Monday, 25 July 2011 20:45
In January this year, NASA will launch a spacecraft, New Horizons, to distant Pluto and its moons, Charon, P1 and P2. This will be the initial reconnaissance of the planets in the outer solar system. A piano size spacecraft which will spend about six months taking pictures of Pluto and its moons and gather data to send back to Earth.
Dr. Alan Stern knows a lot about “New Horizons”. Not only did he win the call for proposals from NASA to design and lead the team of hundreds of scientists and engineers to build the spacecraft, he also got to name it. It's his spacecraft. I caught up with him on the phone before his flight to Baltimore in the days leading to the preparations for the launch on January 17, 2006. He talked about New Horizons, the goals of the mission, and his continued commitment to science education.
Dr. Alan Stern is a planetary scientist and an impressive author. He has published over 175 technical papars and 40 popular articles, and has given over 300 hundred technical talks and over 100 popular lectures and speeches about astronomy and the space program. Dr. Stern has also written two books, The U.S. Space Program after Challenger (Franklin-Watts, 1987), and Pluto and Charon: Ice Worlds on the Rugged Edge of the Solar System (Wiley 1997, 2005). His work has taken him to numerous astronomical observatories, to the South Pole, and to the upper atmosphere aboard high performance military aircrafts. Dr. Stern is also the Executive Director of the Southwest Research Institute's (SwRI's) Space Science and Engineering Division.
“As I waited for a streetlight to change near the intersection of Foothills and Arapahoe and looked west to the Rocky Mountains on the horizon, it just hit me. We could call it "New Horizons"— for we were seeking New Horizons to explore at Pluto and Charon and the Kuiper Belt.” —Alan Stern
Shadi: I would like to start by asking you to give us a little background on the New Horizons Project and how you came to be involved with the project.
Dr. Stern: There are many deep roots going back to as far as 1989. I was at the center of a group of individuals— scientists, who in 1989 were working with NASA to see how we could do a Pluto mission. That effort was fairly successful. In the early and mid-1990s NASA pursued Pluto missions but was not successful in building one [a mission]. This went through a number of versions and iterations. In late 2000, NASA became frustrated with all of its previous attempts which had not resulted in getting anything out of the design stage. So NASA went out for an open competition to industry, academia and the national centers for proposals to compete for a Pluto mission. I headed one of those proposals. I had been involved with NASA, heading various committees [for NASA] involved with instrument development. Our proposal was successful. We won, and that's how it came to be.
Shadi: This is such an exciting project. If you were to explain to the public why it is so important for us to do this project, what would you say?
Dr. Stern: I get that question all the time. First, from a scientific stand point, this is really the frontier of our solar system. The Kuiper Belt, where Pluto orbits, is really amazing. It is an undiscovered country, so to speak. I am in the middle of my life and when I was a boy, this large structure in the solar system was unknown. It has completely revolutionized our knowledge of the solar system, teaching us that dwarf planets are more common than normal planets; teaching us all kinds of fundamental paradigms—yet we have never been to this part of the solar system and this type of planet, to gain an understanding of our own solar system. I think that is the big picture— the scientific answer. This is a highly leveraged project, in terms of what a very small spacecraft could teach us about our own solar system and perhaps [help us] to rewrite the text books.
The other answer really has to do with leadership. Great nations do great things. Spain for example in 15th and 16th century was recognized for being an exploring nation, and I think the United States will go down history as being the first to do the reconnaissance of the planets, and this mission is really the capstone to that. By visiting Pluto, the last of the classical planets, we are really putting a capstone to the initial reconnaissance which the US has led from the beginning. It is part of what we do for posterity and to excite younger people to go into the technology fields—science and engineering, [and also] because it fuels our economy.
Shadi: What will this mission tell us about Pluto?
Dr. Stern: We are carrying a very broad array of instruments [on the spacecraft] that will allow us to map Pluto and its satellites, map its surface composition, map temperature across the surface, study the decomposition of surface structures, map the dynamics of the Pluto's atmosphere, look for smaller moons and rings and a whole variety of other things. These are very powerful instruments—probably the most powerful instruments we have ever flown on a first reconnaissance mission.
Shadi: How long does the trip to Pluto take?
Dr. Stern: This is the fastest spacecraft ever launched. We will reach Jupiter which the most recent spacecraft took four years to reach, in just 13 months. Even at that very high speed, it will take us at least nine and half years to reach Pluto. I say at least, because it depends on when we will launch in the month long window. The sooner we launch, the sooner we will arrive via the more direct route. If it takes us three or four weeks to get launched, it will take us 12 years to reach Pluto.
Shadi: How long will New Horizons'encounter with Pluto last?
Dr. Stern: About six months. So we will be doing a long study of the planet and Pluto's system.
Shadi: What happens after that?
Dr. Stern: The second objective of the mission is to study a variety of objects in the Kuiper Belt. As you probably know there are over 100,000 miniature worlds in the Kuiper Belt. We are going to visit a couple more after Pluto. That is our plan. Soon after we finish the closest portion of the flyby, we will fire engines and head off to the first of these so called Kuiper Belt objects. That will take a couple of years to fly to. That's very far from Pluto. Like the distance of the Earth to the Sun. Hopefully, we will fly on to the second Kuiper Belt object before we leave that portion of our solar system. Ultimately, the spacecraft will escape our solar system because it is traveling so fast that the Sun's gravity can not hold onto it.. It will escape into interstellar space. By the time that happens it will be a century or more from now and we don't expect it to be working.
