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First US television ratings
The A.C. Nielsen Company publishes its first-ever television ratings in the United States, compiling data collected over a “sweep month” running from early April through early May of 1950. The top TV program at the time, according to Nielsen’s data gathering, is Milton Berle’s Texaco Star Theater. The Nielsen ratings and data collection methodology will attract controversy for decades to come, and will spell doom for many shows with small but loyal followings.
The fifth episode of the syndicated science fiction Science Fiction Theatre airs on stations across the U.S. Hosted by Truman Bradley, the episode stars Marshall Thompson and Dean Evans.
The 55th episode of The Adventures Of Superman airs in syndication, starring George Reeves, Noel Neill, and Jack Larson. Harry Tyler guest stars.
The 116th episode of Doctor Who airs on the BBC. This is part two of the story now collectively known as 
The 
The fourth episode of Terry Nation’s post-apocalyptic series 
NASA launches Explorer 53, renamed Small Astronomy Satellite C, from an Italian-owned offshore launch platform off the coast of Kenya. SAS-C is a smaller spacecraft than NASA’s larger Orbiting Astronomical Observatory (OAO) series, but can be aimed very precisely at any cosmic X-ray sources that it detects. One of SAS-C’s discoveries is MXB1730-33, a binary star giving off rapid X-ray bursts. SAS-C will remain in orbit and functional until it re-enters Earth’s atmosphere in 
NBC airs 
The 
The tenth episode of Harold Jack Bloom’s sci-fi series Project UFO airs on NBC, portraying fictionalized investigations into what the show claims are actual cases from the U.S. Air Force’s Project Blue Book investigations. William Jordan and Caskey Swaim star. Anthony Geary (General Hospital) and Dr. Joyce Brothers guest star.
With the Jupiter encounter behind it, NASA’s Voyager 2 unmanned spacecraft is given a new backup mission plan, replacing the original Jupiter/Saturn backup plan implemented after a radio receiver failure befell the spacecraft in 1978. Intended to reap the minimum acceptable science observations (including photography) and transmit them to Earth should Voyager 2’s ability to receive new commands be lost, this new backup mission load now includes automated observation plans for Saturn and Uranus, the latter of which will not be reached until 1986.
ITV airs the 74th episode of the anthology series Tales Of The Unexpected. David Cassidy (The Partridge Family) and Darren McGavin (Kolchak: The Night Stalker) guest star.
NBC premieres 
The week-long national syndication window opens for 
Space Shuttle Endeavour leaves Earth for the first time, carrying a crew of seven to orbit on the 47th shuttle mission. Over nearly nine days, three spacewalks are taken up with the tricky and dangerous task of capturing a four-and-a-half-ton communications satellite into Endeavour’s cargo bay to repair and relaunch it. (The satellite, Intelsat VI, had been stranded in the wrong orbit since its 1990 launch aboard a Titan rocket.) The record-setting spacewalks involved – each lasting over seven hours and marking the first time three astronauts have operated outside their vehicle – force NASA to cancel one of two experimental EVAs to test space station construction techniques. Endeavour’s first crew consists of Commander Daniel Brandenstein, pilot Kevin Chilton, and mission specialists Pierre Thuot, Kathryn Thornton, Richard Hieb, Thomas Akers and Bruce Melnick.
NASA’s Clementine lunar orbiter, its moon mapping mission complete, is directed to fire its engines to put it on a trajectory for asteroid 1620 Geographos, a near-Earth asteroid named for the National Geographic Society (which sponsored a sky survey that led to its discovery). But one of Clementine’s thrusters stays on too long, firing for 11 minutes and revving the vehicle up to an unrecoverable spin of 80 revolutions per minute, exhausting its entire fuel supply in the process. Clementine’s secondary mission to Geographos is abandoned, and its batteries are exhausted a month later.
Previously distributed between computer bulletin board systems and FidoNet BBS nodes as a series of text files, theLogBook makes its debut on the world wide web, on a slice of web space borrowed from the University of Arkansas. In most cases, the episode guides previously distributed via BBS are simply the text files posted on the web, though conversion into HTML documents gradually takes place. The gigantic full-screen graphical menu overwhelms many a dial-up web surfer and is quickly replaced with a simpler, text-based menu.
UPN airs the 
Before Episode I‘s theatrical premiere, the pre-production phase of Star Wars Episode II has already begun, with principal photography to commence toward the end of 1999. Ewan McGregor, Natalie Portman, Ian McDiamid, Ahmed Best, and Anthony Daniels are all slated to reprise their roles, though it will be necessary to recast Anakin Skywalker, since the second film will take place at least a decade after the events of The Phantom Menace.
Showtime airs the 98th episode of The Outer Limits, a revival of the 1960s science fiction anthology series. Cary Elwes (The Princess Bride, Twister) and David Warner guest star.
Sci-Fi Channel premieres the 
The 159th episode of Chris Carter’s modern-day science fiction series The X-Files airs on Fox, starring Gillian Anderson and David Duchovny. Kathy Griffin guest stars.
The 87th episode of Gene Roddenberry’s Earth: Final Conflict, airs in syndication, starring Robert Leeshock, Jayne Heitmeyer, and Von Flores.
The 119th episode of Joss Whedon’s supernatural series Buffy The Vampire Slayer, starring Sarah Michelle Gellar, airs on UPN. James Marsters and Alyson Hannigan also star.
Last flown in the 1975 Apollo-Soyuz mission, the Apollo command/service module is – briefly – given strong consideration by NASA to serve as a “lifeboat” for the crew of the International Space Station, even to the point of conducting a study about un-mothballing the surviving unused Apollo hardware sitting in museums around the world. Part of the reason for this unusual study is that NASA’s budget has run out for finding a workable solution to keeping a “lifeboat” available to station astronauts in the anticipated long gap before the Space Shuttle’s return to service. Ultimately, even the seemingly unthinkable return of Apollo is nixed, since at least a Saturn IB booster would need to be similarly refitted – at huge expense – to lift a 30-year-old Apollo capsule into space.
The 
Syfy airs the 68th episode of the science fiction series Eureka, starring Colin Ferguson, Salli Richardson-Whitfield, and Joe Morton. Tembi Locke (Sliders) and Wil Wheaton (Star Trek: The Next Generation) guest star.
The 45th episode of Arrow, a modern-day reboot of DC Comics’ Green Arrow superhero starring Stephen Amell, airs on the CW. John Barrowman (Torchwood, Doctor Who) and Caity Lotz (Mad Men, Legends Of Tomorrow) guest star.