At the moment there are more and more reports about asteroids that come close to colliding with the earth. As recently as on October 10, 2019, ESA extended its list of risks to include asteroid “2019 SU3”, which could potentially hit the earth in September 2084. In July asteroid “2019 OK” passed the earth almost without being detected. And the “God of Chaos” also caused some consternation as this asteroid is expected to pass us at a distance of only 30,000 km, thus coming dangerously close to the earth. What can we do to protect ourselves from these risks? OHB System AG, a subsidiary of aviation and space group OHB SE, has been exploring this question for some time. Mark Fittock, project manager for the asteroid defense mission Hera, has agreed to answer some of the open questions about asteroids.
Mr. Fittock, there has recently been an increase in the number of reports of asteroids coming perilously close to the earth. What is the reason for this?
Mark Fittock: The main reason for the increased occurrence of asteroids is not that there are more of them but that we can determine their position with greater precision due to advances in technology. Thanks to the progress we have made in detecting and tracking asteroids, we know where they are and where they are heading. Obviously, awareness of these celestial bodies has risen in recent years. In my opinion, this has to do with the fact that our understanding of the risks associated with asteroids has also improved. Now we need to know more about how we can respond to these risks.
We do not want to be in a position in which we simply have to accept our fate. Rather, we want to be able to take our fate into our own hands.
What are these risks? Is it really necessary to develop an asteroid defense system? After all, we have survived the last millennia without such a system...
Fittock: Generally speaking, the greatest risk is that we practically have no response to asteroids at the moment. So if an asteroid were to be heading for the earth, we would be completely at its mercy. So far, we can only observe asteroids and determine where they are. Despite the technical progress that has been made over the last few years, some asteroids still occasionally go undetected. So, we need to improve this aspect. On the other hand, we urgently require a solution in the event that an asteroid is on a collision course with the earth. So far, we have simply been lucky, something which cannot be said of the dinosaurs in earlier times ... We do not want to be in a position in which we simply have to accept our fate. Rather, we want to be able to take our fate into our own hands. That is why asteroid defense missions are so important. It is a question of understanding what we can do in response to asteroids that are headed in our direction.
In the sci-fi classic “Armageddon”, the earth is threatened by an approaching asteroid. Ultimately, the asteroid is blown up. What asteroid defense options do we have in the future?
Fittock: There are several options when it comes to asteroid defense. On the one hand, these depend on how much lead time we have, i.e. how long we know in advance that an asteroid is approaching the earth. On the other hand, the methods available to us depend on the size of the asteroids. If we have sufficient advance warning and the asteroids are relatively small, there are some relatively simple steps that we can take: We can send a space probe to the asteroids to give them a small “push” in the right direction. In this way we can deflect them to make sure that they do not collide with the earth. In the case of somewhat larger asteroids a more forceful impact is required. Ultimately, the larger the asteroids are, the more difficult it is to deflect them. So, we will need to take increasingly drastic measures but we certainly don’t want to do this Armageddon-style by exploding asteroids! Indeed, this would be far too dangerous in view of the risk of subsequently being hit by one or more of the fragments of the asteroid. We do not want to expose ourselves to this danger. Enormous distances are always involved in the vastness of space. This means that a“push” at the right time in the right direction is sufficient to avert the risk of an asteroid impact.
OHB has been conducting research in this area for some time. What contribution is it making to asteroid defense?
Fittock: OHB intends to participate in the “AIDA” collaboration by providing a Hera spacecraft for ESA. “AIDA” stands for Asteroid Impact Deflection Assessment. One part of this collaboration involves the exploration of a binary asteroid system known as “Didymos”. This asteroid system consists of a larger body (“Didymos A”) and a smaller one (“Didymos B”), which orbits Didymos A like a moon. NASA will initially be approaching Didymos B with its DART (Double Asteroid Redirection Test) space probe to give it a good shove, thus altering its orbit around Didymos A. It will be possible for us to observe this maneuver from Earth. This will give us some information on this method of asteroid defense. However, this information is probably not sufficient to inform us on how to effectively protect us in the future. That is where Hera comes in: Assuming that we are awarded the ESA contract, the Hera spacecraft will be assembled by OHB System AG in cooperation with GMV, SpaceBel, QinetiQ and OHB Italia. Hera’s task will be to investigate the effect of DART on Didymos B in order to gain greater insight using various cameras and scientific instruments.
And why exactly is this pair of asteroids being examined?
Fittock: The two asteroids are close enough to the earth for them to be observed closely, but far enough away that they pose no danger to us. So there is no risk of the asteroid pair being deflected in our direction and hitting the earth. Nevertheless, they are close enough to be investigated effectively, something which is of elementary importance for the mission. The most important thing here is the timing: DART and Hera must be launched to coincide with the best time for observing the asteroid pair.
What significance does the collaboration have for future research?
Fittock: This collaboration is vital if we are to protect our planet. It will allow us to assess the effectiveness of the asteroid defense method and to see whether other approaches are needed and how we can best make use of the technologies currently available to us. The collaboration is also of particular importance with regard to our understanding of the composition of the asteroids. One purpose of the Hera mission is to understand what asteroids of this scale and form are made of. This is, of course, something that goes far beyond the mission. However, all asteroid missions conducted in recent years have tried to find out more about what asteroids are made up of. Once we have a better understanding of their composition and know the impact of asteroid deflection, we will be able to plan our missions more effectively and achieve better protection of our planet.
So, Hera will be performing investigations of the asteroid?
Fittock: Exactly, Hera will have several payloads on board. These will include various optical cameras to take precise pictures of the craters and to investigate the impact of the DART mission. In addition, Hera will be transporting two “cube-sats”, i.e. mini-satellites. These will be released from the spacecraftand carry out experiments autonomously. The data they collect will then be sent back to Earth via Hera. To ensure accurate data collection, it is important for all payloads to work in sync. DART and Hera will be the first missions to visit and explore an asteroid pair! This will be very exciting for the scientific community, not only because these asteroids have a certain resemblance to the recently launched missions (such as NASA’s OSIRIS-REx mission), but also because the existence of an orbiting moon clearly sets them apart from other missions. Being able to compare this structure and composition with other asteroid missions will give us a better understanding of the asteroids in our solar system.
What work has been completed so far? What are the special challenges in assembling this space probe?
Fittock: The previous phase of the project was about adapting the mission in the light of the launch possibilities we have. In this respect we are quite limited because the asteroid pair will be moving away from us. This is making the mission a little more difficult for us. We want to make use of the opportunity to fly to the asteroid system while we are still able to communicate conveniently with the earth. That has been our main task so far: to adapt the mission to meet the limited launch options available. Compared to other projects, the launch opportunities are very limited. This makes it all the more important to utilize elements that really work. We need to know how to assemble the spacecraft successfully to meet our launch date in 2024.
Congratulations on reaching the first milestone in the project on September 30, 2019. What’s the next step?
Fittock: Thank you. We had the B2 kick-off for the industry team on Monday, September 30, 2019. This is very important for us so that we can start the next phase of the project. In this phase we will be bringing together some of the various elements of the mission. So far, we have mainly been working on the design of the spacecraft itself. Now we will be expanding the team who are working on the spacecraft to determine exactly how best to execute this mission. We will also be liaising with the various payload teams. This means that we will be determining what potential payloads we can include and how best to get them to Didymoon on board the spacecraft so that we can work out the best methods to protect Earth in the future.
We thank Mark Fittock for this interesting interview.
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