Premium video content for our Spaceflight Now Plus subscribers. NASA through the decades This film looks at the highlights in NASA's history from its creation in the 1950s, through the glory days of the Mercury, Gemini and Apollo programs, birth of the space shuttle and the loss of Challenger, launch of Hubble and much more. Small | Medium | Large STS-49: Satellite rescue If at first you don't succeed, keep on trying. That is what the astronauts of space shuttle Endeavour's maiden voyage did in their difficult job of rescuing a wayward communications satellite. Spacewalkers were unable to retrieve the Intelsat 603 spacecraft, which had been stranded in a useless orbit, during multiple attempts using a special capture bar. So the crew changed course and staged the first-ever three-man spacewalk to grab the satellite by hand. The STS-49 astronauts describe the mission and narrate highlights in this post-flight presentation. Small | Medium | Large First satellite repair The mission for the crew of space shuttle Challenger's April 1984 flight was two-fold -- deploy the experiment-laden Long Duration Exposure Facility (LDEF) and then track down the crippled Solar Max spacecraft, capture it and perform repairs during spacewalks. Initial attempts by the astronauts to grab the craft while wearing the Manned Maneuvering Unit spacewalk backpacks failed, but the crew ultimately retrieved Solar Max and installed fresh equipment while it was anchored in the payload bay. The crew narrates this post-flight presentation of home movies and highlights from mission STS-41C. Small | Medium | Large STS-26: Back in space The space shuttle program was grounded for 32 months in the painful wake of the 1986 Challenger accident. Americans finally returned to space in September 1988 when shuttle Discovery safely launched for its mission to deploy a NASA communications satellite. Enjoy this post-flight presentation narrated by the astronauts as they show movies and tell the story of the STS-26 mission.
Small | Medium | Large Amazing STS-51I flight Imagine a space shuttle mission in which the astronaut crew launched two commercial and one military communications spacecraft, then conducted a pair of incredible spacewalks to recover, fix and redeploy a satellite that malfunctioned just four months earlier. The rescue mission was a success, starting with an astronaut making a catch of the spinning satellite with just his gloved-hand. Enjoy this post-flight presentation narrated by the astronauts as they tell the story of shuttle Discovery's August 1985 mission known as STS-51I.
Small | Medium | Large Discovery's debut In our continuing look back at the classic days of the space shuttle program, today we show the STS-41D post-flight presentation by the mission's astronauts. The crew narrates this film of home movies and mission highlights from space shuttle Discovery's maiden voyage in August 1984. STS-41D deployed a remarkable three communications satellites -- a new record high -- from Discovery's payload bay, extended and tested a 100-foot solar array wing and even knocked free an icicle from the shuttle's side using the robot arm. Small | Medium | Large "Ride of Your Life" As the title aptly describes, this movie straps you aboard the flight deck for the thunderous liftoff, the re-entry and safe landing of a space shuttle mission. The movie features the rarely heard intercom communications between the crewmembers, including pilot Jim Halsell assisting commander Bob Cabana during the landing. Play video Message from Apollo 8 On Christmas Eve in 1968, a live television broadcast from Apollo 8 offered this message of hope to the people of Earth. The famous transmission occurred as the astronauts orbited the Moon. Play video Become a subscriber More video
Monster black holes grow after galactic mergers ARIZONA STATE UNIVERSITY NEWS RELEASE Posted: January 10, 2006
An analysis of the Hubble Space Telescope's deepest view of the universe offers compelling evidence that monster black holes in the centers of galaxies were not born big but grew over time through repeated galactic mergers.
