Symposium on Remote Sensing for Resources Development and Environmental Management/Enschede /August 1986 
© 1987 Balkema, Rotterdam. ISBN 90 6191 674 7 
Comparison of MOMS and Thematic Mapper, data for geoscientific 
application and aspects for future development of multispectral 
sensors 
J.Bodechtel 
AGF -Working Group Geoscientific Remote Sensing, Faculty of Geosciences, University of Munich, FR Germany 
The missions of the German Modular Optoelectronic Multispectral Scanner MOMS aboard two flights of the 
United States Space Transportation System STS demonstrated the feasibility of a novel concept with regard 
to both technical and scientific objectives. On account of the successful missions a cooperation was 
agreed between the German Federal Minister of Research and Technology and NASA for comparting MOMS observations 
with the more familiar operational Landsat-Thematic Mapper data over selected testsites as a means of 
obtaining some relative measure of performance. This paper summarizes the results obtained and presents the 
M0MS-02, a further experimental representative in the MOMS program aiming at the realzation of an operational 
system for the midnineties. 
INTRODUCTION 
The past successes in the field of remote sensing - 
based on the Landsat-MSS family - have supported 
the definition of a new generation of earth 
observation satellites. With the launch of the 
Thematic Mapper sensoraboard the Landsat-4 and -5 
spacecrafts the U.S.A. are able to offer multi 
spectral imagery with a ground pixel size of 30 m 
and 7 spectral bands from which an optimum 
combination can be selected. 
In February 1986, France launched its SPOT into 
orbit. It is designed as an operational system and 
incorporates the new CCD technology. Particularly 
worth to be mentioned is its high ground resolution 
of 20 m in the multisprectral and 10 m in the 
panchromatic operating mode. SPOT is also the 
first scanner providing an experimental track-by 
track stereo imaging mode with tiltable mirrors. 
Within that scope the MOMS instrument development 
has been constituted by the Federal Minister for 
Research and Technology 8MFT. Due to its flexible 
modular concept, MOMS can be modified and adapted 
to fulfil specific requirements for a large 
variety of geoscientific tasks. 
M0MS-01 TECHNICAL CONCEPT 
The two experimental missions of M0MS-01 on the 
carrier structure SPAS aboard Shuttle flights 
STS-7/June '83 and STS-11 (%1-8)/February '84 were 
the first spacetests of an optoelectronic Scanning 
system for earth resources applications. The 
missions were to verify the technical concept under 
space conditions and to prove the applicability of 
high resolution CCD-data for geoscientific 
thematic mapping up to sales 1 : 50 000 / 
1 : 25 000. 
A primary concept underlying the MOMS design and 
program is that of sensor and mission versatility. 
The modular construction facilitates the use of 
different sensor units or peripheral devices to 
suit the application and carrier platform for each 
mission. 
The modularity like 
- optical system per channel, exchange of lenses or 
filters, 
- focal plane assembly (detector arrays and immedi 
ate electronics variable in type and number), 
- different orientation of modules for stereo 
imaging enables e.g. the combination of high 
spatial resolution modules with medium spatial/ 
high spectral resolution modules (different focal 
lengths and ground pixel sizes), and an easy 
refurbishment or the use of newest developed 
technology (e.g. sensor arrays)(Fig. 1). 
Detector elements are charge coupled devices (CCD's) 
with 1723 pixels per array (Reticon CCPD 1728). 
Scan line extension beyond 1 CCD array (up to 6 per 
focal plane feasible) is done by the dual optics 
principle (Fig. 2). 
The essential advantages of the "pusch-broom" 
technology are: 
- simple, compact construction, no moving mechanical 
parts, 
- central geometry in the scanline/acquisition of a 
total scan line simultaneously, 
- digitized image coordinate data for the pixel 
coordinate correlation and their radiometric 
intensity, 
- high geometric and radiometric precision, reduced 
geometric data preorocessing effort. 
MOMS/THEMATIC MAPPER COMPARISON 
During the 2 M0MS-01 missions aboard Space Shuttle 
Challenger, a total number of 26 image sequences, 
could be recorded under mostly optimum weather 
conditions due to controlling the data acquisition 
in real-time on the basis of a global weather 
information network (Fiq. 4). 
Out of these data takes 5 testsites v/ere selected 
for a mutual exchange of MOMS and Thematic Mapper 
data. The testsites for the joint evaluation 
include a section of the Red Sea Hills in Northern 
Sudan, the Cordillera coast and mountain chains of 
the Atacama desert near Antofagasta, Chile, a scene 
in the vicinity of Nairobi, Kenya, a desertifica 
tion threatened section of the Sahel channel in 
Mali and in Saudi Arabia the cities of Jeddah, 
Makkah and At'Taif (see circles in Fig. 4). 
For comparison with the 575 - 625 nm MOMS band the 
Landsat-TM bands 2 and 3 (520 - 600 nm and 630 - 
690 nm) were used. The MOMS 825 - 975 nm band was 
compared with the TM 790 - 900 nm band (see Fig. 5). 
Table 1 provides a breakdown of the differences 
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