Shadi: Who came up with the name “New Horizons”?
Dr. Stern: I chose the name. I can direct you to a piece on our website which includes the account of how I chose the name. http://pluto.jhuapl.edu/overview/piPerspectives/piPerspective_05_2005_1.htmlrspective_05_2005_1.html
Shadi: How long did it take you to design the whole project and the spacecraft, and how long did it take to build it?
Dr. Stern: We conceptualize it in a matter of weeks and that conceptualization ended up being very much what we built. That was in early 2001. The design phase continued, very detailed design—down to every component and every circuit board, the optics for every instrument, and literary a million lines of software code. The construction began in early 2003 and continued until April 2005 when the spacecraft was complete. It has been undergoing vigorous testing ever since.
Shadi: .You are someone who is very passionate about science education. This is obviously a very long project. I was wondering how you think this project could be a tool to educate the younger generation about space and science.
Dr. Stern: In several ways. First, this is a very high profile project, particularly for a robotic mission. I am told we have more invited guests and more hits on our websites than anyone can remember for a robotic scientific mission which has not been launched yet. By the time New Horizons reaches Pluto, half of the US population will not have even been born at the time when the last spacecraft reached planet Neptune 1989. So, it is attracting lots of attention and it is giving us a platform. Additionally we have a large education and public outreach program that I mandated as the part of the project. We are spending about 2% of the project or $2 million for education from working with school children to museum exhibits to public speaking.
Also, one of our scientific instruments has been built by students and that is the first time that has ever been done on any planetary missions. So we are putting a lot of different efforts together and we are getting a lot of benefit simply from the fact that it is a high profile project and is exciting people.
Shadi: What other areas of space and planetary science do you think we should research and invest in as a nation?
Dr. Stern: I think that there are really two. I think we are simply lacking in the knowledge of our sister planet Venus. We need to gain a better understanding of that world. And secondly, we are really falling behind in what we should be exploring in the outer solar system. We have many missions to Mars and the moon, orbiters to Mercury, missions planned to Venus. In the areas of missions to the outer solar system, we really have one mission on the books and that's New Horizons. Unlike the inner solar system where we have many missions planned out, the outer solar system has been left unexplored. We owe it to ourselves to send orbiters and probes and probably a second mission to the Kuiper Belt.
Shadi: We recently read about the discovery of the two new moons around Pluto. I know that you were the PI on that project too. Could you tell us a little about these new moons? Does the discovery of these two moons have any effect on the calculations you made and the trip New Horizons will be making to Pluto?
Dr. Stern: The two moons that were discovered recently are called P1 and P2 until we give them names. We will be naming them in the next month or two. We are also about to go back and look for companion moons, other small moons that are there. P1 and P2 orbit outside the orbit of Pluto's large moon, Charon. It takes them weeks to go around Pluto and they are relatively small about 100 miles across. We do not know precisely yet, because we do not know their surface reflectivity. We know their brightness only from Earth. From that we can make an estimate of their size. We do not know anything about their surface composition, but there is some information now which tells us they are different from one another. One is pretty red, and the other one is relatively neutral like the Earth's moon. We expect them to be icy because they are deep in the solar system where ice is the most common surface material. But we don't know that yet. That is only supposition. We think they were formed from one giant impact event in which Charon, Pluto's large moon, was formed. This is based on circumstantial evidence and clues which have to do with their orbital parameters that make them similar to Charon, and therefore suggesting that their origin was from the same event.
The discoveries of these moons will affect the to-do list, so to speak, and the schedule of activities in the Pluto system. Because now instead of two targets, Pluto and large moon Charon, we have at least four targets. So, it has complicated our fly-by plans but in a good way. It's like the dilemma of going on a vacation and finding out that there is more to do there, in a very limited time. So it is a good kind of problem we have.
Shadi: What are your hopes for the future in terms of where you want us to be in 10-20 years with respect to space explorations?
Dr. Stern: In 10 to 20 years, I hope to see three things. I hope that in 10-20 years time, we are on the hills of human return to the moon, so that we could then go on with humans to explore the solar system. I think this is our destiny. Second: I hope that in 10-20 years time space travel will become common place for the interested individual, the same way traveling to Antarctica or the top of Everest is possible for the interested individual today. I think that this is the beginning of a great transformation for space exploration in this millennium for our species. And finally, I hope we will have much more vigorous robotic explorations of the planets, particularly the places where humans can not go yet, to really understand our home the same way a baby does when it leaves its cradle. We are just emerging from that cradle, the cradle of the Earth as a species. These are my wishes and hopes.
Shadi: Dr. Stern, Thank you for talking to us today. This is a very exciting project. We wish you the best and will be watching the launch of New Horizons to Pluto.
"If I and my "Pluto underground" colleagues had known then what it would take, how many meetings, proposals, presentations, reversals, setbacks, and outright cancellations it would take to get that study turned into flight hardware at the launch pad, we probably would not have had the courage to take on the task. But who could have known? And so we began.................... Of course, it wasn't easy. But here we are, about 6,060 days, or 211 months later, and it's finally possible to say: "Next month, we set sail for Pluto."