A team of researchers has proposed that the celestial object 1998 KY26, the intended target of Japan’s Hayabusa2 spacecraft, may actually be the derelict Soviet Mars probe Phobos 1. The hypothesis, detailed in a paper by Adam Hibberd of the Initiative for Interstellar Studies and senior author Abraham Loeb of Harvard University, suggests the object is a piece of artificial space junk rather than a natural asteroid, according to Skyatnightmagazine.
The Nature of 1998 KY26
Originally discovered in 1998 by the Kitt Peak National Observatory, 1998 KY26 has been categorized by some as a “dark comet.” Dark comets are a proposed class of objects that exhibit non-gravitational accelerations—similar to how gas jets nudge a comet’s trajectory—but show no signs of the outgassing, comas, or tails typically associated with comets, as described by Medium.
Several physical characteristics of 1998 KY26 have raised questions among scientists:
- Size and Shape: It is a small object, approximately 11 meters across, and is described as having a “quite elongated” shape.
- Reflectivity: It possesses an unusually high albedo of approximately 0.5 (with one source citing 0.52 ±0.08), making it much shinier than the Moon, which has an albedo of 0.12.
- Rotation: The object has an extremely fast spin, rotating roughly once every five minutes.
The Phobos 1 Connection
The Soviet mission Phobos 1 was launched in 1988 but was lost after a faulty command—specifically a missing hyphen in a typo—deactivated attitude thrusters. This caused the spacecraft to lose its solar arrays’ lock on the Sun and depleted its batteries, according to Futurism.
Researchers argue that the orbit of 1998 KY26 is uncannily close to the transfer trajectory Phobos 1 would have taken from Earth to Mars. To align the two orbits, the team proposes that the probe would have needed to fire its rockets twice: once on September 2, 1988, and again on May 19, 1996. The researchers note there is historical evidence that Phobos 1 did fire its rocket without being commanded shortly after the mission failed. The European Southern Observatory attempted to locate the probe three weeks after the failure but could not find it at the predicted coordinates.
Mission Stakes for Hayabusa2
The Japan Aerospace Exploration Agency (JAXA) originally used Hayabusa2 to explore the 900-meter-diameter asteroid Ryugu in 2018, returning samples to Earth in 2020. Because the spacecraft had remaining fuel, it was redirected to rendezvous with 1998 KY26 in July 2031. This will mark the first time a space mission encounters an object on the 10-meter size scale.
While mainstream astronomers hope the mission will reveal the nature of outgassing in dark comets, Avi Loeb suggests that if 1998 KY26 is found to be technological, it could support his theories regarding other interstellar objects, such as ‘Oumuamua. However, the object’s rapid spin may make it extremely difficult for Hayabusa2 to land.
Summary of Object Comparisons
| Feature | 1998 KY26 (Observed) | Phobos 1 (Hypothesized) |
|---|---|---|
| Size | ~11 meters | Comparable to spacecraft size |
| Albedo | High (~0.5) | Consistent with artificial material |
| Orbit | “Dark Comet” trajectory | Statistically compatible after two thrusts |
The researchers acknowledge the hypothesis is speculative, but they argue that the 2031 observations will be decisive in resolving whether Hayabusa2 will encounter a natural space rock or a robotic relic lost for four decades.
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