Frequently Asked Questions

General

How can I get a copy of Alan's books?
All of Alan's books can be ordered from most bookstores, the publisher, or internet retailers such as Amazon.com. Links to these sites are provided on the summary page for each book. Click on the "books" link at left and you're on your way.

When will the next course in my area be offered?
The schedule for each course is provided on the summary page for each course. With sufficient interest, Alan can schedule an on site course at your facility. Contact us if you'd like to explore this possibility.

Can Alan come speak to my group?
Yes. Alan is available to speak to groups across the country. It all depends on the schedule. Click on the speaking link and fill out our questionnaire to find out if he's available on the date in question.

About the Author

What’s your background? Why are you qualified to write a book on space exploration?
I’ve got what would be called a hard-core technical background. I have a B.S. in Physics from the University of Arkansas and a Ph.D. in Space Physics from the University of Iowa. I’ve spent a dozen years since then working in the aerospace industry. I worked at what is now Boeing’s Space Systems Division in California for about 8 years, providing support to a lot of satellite designs, like the Global Positioning System, and even the International Space Station. I’ve also led a number of research programs for NASA.

How did you first get interested in space?
When I was a little kid I got hooked watching the Gemini and Apollo missions. I remember shortly before my 8th birthday being glued to the TV when Neil Armstrong and Buzz Aldrin walked on the Moon on Apollo 11. By the time I was in High School Carl Sagan’s Cosmos TV series was on. That, and the telescope I got for my 16th birthday, pretty much got me hooked.

About A Tribble's Guide to Space

Why is this book different? What sets it apart from other space books?
It’s different in that its written by a rocket scientist who’s been in the trenches, trying to make spacecraft actually do what they’re supposed to do. There are a lot of books on space, but many of them are written by academics—who can be somewhat distanced from the day to day intricacies of how it works—or astronauts—who have an exciting job, but are the operators and not the designers. I think this book is unique in that regard.

Will this book appeal to everyone? After all, it is rocket science.
This book will appeal to anyone who has an interest in space exploration and wants to understand the technical challenges we face in getting there. It’s not science fiction where some one fantasizes about how exciting it could be if we can just invent a new kind of physics to make it possible, its science fact that tells people this is how it really works. I’m very pleased that I was able to do this in a non-technical manner that I think will appeal to people in their teens to seasoned veterans of the space program.

Why did you decide to write this book, and why now?
I’ve wanted to write a book like this for a long time. I’ve always had friends who liked space, and I’ve also done a lot of talks to kids in school. They are all fascinated by the idea of space exploration, but don’t have the time to spend years learning the intricate details. I thought a book that could explain the basics in a simple way would be a great way to share with them the excitement I feel. As far as why now, the timing just seemed right. The book will hit the shelves just a few weeks before the 100th Space Shuttle mission and the first crew going to the International Space Station. It’s a time of great accomplishments, and there’s more to come.

What’s this books main thrust?
The book's main chapters deal with:

Why will people want to buy this book? What will they know after reading it that they didn't know before?
It will give them a much better understanding of the who, what, when, where, why, and how about space exploration. It’s a good summary to the subject and a great starting point for people who want to learn more.

Space Exploration

Given all the problems we’re having down here, wouldn’t we be better served to reduce the money spent on space exploration and spend it on social programs instead?
That’s a very good question, but one that I think has a very good answer. If we compare the amount of money the U.S. spends on space exploration—the NASA budget—to social programs like Social Security, Medicare, and Medicaid we find that we spend 60 times more on social programs than we do on space. In fiscal year 2001, the NASA budget of $14B is only 1.6% of the $848B we'll spend on social programs. Another way to look at that is if we took the entire NASA budget and gave it to social programs it would fund Social Security, Medicare, and Medicaid for only 6 days. In 6 days those social programs wouldn’t be able to do much to solve the real issues about why people get to be old and don’t have any way to support themselves or pay for their medical needs. I’ve got an 83 year old grandmother who needs these programs and I’m all for them, but I've also got a 9 year old son who needs inspiration. NASA is an investment in our future. The stuff that NASA does is spent acquiring new knowledge or inspiring people to do things they never thought they could. Your tomorrow's are determined by what you do today. Space exploration is pure and simply an investment in tomorrow.