These postage-stamp-size images reveal 36 young galaxies caught in the act of merging with other galaxies. Each postage-stamp image is roughly 84,000 light-years on a side, which is about the size of our Milky Way Galaxy today. Credit: NASA, A. Straughn, S. Cohen, and R. Windhorst (Arizona State University), and the HUDF team (Space Telescope Science Institute)
Download larger image version here
"By studying distant galaxies in the Hubble Ultra Deep Field (HUDF),
we have the first statistical evidence that supermassive black-hole
growth is linked to the process of galaxy assembly," said astronomer
Rogier Windhorst, of Arizona State University in Tempe, Ariz., and
a member of the two teams that conducted the analysis. "Black holes
grow by drawing in stars, gas, and dust. These morsels come more
plentifully within their reach when galaxies merge."
The two teams will present their results in a press conference on
Jan. 10 at the 207th meeting of the American Astronomical Society
in Washington, D.C.
The HUDF studies also confirm the predictions of recent computer
simulations by Lars Hernquist, Philip Hopkins, Tiziana di Matteo,
and Volker Springel of the Harvard Smithsonian Center for
Astrophysics in Cambridge, Mass., that newly merging galaxies are
enshrouded in so much dust that astronomers cannot see the
black-hole feeding frenzy. The computer simulations, as supported
by Hubble, suggest that it takes hundreds of millions to a
billion years before enough dust clears so that astronomers can
see the black holes feasting on stars and gas from the merger. The
telltale sign that black holes are dining is seeing light from
galaxies that varies with time.
The two HUDF teams believe they are seeing two distinct phases in
galaxy evolution: the first phase - the tadpole stage -
representing the early-merging systems where central black holes are
still enshrouded in dust, and the much later "variable-object phase,"
in which the merged system has cleared out enough gas for the inner
accretion disk around the black hole to become visible.
"The fact that these phases were almost entirely separate was a
surprise, because it is commonly believed that galaxy mergers and
central black-hole activity are closely related. Our nearby universe
has mature galaxies, but in order to understand how they formed and
evolved, we must study them over time," Windhorst explained. "The
HUDF provides an actual look back in time to see snapshots of early
galaxies so that we can study them when they were young."
A link between the growth of galaxies through mergers and the feeding
of the central black holes has long been suspected. The evidence,
however, has been inconclusive for many years. "The HUDF has provided
very high-quality information. It is the first data we could use to
test this theory, since it allowed us to study about 5,000 distant
galaxies over a period of four months," said Seth Cohen of Arizona
State University and leader of one of the teams.
The HUDF observations have now shed light on how the growth of monster
black holes kept pace with that of galaxies. A team of astronomers,
led by Amber Straughn of Arizona State University, searched the HUDF
for "tadpole galaxies," so-called because they have bright knots and
tails caused by mergers. These features are produced when the galaxies
lose their gravitational grip on their stars, spewing some of those
stars into space. The team found about 165 tadpole galaxies,
representing about 6 percent of the 2,700 galaxies in the tadpole
galaxy study.
"To our surprise, however, these tadpole objects did not show any
fluctuation in brightness," Straughn said. "The flickering light -
when it is present - comes from the material swirling around an
accretion disk surrounding a black hole. The material is heated and
begins to glow. As it spirals down toward the black hole, it can
rapidly change in brightness. This study of tadpole galaxies suggests
that black holes in newly merging galaxies are enshrouded in dust,
and therefore, we cannot see them accreting material."
Cohen's team studied the brightness of about 4,600 HUDF objects over
several weeks to many months. The Hubble team found that about 45
(non-tadpole) objects, representing 1 percent of the faint galaxies
in the study, fluctuated significantly in brightness over time. This
result indicates that the galaxies probably contain supermassive
black holes that are feeding on stars or gas.
"A black hole's typical mealtime lasts at least a few dozen million
years," Windhorst said. "This is equivalent to black holes spending
no more than 15 minutes per day eating all their food - a veritable
fast food diet."
The HUDF analysis also reinforces previous Hubble telescope studies of
monster black holes in the centers of nearby, massive galaxies. Those
studies showed a close relationship between the mass of a galaxy's
"central bulge" of stars and that of the central black hole. Galaxies
today have central black holes with masses ranging from a few million
to a few billion solar masses.