What is it like working at NASA?
Probably one of the more important things is that everyone must work together as a team. If you are launching the shuttle, designing a spacecraft, or running a science satellite, it's a very big job that involves many people. Some are scientists, some are engineers, computer programmers, managers, or secretaries. Everyone has his or her own point of view. A scientist doesn't talk about things or have the same concerns as an engineer or a computer programmer. But we all try to work together and learn each other's way of doing things. That is one of the things that I like. I have learned about instrumentation, engineering, computers, software, etc. by working at NASA. I enjoy that interaction between different people with various backgrounds. You get a chance to learn and grow.

What are the names of a few different NASA probes?
There have been many! NASA probes which have explored the solar system include Voyager 1 and 2 and Pioneer (I don't recall the numbers). Mariner went to Mars. Magellan visited Venus. Galileo is soon going to arrive at Jupiter. Some U.S. astronomy satellites include Einstein, Copernicus, Hubble Space Telescope, IRAS (for Infrared Astronomy Satellite), IUE (my satellite, the International Ultraviolet Explorer). ROSAT, EXOSAT, and Hipparcus are European astronomy satellites, while GINGA is a Japanese astronomy satellite. As you can see, I mostly know the astronomy satellites!

Does NASA use rockets any more?
We sure do. We use the Delta and the Atlas. The Europeans use the Ariane rocket, and the Russians have the biggest rocket. The shuttle is great at putting things into orbit around Earth, at about 300 to 400 miles above the surface, but you need more power to get higher or to leave Earth. One way to do this is to put an extra rocket motor on the space probe that you take up in the shuttle. Once the shuttle has put it into orbit, you fire the extra motor. If I recall correctly, they did this with Galileo. Another way is to put your probe into space with a big rocket. My satellite, the IUE, was launched on a Delta rocket.

When shuttles orbit Earth, why do they always orbit it ONE direction every time?
You're right. When we launch the shuttle (and most spacecraft) it always goes east. The reason is that Earth is rotating. When we go east, the rotation of Earth helps give us a "boost" so we can get up to the speed we need to go to stay in orbit. If we go west, then the rotation of Earth is working against us.

What happened to Skylabs 1, 2, 3? When were they done with their missions? Where did they go?
As you may know, Skylab was the U.S.'s first space station (although many people have forgotten about it). It was launched in May 1973. The first trio of astronauts visited it 11 days later, docking their Apollo spacecraft with Skylab. They had to try to repair problems with the solar panels and thermal shields. They stayed there for 28 days.

The Skylab 2 astronauts visited the station in July and stayed for 59 days. The last trio of astronauts arrived in November and stayed for 84 days into February 1974. They set the new endurance record for staying in space, and did many medical and scientific experiments. After this, no one visited Skylab again. Finally in 1979 Skylab fell to Earth. It had been in low earth orbit, and the slight atmospheric drag was enough to bring it lower and lower until it couldn't stay in orbit. Pieces of Skylab fell into the Indian Ocean and over Australia.

Please describe the Apollo 9 mission.
As far as I know, there were no big problems on that flight. Apollo 8 was the first to fly to the moon and come back. They didn't land (that didn't happen until Apollo 11). Apollo 9 flew from March 3 to 13, 1969. The crew was James A. McDivitt, David R. Scott, and Russell L. "Rusty" Schweickart. They called their command module "Gumdrop" and their lunar module "Spider" (all of the astronauts got to name their modules).

The Apollo 9 astronauts were the first to try piloting the lunar module in space, separate from the command module. While they were trying this, they drifted 100 miles away, so far away they couldn't be seen from the command module. This got everyone nervous but everything worked out fine. They were able to get back to the command module and practice docking with it. This was important to try out. When the later astronauts landed on the moon, the only way they could get home to Earth again was to dock their lunar module with the command module, then together they would travel back to Earth. If they couldn't join the modules again, they wouldn't get back!

They also tried out a new spacesuit by going on a space walk. The new suit had a built-in backpack life-support system. They orbited Earth 151 times before landing (they did not orbit the moon).

What went wrong with the Challenger?
As you know, the Challenger space shuttle exploded only a minute or two after it had lifted off from Kennedy Space Center. There was a very thorough investigation of this tragic accident. This was not easy since the pieces of the shuttle fell into the ocean, and they had to be found and brought back. Also there were lots of telemetry records (readings from the various instruments and sensors on the shuttle transmitted by radio) to examine for clues.

After this investigation, it was decided that probably an O-ring in one of the solid rocket boosters had leaked. An O-ring is a ring-shaped piece made of plastic, rubber, or some other flexible material that is used as a seal in lots of equipment. The leaking fuel caused an explosion that blew most of the shuttle apart. It was especially cold just before the launch and the cold may have made the O-ring too rigid. It may not have sealed the joint well enough.

If you did a shuttle mission and all you took up with you was as much air, food, and energy as you can, how long would you last? How far could you travel in that much time?
Well, I guess to set a record like this we would have to take only the minimum number of people needed for the crew — say, four people. Then we would pack up the shuttle bay with a special container full of water, food, oxygen, etc. I don't know if anyone has tried to figure this out before. On a normal mission they have kept the shuttle up for as long as two weeks. So in this case, I think they could stay up for several months, maybe six to nine months. This is pretty similar to the Russian space station, Mir. But it would get pretty boring up there with nothing to do but eat and sleep!