Why send people into space when robotic spacecraft usually cost less?
Robotic spacecraft, or satellites, usually cost much less because we can afford to take chances with them. Like the two Mars landers that went awry about a year ago. It was embarrassing to NASA, but being embarrassed is a heck of a lot better than taking chances with people’s lives. The question of people or satellites comes down to what are we trying to do. If we want to gather some scientific data, or broadcast radio and TV signals or cell phone calls, satellites will be the cheaper choice. In some situations, like the Galileo spacecraft that went to Jupiter, the environment is so harsh humans couldn't survive there. But what humans do best though is adapt to the situation and inspire other people. As Buzz Aldrin says on the cover of my book, A Tribble's Guide to Space, the real benefit of Apollo was not the rocks that were brought back but the involvement of masses of people, the impact it made on their lives, and the vision it provided them for the future. That’s something that the space program can do only if people get inspired to strive for something new.

What's the future of space exploration?
For the immediate future the big goal for the human exploration of space is the completion of the International Space Station. Exploration of the planets will continue with regular missions to Mars. The commercial world will continue to grow, with low Earth orbit constellations of communications satellites. Look for big increases in the use of remote sensing as well, with materials processing being close behind.

When will we go to Mars?
Gene Kranz, the former NASA Flight Director, says it will take us about 20 years to put humans on Mars and I’m inclined to believe him. In the past ten years the size of the aerospace industry has shrunk dramatically. What that means is we now have fewer people who know how to build space systems, and we have fewer companies that are even capable of doing it. The first step in getting to Mars would require us to spend about ten years re-building our infrastructure to even be able to address the challenge. Then we’d need another ten years to actually do it. To get to Mars we’d need to have rockets bigger than the Saturn V that was used to send Apollo to the Moon. We haven’t tried to build anything that big in almost 30 years, so it will take quite a while to remember how.

What kind of people are interested in space? Isn't space just for geeks and nerds?
Everybody’s interested in space. From the time you’re a tiny baby everybody looks at the stars, tries to learn the constellations, and wonder what’s there. Even if you choose a completely different career path, that basic curiosity about what’s out there stays with all of us our whole lives. You don’t lose the desire to learn about it. Over 3 billion people tuned in to watch the Olympics in Syndey. Everybody likes the Olympics because we all like seeing humans stretch their limits, it’s the same with space exploration—it stretches the limits of the human imagination.

Space Basics

How far is it to space?
Space is a lot closer than most people think. It’s only about 50 miles away, but the tricky part is that its straight up. Most of the stuff we associate with space, like the Space Shuttle, the Space Station, the Moon, the Sun, are farther away than that, but if we manage to go just 50 miles straight up we’ll be in space.

How much does a spacecraft weigh when it is in space?
One of the side effects of being in orbit is weightlessness. Strictly speaking a spacecraft isn’t truly weightless, it really does have weight, it's just “apparently” weightless. That is, the spacecraft has weight but it just can’t feel its weight. If you’re sitting in your chair or standing on the floor you can feel your weight, but if you were to jump off a tall building you’d feel weightless, (at least until you reached the ground). It’s the same with spacecraft, they feel like they’re always falling and as a result they can’t feel their weight. They are weightless.

What is the temperature in space?
When something gets put into space it draws heat in from its surroundings, and gives heat off to its surroundings, just like we do on the Earth’s surface. The big difference is that without any air to help heat you up or cool you down, the processes are a little different. In Earth orbit things typically heat up to about +120° F when they are exposed to the Sun. They cool off to about –70° F when they’re in the shade. This makes it especially difficult to design space suits to keep astronauts comfortable when they’re out on a space walk. If we move away from the Sun, things cool down just as if they were in the shade. If we go to deep space, far away from any stars, we’d cool down to about -450° F. Closer to the Sun, our temperature would go up dramatically, reaching about +10,000° F near the surface.

Isn’t space a perfect vacuum?
If we got to deep space, into the region between stars for example, we’d find that space was a far more perfect vacuum than we’d ever be able to create in the laboratory here on the Earth. But even in deep space there’s still some small amount of stuff there. If we go to where the International Space Station is, about 250 miles up, we find that there’s only about one one billionth the amount of air up there as opposed to what we find on the ground. On the ground though we’ve got about one million billion billion molecules in a square yard of air. One billion times less than that is still one million billion, and that’s a large number. As we move farther from the Earth this number drops dramatically, but we’d still find about 1 particle per cubic yard in deep space.

