Adaptive parabolic membrane mirrors for large deployable space telescopes

Area of Science:

• Optics and Astronomy
• Materials Science

Background:

• Extremely large telescopes require lighter primary mirrors to reduce launch costs and enable larger apertures.
• Current manufacturing methods for large mirrors are costly and heavy, limiting telescope size and scope.
• Membrane mirrors offer low areal weight but achieving optical quality has been a significant challenge.

Purpose of the Study:

• To demonstrate a practical method for manufacturing optical-quality membrane mirrors.
• To overcome the limitations of producing large, lightweight mirrors for space-based observatories.
• To explore the potential of adaptive optics for correcting membrane mirror imperfections.

Main Methods:

• Growing parabolic membrane mirrors on a rotating liquid surface within a test chamber.
• Utilizing polymer prototypes up to 30 cm in diameter, assessing surface roughness.
• Applying radiative adaptive optics to correct local shape imperfections via minor temperature changes.

Main Results:

• Successfully produced optical-quality parabolic membrane mirrors with low surface roughness.
• Demonstrated the ability to achieve significant shape correction (micrometers of stroke) using adaptive optics.
• Confirmed the scalability of the method for producing meter-class mirrors using existing technology.

Conclusions:

• The developed method offers a viable pathway to affordable, extremely large primary mirrors for space telescopes.
• The inherent flexibility of membrane mirrors allows for compact storage and in-space deployment.
• This innovation could significantly advance the capabilities of future space observatories.