Typically the shuttle orbits Earth (circumference 25,000 miles) every 90 minutes. That's almost 17,000 miles per hour. In six months, it would go about 72,000,000 miles, most of the way from Earth to the sun! However the shuttle isn't equipped to leave Earth orbit.

What does a current Russian spacecraft look like?
Currently the Russians use the Soyuz spacecraft to get to the space station, Mir. Soyuz means "union," and has a docking capability so it can attach to the station. The launch vehicle looks like a white cylinder with a white funnel on top. This is pretty similar to our Gemini and Apollo spacecraft. At launch, the top of the spacecraft has to be aerodynamic so that the air and heat will flow smoothly past the tip. So they all look pretty much the same.

In orbit, that outer shell is shed. At the front is the round, silvery orbital module, with thin antennas protruding. In the middle is the descent module, and at the back is a white cylinder for the instruments and equipment, with attached solar panels. The three-jointed body reminds me of a giant ant with the wings at the back.

The Mir spacecraft is a collection of round silvery orbital modules and white cylindrical instrument modules. It looks like a toy set where you plug various pieces together. And that's just how they designed it to work! I have a great book that describes various spacecraft — Spaceflight: A Smithsonian Guide by V. Neal, C. S. Lewis, and F. H. Winten (Macmillan). You may be able to find this or a similar book at your school or local library. A picture would be worth 1,000 of my words describing how the spacecraft appear!

Can warp speed be achieved?
Sorry, but no. As far as we know, nothing can go faster than the speed of light (186,000 miles per second!). Warp speed on Star Trek and other science fiction shows is supposed to be much faster than that.

How far out in space could you travel in a space shuttle?
Not very far. The shuttle only goes up to "low earth orbit," which is several hundred miles up. By the way, the Hubble Space Telescope is in such an orbit, as are many other satellites. Communications satellites, some weather satellites, and my astronomy satellite, the IUE, are in "synchronous orbit." That means they are far enough out that they circle the earth once a day, which means they seem to hover over the earth (which is turning once a day, of course) in one spot. They are about 25,000 miles up.

For comparison, the moon is 250,000 miles away. When the Apollo astronauts visited the moon, they had to travel in very specially designed spacecraft so that they could safely go that far and come back.

What is the farthest a spaceship could go?
Right now the farthest that we have sent a spaceship that has people onboard has been to the moon. That's only 250,000 miles away. That seems far, but the sun is 93,000,000 miles away!

The farthest unmanned spaceships are the Pioneer and Voyager probes that visited Jupiter, Saturn, Neptune, and Uranus. They have crossed our entire solar system! That's 40 times the distance between Earth and the sun, or 4,000,000,000 miles!

How smart were the computers that helped launch the Saturn 5 rocket and Apollo 11?
In the late 1960s there were several big mainframe computers in use, including IBM, Xerox, and Univac. At that time there were no personal computers, no hand calculators, no workstations. Of course these "big" computers could do much less than computers today. A good personal computer today could probably out-computer those old computers!

I'll give you an example. We are still running my satellite, the International Ultraviolet Explorer, on a 30-year-old computer called a Sigma 5 (made by Xerox). It is a specially designed computer that can handle "real-time" activities like monitoring the data being sent from the satellite and sending commands to satellite. So it is from the Apollo era too. All the hardware from this computer fills a good-sized room. Today you could do what it does with a workstation and a few small boxes of electronics.

The computer onboard our satellite (which is 17 years old) has 8K of RAM. Your programmable hand calculator probably has more memory!

What amount of fuel is used by a shuttle flight?
The shuttle first uses its solid-rocket boosters (SRBs) — the two smaller rockets that are strapped onto the shuttle. Each of those SRBs contains a million pounds of solid propellant.

The shuttle itself has three rocket engines. During the launch, they use fuel from the big external tank strapped to the side of the shuttle. The tank contains 500,000 gallons of supercold liquid hydrogen and oxygen, which are mixed and burned in the shuttle's engines.

If you look at a picture of the shuttle on the launchpad, you can pick out the big external tank and the two solid-rocket boosters strapped to the shuttle.

We saw pictures of the Polar Lander being built and wanted to know why the men were wearing protective clothing.
The workers (women too) are wearing protective clothing to protect the Lander! Spacecraft are assembled in a "Clean Room," a room specially designed to keep all forms of dust and contamination (mold, ants, gas fumes...) out. People are also possible sources of contamination — hair, skin cells, sweat, sneezes — you name it! So the people who work in clean rooms must dress in protective gear.

When astronauts are close to the moon, is there a lag time between the transmission of the message and the reception of the message?
Yes, it takes a little over a second for a signal to travel from the moon to Earth (or vice versa). So if you were talking to someone on the moon, there would be a delay of over a second for your radio message to get to them and another delay of more than a second for their reply to come back to you.