Is it true that a gigantic meteor could hit the Earth and destroy all life?
Yes. In fact, scientists tell us that’s probably happened to the Earth once or twice in the past 4 billion years or so. Most recently, about 65 million years ago, a ten mile meteor may have struck the Earth and ultimately caused the extinction of the dinosaurs. The large meteor crater in Arizona is proof positive that “large” meteors strike us regularly—on the astronomical time scale. While these things are possible, I wouldn’t waste any time worrying about it. The chances of it happening in your lifetime are so remote you’d be better off making plans to eat healthy foods, exercise, and take care of yourself as though you planned on living to 100.

Space Shuttle (STS)

How fast does the Space Shuttle travel?
To get into orbit, the space shuttle has to be traveling about 18,000 mph. That’s 5 miles per second, or 8 kilometers per second.

Can the Shuttle go to the Moon?
No. Even though the Shuttle must be moving 18,000 mph to get into orbit that’s too slow to allow it to get to the Moon. The Shuttle is still under the influence of the Earth’s gravitational field. To get beyond the Earth it would have to accelerate to escape velocity of about 25,000 mph. That’s how fast the Apollo spacecraft had to travel. To accelerate the Shuttle to that speed would require more fuel that the Shuttle can carry. It will never go to the Moon. In fact, the Shuttle only gets about 300 miles from the Earth at its farthest point.

How much fuel does the Shuttle use?
The Shuttle uses over 4 million pounds of fuel to get to orbit. About 94% of the total weight of the Space Transportation System, including fuel tanks and solid rocket boosters, is fuel.

Where in the sky can I see the Space Shuttle?
When the Shuttle is in orbit it often passes overhead and is visible as a bright star just before Sunrise or just after Sunset. The specific times and locations vary. To learn where you can see the Shuttle in your town you can check the NASA web site via the internet, or also places like heavens-above.com.

How much does the Space Shuttle cost?
The last Space Shuttle to be built was the Endeavour, which was built to replace the Challenger after it was destroyed in 1986. The Endeavour cost approximately $1.7 billion to build. If we tried to build another Shuttle today I'd guess it would surely cost more than $2.5 billion.

What happens to used spacecraft?
Most used spacecraft that carry people into space wind up in a museum or some kind of display. The Shuttle, which is reusable, is the exception to this rule since its still being used. Most used satellites are either left in orbit and forgotten, or burn up when they re-enter the Earth’s atmosphere.

International Space Station (ISS)

What will the international Space Station be used for?
The International Space Station will be an orbiting laboratory for long-term research. Key things they'll be looking for are how to use the absence of gravity to build purer, or better, materials - for semiconductors and medical uses as well. Medical Doctors will examine the long term effects of space on humans, a key element we must understand before continuing to Mars.

How much will the International Space Station cost?
NASA puts the cost to design and develop the station at somewhere between $22 - $24B. We'll spend another $13B or so maintaining it during its lifetime, so the total will be about $35B. Though it should be noted that some critics claim the true cost will be double this.

Where in the sky can I see the International Space Station?
In most locations, you should be able to see the International Space Station fly overhead several times each month. It looks like a bright, fast moving star and is visible just before Sunrise or just after Sunset. The best way to find out when you can see it is to check the NASA web site or places like heavens-above.com on the internet. These sites can tell you where to look and how bright the station will appear.

Hubble Space Telescope (HST)

Why is the Hubble Space Telescope able to take so much better pictures than ground based telescopes?
The HST is able to take better pictures because its above the Earth's atmosphere. That means its never cloudy, and we don't have to look through the turbulence and pollution that makes viewing difficult in many cities. Only about 25% of the light from a star makes it directly to the ground without being scattered in some way by the atmosphere. Putting the HST in orbit gets it above the air, which gives it a crystal clear view of space.

Astronauts

How do astronauts in space go to the bathroom and take care of their personal hygiene?
Astronauts brush their teeth just like they do on Earth. There is no shower on the Shuttle, so astronauts must make do with sponge baths until they return home. Each Space Shuttle has a toilet that can be used by both men and women. Designed to be as much as possible like those on Earth, the units use flowing air instead of water to move waste through the system. When Astronauts or Cosmonauts are on spacewalks in their space suits, they do it the old fashioned way, with diapers.

How can I become an astronaut?
The most basic requirement is a four year college degree in a technical field like engineering or physics, plus some on the job experience. The youngest person ever chosen for Astronaut training, Tammy Jernigan, was 26. Most astronauts are in their 30's when selected, and a few have been in their 40's. Don't forget, John Glenn's second ride into space happened when he was 78.

