# 2015 XF261

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Near-Earth asteroid

2015 XF261 Discovery[1] Discovery date 8 December 2015 (Initial reported obs.) Designations Minor planet category NEO Aten Orbital characteristics[2] Epoch 21 November 2025 (JD 2461000.5) Uncertainty parameter 1 Observation arc 2,991 days Aphelion 1.306 AU Perihelion 0.674 AU Semi-major axis 0.990 AU Eccentricity 0.319 Orbital period (sidereal) 0.985 years Mean anomaly 126.230° Mean motion 1.001°/day Inclination 0.794° Longitude of ascending node 209.818° Argument of perihelion 100.882° Earth MOID 0.00244 AU Jupiter MOID 3.928 AU Physical characteristics Absolute magnitude (H) 25.25[2]

**2015 XF261** is an [Aten](/source/Aten_asteroid)-type [near-Earth asteroid](/source/Near-Earth_object) with an estimated diameter of around 16 m (52 ft). It completes one orbit around the [Sun](/source/Sun) every 359.7 days, placing it near the 1:1 [mean-motion resonance](/source/Mean-motion_resonance) with Earth. It is the target asteroid for a planned asteroid redirect mission by the [China National Space Administration](/source/China_National_Space_Administration) (CNSA).

## Orbit

2015 XF261 is a [near-Earth asteroid](/source/Near-Earth_object) following an elliptical orbit around the Sun, with a [semi-major axis](/source/Semi-major_axis) of 0.99 [astronomical units](/source/Astronomical_unit) (AU), an [orbital period](/source/Orbital_period) of about 359.7 days, and an [orbital inclination](/source/Orbital_inclination) of 0.79°. Due to an [orbital eccentricity](/source/Orbital_eccentricity) of 0.32, its distance from the Sun varies from 0.67 AU at [perihelion](/source/Perihelion) to 1.31 AU at [aphelion](/source/Aphelion).[2] Since it is an Earth-crossing asteroid with a semi-major axis under 1 AU, it is classified as an [Aten asteroid](/source/Aten_asteroid).[2][3] Its orbital period nearly matches with Earth's, placing it in a near-1:1 [mean-motion resonance](/source/Mean-motion_resonance) with Earth.[4]: 2

## 2029 mission

2015 XF261 is the target for an asteroid-deflecting mission planned by China in 2029, launching in 2027, two years after its previous launch target of 2025. Its original target was [2019 VL5](/source/2019_VL5). The spacecraft is planned to be launched on a [Long March 3B](/source/Long_March_3B) in 2027, making a flyby of [Venus](/source/Venus) before arriving at the asteroid in early 2029, and colliding with the asteroid in April 2029 at an estimated speed of 10 km/s (6.2 mi/s).[5]

## See also

- [Double Asteroid Redirection Test](/source/Double_Asteroid_Redirection_Test) (DART), another asteroid-deflecting mission which collided with [Dimorphos](/source/Dimorphos)

## References

1. **[^](#cite_ref-MPC-object_1-0)** ["2015 XF261"](https://www.minorplanetcenter.net/db_search/show_object?object_id=2015+XF261). Minor Planet Center. Retrieved 9 November 2025.{{[cite web](https://en.wikipedia.org/wiki/Template:Cite_web)}}: CS1 maint: url-status ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_url-status)) (38 obs)

1. ^ [***a***](#cite_ref-jpldata_2-0) [***b***](#cite_ref-jpldata_2-1) [***c***](#cite_ref-jpldata_2-2) [***d***](#cite_ref-jpldata_2-3) ["JPL Small-Body Database Lookup: (2015 XF261)"](https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2015%20XF261) (2024-02-15 last obs.). [Jet Propulsion Laboratory](/source/Jet_Propulsion_Laboratory). Retrieved 16 April 2026.{{[cite web](https://en.wikipedia.org/wiki/Template:Cite_web)}}: CS1 maint: url-status ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_url-status))

1. **[^](#cite_ref-NEO-groups_3-0)** ["NEO Groups"](https://web.archive.org/web/20020202160655/http://neo.jpl.nasa.gov/neo/groups.html). NASA/JPL Near-Earth Object Program Office. Archived from [the original](https://neo.jpl.nasa.gov/neo/groups.html) on 2 February 2002. Retrieved 4 June 2012.

1. **[^](#cite_ref-Zhang2025_4-0)** Zhang, Nan; Wu, Di; Zhang, Zhong; Li, Haiyang; Baoyin, Hexi (April 2025). "Preliminary trajectory design of implementing the asteroid rendezvous and impact in a single launch". *Aerospace Science and Technology*. **159**. [doi](/source/Doi_(identifier)):[10.1016/j.ast.2025.109959](https://doi.org/10.1016%2Fj.ast.2025.109959).

1. **[^](#cite_ref-spacenews202407_5-0)** Foust, Jeff (16 July 2024). ["China reschedules planetary defense mission for 2027 launch"](https://spacenews.com/china-reschedules-planetary-defense-mission-for-2027-launch/). *spacenews.com*. Retrieved 23 July 2024.

## External links

- [2015 XF261](https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=3736497) at the *[JPL Small-Body Database](/source/JPL_Small-Body_Database)* - [Close approach](https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=3736497&view=C) **·** [Discovery](https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=3736497&view=D) **·** [Ephemeris](https://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=3736497) **·** [Orbit viewer](https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=3736497&view=V) **·** [Orbit parameters](https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=3736497&view=O) **·** [Physical parameters](https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=3736497&view=P)

- Zou, Yongliao; Xue, Changbin; Jia, Yingzhuo; Li, Mingtao; Xu, Haitao; Lyu, Bohan; Gu, Zhang; Tang, Yuhua; Chen, Qi; Wang, Chi (April 2024). ["小行星防御试验任务科学目标设计与有效载荷配置"](https://jdse.bit.edu.cn/sktcxb/en/article/doi/10.15982/j.issn.2096-9287.2024.20230020) [Scientific Objectives and Configuration Payloads of Asteroid Defense Test Missions]. *Journal of Deep Space Exploration* (in Chinese). **11** (2): 169–176. [doi](/source/Doi_(identifier)):[10.15982/j.issn.2096-9287.2024.20230020](https://doi.org/10.15982%2Fj.issn.2096-9287.2024.20230020).

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Adapted from the Wikipedia article [2015 XF261](https://en.wikipedia.org/wiki/2015_XF261) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/2015_XF261?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.