America at the threshold  report 
of the Synthesis Group on America's space exploration initiative. 
 - Washington, D.C.  Supt. of Docs., U.S. G.P.O.  [1991] 
 - vi, 114, 67 p.  ill. (some col.)  28 cm. 
<br/><br/> "Thomas P. Stafford, Chairman Synthesis Group" -- p. [iii].  "May 6, 1991." -- p. [ii]. 
<br/><br/>Includes bibliographical references. 
<br/><br/><label>Subjects--Corporate Names: </label><br/>United States National Aeronautics and Space Administration. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Space flight to Mars.<br/>NASA SPACE PROGRAMS<br/>MARS PROBES<br/>MARS LANDING