On Sunday the 21st, the satellite Galileo, first launched into space in 1989 on the shuttle Atlantis, will float into Jupiter's atmostphere and disintegrate in the heat. The NASA events surrounding Galileo's final day will be webcast live.
It seems like the space program can do no right these days, but the story surrounding Galileo is an amazing one and reflects the heroic resourcefulness of teams of smart people trying to overcome one crisis after another. The first problem was how to get the satellite to Jupiter. The use of certain types of propellent on the satellite was rejected because of the risk of carrying that propellent up in the shuttle.
A scientist devised an ingenius method for overcoming this problem. Instead of launching the satellite towards Jupiter, he proposed launching it in the other direction, towards Venus, where it would use the gravitational pull of Venus as a slingshot. Another scientist built on this idea and proposed that Galileo then hurtle back towards Earth where it would circle Earth twice, using Earth's gravitational pull as a slingshot as well, multiplying its speed enough to whip around and shoot across the gap to Jupiter. Ingenious.
But then, soon after Galileo was launched, another problem arose. The high gain antenna on Galileo was stuck for some reason and would not open. The low gain antenna could not send information quickly enough, putting the entire value of the project at risk. Just as in Apollo 13, teams were formed to work around the problems. One worked to try and free the high gain antenna, and another team to see if the software on Galileo could be rewritten to improve the throughput of data from the remaining systems on board.
The high gain antenna was never fixed, but the other team managed to beam up completely new software, taking advantage of additional memory modules and advances in software design. In addition, a tape recorder that had been installed on board for backup was repurposed as a cache to store data being collected by the satellite but that couldn't be beamed back through the low gain antenna quickly enough to free up memory. This cache would store this data for beaming back during downtime between Galileo's intense data collection assignments. This all had to happen as the satellite was in space, on its way through space. Amazing!
The rest is history. Galileo became the first satellite to discover that asteroids can have their own moons (the asteroid was Gaspra, its moon Dactyl). It witnessed the comet Shoemaker-Levy 9 crashing into Jupiter, generating explosions more powerful than the largest hydrogen bomb. Ironically, because of Moore's Law, Galileo has had to do all of this with computing power dwarfed by that of your average child's video game console today.
It's a reminder of the promise of the space program. There are a few events which, if witnessed during my lifetime, would fundamentally alter my entire world view (no, I'm not referring to a Cubs victory in the World Series, though the Astros can start losing anyday now, okay?). For example, a catastrophic nuclear war. Another country dethroning U.S. as the pre-eminent superpower (China?). And the discovery and contact of extra terrestrial intelligence or beings. Someday, and perhaps unexpectedly, we may confirm we are not alone in this universe, and perhaps that will unite us all as human beings.