Satellites, like ships or accelerator experiments, need a name: the more poetic, or the
more apt, the better. The very first name of all, "Sputnik", in '57 was not bad: "someone who travels
with you". It was to be followed by a series of (rather unimaginative) "Explorers" from the US,
and of predictable "San Marco" from Italy and "Ariels" from the UK.
A touch more of imagination for NASA's UHURU ("freedom" in Swahili), launched in 1970 on Kenia's indipendence
day; then came names of famous scientists, from Netherland's "Copernicus" to NASA's "Einstein",
launched in '78 on the centennial of Albert's birth.
The custom stuck, and actually grew in significance. ESA has had "Hipparcos" (Greek founder of astrometry),
Germany "ROSAT" (after W.G. Roentgen, discoverer of X-rays), NASA, in turn, "Hubble, "Compton"
and now "Chandra", for the great astrophysicist S. Chandrasekar. Japan, on the other hand, has opted
not for people's names but for elegant and clever ones, mostly related to celestial objects (e.g. "Hakucho"
for Cygnus, etc.)
No doubt in part owing to chance, there are now five scientific missions somewhere in the solar system which bear
the names of illustrious Italians: one artist and four scientists. The missions are: ESA's Giotto, which flew
by the nucleus of comet Halley in '86 and is still active for further cometary rendez-vous; NASA's Galileo probe
to the Jovian system launched in '89 and now exploring Jupiter and its satellites; NASA's and ESA's Cassini mission,
launched in '97 and currently on its way to Saturn; NASA's "Rossi X-Ray Timing Explorer" ('95) and ASI's
"Beppo SAX" ('96), both doing X-ray astronomy from low Earth orbits.
The illustrious Italians are, of course, painter Giotto di Bondone (1267-1337), Galileo Galilei (1564-1642), astronomer
Giovanni Domenico Cassini (1625-1712), and physicists-astronomers Bruno Rossi (1905-1992) and Giuseppe (Beppo)
Occhialini (1907-1993). In this talk I shall review pictorially some of their accomplishments, together with those
of their namesake missions.