ISS Utilization: JEM/Kibo-EF (Exposed Facility) experiments of USA

HREP (HICO-RAIDS Experiment Payload)

HREP represents the first two US payloads allocated for deployment on the JEM/Kibo-EF of Japan. According to the JAXA/NASA agreement, the ten JEM/Kibo-EF experiment modules are evenly shared between the two countries, Japan and USA.

HICO (Hyperspectral Imager for the Coastal Ocean) and RAIDS (Remote Atmospheric and Ionospheric Detection System) are two technology demonstration instruments designed and developed at NRL (Naval Research Laboratory), Washington D. C.

In the spring of 2007, the combined payload of HICO and RAIDS, referred to as HREP, was manifested for the Japanese Experiment Module – Exposed Facility (JEM-EF) on the International Space Station (ISS). HICO and RAIDS are being flown under the STP (Space Test Program) of DoD. As of fall 2008, both instruments are ready for payload integration. ^{1) 2) 3) 4) 5)}

Launch: A launch of HREP took place on Sept. 10, 2009 (UTC) on the inaugural flight of the Japanese H-II Transfer Vehicle (HTV-1) to the ISS. The launch site is the Tanegashima Space Center located off the southern coast of Japan.

After the HTV-1 docked with JEM, a mechanical arm, referred to as JEM-RMS (JEM-Remote Manipulator System), transfered the HREP assembly to the JEM-EF instrument slot.

Figure 1: View of JEM and EF (right) on the ISS. The arrow indicates the mounting location of the HREP assembly (image credit: JAXA, NRL)

Figure 2: Overview of attachment positions of the JEM-EF payloads (image credit: JAXA) ⁶⁾

HICO (Hyperspectral Imager for the Coastal Ocean)

HICO is an INP (Innovative Naval Prototype) instrument sponsored by the Office of Naval Research (ONR), Washington, D. C. In 2005, ONR and the Naval Research laboratory (NRL) began a program to design, build, and operate the first spaceborne hyperspectral imagers optimized for the coastal ocean. This transition to space platforms is based on more than a decade of airborne hyperspectral imaging experience at NRL and other laboratories, which provides the basis for imager performance requirements and algorithms for atmospheric removal and littoral product retrievals. ^{7) 8)}

The HICO instrument incorporates COTS (Commercial Off The Shelf) components, including a CCD camera, a rotation mechanism, and a computer to reduce schedule and cost. To facilitate this approach, hermetic enclosures are used for the camera, computers and electronics.

The NRL HICO team built and tested the HICO instrument in only 16 months. Partners in the HICO team were NASA, SDL (Space Dynamics Laboratory) of Utah State University, University of Hawaii, Oregon State University, and Brandywine Optics, Chester, PA. SDL and the University of Hawaii temed with NOVASOL to build the HICO instrument.

The airborne instrument of NRL that preceded HICO was called PHILLS (Portable Hyperspectral Imager for Low Light Spectroscopy). The Ocean PHILLS was specifically designed to produce high quality hyperspectral imagery of the coastal environment. In conclusion, two key elements in this success were the VS-15 Offner spectrograph, which produced an image with minimal smile and keystone distortion, and the thinned backside-illuminated CCD cameras which provided a high quantum efficiency in the blue. Both the spectral and radiometric responses of the instrument were highly linear. All of the components of the Ocean PHILLS were commercially available. Excellent agreement between atmospherically corrected remotesensing spectra and ground-truth radiometric measurements was demonstrated. ^{9) 10)11)}

Table 1: Performance characteristics of the HICO instrument

Figure 3: HICO assembly with the instrument in the imaging position (image credit: NRL)

Figure 4: Photo of the HICO flight hardware (image credit: NRL)

The overall objective of HREP-HICO is to launch and operate a rapid-development, cost-constrained VNIR (Visible and Near-Infrared) Maritime Hyperspectral Imaging (MHSI) system, to demonstrate the detection, identification and quantification of littoral (coast of an ocean or sea) and terrestrial geophysical features. HICO will validate the performance of MHSI technology in space and demonstrate its utility to meet DoD requirements. The instrument will provide an initial data stream to introduce new DoD users to MHSI data products and develop data dissemination channels. Hyperspectral image data from HICO also has significant application in the civil remote sensing community.

Coastal imaging complexity:

Visible and near infrared wavelengths in the approximate range 0.4 to 0.8 µm constitute the only portion of the electromagnetic spectrum that penetrates water and directly probes the water column. In the coastal environment where the water contains significant dissolved and suspended matter and the bottom may be visible, the scene image is spectrally complicated requiring well-calibrated hyperspectral imaging to retrieve bathymetry, bottom type, chlorophyll content, and water inherent optical properties. ¹²⁾

Furthermore the coastal ocean scene is dark, with an albedo of only a few percent, and from space it is viewed through the atmosphere which is significantly brighter in the visible wavelengths than the water surface, due to scattered sunlight. These conditions impose stringent requirements for a MHSI system which are in general not met by systems designed for land applications (Figure 5).

