Astrogeology Science Center

Kaguya Ortho Global Mosaic
Kaguya Ortho Global Mosaic

The Japan Aerospace Exploration Agency (JAXA) launched "KAGUYA (SELENE)" to obtain scientific data of the lunar origin and evolution and to develop the technology for the future lunar exploration. With permission from JAXA, researchers at the U.S. Geological Survey (USGS) Astrogeology Science Center have compiled and are releasing multiple near-global mosaics derived from data acquired by the Kaguya Terrain Camera (TC) instrument. The five mosaics were produced at 4096 pixels/degree (7.4 meter spatial resolution) and include two versions each of both low-sun Morning (early or right-to-left low-angle solar illumination) and Evening (late or left-to-right solar illumination) illuminations, along with a merged best-of “Ortho” version, a Kaguya team term indicating simulated vertical illumination.

For use, refer to the JAXA Conditions for material usage page ( http://jda.jaxa.jp/en/service.php ) and please credit JAXA and the SELENE/Kaguya data. ©JAXA/SELENE

The Integrated Software for Imagers and Spectrometers (ISIS) [7] along with local compute and storage cluster configurations were used to merge the original Kaguya TC tiles. Each mosaic is presented in Simple Cylindrical projection with a 16-bit image array sized at 1,474,560 samples by 737,280 lines and requires ~2 TB digital storage. The following provides brief product descriptions.

  • TC Morning (v2 & v4). Map-projected mosaicked TC data taken under east solar azimuth illumination conditions. Each pixel has reflectance value for incidence, emission, and phase angles of 30, 0, 30 degrees, respectively. Coverage consists of 6,371 (v2) and 7,200 (v4) available tiles from the 7,200 possible tiles.
  • TC Evening (v2 & v4). Map-projected mosaicked TC data taken with west solar azimuth conditions. Each pixel has reflectance value for incidence, emission, and phase angles of 30, 0, 30 degrees, respectively. Coverage consists of 6,409 (v2) and 7,200 (v4) available tiles from the 7,200 possible tiles.
  • TC Ortho (v2). Map-projected mosaic of appropriate TC ortho data from plural DTM TC Ortho products. TC ortho pixel values are in radiance units. Although all 7,200 tiles are available, coverage within each tile can contain data gaps.

 

Science Impact and Relevance

With Kaguya DTM coregistration, the source tiles match very well with the positions of the Apollo Lunar Retroreflector array (-17 to 5 m longitude, -20 to 48 m latitude, 3 to 5 m elevation; [6]). Quality of registration, high spatial resolution, and image clarity are impressive and these data provide excellent complements to color data such as those from the Lunar Reconnaissance Orbiter Wide Angle Camera (LROC WAC) and the Clementine Ultraviolet/Visible (UVVIS) mosaic products for geologic studies, mapping, and morphologic and structural analyses of the lunar surface.

One of the primary goals for the Kaguya mission was to augment the high-resolution image data available for the lunar surface, particularly the far side. At 10 m/pixel globally, the TC data effectively bridge the resolution gap between the LROC WAC (100 m/pixel) and the LROC NAC (~1 m/pixel) data and thus they provide invaluable contextual information. The data have enabled discoveries of relatively small lunar features such as lava-tube skylights [8], small impact craters used to determine relative age [9], lack of exposed ice at Shackleton crater (lunar south pole, [1]) and mare eruption ages [10]. Availability of the global TC data will greatly facilitate a wide variety of lunar studies, including relative and absolute chronology (e.g., crater counting), geologic mapping, structural analyses, site characterization, etc. to better understand the Moon’s geologic record. The low-sun and dual-illumination TC data provide unmatched morphologic information that support geologic and feature mapping at local to regional scales (~1:50,000 to ~1:250,000). The availability of coverage at multiple illuminations will help to ensure that any given site can be studied.

References

[1] Haruyama, J. et al. and the LISM Working Group (2008) Earth Planets Space, 60, 243-255. [2] Kato, M., Y. Takizawa, and S. Sasaki (2007) LPS XXXVIII, Abstract #1402. [3] Ohtake, M., et al. (2008) Earth Planets Space, 60, 257-264. [4] Matsunaga, T., et al. (2008) Geophys. Res. Letters. 35, L23201, doi:10.1029/2008GL035868. [5] Kato, M., Y. Takizawa, and S. Sasaki, Selene Project Team (2006) LPS XXXVII, Abstract #1233. [6] Haruyama, J., S. Hara, et al. (2012) LPS XLIII, Abstract #1200. [7] Kestay, L., et al., this volume. [8] Haruyama, J., et al. (2009) Geophys. Res. Letters, 36, L21206, doi:10.1029/2009GL040635 [9] Morota, T., et al. (2009) Meteoritics and Planetary Science 44, 1115-1120. [10] Cho, Y., et al. (2012) Geophys. Res. Letters, doi:10.1029/2012GL051838.

For use, refer to the JAXA Conditions for material usage page ( http://jda.jaxa.jp/en/service.php ) and please credit JAXA and the SELENE/Kaguya data. ©JAXA/SELENE