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There are currently two approved and funded planetary missions. 
The first of these is Mariner Jupiter Saturn which will consist of 
two identical spacecraft to be launched in 1977. The imaging system 
will be a 200 mm focal length wide angle and a 1500 mm focal length 
narrow angle camera with vidicon sensor (47). The spacecraft will 
reach the vicinity of Jupiter in 1981 and will acquire data on the 
planet and its satellites for 90 days prior to closest approach and 
50 days after. The spacecraft will then continue to Saturn where a 
similar data acquisition cycle will take place in 1984. 
The second approved mission is the Venus Pioneer which will 
consist of two spacecraft to be launched in 1978. The first will 
contain several probes which will be deployed to explore the atmos- 
phere of Venus (48). The second orbiter will carry a radar altimeter 
to produce terrain profiles. These profiles will be combined with 
images from the Earth based radars at Arecibo and Goldstone to 
compile provisional maps of the planet's surface which is continually 
obscured by dense clouds. 
Other planetary missions of high scientific interest which are 
planned but not yet funded include: 
1. MJU/79 - A Mariner type spacecraft launched in 1979 
would use a Jupiter gravity assist to conduct a fly-by 
reconnaissance of Uranus in 1985. If the spacecraft 
survived long enough it could conceivably continue on out 
to Neptune (49,50). f 
2. VOIR (Venus Orbiter Imaging Radar) This mission, con- 
sidered for launch about 1983, would use either a Mariner 
spacecraft or one derived from the Viking Orbiter to carry 
a side-looking radar which would record the surface of 
Venus at a resolution of 100 to 500 meters (51). 
3. Jupiter Orbiter. This mission would use either the 
Mariner Jupiter Saturn/77 or the Venus Pioneer/78 spacecraft 
with probes to perform high resolution imaging from orbit 
around Jupiter (52,53). 
4. Mars Rover. This mission would use a modified version 
of the Viking lander for more extensive exploration of the 
surface of Mars (54). 
Future Landsat Missions 
  
Landsat-C has been approved for launch in 1977. Its orbit con- 
figuration will be identical with that of Landsat 1 and 2. However 
the imaging sensors will be different. The multispectral scanner 
(MSS) will continue to provide 4 spectral bands with 80 m. pixel in