Richard C. Henry
Center for Astrophysical Sciences
The Henry A. Rowland Department of Physics and Astronomy
The Johns Hopkins University
Baltimore, Maryland 21218-2686
Abstract. The study of the interstellar medium has been, and remains, a rich field for
exploitation using small missions in the ultraviolet and X-ray spectral regions. I review
the history of some such missions (of various sizes), and I also review the capabilities
for study of the interstellar medium of "Hot Universe Background Explorer" (HUBE),
as it was submitted in the second MIDEX round. A new technique for the three-
dimensional visualization of the local interstellar medium is also exhibited.
The emission line of Lyman from cool stars has been available for use in study of the
interstellar medium since the rocket measurement of Rottman, Moos, Barry, and Henry (1971).
It is remarkable to contemplate the history of that measurement. Paul Patterson had completed a
theoretical PhD thesis at Yale, under the direction of Ludwig Oster, examining the possibility of
detection of the Lyman emission line of cool stars by means of rocket observations. The issue