J. Eur. Opt. Society-Rapid Publ. 22, 35( 2026) 353
Figure 4. Optical design and ray-tracing of the off-axis Kim TMS Type-II configuration( adapted from [ 19 ]). The 14-m inflatable M1 is positioned far from the other optics( shown in the dashed box), allowing for independent deployment and inflation while the M2 – M3 component can be assembled, tested, and packaged as a subsystem.
Table 1. Comparison of Kim TMS Type-I and Type-II telescope specifications.
Parameter |
Kim TMS Type-I |
Kim TMS Type-II |
Reference |
[ 17 ] |
[ 19 ] |
Nominal wavelength( lm) |
0.650 |
30 |
Primary mirror diameter( m) |
6.420 |
14 |
Central obscuration |
On-axis optical design with 1.38 m inner diameter on the primary mirror |
Off-axis optical design without obscuration |
Full field of view( deg)* |
± 0.115 0.043 ° |
± 0.02 0.02 ° |
Primary mirror surface shape |
Ellipse( on-axis conic surface) |
Parabola( off-axis conic surface) |
Primary mirror type |
Rigid mirror |
Inflatable mirror |
Telescope F /# |
15 |
16 |
Airy disk radius( lm) |
11.97( at 0.650 lm wavelength) |
585( at 30 lm wavelength) |
Nominal strehl ratioy |
0.90 – 0.99 |
0.82 – 0.94 |
* Refer to the cited references for detailed FoV descriptions and focal plane definitions. |
yRefer to the corresponding references for further details regarding field-dependent performance. |
Precision cosmology with weak and strong gravitational lensing: A large aperture space telescope with a stable PSF significantly enhances gravitational lensing analyses. In weak lensing, reduced blending increases the effective source number density and improves shape measurement accuracy and cosmic shear constraints. For strong lensing, superior resolution facilitates the identification of a much larger number of multiple-image systems and enhances sensitivity to lensing substructures, enabling unified weak-and-strong lensing analyses from homogeneous datasets.
Galaxy evolution across cosmic time and environment: Resolving internal galaxy structures( e. g., morphology, color gradients, stellar mass distributions) is critical for evolution studies but often degraded by blending, particularly in dense regions. Large RWE surveys reduce confusion noise, ensuring accurate photometry and classification for statistically powerful samples across diverse environments and redshifts.
Low-surface-brightness structures: Features such as intracluster light, tidal streams, and ultra diffuse galaxies are highly sensitive to PSF wings and spatial non-uniformity. A space telescope with large RWE and smooth, well-characterized PSFs enables robust separation of diffuse emission from compact sources across wide areas. Its improved resolution reduces contamination from unresolved background objects and allows accurate modeling of extended structures, providing insights into the halo assembly histories.
Complementarity with existing facilities: Large-RWE space missions fill the gap between seeing-limited groundbased surveys and narrow-field space telescopes. They