Last year, astronomers detected the Near-Earth Asteroid (NEA) 2024 YR4 that orbits the Sun every four years and periodically crosses Earth’s orbit. The nature of its orbit makes it a Potentially Hazardous Object (PHO), meaning it could pose a collision risk with Earth someday. Recently, refined estimates of its orbit have ruled out the possibility that it will strike Earth in 2032. Nevertheless, there will likely be further close encounters with Earth well into the distant future.
This also presents opportunities for a close flyby mission to study YR4 up close, thus providing insight into the early Solar System. In a recent paper, Adam Hibberd and Marshall Eubanks explore the feasibility of various mission architectures. The mission could encounter the asteroid as early as 2028, but multiple launch windows are identified. This mission could also conduct a sample return, complementing the Hayabusa I and I, OSIRIS-REx missions, and future attempts to explore NEAs.
Adam Hibberd is a software and research engineer in Astronautics with the Initiative for Interstellar Studies (i4is) and the owner/director of Hibberd Astronautics Ltd. T. Marshall Eubanks is the Chief Scientist at Space Initiatives Inc. and the CEO of Asteroid Initiatives LLC. The draft version of their paper, “Preliminary Analysis into the Feasibility of Missions to Asteroid 2024 YR,” recently appeared online and will be submitted for publication soon.
Asteroids are essentially leftover material from the formation of the Solar System ca. 4.5 billion years ago. Therefore, studying these bodies can reveal tantalizing clues about how our system evolved and address major questions about how life emerged. This makes NEAs particularly interesting to scientists, as they are more easily reached than asteroids in the Main Belt or beyond. As Eubanks told Universe Today via email:
“Well, I personally doubt it’s primordial. I suspect it is a piece of an asteroid, probably knocked out of an orbit at ~4.18 AU (its aphelion). Getting a good look at it might help characterize objects in the currently poorly explored range between 2.77 AU (Ceres, which had a long-term visit from Dawn) and 5.2 AU (where the Jupiter Trojans are, and where Lucy is going).”
Multiple sample returns have been conducted with NEAs in recent years, leading to some very interesting revelations. This includes JAXA’s Hayabusa mission, which rendezvoused with the asteroid 25143 Itokawa in 2005, and Hayabusa2, which rendezvoused with 162173 Ryugu in 2018. Most recently, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) obtained samples from asteroid 101955 Bennu.
In addition to confirming that S-type asteroids are the source of the most common type of meteorites, the Itokawa samples also revealed the presence of water and extraterrestrial mineral grains. Meanwhile, the Bennu samples revealed comet particles and 20 different types of amino acids. The OSIRIS-REx sample, the largest ever returned to Earth (in September 2023), contained organic compounds and hydrated minerals. These samples support the theory that asteroids and comets were responsible for delivering water and the building blocks of life to Earth billions of years ago.
However, what makes YR4 a good candidate for future missions goes beyond science. As Eubanks indicated, its status as a PHO also means it could help inform planetary defense strategies. “It is a potentially hazardous asteroid that may still hit the Moon in 2032, and even if it doesn’t, it could certainly become an actual hazard in the future,” he said. “Characterizing it is important both in case it becomes a future hazard and (as the NASA Planetary Decadal survey states) a useful exercise to teach us better how to inspect these bodies.”
As part of their study, Eubanks and Hibberd explored various mission architectures that could rendezvous with YR4 up to and including its close encounter in 2032. This mission would exploit the software known as “Optimum Interplanetary Trajectory Software” (OITS) developed by Hibberd and the i4is. They also adopted the New Horizons as a reference mission as an example. However, their mission architectures were not limited to this or a 2032 launch window.
In particular, Eubanks explained how advancements in small satellite and gram-scale wafercraft could enable a low-cost mission that could fly as part of a larger mission:
“2024 YR4 presents us with an opportunity-rich environment, and one of the things that excites me here is that we could use small spacecraft – Cubesats or Disksats – to explore it. As a specific example, any CLPS or Artemis launch in mid-2028, for example, could potentially send a small nanospacecraft to YR4 in late December of that year (2028) using its lunar transfer orbit. Clearly, if we are going to routinely explore many of the PHA (and even prospect them for asteroid mining), this will have to be done with small spacecraft, and YR4 provides an opportunity to begin this process.”
The study of asteroids is a growing field, with missions to NEAs paralleled by the study of populations in the Main Belt and outer Solar System. In the coming years, missions to interstellar objects (ISOs)—like Project Lyra, another proposal from Eubanks and researchers with the i4is—could also be realized. The results of their investigations could not only expand our knowledge of the Solar System and how extrasolar star systems have evolved with time.
Further Reading: arXiv
