Don Shedrick

May, 2000

May DAS Focus

COMPUTERS IN ASTRONOMY by Don Shedrick

We are coming to the time of year in which we plan our summer vacations. Have you ever wondered how long it will be before we will not be limited to the third rock from the Sun for our destinations? Well, through some stimulating web sites, we can imagine we are travelers over the vast distances and time of space.

Let’s start our virtual vacation tour close to home in the new International Space Station.

NASA’s web site for the International Space Station is at:

http://spaceflight.nasa.gov/station/

Construction in orbit began in November 1998 with the launch of Zarya, the Functional Cargo Block, from Russia on a Russian Proton rocket. After 44 more launches by 2005, it will provide living space for up to seven astronauts and scientists. The pressurized living and working space aboard the completed station will be roughly equivalent to the passenger cabin volume of two 747 jetliners.

You can get a preview of what your accommodations inside the space station will look like with NASA’s virtual tour and see where the astronauts will live and work. There is also info on the spacecraft statistics, activities, and experiments on board

The first crew -- a U.S. astronaut and two Russian cosmonauts -- will be launched on a Russian Soyuz spacecraft to begin a three-month stay on the station in October 2000. From that point on, it will be permanently staffed.

NASA SkyWatch at:

http://spaceflight.nasa.gov/realdata/sightings/

is a web-based Java application that provides sky watchers worldwide with a picture of when and where the International Space Station, the space shuttle and other spacecraft can be seen with the unaided eye as they pass overhead.

J-Pass at:

http://liftoff.msfc.nasa.gov/RealTime/JPass/

is another Java applet to help you view some of the most visible satellite passes. It shows the satellite against a sky star map.

J-Track at:

http://liftoff.msfc.nasa.gov/RealTime/JTrack/Spacecraft.html

shows the satellite track over a map of the earth.

The International Space Station draws upon the resources and the scientific and technological expertise of 16 cooperating nations, including the United States, Canada, Japan, Russia and 11 participating member nations of the European Space Agency -- Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, Switzerland and the United Kingdom. In addition, Brazil and Italy have signed on as payload participants.

If you would like to visit Jupiter or Saturn, seeing much more than from the Earth or from the Hubble Space Telescope, you will need to book a tour similar to one of the planetary exploration probes currently in route to one of the giant gas planets.

The Galileo Mission to Jupiter has a web site at:

http://www.jpl.nasa.gov/galileo/index.html

where you can sample some of the many photos and extensive info on this historic journey. Launched in 1989, the Galileo spacecraft arrived at Jupiter on December 7, 1995, when it fired its main engine for a successful orbit capture around Jupiter. On that day, Galileo's atmospheric probe plunged into Jupiter's atmosphere and relayed information on the structure and composition of the solar system's largest planet. Since then, Europa and Io flybys occurred in early 2000. The next satellite flybys will occur when Galileo flies by Ganymede on May 20 and December 28, 2000, and joint observations of Jupiter with the Cassini spacecraft in December 2000. Although radiation has created some problems with the spacecraft instruments, Galileo is still functioning well. There's no way to predict how long the spacecraft will remain healthy, but as long as it does, it provides valuable opportunities for exploration.

At The Cassini-Huygens Mission to Saturn and Titan web site:

http://www.jpl.nasa.gov/cassini/Mission/

you can follow how NASA and the JPL planned an international extended trip to Saturn, involving the European Space Agency (ESA), the Italian Space Agency (ISA), and several separate European academic and industrial partners.

You had better get some extra time off from your boss for a trip like this, since this started in October of 1997, and is scheduled to conclude, after spending four years at Saturn, in July of 2008. But extended missions are anticipated, and scientists estimate the probe could stay active for 200 years, continuing to gather data and map this vast realm.

From this web site, you can follow the progress of this journey of many years, and see Saturn’s mysteries revealed as Cassini approaches the ringed planet. Some sights to anticipate include Saturn's interesting atmosphere and interior, the most spectacular of the four planetary ring systems, numerous icy satellites with a variety of unique surface features, a huge magnetosphere teeming with particles that interact with the rings and moons, and the intriguing moon Titan, which is slightly larger than the planet Mercury, and whose hazy atmosphere is denser than that of Earth. The large spacecraft will consist of an orbiter and ESA's Huygens Titan Probe, which will descend to the frozen surface of Titan.

The mission is named in honor of the seventeenth-century, French-Italian astronomer Jean Dominique Cassini, who discovered the prominent gap in Saturn's main rings, as well as the icy moons Iapetus, Rhea, Dione, and Tethys. The ESA Titan probe is named in honor of the exceptional Dutch scientist Christiaan Huygens, who discovered Titan in 1655, followed in 1659 by his announcement that the strange Saturn "moons" seen by Galileo in 1610 were actually a ring system surrounding the planet. Huygens was also famous for his invention of the pendulum clock, the first accurate timekeeping device.

Finally, if you need that feeling that you really got away from it all, you will need to head for the stars. With StarStrider, you can take a virtual tour to the stars. Download this program from the web site:

http://www.starstrider.com/

Usually, planetarium programs bring the stars down to your monitor. Now, with StarStrider, your monitor will instead transport you out to the stars. Using a large database of 118,218 stars, compiled from the Hipparcos satellite mission of the European Space Agency (ESA), you will experience a truly three-dimensional universe. Use your computer mouse and keyboard to easily navigate the stellar neighborhood. See how the constellations change during your departure from the Sun and visit the stars to watch their starry skies. Using ordinary red/blue 3D glasses, your three dimensional experience will be even greater. See what it would really look like to depart from our solar system at relativistic speeds! This program is 7 MB in size, and will require you have Direct X version 8 or later on your PC, and an accelerated 3D graphics card is recommended. It is shareware, and after the free 30 day trial period, you will need to ante up $50 to keep full functionality and remove the nag-boxes.