Viewing page 3 of 9

This transcription has been completed. Contact us with corrections.

Maybe the biggest question of all was whether on reentry it could reenter the atmosphere at Mach 25, and successfully fly like an airplane and slow itself down through hypersonic and supersonic and then subsonic flight.  Then could it land like an airplane on something that's sort of like a conventional runway and be used again and again?  So those first four flights were test flights.  We didn't carry any experiments nor satellites. 

The first four flights each had a crew of two astronauts only.  All of the astronauts who flew on those four flights were from the mid-1960s.  They had been around NASA for a long time.  There were the veterans of the program.  The reason they only had two astronauts on board those flights was really pretty straightforward.  They wanted to fly ejection seats just in case something went wrong either right after lift-off or just before landing, and only two ejection seats fit in the space shuttle.  They thought it would be kind of bad for morale to have a crew of four and only two ejection seats.  So the early flights only carried two astronauts.  

Once those flights were successfully completed, NASA declared the space shuttle operational and the crew was expanded to five.  That remains the standard space shuttle crew today.  That crew of five includes, usually, two pilots (people with test pilot background) and three scientists or engineers, who actually conduct the experiments and deploy the satellites once we're in orbit.

I want to quickly run through the sorts of things the space shuttle has done and can do.  I'm sure that many of you are at least as familiar with this as I am.  The shuttle has launched several communications satellites.  On my first flight, we launch two of them, one for the country of Indonesia and one for Telsat (satellite program).  So NASA has launched them both commercially and for other countries. 

There are also several missions that have been dedicated purely to science.  My second flight was an example of that.  We carried, as you heard, the earth radiation budget satellite.  That was one of three satellites that's been in orbit.  We launched in 1984.  It just died a couple of months ago.  So, it had a nice, long, extended life.  It was looking at the amount of radiation that comes at us from the sun, and also at the amount of radiation that the earth radiates back into space. 

For those of you who are familiar with this sort of thing or have been reading about it in the paper, that's in some sense a measure of the greenhouse effect.  That satellite is one of the very few ways that we've gotten data on global warming and the role of clouds in the warming of the planet.  Actually, it turns out that we've learned from this satellite that clouds overall tend to cool the planet.  I believe that right now. 

The shuttle also has deployed telescopes.  The Hubble Space Telescope is perhaps one semi-unfortunate example of that.  From the Hubble Telescope, we expect to get probably about 50 percent of the data that it was originally scheduled to gather.  If we can successfully repair one of the primary instruments or replace one of the primary instruments in a couple of years once the instrument is ready, we hope to get even more than that. 

The shuttle has also launched probes to explore other planets.  Galileo is on its way to Jupiter right now.  Ulysses—assuming that they've deployed it, which they're scheduled to do in about 20 minutes—is scheduled to study the sun.  It's doing that in an interesting way.  You may have read about this.  It's going to the sun by way of Jupiter, which doesn't seem like the most logical way to do things, but it's trying to study the north and south poles of the Sun.  Of course we're in the equatorial plane of the Sun.  So it turns out that to get this satellite into the right orbit, you have to send it to Jupiter and then let it swing around Jupiter down into an orbit that will take it first down below the Sun and then up above the

11