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Expedition 15
The Russian Soyuz spacecraft with Expedition 15 cosmonauts Fyodor Yurchikhin and Oleg Kotov, along with tourist Charles Simonyi, fly to the space station following launch from Baikonur Cosmodrome.

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STS-61: Fixing Hubble
One of the most daunting yet crucial human spaceflights occurred in December 1993 as the crew of shuttle Endeavour embarked on a mission to repair the Hubble Space Telescope. The observatory had been launched three-and-a-half years earlier with a crippling vision flaw. Two teams of spacewalkers carried out five EVAs to install corrective optics and other equipment to fix the telescope's problems. The astronauts take you through the mission in this post-flight film.


STS-51: Satellite technology launch
Narrating a highlights film from their STS-51 mission, the shuttle astronauts from Discovery's September 1993 flight describe launching the Advanced Communications Technology Satellite with its Transfer Orbit Stage plus the deployment and retrieval of the Shuttle Pallet Satellite carrying the German ORFEUS ultraviolet telescope. TV and IMAX cameras on the SPAS craft provide stunning views of the shuttle. A spacewalk also occurs to test tools and procedures for the upcoming first servicing of the Hubble Space Telescope.


The Flight of Apollo 7
This documentary looks back at Apollo 7, the first manned flight of the Apollo program. Apollo 7 was designated as the essential engineering test of the spacecraft before the ambitious lunar missions could be attempted.


Running the Boston Marathon in space
NASA astronaut Suni Williams will run the Boston Marathon on a treadmill aboard the International Space Station. To preview the event, Williams, an accomplished marathoner, and Expedition 14 commander Michael Lopez-Alegria talk with The Boston Globe and the New England Sports Network.


Exercising on ISS
International Space Station Expedition 14 commander Michael Lopez-Alegria and flight engineer Suni Williams give a show-and-tell about the exercise equipment and routines aboard the orbiting complex.


STS-57: EURECA retrieved
After nearly a year in space, the European Retrievable Carrier (EURECA) satellite was plucked from orbit and stowed aboard Endeavour for return to Earth during STS-57. The June 1993 mission also featured the first flight of the commercial Spacehab module outfitted with a range of microgravity experiments for the crew to use. A spacewalk to demonstrate working on the end of the shuttle robot arm was performed as well.


STS-56: Sun and Earth
Working in two shifts around the clock, the astronauts of shuttle mission STS-56 conducted extensive observations of the Earth's atmosphere using the ATLAS 2 payload in the spring of 1993. The SPARTAN Sun-studying satellite was deployed and then retrieved during Discovery's flight too. The crew narrates the highlights in this presentation.


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Deep Impact could probe deeper into origins
Posted: April 12, 2007

In July, 2005, the Deep Impact spacecraft released a probe that blasted a crater in comet Tempel 1, spilling its elements into space so scientists could discover its composition. The assault was justified because comets are thought to be leftovers from the formation of our solar system, so learning more about them helps to understand how our solar system came to be.

Since those fireworks, the spacecraft has cruised silently through space, healthy and able to take on another mission, if needed. The Deep Impact team realized that with the spacecraft already built and launched, extra discoveries could be made at very little cost, a bonus for an already successful mission.

The team put together a proposal to use the spacecraft's telescope to observe the atmospheres of alien worlds, and to visit another comet. The proposed extended mission is called EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation), and it has received $500,000 from NASA for an initial study to determine the requirements and costs in greater detail.

An artist's concept of a "Hot Jupiter" extrasolar planet. Credit: NASA/JPL-Caltech
If approved, as Deep Impact passes by Earth on December 31, 2007, it will use our planet's gravity to direct itself to comet Boethin. While it cruises toward the comet, the first part of the extended mission -- the investigation of alien worlds --would begin in January, 2008. More than 200 alien (extrasolar) planets have been discovered to date. Most of these are detected indirectly, by the gravitational pull they exert on their parent star. Directly observing extrasolar planets is very difficult, because the star is so brilliant compared to the planet. Planets simply get lost in the glare, like fireflies near a headlight.