Figure 5: Illustration showing the optical complexity found in the coastal ocean, particularly when imaging the bottom (image credit: NRL)

Hyperspectral imaging of the littoral zone from space offers repeat, all-season coverage of coastal zones worldwide to produce environmental products including bathymetry, water clarity, suspended and dissolved matter, bottom type, classification of on-shore vegetation, and the opportunity to build time series of images to initialize and validate predictive coastal models. However, hyperspectral imaging of the littoral environment involves specific challenges not found in hyperspectral imaging of the land. While land generally presents a bright, high albedo scene, the coastal ocean has a low albedo and is dark. In fact, when a maritime scene is viewed from a high-altitude aircraft or space, the scattered light from the atmosphere is significantly brighter than the underlying water scene over most of the visible spectrum (Figure 6), and careful removal of the effects of the atmosphere is required to obtain accurate water-leaving radiances. Water surface reflections of both direct sunlight and sky background are also significant and must be accounted for (Ref. 7).

Figure 6: Spectral radiance modeled (using MODTRAN), Image credit: NRL

Legend to Figure 6: The spectral radiance is modeled above the atmosphere for 5% surface albedo and 45 degree solar zenith angle. In the blue wavelengths, the atmosphere (total minus surface) is significantly brighter than the surface.

Initial calibration and processing of the HICO data is performed at the NRL Remote Sensing Division. The data is then sent to NRL's Oceanography Division at Stennis Space Center, Miss., for further processing, archiving, and distribution to government users. Data will also be archived at Oregon State University, which is the primary repository for distribution of HICO data products to civilian users. The Office of Naval Research (ONR) as part of their "Space Innovative Naval Prototype" program funded HICO instrument design and fabrication.

RAIDS (Remote Atmospheric and Ionospheric Detection System)

RAIDS is a hyperspectral satellite experiment suite, designed and developed in a joint project between NRL (Naval Research Laboratory), Washington, D. C. and the Aerospace Corporation of El Segundo, CA. The PI is Scott Budzien of NRL.

The goal of the RAIDS experiment is to obtain a set of simultaneous airglow profiles at a number of wavelengths which will be used to develop and evaluate techniques for neutral atmospheric and ionospheric remote sensing. The RAIDS instrumentation will acquire a global database of airglow intensities which will be used in conjunction with, and compared to, theoretical models of radiation transport, photochemistry and dynamics to examine in detail the relationships between atmospheric composition and airglow. The primary focus of RAIDS will be on the remote sensing of the ionosphere since there is considerable interest by the ionospheric and high frequency propagation communities in monitoring the ionosphere in real-time on a global basis. ^{13) 14) 15)}

Background: The RAIDS experiment was originally developed through the support of the Office of Naval Research (ONR) and the DoD Space Test Program (STP) to fly aboard the NOAA-J satellite (NOAA-14 on-orbit, launch Dec. 30, 1994), and both organizations provided support to refit and integrate the experiment for this new ISS mission opportunity. - However, when NOAA-13 (-I) failed 12 days after launch (launch on Aug. 9, 1993) due to a power loss of the S/C, the SSBUV (Shuttle Solar Backscatter Ultraviolet) instrument replaced RAIDS on NOAA-J, and RAIDS was mothballed. Thereafter, many different launch opportunities were explored for RAIDS - when a new launch opportunity turned up to fly RAIDS and HICO as an integrated experiment payload on the Japanese JEM-EF of ISS (International Space Station).

Both organizations (ONR and the DoD STP) provided support to refit and integrate the RAIDS experiment for this new ISS mission opportunity. As of fall 2008, RAIDS as well as HICO were ready for payload integration.

Figure 7: Illustration of the RAIDS instrument (image credit: NRL)

RAIDS science objectives:

• Lower thermosphere temperature & composition (primary objective). Complete description of the major constituents of the thermosphere and ionosphere:

- Investigate temperature and compositional structure, including solar activity, seasonal, latitudinal variations

- Investigate importance of internal and external forcing in the region 100-300 km.

• Ionosphere (secondary objectives)

- Measure initial O⁺ 834 source, separately from multiple scattering source

- Comprehensive nightglow observations of O⁺(911/6300/7774 Å)

• Chemistry (secondary objectives)

- Global distribution of minor species

- Basic understanding of their role in chemical and ionic reactions in the lower thermosphere.

Figure 8: Schematic view of the region of interest for RAIDS observations (image credit: NRL, The Aerospace Corp.)

The RAIDS measurement approach is to provide limb-view airglow observations in the UV and visible spectral regions.

