This article was written by Matt Williams for Universe Today.
Back in October, the announcement that the first interstellar asteroid triggered a flurry of excitement. Since that time, astronomers have conducted follow-up observations of the object known as 1I/2017 U1 (aka. `Oumuamua) and noted some rather interesting things about it. For example, from rapid changes in its brightness, it has been determined that the asteroid is rocky and metallic, and rather oddly-shaped.
Observations of the asteroid’s orbit have also revealed that it made its closest pass to our Sun back in September of 2017, and it is currently on its way back to interstellar space. Because of the mysteries this body holds, there are those who are advocating that it be intercepted and explored. One such group is Project Lyra, which recently released a study detailing the challenges and benefits such a mission would present.
The study, which recently appeared online under the title “Project Lyra: Sending a Spacecraft to 1I/’Oumuamua (former A/2017 U1), the Interstellar Asteroid“, was conducted by members of the Initiative for Interstellar Studies (i4iS) – a volunteer organization that is dedicated to making interstellar space travel a reality in the near future. The study was supported by Asteroid Initiatives LLC, an asteroid-prospecting company that is dedicated to facilitating the exploration and commercial exploitation of asteroids.
To recap, when `Oumuamua was first observed on October 19th, 2017, by astronomers using the University of Hawaii’s Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), the object (then known as C/2017 U1) was initially believed to be a comet. However, subsequent observations revealed that it was actually an asteroid and it was renamed 1I/2017 U1 (or 1I/`Oumuamua).
Follow-up observations made using the ESO’s Very Large Telescope (VLT) were able to place constraints on the asteroid’s size, brightness, composition, color and orbit. These revealed that `Oumuamua measured some 400 meters (1312 feet) long, is very elongated, and spins on its axis every 7.3 hours – as indicated by the way its brightness varies by a factor of ten.
It was also determined to be rocky and metal rich, and to contain traces of tholins – organic molecules that have been irradiated by UV radiation. The asteroid also has an extremely hyperbolic orbit – with an eccentricity of 1.2 – which is currently taking it out of our Solar System. Preliminary calculations of its orbit also indicated that it originally came from the general direction of Vega, the brightest star in the northern constellation of Lyra.
Given that this asteroid is extra-solar in nature, a mission that would be capable of studying it up close could certainly tell us a great deal about the system in which it formed. It’s arrival in our system has also raised awareness about extra-solar asteroids, a new class of interstellar object that astronomers now estimate arrive in our system at a rate of about one per year.
Because of this, the team behind Project Lyra believe that studying 1I/`Oumuamua would be a once-in-a-lifetime opportunity. As they state in their study:
“As 1I/‘Oumuamua is the nearest macroscopic sample of interstellar material, likely with an isotopic signature distinct from any other object in our solar system, the scientific returns from sampling the object are hard to understate. Detailed study of interstellar materials at interstellar distances are likely decades away, even if Breakthrough Initiatives’ Project Starshot, for example, is vigorously pursued. Hence, an interesting question is if there is a way to exploit this unique opportunity by sending a spacecraft to 1I/‘Oumuamua to make observations at close range.”
But of course, rendezvousing with this asteroid presents many challenges. The most obvious is that of speed, and the fact that 1I/`Oumuamua is already on its way out of our Solar System. Based on calculations of the asteroid’s orbit, it has been determined that 1I/`Oumuamua is traveling at a speed of 26 km/s – which works out to 95,000 km/hour (59,000 mph).
No mission in the history of space exploration has traveled this fast, and the fastest missions to date have only been able to manage about two-thirds that speed. This includes the fastest spaceship to leave the Solar System (Voyager 1) and the fastest spaceship at launch (the New Horizons mission). So creating a mission that could catch up to it would be a major challenge. As the team wrote:
“This [is] considerably faster than any object humanity has ever launched into space. Voyager 1, the fastest object humanity has ever built, has a hyperbolic excess velocity of 16.6 km/s. As 1I/‘Oumuamua is already leaving our solar system, any spacecraft launched in the future would need to chase it.”
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