List of unnumbered minor planets: 2003 U (290–379)

This is a partial list of unnumbered minor planets for principal provisional designations assigned during 16–31 October 2003. Since this period yielded a high number of provisional discoveries, it is further split into several standalone pages. , a total of 170 bodies remain unnumbered for this period. Objects for this year are listed on the following pages: A–E · F–G · H–L · M–R · Si · Sii · Siii · Siv · T · Ui · Uii · Uiii · Uiv · V · Wi · Wii and X–Y. Also see previous and next year.

U

|- id="2003 US291" bgcolor=#C2E0FF | 9 || || TNO || 7.1 || 158 km || single || 33 days || 24 Nov 2003 || 6 || align=left | LoUTNOs, other TNO || |- id="2003 UT291" bgcolor=#C2E0FF | 3 || || TNO || 6.4 || 174 km || multiple || 2003–2013 || 07 Oct 2013 || 15 || align=left | LoUTNOs, cubewano (cold) || |- id="2003 UV291" bgcolor=#C2E0FF | 4 || || TNO || 7.3 || 115 km || multiple || 2003–2017 || 23 Sep 2017 || 42 || align=left | LoUTNOs, cubewano (cold) || |- id="2003 UW291" bgcolor=#C2E0FF | 9 || || TNO || 6.3 || 189 km || single || 28 days || 20 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UX291" bgcolor=#C2E0FF | 9 || || TNO || 7.0 || 137 km || single || 28 days || 20 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UY291" bgcolor=#C2E0FF | 4 || || TNO || 7.21 || 120 km || multiple || 2003–2021 || 11 Jan 2021 || 17 || align=left | LoUTNOs, cubewano (cold), BR-mag: 1.39; taxonomy: BB || |- id="2003 UZ291" bgcolor=#C2E0FF | 4 || || TNO || 7.09 || 196 km || multiple || 2003–2021 || 05 Nov 2021 || 23 || align=left | LoUTNOs, cubewano (hot) || |- id="2003 UA292" bgcolor=#C2E0FF | 9 || || TNO || 6.1 || 207 km || single || 29 days || 20 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UB292" bgcolor=#C2E0FF | 3 || || TNO || 5.88 || 277 km || multiple || 2003–2021 || 03 Oct 2021 || 30 || align=left | LoUTNOs, other TNO || |- id="2003 UC292" bgcolor=#C2E0FF | 9 || || TNO || 6.9 || 143 km || single || 28 days || 20 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UD292" bgcolor=#C2E0FF | 9 || || TNO || 6.6 || 164 km || single || 29 days || 21 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UE292" bgcolor=#C2E0FF | 9 || || TNO || 6.7 || 190 km || single || 29 days || 21 Nov 2003 || 4 || align=left | LoUTNOs, other TNO || |- id="2003 UF292" bgcolor=#C2E0FF | 9 || || TNO || 7.3 || 144 km || single || 28 days || 20 Nov 2003 || 4 || align=left | LoUTNOs, other TNO || |- id="2003 UG292" bgcolor=#C2E0FF | – || || TNO || 7.0 || 204 km || single || 59 days || 21 Dec 2003 || 7 || align=left | LoUTNOs, cubewano (hot) || |- id="2003 UH292" bgcolor=#C2E0FF | E || || TNO || 7.7 || 99 km || single || 27 days || 20 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UK292" bgcolor=#C2E0FF | E || || TNO || 7.2 || 125 km || single || 28 days || 21 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UL292" bgcolor=#C2E0FF | E || || TNO || 7.3 || 119 km || single || 28 days || 21 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UM292" bgcolor=#C2E0FF | E || || TNO || 7.0 || 166 km || single || 28 days || 21 Nov 2003 || 4 || align=left | LoUTNOs, other TNO || |- id="2003 UN292" bgcolor=#C2E0FF | 4 || || TNO || 7.5 || 105 km || multiple || 2003–2016 || 04 Feb 2016 || 16 || align=left | LoUTNOs, cubewano (cold) || |- id="2003 UO292" bgcolor=#C2E0FF | E || || TNO || 7.4 || 157 km || single || 30 days || 21 Nov 2003 || 4 || align=left | LoUTNOs, plutino? || |- id="2003 UQ292" bgcolor=#C2E0F | E || || TNO || 7.0 || 188 km || single || 32 days || 24 Nov 2003 || 4 || align=left | LoUTNOs, plutino? || |- id="2003 UU292" bgcolor=#C2E0FF | 9 || || TNO || 8.2 || 108 km || single || 28 days || 21 Nov 2003 || 4 || align=left | LoUTNOs, plutino? || |- id="2003 UV292" bgcolor=#C2E0FF | 4 || || TNO || 7.39 || 157 km || multiple || 2003–2021 || 01 Dec 2021 || 21 || align=left | LoUTNOs, plutino || |- id="2003 UX292" bgcolor=#C2E0FF | 9 || || TNO || 6.6 || 164 km || single || 28 days || 20 Nov 2003 || 4 || align=left | LoUTNOs, cubewano? || |- id="2003 UY292" bgcolor=#C7FF8F | E || || CEN || 10.2 || 51 km || single || 29 days || 21 Nov 2003 || 4 || align=left | — || |- id="2003 UZ292" bgcolor=#C2E0FF | E || || TNO || 7.7 || 120 km || single || 28 days || 21 Nov 2003 || 4 || align=left | LoUTNOs, other TNO || |- id="2003 UK293" bgcolor=#C2E0FF | 2 || || TNO || 7.4 || 110 km || multiple || 2003–2017 || 16 Dec 2017 || 44 || align=left | LoUTNOs, cubewano (cold) || |- id="2003 UU294" bgcolor=#fefefe | 0 || || MBA-I || 19.1 || data-sort-value="0.45" | 450 m || multiple || 2003–2020 || 23 Nov 2020 || 26 || align=left | — || |- id="2003 UV295" bgcolor=#fefefe | 0 || || MBA-I || 19.6 || data-sort-value="0.36" | 360 m || multiple || 2003–2017 || 23 Sep 2017 || 19 || align=left | — || |- id="2003 UX295" bgcolor=#E9E9E9 | 0 || || MBA-M || 19.2 || data-sort-value="0.61" | 610 m || multiple || 2003–2020 || 12 Dec 2020 || 56 || align=left | Disc.: SpacewatchAdded on 17 January 2021 || |- id="2003 UP296" bgcolor=#d6d6d6 | 0 || || MBA-O || 17.15 || 2.1 km || multiple || 2003–2021 || 30 Dec 2021 || 48 || align=left | Disc.: SpacewatchAdded on 17 June 2021 || |- id="2003 UG297" bgcolor=#fefefe | 2 || || MBA-I || 18.1 || data-sort-value="0.71" | 710 m || multiple || 2003–2019 || 24 Nov 2019 || 44 || align=left | — || |- id="2003 UV297" bgcolor=#fefefe | 1 || || MBA-I || 18.9 || data-sort-value="0.49" | 490 m || multiple || 2003–2020 || 14 Dec 2020 || 24 || align=left | Disc.: SpacewatchAdded on 17 June 2021 || |- id="2003 UZ297" bgcolor=#d6d6d6 | 0 || || HIL || 16.3 || 3.1 km || multiple || 2003–2020 || 19 Jan 2020 || 74 || align=left | — || |- id="2003 UJ298" bgcolor=#fefefe | 0 || || MBA-I || 19.16 || data-sort-value="0.44" | 440 m || multiple || 2003–2021 || 30 Oct 2021 || 37 || align=left | Disc.: SpacewatchAdded on 5 November 2021Alt.: 2014 WB225 || |- id="2003 UB299" bgcolor=#fefefe | 0 || || MBA-I || 19.33 || data-sort-value="0.40" | 400 m || multiple || 2003–2022 || 07 Jan 2022 || 38 || align=left | — || |- id="2003 UR301" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.76 || data-sort-value="0.99" | 990 m || multiple || 2003–2021 || 29 Nov 2021 || 67 || align=left | Disc.: SpacewatchAdded on 5 November 2021 || |- id="2003 UF302" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.3 || 1.2 km || multiple || 2003–2019 || 28 Feb 2019 || 35 || align=left | — || |- id="2003 UW302" bgcolor=#d6d6d6 | 1 || || MBA-O || 18.4 || 1.2 km || multiple || 2003–2019 || 01 Nov 2019 || 22 || align=left | Disc.: SpacewatchAdded on 17 June 2021Alt.: 2019 QD66 || |- id="2003 