Doubt Creeps Into Hayabusa 2’s Deliberate Go to To Its Subsequent Asteroid

In November 2019, Japan’s Hayabusa 2 mission departed the asteroid Ryugu after 1.5 years of observations. It had efficiently collected a pattern from the near-Earth object and in December 2020, the spacecraft returned the precious pattern to Earth. If its mission had ended there, it could’ve been deemed probably the most profitable and difficult missions ever performed.

However Hayabusa 2 nonetheless had 30 kg of xenon propellant remaining for its ion drives. JAXA, the Japan Aerospace Exploration Company, applied a mission extension. They directed the spacecraft to go to two extra asteroids. It might carry out a fly-by of the 500-meter 98943 Torifune in July 2026, coming to inside 100 meters of the asteroid. In July 2031, the spacecraft would rendezvous with 1998 KY26. On the time, astronomers thought that 1998 KY26 was about 30 meters in diameter, and rotating each 10.7 minutes.

Visiting KY26 was a chance to go to and perceive a small, decameter-sized asteroid. Whereas our information of bigger asteroids has grown as a result of we have sampled them and so they’re simpler to look at, these smaller asteroids are tougher to review. Asteroids maintain clues to the evolution of the Photo voltaic System and the way planets shaped, so that they’re essential scientific targets. Nevertheless, there’s one other compelling cause to review smaller ones like KY26. Each the Tunguska and Chelyabinsk impactors had been on this dimension vary, and so are most different potential impactors, so understanding KY26 is essential for planetary protection. Moreover, KY26 is about the identical dimension of the boulders noticed on the surfaces of the asteroids Itokawa, Ryugu, and Bennu, all of which have have been efficiently sampled.

These laptop 3D fashions of 1998 KY26 had been generated from information accessible in 1998. It took many years earlier than higher observations had been accessible. Picture Credit score: By NASA’s JPL Digital Picture Animation Laboratory. – [1]: Steven Ostro’s Homepage: 1998KY26Transferred from en.wikipedia to Commons by Consumer:Bulwersator utilizing CommonsHelper., Public Area,

New analysis means that Hayabusa 2 could also be restricted to observing KY26 and {that a} landing is inconceivable. The asteroid seems to be a lot smaller, and likewise rotating extra shortly, than thought. That would prohibit any contact.

The analysis is titled “Hayabusa2 extended mission target asteroid 1998 KY26 is smaller and rotating faster than previously known,” and it seems in Nature Communications. The lead creator is astronomer Toni Santana-Ros, a researcher from the College of Alicante in Spain.

“The superb story right here is that we discovered that the dimensions of the asteroid is corresponding to the dimensions of the spacecraft that’s going to go to it!” – Toni Santana-Ros, College of Alicante.

1998 KY26 was found, clearly, in 1998. Despite the fact that it is very small, it reached magnitude 16 throughout its shut strategy to Earth. It was solely 2 lunar distances away. Observations decided that its spin interval was solely 10.7 min, which was the quickest asteroid rotation charge ever measured at the moment. Observations additionally confirmed that its diameter was about 30m, plus or minus 10 m. With these measurements being the one revealed traits of the asteroid, JAXA selected it as a goal for Hayabusa 2’s prolonged mission.

The issue is that within the intervening many years, the asteroid by no means exceeded magnitude 24. Solely in 2024 did the asteroid attain magnitude 20.2 throughout one other shut strategy to Earth at 12 lunar distances. This was a chance to look at KY26 once more and to verify its traits. The brand new analysis is predicated on these observations.

“We discovered that the fact of the item is totally completely different from what it was beforehand described as,” stated lead creator Santana-Ros in a press release. The analysis staff’s new observations, mixed with earlier radar information, present that the asteroid is barely 11 meters vast. Additionally, it is rotation charge is sort of double the unique measurement. “In the future on this asteroid lasts solely 5 minutes!” Santana-Ros stated. It is a massive change from earlier measurements.

The left and proper columns every present a special technique of figuring out 1998 KY26’s form used within the analysis. The mannequin is proven from the attitude of every principal axis (X, Y, Z), that are three mutually perpendicular instructions that kind a right-handed coordinate system. The rotation axis is aligned with the Z axis. Each fashions present that 1998 KY26 is an uneven, reasonably elongated object. Picture Credit score: Santana-Ros et al. 2025. NatComm

“The smaller dimension and quicker rotation now measured will make Hayabusa2’s go to much more attention-grabbing, but in addition much more difficult,” stated co-author Olivier Hainaut, an astronomer at ESO in Germany.

“These outcomes counsel the necessity to reassess the scientific aims and mission operations of Hayabusa2, whereas additionally highlighting the worth of mixing a number of distant sensing methods for the research of decametre-scale objects,” the authors write of their analysis.

There is no doubt that Hayabusa 2 can nonetheless go to KY26. The go to is an opportunity to validate the way in which astronomers observe these small objects and the way the outcomes are greatest understood. Since objects on this dimension vary pose probably the most menace to Earth, understanding how their orbits evolve is essential for planetary protection. “Moreover, gaining insights into the non-gravitational forces performing on these our bodies will allow extra correct orbit predictions. This information is important for future planetary protection operations, the place it is going to assist establish and mitigate potential influence threats,” the authors write.

“Nevertheless, 1998 KY26’s smaller dimension, quicker rotation, and better albedo current challenges for mission operations,” the researchers clarify. For instance, a few of its devices require lengthy integration instances which may not be doable with such a fast rotation. However there’s six years till the spacecraft reaches the asteroid, so some planning might mitigate a few of the challenges.

JAXA will solely have a restricted alternative to get this go to proper. Hayabusa 2 can be on the finish of its gas when it reaches KY26, so effectivity can be key. Even when the spacecraft cannot contact down on the asteroid, the mission will nonetheless be successful as a result of it is going to be the one go to to a decameter-sized object. “We’ve by no means seen a ten-meter-size asteroid in situ, so we do not actually know what to anticipate and the way it will look,” stated Santana-Ros.

This artist’s illustration reveals Hayabusa 2 touching down and gathering a pattern from an asteroid. Will that be doable at 1998 KY26? Picture Credit score: By JGarry at English Wikipedia – Transferred from en.wikipedia to Commons by Drilnoth utilizing CommonsHelper., Public Area,

Past the mission itself, this analysis reveals how astronomers can characterize even small asteroids.

“The superb story right here is that we discovered that the dimensions of the asteroid is corresponding to the dimensions of the spacecraft that’s going to go to it! And we had been in a position to characterize such a small object utilizing our telescopes, which implies that we will do it for different objects sooner or later,” says Santana-Ros. “Our strategies may have an effect on the plans for future near-Earth asteroid exploration and even asteroid mining.”

“Furthermore, we now know we will characterize even the smallest hazardous asteroids that would influence Earth, such because the one which hit close to Chelyabinsk, in Russia in 2013, which was barely bigger than KY26,” stated Hainaut.

“If profitable, Hayabusa2 will present invaluable in situ information on a uncommon brilliant decametre object, providing distinctive insights into this class of asteroids,” the researchers conclude.