Very Large Structures in Space 10YearsACT... · Lake, M., Launching a 25-Meter Space Telescope: Are Astronauts a Key to the Next Technically Logical Step after NGST?, 2001 IEEE Aerospace

Very Large Structures in Space

Visions and Interesting Research Directions

Gunnar Tibert Associate Professor in Structural Mechanics

KTH Mechanics Stockholm, Sweden

Need for Large Space Structures

Future missions, • Solar Power Satellites • Sails (Solar, Magnetic, Electric, etc.) • Telescopes • Antennas • etc.,

envision large space structures technology with a high TRL readily is available. Focus: large apertures (30+ m)

ESA ACT 10 Years Anniversary 04.07.12 2

In-Orbit Assembly of Large Structures


Sources: CalTech- KISS Large Space Apertures Workshop, 10–11 November 2008 Lake, M., Launching a 25-Meter Space Telescope: Are Astronauts a Key to the Next Technically Logical Step after NGST?, 2001 IEEE Aerospace Conference, 10–17 March 2001.

• “Astronomical” costs of advancing the technologies to near flight readiness for on-orbit assembly.

• Self-deployable structures remained viable candidate for limited applications.

• In 50 years: antennas up to 30 m diameter.

Large “Mesh” Deployable Structures


Sources: CalTech- KISS Large Space Apertures Workshop, 10–11 November 2008 ESA

• Limited to RF wavelengths • Not scalable

Inflatable Large Structures


Sources: CalTech- KISS Large Space Apertures Workshop, 10–11 November 2008. M. C. Bernasconi, Flexible-Wall Expandable Structures for Space Applications: Forty Years of Trying, First European Workshop on Inflatable Space Structures, ESTEC, 21–22 May 2002.

• Low TRL for rigidization technology (Fifty years of trying…) • Numerous shape problems (W-shape, creases, clear canopy, etc.) • ESA-Contraves: “Could not control the deflation-rigidization shape” • 2D-to-3D: Not accurate enough for optical wavelengths

ESA & KTH: Space Webs and Tensegrities


Sources: Gärdsback, M. & Tibert, G., Optimal Deployment Control of Spinning Space Webs and Membranes, AIAA Journal of Guidance, Control, and Dynamics , 32(5):1519–1530, 2009. Gärdsback, M. & Tibert, G., Deployment Control of Spinning Space Webs, AIAA Journal of Guidance, Control, and Dynamics, 32(1):40–50, 2009. Zolesi, V. S. et al., On an Innovative Deployment Concept for Large Space Structures, 42nd AIAA ICES, 15–19 July 2012, San Diego.

Ariadna study (2006– ) SME study (2010– )

ESA patent application in 2012

1: Passive versus Active


• Lighter and flexible structures means more active control

Sources: Lake, M.S., Peterson, L.D. & Levine, M.B., Rationale for Defining Structural Requirments for Large Space Telescopes, Journal of Spacecraft and Rockets, 39(5):674–681, 2002. CalTech- KISS Large Space Apertures Workshop, 10–11 November 2008.

2: Packaging Efficiency


”The aperture of practical microwave and optical sensors...will be limited to less than about 30 meters...because of the enormous weight, complexity, difficult packaging for launch and deployment...” (Bekey, 2003)

Sources: Lake, M., Launching a 25-Meter Space Telescope: Are Astronauts a Key to the Next Technically Logical Step after NGST?, 2001 IEEE Aerospace Conference, 10–17 March 2001. Bekey, I., Advanced Space System Concepts and Technologies: 2010–2030+, AIAA/Aerospace Press, 2003.

3: On-Ground Testing Requirements


Sources: Peterson, L.D. & Hinkle, J.D., What Limits the Achievable Areal Densities of Large Aperture Space Telescopes?, SPIE, paper 5899-11, 2005. CalTech- KISS Large Space Apertures Workshop, 10–11 November 2008.

”…the requirement for ground-test-ability results in an order of magnitude or more depth in the structure than is required by the on-orbit loads.” (Peterson & Hinkle, 2005)

”Validation by simulation: will project managers be prepared to fly structures whose performance has not been verified on the ground?” (Pellegrino, 2008)

1-g testing (with gravity off-loading system): •  Sag and kinematic friction due to loading •  Non-linearities and poor repeatability •  Wrong initial and boundary conditions •  Facilities limited in size

4: Scalability


Source: Greschik, G., Solar Sail Scalability and a “Truly Scalable” Architecture: The Space Tow, Journal of Spacecraft and Rockets, 44(4):831–839 ,2007.

”To rescue this term from degrading into a technically meaningless marketing word, one should rigorously define degrees of scalability to grasp key characteristics of various performance-size relations” (Greschik, 2007)

”A definition of performance scalability shall undoubtedly focus on the weight of compression elements as a function of dimensions and loads because stability issues render such component masses to scale with degrees of nonlinearity higher than the rest.” (Greschik, 2007)

Capability for increased performance!

Future Large Space Structures


• Bekey, I., An Extremely Large yet Ultralight Space Telescope and Array, NIAC Final Report, May 1999.

• Crowe, D.G. et al., Self-Deployed Space or Planetary Habitats and Extremely Large Structures, NIAC Final Report, June 2007.

• Wertz, J. R., High Resolution Structureless Telescope, NIAC Final Report, April 2004.

• Ulmer, M.P. & Schatz, G.C., Self Assembly of Optical Structures in Space, NIAC Final Report, 200X.

• Powell, J. et al., Magnetically Inflated Cable (MIC) System for Large Scale Space Structures, NIAC Final Report, May 2006.

Future: Bekey Telescope Concept


”...shape the reflector not on the ground but only when in space, and use an adaptive membrane to attain and hold an arbitrary shape...” (Bekey, 2003)

Source: Bekey, I., An Extremely Large yet Ultralight Space Telescope and Array, NIAC Final Report, May 1999.

Future: Bekey Telecope Concept


Source: Bekey, I., An Extremely Large yet Ultralight Space Telescope and Array, NIAC Final Report, May 1999.

Future: In-Orbit Sail Fabrication


”...by taking advantage of the near zero gravity forces in orbit,...possible to fabricate in space...perfect spheres with extremely smooth surfaces” (Bekey, 2003)

Source: Crowe, D.G. et al., Self-Deployed Space or Planetary Habitats and Extremely Large Structures, NIAC Final Report, June 2007. Bekey, I., Advanced Space System Concepts and Technologies: 2010–2030+, AIAA/Aerospace Press, 2003.

Future: In-Orbit Sail Fabrication


Source: Crowe, D.G. et al., Self-Deployed Space or Planetary Habitats and Extremely Large Structures, NIAC Final Report, June 2007. Bekey, I., Advanced Space System Concepts and Technologies: 2010–2030+, AIAA/Aerospace Press, 2003.

Recommendations for the next 10+ years


1. Performance scalable concepts

•  Perfect performance scaling with all-tension members

•  Modularity for testing and verification to raise TRL 2. In-Space Fabrication Concepts •  Inflation, branch growing, etc. for light yet stiff structures

3. Folding and Deployment •  Mitigation of surface degradation due to packaging

•  Structure has no stiffness during deployment – reliable?

A Swedish Red Cottage on the Moon…


www.lunaresort.se …or at least on ISS J

Very Large Structures in Space 10YearsACT... · Lake, M., Launching a 25-Meter Space Telescope: Are Astronauts a Key to the Next Technically Logical Step after NGST?, 2001 IEEE Aerospace

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