the half hypotenuse

length the complete sail membrane is free to drift (0.3H)

- Is it possible to keep the triangular sail segments well mounted during the

whole deployment?

The Space Sailors Experiment from ISSS 2013 [8], www.spacesailors.de



The Gossamer-1 deployment technique

- Solution: deploying the full hypotenuses at the end of the deployment process

=> start the coiling process from the outer edges



The Gossamer-1 deployment technique

- The coiled sails are mounted on deployment units that, during deployment,

move away from the overall sail and spacecraft center.



Mathematical description

- Folding lines are zig-zag lines that may be described as




- The coiling of the folded sail can be represented by a logarithmic spiral




- The zig-zag folding lines translate into a helix with alternating slope when

folded segment is coiled




- The deployed length of the cathetus can be calculated as arc-length of the

of the helix as

- The deployed length of the hypotenuses can be calculated as arc-length

of the logarithmic spiral




- The deployment mechanism related force (spring that engages a gear) are

oscillating according to has a sawtooth function that may be described as

- In combination with the geometry a prediction of the deployment load progression

is possible (will be explained in 10 )

>ISSS2017 Patric Seefeldt • 20.01.2017


Verification testing with an engineering-qualification

model of the deployment unit

- Two sail segments (one with functional photovoltaic) mounted on two

spools each.

- The stowed with the spool are mounted to the deployment unit

- Instead of a central spacecraft bus a test adapter with flight representative

bearings and launch locks is used.



Integration

- Membrane stowing and

integration in a

reproducible manner in

order to ensure that

always the same

configuration is achieved

(e.g. for the qualification

testing model and the

flight model)


Gossamer-1 Deployment Unit EQM Testing

DLR.de • Chart 16

• Mechanical Vibration Testing according to

Gosssamer-1 launch load envelope

• Venting Test

• Thermal Vacuum Test


Verification testing – ambient deployment

DLR.de • Chart 17 >ISSS2017 Patric Seefeldt • 20.01.2017

Conclusion

DLR.de • Chart 18 >ISSS2017 Patric Seefeldt • 20.01.2017

- A possible deployment strategy is described that allows a controlled

deployment with a very little slack during deployment

- A mathematical model for the analysis of the deployment geometry and

forces is provided

- Environmental and deployment tests verified the deployment mechanisms

and the overall stowing and deployment strategy

- The stowing and deployment strategy can also be used without

deployment units if a central boom deployment can be implemented and it

might also be useful for a spin deployment.

Deployable Systems at DLR’s Institute of Space Systems

available for partnership and cooperation

DLR’s Development of Deployable Systems

Design / Deployment Strategy Deployment Test Mission / Requirements

Structural Analysis

Thermal Analysis

Manufacturing Degradation (e-

, p+, EMR) Vibration Tests

Centrifuge Test

Venting

Thermal-Vacuum Test

ISSS2017 Patric Seefeldt • 20.01.2017 www.DLR.de • Chart 19

References

References

1) Miura K.: Method of packaging and deployment of large membranes in space, Proceedings of the 31st Congress

International Astronautical Federation, 1985

2) Seefeldt, P., Steindorf, L. and Spröwitz, T.: Solar Sail Membrane

Testing and Design Considerations, Proceedings of the European

Conference on Spacecraft Structures, Materials & Environmental

Testing, 2014.

3) Guest, S. D., and Pellegrino, S: Inextensional wrapping of flat

membranes, Proceedings of the First International Seminar on Structural Morphology (pp. 203-215), 1992.

4) De Focatiis, D. S. A., & Guest, S. D.: Deployable membranes

designed from folding tree leaves, Philosophical Transactions of

the Royal Society of London A: Mathematical, Physical and

Engineering Sciences, 360(1791), 227-238, 2002.

5) Leipold, M., Eiden, M., Garner, C. E. et al.: Solar sail technology

development and demonstration, Acta Astronautica, 52(2), 317-

326, 2003.

6) Stohlman, O. R., Fernandez, J., Lappas, V. J. et al., Testing of

the Deorbitsail drag sail subsystem, Proceedings of the 54

AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics,

and Materials Conference, 2013

7) Tsuda, Y., Mori, O., Funase, R. et al.: Achievement of IKAROS-

Japanese deep space solar sail demonstration mission, Acta Astro-

nautica, 82(2), 183-188, 2013

8) Wolff, N., Seefeldt, P., Bauer et al.: Alternative application of solar

sail technology, Advances in Solar Sailing (pp. 351-365), Springer

Berlin Heidelberg, 2014.

9) Seefeldt, P., Spietz, P., Sproewitz et al.: Gossamer-1: Mission Con-

cept and Technology for a Controlled Deployment of Gossamer

Spacecraft, Advances in Space Research, 2016

10) Seefeldt, P.: A stowing and deployment strategy for large

membrane space systems on the example of Gossamer-1, Submitted

to Advances in Space Research, December 23rd 2016

ISSS2017 Patric Seefeldt • 20.01.2017 www.DLR.de • Chart 20

Controlled Deployment of Gossamer Spacecraft · 2016-12-23 · sail technology, Advances in Solar...

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