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There's more to the North Star than meets the eye SPACE TELESCOPE SCIENCE INSTITUTE NEWS RELEASE Posted: January 9, 2006 We tend to think of the North Star, Polaris, as a steady, solitary point of light that guided sailors in ages past. But there is more to the North Star than meets the eye. The North Star is actually a triple star system. And while one companion can be seen easily through small telescopes, the other hugs Polaris so tightly that it has never been seen - until now. By stretching the capabilities of NASA's Hubble Space Telescope to the limit, astronomers have photographed the close companion of Polaris for the first time. They presented their findings today in a press conference at the 207th meeting of the American Astronomical Society in Washington, D.C.
"The brightness difference between the two stars made it even more difficult to resolve them," stated Howard Bond of the Space Telescope Science Institute (STScI). Polaris is a supergiant more than two thousand times brighter than the Sun, while its companion is a main-sequence star. "With Hubble, we've pulled the North Star's companion out of the shadows and into the spotlight." By watching the motion of the companion star, Evans and her colleagues expect to learn not only the stars' orbits but also their masses. Measuring the mass of a star is one of the most difficult tasks facing stellar astronomers. Astronomers want to determine the mass of Polaris accurately, because it is the nearest Cepheid variable star. Cepheids' brightness variations are used to measure the distances of galaxies and the expansion rate of the universe, so it is essential to understand their physics and evolution. Knowing their mass is the most important ingredient in this understanding.
"We only have the binary stars that nature provided us," added Bond. "With the best instruments like Hubble, we can push farther into space and study more of them up close." The researchers plan to continue observing the Polaris system for several years. In that time, the movement of the small companion in its 30-year orbit around the primary should be detectable. "Our ultimate goal is the get an accurate mass for Polaris," said Evans. "To do that, the next milestone is to measure the motion of the companion in its orbit. |
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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.
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.
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.
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.
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.
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.
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.
The International Space Station receives its 20th Russian Progress cargo ship, bringing the outpost's two-man Expedition 12 crew a delivery of fresh food, clothes, equipment and special holiday gifts just in time for Christmas.