Other

What are black holes? White holes? Worm holes?
Black holes are predicted by Einstein’s General Theory of Relativity. Einstein showed that even light could be bent by a gravitational field. The larger the gravitational field the larger the bending. This affect is far too small to notice on a planet like the Earth, it takes something much larger like a star. Astronomers have shown that even smaller stars like our Sun can bend light a little. If we look for larger stars, we’d see the light get bent more and more. If the star gets massive enough the light gets bent completely around and gets sucked back in by the gravitational field. Because not even light can escape these incredibly massive objects they’re called black holes. It would take the mass of thousands of Sun-like stars to create a single black hole, so we only expect to find them near the center of galaxies. We have evidence that black holes exist in nature.

When physicists solve Einstein’s theory they actually find two mathematical possibilities, a positive and negative solution. The positive solution is the black hole. A point in spacetime where things enter, but don’t leave. The opposite solution, which is mathematically allowed by the equations, would be a point where things exit, but don’t come in. This is a white hole. The exact opposite of a black hole. We don’t have any evidence that they actually occur in nature.

If we have entrance points, black holes, and exit points, white holes, could they be connected? Some people think so and call this connection a worm hole.

What is " The Face on Mars"?
In 1976 the Viking 1 Mars orbiter took pictures of a region of the planet known as Cydonia that showed a small region that looked vaguely like a face carved into stone. Many people thought this was the sign of intelligent life on Mars in past times. Unfortunately, the face is nothing more than an eroded set of hills that just happened to have shadows falling in the right places to make it look vaguely face like. In 1998 the Mars Global Surveyor spacecraft took pictures of the same region that were ten times sharper than the Viking pictures. The new pictures showed nothing other than natural geological erosion. As Time magazine reported in its issue of April 20, 1998, “NASA took the first new pictures of the Face in two decades. The result: it doesn't look like a face anymore."

Why can’t we travel faster than the speed of light?
Einstein’s Special Theory of Relativity predicts that nothing, except light itself, can travel at the speed of light. It all comes from the fact that things get heavier as they move faster. As you get heavier it takes more fuel to accelerate you to a faster speed. As you get faster still you get even more massive, which requires even more fuel, and so on. It turns out that it would take an infinite amount of fuel to accelerate you to the speed of light, and an infinite amount of anything just isn’t available.

Why do spacecraft hatches open outward, and submarine hatches open inward?
The one word answer: pressure. Inside a spacecraft, the pressure from the air will push outward on the door. You’d think that would be a good reason to design the door to open inward, so that the pressure from the air keeps it closed. However, as we learned the hard way with the Apollo 1 fire, if the air itself is trying to push the door closed you can’t open the door when you need to. At normal atmospheric pressure of 14.7 lbs per square inch, (101 kPa), the force on a typical door in your house measuring 3 feet by 6 feet would be over 38,000 pounds. This is so great you couldn’t open it and get out if you needed to. To make sure people can get the doors open they design spacecraft hatches to open outward so that the air pressure will help push them open in an emergency.

Submarines have the opposite problem. The water pressure from outside wants to push the door in, so it would be nice to make the door open out so the water keeps the door closed. But if the door has to open outward, the submarine occupants would never be able to get the door open in an emergency. For that reason, they make submarine hatches open inward.

What do curveballs and satellites have in common?
They both spin to stabilize their motion. Curveballs curve because the pitcher puts a spin on the ball. As the ball spins through the air the motion of the air gives the ball a little push in one direction and the ball curves. It also gives the ball stability. When a pitcher throws a knuckleball it bounces all over the place. Satellites spin to make them easier to control. If you set a satellite spinning the axis of the spin stays pointed very accurately. If the satellite is designed not to spin even a small force can cause it to start wobbling.

Why did Mr. Scott, the Chief Engineer on the USS Enterprise, always need more power?
Because everything takes power. We sometimes forget this because power is often easy to come by. Need some electrical power to run your stereo, your TV, your air conditioner, your refrigerator, and whatever else you can think of? You just plug them into the outlet on the wall. But that power has to come from somewhere. It has to come from a power plant that is converting some other form of energy into electricity. If the plant stops working, you don’t get any power delivered to your house and you can’t do anything. On a spacecraft, when the engines stop working they aren’t generating any power. This means they can’t do those important things like filter the carbon dioxide out of the atmosphere, keep the inside of the spacecraft at a comfortable temperature, and so on. Mr. Scott always needed more power because everything Captain Kirk asked him to do took power, but in an emergency he rarely had a fully functioning spacecraft to generate the power with.