However, sometimes by chance the orbit of an extrasolar planet is aligned so that it eclipses its star as seen from Earth. In these rare cases, light from the extrasolar world can be seen directly. "When the planet appears next to its star, your telescope captures their combined light. When the planet passes behind its star, your telescope only sees light from the star. By subtracting light from just the star from the combined light, you are left with light from the planet. We can analyze this light to discover what the atmospheres of these planets are like," said Drake Deming of NASA's Goddard Space Flight Center, Greenbelt, Md., Deputy Principal Investigator for EPOXI.

Deep Impact will observe three nearby stars with "transiting extrasolar planets," so named because the planet transits, or passes in front of, its star. The planets were discovered earlier and are giant planets with massive atmospheres, like Jupiter in our solar system. They orbit their stars much closer than Earth does the sun, so they are hot and belong to the class of extrasolar planets nicknamed "Hot Jupiters".

These giant planets may not be alone. If there are other worlds around these stars, they might also transit the star and be discovered by the spacecraft. Even if they don't transit, Deep Impact could find them indirectly. Their gravity will pull on the transit planets, altering their orbits and the timing of their transits. "Since Deep Impact will be able to stare at these stars for long periods, we can observe multiple transits and compare the timing to see if there are any hidden worlds," said Deming.

Around May of 2008, the extended mission will transition to the second phase as the spacecraft approaches comet Boethin. In mid-December 2008, Deep Impact will come within 700 kilometers (435 miles) of Boethin. Passing by at more than 10 kilometers per second (6.2 miles per second), Deep Impact will only have about a half-dozen hours to make detailed observations.

"The comet hit by Deep Impact's probe, Tempel 1, was unusual compared to other comets we have seen up close," said Michael A'Hearn of the University of Maryland, College Park, Principal Investigator for EPOXI. For example, it appears that several pieces may have come together to build up the comet's nucleus, the lump of ice and dust that comprises the solid part of a comet. Second, comets vent gases as they come closer to the sun and warm up. Tempel 1 did this as well, but in an unusual way. Water vapor vents appeared all over the nucleus, as expected, but carbon dioxide only vented from certain parts. Also, since comets are a mixture of dust and ice, scientists expected dust to be dragged out from any gas vent, but dust only came from the carbon dioxide vents. Third, there are some very smooth areas on the nucleus, as if something had flowed there. However, the comet's gravity is extremely weak, so scientists don't understand how any material could be pulled down to flow across the surface. Finally, there are circular areas with raised rims that resemble impact craters. However, craters haven't been seen on any other visited comets so far. Scientists are surprised to see them on Tempel 1 because it's hard to understand how craters would last, since the surface gets vaporized every time the comet's orbit takes it close to the sun.

"We want a close look at Boethin to see if the surprises of Tempel 1 are more common than we thought, or if Tempel 1 really is unusual," said A'Hearn.

Deep Impact does not have another probe, so Boethin will not get hit, but the close-up view will allow the spacecraft's infrared spectrometer to make a map of the comet's surface composition, while the telescope observes surface features.

"It's exciting that we were able to combine two totally independent science investigations into a single project. However, both relate to understanding how solar systems form and evolve," said A'Hearn.

According to the team, comets and their asteroid kin are the leftover building blocks of planets, and might have contributed water and organic material to the ancient Earth, aiding the start of life. By observing extrasolar planets, scientists can compare them to our own and discover what we have in common, what we don't, and perhaps why.

"The EPOXI mission is short, sweet, focused, and gives a rich science return," said Deming.

Elements of the EPOXI mission were among approximately two dozen proposals submitted in response to NASA's Discovery Program 2006 Announcement of Opportunity last April. NASA selected three proposed new Discovery-class missions, and three "mission of opportunity" proposals that would make use of existing NASA spacecraft, for concept development funding. Two of the three existing spacecraft proposals used the Deep Impact spacecraft, and were later combined into the EPOXI proposal. NASA may select one or more investigations to continue into a development effort after detailed review of the concept studies. Decisions about which mission concepts will proceed to development are expected in late 2007. If selected, the EPOXI project will be managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif.