Defending the Planet from Asteroids - All in a Day’s Work at the HSE Lab
David W. Dunham, the famous American astronomer and NASA expert on asteroids is Academic Supervisor at the HSE International Laboratory of Space Research, Technologies, Systems and Processes. The HSE News Service asked him to tell us about working at the laboratory, what they do and what they hope to achieve.
— What are the goals and challenges for the Laboratory in the short and long term?
— It’s probably best to describe the long-term goals first. There are 3 major goals:
Defend the Earth from hazardous asteroids and comets. The dinosaurs perished because they had no astronomy or space programs, and the damage in Chelyabinsk last year underscores that there is a continuing threat from the numerous relatively small objects that pass near, and occasionally hit, the Earth. We have ideas for dealing with this problem, both to find objects that approach the Earth even from the direction of the Sun (like the Chelyabinsk meteor), and with enough warning, to deflect them away from the Earth.
Develop advanced spacecraft trajectory concepts that will enable humans to explore the Moon and interplanetary destinations, including asteroids that pass near the Earth, and Mars and its moons. By using “weak stability” regions where the gravitational attractions of the Sun, Earth, and Moon nearly cancel each other, and the large change in a spacecraft trajectory that a close swingby of the Moon can provide, we have already proven the basic concepts with robotic spacecraft. Using the same techniques with a station and an “interplanetary transfer vehicle” (ITV) placed in high-energy orbits, such as near the gravitational balancing point called “L2” above the far side of the Moon, only the cosmonauts and some supplies, but not most of the hardware, need to be moved out of the Earth’s deep gravity well; the ITV can then be sent to (and returned from) its destinations using much less fuel than standard methods that launch each time from the Earth, or from low-Earth orbit.
Develop a small constellation of satellites in elliptical “Molniya” orbits designed to optimally monitor high-latitude regions of the Earth (especially Russia, but also Canada, northern Europe, and other areas) for forest fires, ice and snow cover, and other problems.
The short-term goals are related to the long-term goals:
For protection against dangerous asteroids: Our laboratory has entered into discussions with Roscosmos, NASA, Emercom, and the US FEMA to promote the concept of a space telescope placed in orbit about the balancing point “L1” that is located 4 times the distance from the Earth to the Moon, in the direction towards the Sun, from which it can look back at the whole region around the Earth to find small asteroids that approach the Earth from the direction of the Sun, in order to provide about a day’s warning of Chelyabinsk-like meteors. We are also exploring the idea of moving small asteroids, in the same way as NASA’s Asteroid Redirect Mission, to use the leveraging effect of the Earth’s gravity to propel a small asteroid into the path of a larger threatening asteroid; the impact will deflect the dangerous asteroid away from Earth.
For human space exploration: Our first job is to complete tasks, begun late last year, to find trajectories that use the lowest possible amount of fuel to reach near-Earth asteroids and Mars from the “L2” balancing point region above the lunar far side. Then we need to write papers and present the results at international conferences. We have some additional tasks, to show how we can link these trajectories together with some specific examples for a truly re-usable ITV system.
We will present our concepts for monitoring the Earth from Molniya orbits, for finding forest fires while they are small, and monitoring other problems in high-latitude regions, to Emercom and other agencies and companies who might benefit from our proposed system. We also plan to present the information to corresponding agencies in Europe, Canada, the USA, and elsewhere to obtain some support and collaboration, to make it a truly international endeavor.
— How is it to work in an international research team? What are the advantages and benefits?
— Of course, it is interesting and challenging, taking a lot of effort, to do good research with students in both Russia and the USA. But we have also had many enjoyable experiences and have developed good friendships. We have established a collaboration with the University of Arizona, which allowed us to use their facilities for a successful course about our work in 2012. This year, we expect to begin work with 3 young Italian scholars; we look forward to this wider collaboration, to infuse their interesting ideas with ours, this will clearly promote and benefit the work of our laboratory to achieve the lofty goals described above.
— What are the latest achievements and scientific suggestions put forward by the Laboratory?
— I have described some of the achievements and suggestions in the short-term goals above:
We are exploring the idea of moving small asteroids, in the same way as NASA’s Asteroid Redirect Mission, to use the leveraging effect of the Earth’s gravity to propel a small asteroid into the path of a larger threatening asteroid.
For protection against dangerous asteroids: Last year, we gave presentations at 3 international conferences, held in the USA, 2 of them about our concept of a space telescope placed in orbit about the Sun-Earth “L1” balancing point to find small asteroids that approach the Earth from the direction of the Sun, and the other about using small asteroids as projectiles to deflect larger dangerous asteroids. Recently, we conducted a joint telecom about defense against dangerous asteroids with representatives from Roscosmos, Emercom, and the US counterpart agencies, NASA and FEMA. They endorsed our proposed concepts described above and established a working group to study them in more detail. We published a paper in Cosmic Research about the L1 satellite concept to warn Earth of impacts by small asteroids, and also a book about my past spacecraft orbit design work, and about the L1 satellite concept. Also, relating to asteroids, I published a paper in Planetary and Space Science about the size and shape of the Trojan asteroid (911) Agamemnon, determined mainly from my observations of an occultation of a star by that asteroid, and describing the discovery of a probable satellite of the asteroid.
For human space exploration: We computed a very low-cost trajectory, that starts from a “halo” orbit about the Earth-Moon L2 balancing point over the far side of the Moon, applies small propulsive maneuvers at strategic locations to use the gravitational leveraging that can be provided by the Moon and the Earth, then travels several million kilometers to fly by the interesting 200-meter near-Earth asteroid 1994 XL1, and returns to the Earth-Moon L2 halo orbit. This was accomplished with a total change in velocity of only 432 meters/second, less than 10 times the cost that it would take to accomplish the same task from a low-Earth orbit. Officials from NASA and other organizations were impressed by my presentation of this accomplishment at the International Astronautical Congress that was held in Beijing last September. We also conducted extensive studies of lower-cost trajectories to study the far side of the Moon, and presented those results at the international Space Flight Mechanics conference that was held in the USA in late January this year.
We have studied how high “Molniya” orbits can be used for studying the high-latitude regions of the Earth, to quickly find forest fires, dangerous ice conditions, and other problems. We have begun discussions with Emercom, which expressed an interest in the concept, and asked our laboratory to study other ways in which natural disasters can be studied from space.
— How often do you come to Moscow? What do you like about it and what not?
— I come to Moscow 4 to 6 times a year. I enjoy working with the professors, students, and administrators in the laboratory. It has enabled me to further my research interests, and establish contacts with collaborators around the world. I am impressed with Moscow’s metro system; in the US, I need a car for most errands, but one is not needed (and would be a liability) in Moscow.
There are many “Producti” and other small stores, within a short walk from anywhere in the city, where one can obtain groceries and most other necessities very conveniently. I don’t like the generally damp, cloudy, and cold weather; I grew up in sunny, warm California. But the summers in Moscow are pleasant, with many pleasantly warm, but not too hot, days in a row. The Russian language is very difficult to learn; I know many words now, but the grammar is almost impossible and unfortunately my work has kept me too busy to really learn the language. But most of the people I work with have a good knowledge of English, and my wife has been able to learn more Russian than me. Any problems are more than offset by the hospitality of my Russian hosts and colleagues.Anna Chernyakhovskaya, specially for the HSE news service
How dangerous are asteroids for the Earth? What technologies can we use to protect the planet? These and other questions were discussed at a two-day seminar ‘The Solar System and the Asteroid Threat’ at HSE MIEM.