In October, the announcement that the first interstellar asteroid triggered a flurry of emotion. Since that time, astronomers have made follow-up observations of the object known as 1I / 2017 U1 (also known as & # 39; Oumuamua) and have noticed some very interesting things about it. For example, from rapid changes in its brightness, it has been determined that the asteroid is rocky and metallic, and has a strange shape.
Observations of the asteroid's orbit have also revealed that it made its closest pass to our Sun in September 2017, and is currently returning to interstellar space. Due to the mysteries that this body has, there are those who defend that it is intercepted and explored. One of these groups is Project Lyra, which recently published a study detailing the challenges and benefits that such a mission would present.
The study, which appeared recently online under the title "Project Lyra: sending a spacecraft to 1I / & # 39; Oumuamua (formerly A / 2017 U1), the Interstellar Asteroid", was made by members of the Initiative for Interstellar Studies (i4iS), a voluntary organization 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 recapitulate, when Oumuamua was first observed on October 19, 2017, by astronomers using the University of the Panoramic Study Telescope and the Rapid Response System of Hawaii (Pan-STARRS), it was initially he believed that the object (then known as C / 2017 U1) was a comet. However, later observations revealed that it was actually an asteroid and was renamed 1I / 2017 U1 (or 1I / 'Oumuamua).
Follow-up observations using ESO's Very Large Telescope (VLT) could impose restrictions on the size, brightness, composition, color and orbit of the asteroid. These revealed that Oumuamua measured about 400 meters (1312 feet) long, is very elongated and rotates on its axis every 7.3 hours, as indicated by the way in which its brightness varies by a factor of ten.
It was also determined to be rocky and rich in metals, 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.
Since this asteroid is extrasolar in nature, a mission that would be able to study closely could certainly tell us a lot about the system in which it was formed. Their arrival in our system has also raised awareness of extra solar asteroids, a new class of interstellar object that astronomers estimate to reach our system at the rate of approximately one per year.
Because of this, the team behind the Lyra Project believe that studying 1I / & # 39; Oumuamua would be a once-in-a-lifetime opportunity. As they say in their study:
"As 1I / & # 39; Oumuamua is the closest macroscopic sample of interstellar material, probably with an isotopic signature distinct from any other object in our solar system, the scientific benefits of object sampling The detailed studies of interstellar materials at interstellar distances are probably decades away, even if Breakthrough Initiatives' Starship Project, for example, is pursued vigorously.Therefore, an interesting question is whether there is a way to exploit This unique opportunity sending a spacecraft to the Oumuamua to make observations at close range. "
But, of course, meeting this asteroid presents many challenges. The most obvious one is the speed and the fact that 1I / & # 39; Oumuamua is already on the way out of our Solar System. Based on calculations of the asteroid's orbit, it has been determined that 1I / 'Oumuamua travels at a speed of 26 km / s, which is equivalent to 95,000 km / hour (59,000 mph).
No mission in the history of space exploration has traveled so fast, and the fastest missions to date have been able to manage only about two thirds of that speed. This includes the fastest spacecraft to leave the Solar System (Voyager 1) and the fastest spacecraft at launch (the New Horizons mission). So, creating a mission that could achieve it would be a great challenge. As the team wrote:
"This [is] considerably faster than any object that humanity has thrown into space, Voyager 1, the fastest object that mankind has ever built, has a surplus hyperbolic velocity of 16.6 km / s As 1I / & # 39; Oumuamua is already coming out of our solar system, any spacecraft launched in the future would have to chase it. "
However, as they continue to claim, assume this The challenge would inevitably result in key innovations and developments in space exploration technology. Obviously, the launch of such a mission would have to happen sooner rather than later, given the fast pace of the asteroid's travel. But any mission that is launched within a few years will not be able to take advantage of subsequent technical developments.
As noted by the famous writer Paul Glister, one of the founders of the Tau Zero Foundation and the creator of Centauri Dreams. on its website:
"The challenge is formidable: 1I / & # 39; Oumuamua has a surplus hyperbolic speed of 26 km / s, which translates to a speed of 5.5 AU / year. of Saturn's orbit within two years, this is much faster than any object that humanity has ever thrown into space. "
As such, any mission mounted on 1I / & # 39; Oumuamua would involve three notable exchanges. These include the compensation between the travel time and delta V (that is, the speed of the spacecraft), the compensation between the launch date and the travel time, and the compensation between the launch date / travel time and the characteristic energy. The characteristic energy (C3) refers to the square of the hyperbolic excess velocity, or the velocity at infinity with respect to the Sun.
Last but not least, it is the compensation between the excess speed of the ship in the launch and its excess velocity relative to the asteroid during the encounter. Speeding is preferable at launch, as it will result in shorter travel times. But excessive excessive speed during the encounter would mean that the spacecraft would have less time to make measurements and collect data on the asteroid itself.
With all that was considered, the team considers several possibilities to create a spacecraft that would depend on an impulsive propulsion system (that is, one with sufficiently short thrust). In addition, they assume that this mission would not involve any planetary or solar flight, and would fly directly to IO / & # 39; Oumuamua. From this, some basic parameters are established and then established.
"To sum up, the difficulty of reaching 1I / & # 39; Oumuamua is a function of when to launch, the hyperbolic hyper speed and the duration of the mission," they indicate. "Future mission designers would need to find appropriate tradeoffs between these parameters.For a realistic launch date in 5 to 10 years, the hyperbolic surplus speed is in the range of 33 to 76 km / s with a remote encounter. Pluto (50-200 AU). "
Last but not least, the authors consider several mission architectures that are currently being developed. These include those that would prioritize urgency (that is, launch within a few years), such as NASA's Space Launching System (SLS), which they said would simplify the design of the mission. Another is the Big Falcon Rocket (BFR) from SpaceX, which according to them could allow a direct mission by 2025 thanks to its refueling technique in space.
However, this type of mission would also require a Jupiter flyby to provide gravity-help. Looking for more long-term techniques, which would emphasize the most advanced technologies, also consider solar-powered sailing technology. This is exemplified by the Starshot concept of Breakthrough Initiatives, which would provide mission flexibility and the ability to react quickly to unexpected future events.
While this approach would imply waiting, the possibility of future encounters with an interstellar asteroid, would allow a quick response and a mission that could eliminate gravity aids. It could also allow a particularly attractive mission concept, which is to send small swarms of probes to meet the asteroid. While this would mean a significant investment, the value of the infrastructure would justify the expense, they say.
In the end, the team determined that further research and development is necessary, which supports the importance of the Lyra Project. As they concluded:
"[A] the mission to the object will stretch the limit of what is technologically possible today.A mission using a conventional chemical propulsion system would be feasible using a Jupiter flyby to help the gravity in a close encounter with the Sun. Given the right materials, solar candle technology or laser sails could be used … Future work within the Lyra Project will focus on analyzing different mission concepts and technology options in more detail and selecting 2 – 3 promising concepts for further development. "
It is an ancestral axiom that overwhelming challenges are essential for innovation and change. In this sense, the appearance of Oumuamua in our Solar System has stimulated interest in exploring interstellar asteroids. And although the opportunity to explore this asteroid might not be possible in the next few years, the arrival of future rocky intruders in our System might be achievable.
ESO observations show that the first interstellar asteroid is like nothing seen before
Arxiv : arxiv.org/ftp/arxiv/papers/1711/1711.03155.pdf