- Limb radiances from EUV (55 nm) to NIR (870 nm) covering the 90–350 km altitude range

- Atmospheric composition retrieved by inverting limb radiances using state-of-the-art science algorithms

- Monitor dynamic variability in response to space weather and forcing from lower atmosphere.

Figure 9: RAIDS observables at thermospheric/inonospheric altitudes (image credit: NRL, The Aerospace Corp.)

Figure 10: Illustration of the RAIDS subsystems (image credit: NRL, The Aerospace Corp.)

Table 2: RAIDS instrument summary

Figure 11: Artist's rendition of the RAIDS limb-viewing geometry (image credit: The Aerospace Corp.)

Figure 12: FOV comparison of RAIDS (image credit: The Aerospace Corp.)

Figure 13: Schematic of the HICO-RAIDS combined payload mounting on JEM-EF (image credit: NRL)

Mission status of HREP:

• Afterwards in September 2009, the HREP instrumentation successfully progressed through a series of internal electrical verification checks that culminated in the release of the latching mechanism and the initiation of the scanning motion for the sensor section of the instrument.

• Transfer from the HTV and installation of HREP was carried out on Sept. 24, 2009 using Kibo's robotic arm (JEM-RMS). Then, the HREP was removed from the HTV Exposed Pallet (EP) and installed on the JEM-EF at attachment position No. 6.

2) “NRL HICO-RAIDS Experiments Ready For Payload Integration,” Spacemart, Sept. 29, 2008, URL: http://www.spacemart.com/reports/NRL_HICO_RAIDS_Experiments_Ready_For_Payload_Integration_999.html

3) “HICO-RAIDS experiments ready for payload integration,” Sept. 26, 2008, URL: http://www.physorg.com/news141650554.html

4) M. R. Corson, J. H. Bowles, W. Chen, C. O. Davis, K. H. Gallelli, D. R. Korwan, P. G. Lucey, T. J. Mosher, R. Holasek, “The HICO Program – Hyperspectral Imaging of the Coastal Ocean from the International Space Station,” Proceedings of the IGARSS 2004, Anchorage, AK, USA, Sept. 20-24, 2004

5) http://www.nasa.gov/mission_pages/station/science/experiments/HREP-RAIDS.html

6) http://iss.jaxa.jp/en/htv/mission/htv-1/payload/

7) Michael R. Corson, Daniel R. Korwan, Robert L. Lucke, William A. Snyder, Curtiss O. Davis, “The Hyperspectral Imager for the Coastal Ocean (HICO) on the International Space Station,” Proceedings of IGARSS 2008 (IEEE International Geoscience & Remote Sensing Symposium), Boston, MA, USA, July 6-11, 2008

8) Curtiss O. Davis, “Hyperspectral Imaging of the Coastal Ocean,” 2008, URL: http://www.onr.navy.mil/sci_tech/32/reports/docs/08/obdavis.pdf

9) Curtiss O. Davis, Jeffrey Bowles, Robert A. Leathers, Dan Korwan, T. Valerie Downes, William A. Snyder,W. Joe Rhea,Wei Chen, John Fisher, W. Paul Bissett, Robert Alan Reisse "Ocean PHILLS Hyperspectral Imager: Design, Characterization, and Calibration", Optics Express, Vol. 10, No 4, Feb. 25, 2002, pp. 210-221

10) Detlev Even, Arleen Velasco, “Hyperspectral Imager for Coastal Ocean (HICO),” URL: http://www.onr.navy.mil/sci_tech/32/reports/docs/08/obeven.pdf

11) M. R. Corson, R. L. Lucke, D. R. Korwan, W. A. Snyder, C. O. Davis, “The HICO Program for Hyperspectral Imaging of the Coastal Ocean from Space,” URL: http://hico.coas.oregonstate.edu/publications/HICO%20Poster%20for%20OOXIX.ppt

12) Z. P. Lee, K. L. Carder, “Effects of spectral-band number on retievals of water column and bottom properties from ocean-color data”, Applied Optics, Vol. 41, 2002 pp. 2191-2201

13) http://www.nrl.navy.mil/tira/Projects/raids/

14) Scott A Budzien, Andrew W Stephan, J. Michael Picone, Paul R. Straus, Andrew B Christensen, Rebecca L Bishop, James H Hecht, Robert P McCoy, “Everything Old Becomes New: RAIDS on the ISS,” URL: http://ccar.colorado.edu/muri/DoD%20Missions-Budzien.pdf

15) Andrew Stephan, “RAIDS: The Remote Atmospheric and Ionospheric Detection System,” ITMR (Ionosphere-Thermosphere-Mesosphere Research) Conference, February 10,12, 2009, El Segundo, CA, USA, URL: http://www.aero.org/conferences/itmr/pdf/24_Stephan.pdf