UD303" bgcolor=#d6d6d6 | 1 || || MBA-O || 17.9 || 1.5 km || multiple || 2003–2020 || 14 Nov 2020 || 42 || align=left | Alt.: 2014 SW6 || |- id="2003 UF304" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.1 || data-sort-value="0.71" | 710 m || multiple || 2003–2007 || 09 Oct 2007 || 24 || align=left | Alt.: 2007 TJ75 || |- id="2003 UR304" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.28 || 1.2 km || multiple || 2003–2021 || 09 Oct 2021 || 46 || align=left | Disc.: SpacewatchAdded on 30 September 2021Alt.: 2021 PH71 || |- id="2003 UL305" bgcolor=#E9E9E9 | 1|| || MBA-M || 19.0 || data-sort-value="0.67" | 670 m || multiple || 2003–2020 || 10 Dec 2020 || 22 || align=left | Disc.: SpacewatchAdded on 17 June 2021Alt.: 2020 WH11 || |- id="2003 UT305" bgcolor=#d6d6d6 | 0 || || HIL || 16.2 || 3.2 km || multiple || 2003–2021 || 06 Jan 2021 || 48 || align=left | — || |- id="2003 UN306" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.3 || data-sort-value="0.65" | 650 m || multiple || 2003–2019 || 29 Oct 2019 || 67 || align=left | Alt.: 2015 TT21 || |- id="2003 UQ306" bgcolor=#d6d6d6 | 0 || || MBA-O || 18.0 || 1.4 km || multiple || 2003–2020 || 09 Dec 2020 || 36 || align=left | Alt.: 2014 SG45 || |- id="2003 UK307" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.60 || data-sort-value="0.80" | 800 m || multiple || 2003–2022 || 28 Jan 2022 || 27 || align=left | Disc.: SpacewatchAdded on 29 January 2022 || |- id="2003 UT308" bgcolor=#fefefe | 0 || || MBA-I || 18.76 || data-sort-value="0.53" | 530 m || multiple || 2003–2018 || 17 Nov 2018 || 48 || align=left | — || |- id="2003 UQ309" bgcolor=#d6d6d6 | 0 || = (887251) || MBA-O || 17.6 || 1.7 km || multiple || 2003–2021 || 15 Jan 2021 || 43 || align=left | — || |- id="2003 UB310" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.7 || 1.2 km || multiple || 2003–2021 || 05 Jan 2021 || 92 || align=left | Disc.: SpacewatchAdded on 17 January 2021 || |- id="2003 UH315" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.78 || data-sort-value="0.41" | 410 m || multiple || 2003-2024 || 26 Dec 2024 || 43 || align=left | — || |- id="2003 UJ315" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.4 || data-sort-value="0.62" | 620 m || multiple || 2003–2019 || 03 Jun 2019 || 42 || align=left | — || |- id="2003 UB318" bgcolor=#E9E9E9 | 2 || || MBA-M || 18.6 || data-sort-value="0.57" | 570 m || multiple || 2003–2015 || 09 Sep 2015 || 24 || align=left | — || |- id="2003 UN320" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.73 || 1.6 km || multiple || 2003–2021 || 02 Oct 2021 || 30 || align=left | Alt.: 2003 SC406 || |- id="2003 UX321" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.0 || 1.1 km || multiple || 2003–2020 || 15 Dec 2020 || 89 || align=left | — || |- id="2003 UL322" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.0 || 1.4 km || multiple || 2003–2017 || 16 Nov 2017 || 26 || align=left | — || |- id="2003 UQ322" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.07 || 1.4 km || multiple || 2003–2021 || 06 Nov 2021 || 46 || align=left | Disc.: SpacewatchAdded on 30 September 2021 || |- id="2003 US322" bgcolor=#fefefe | 1 || || MBA-I || 19.1 || data-sort-value="0.45" | 450 m || multiple || 2003–2020 || 12 Sep 2020 || 39 || align=left | Disc.: SpacewatchAdded on 17 June 2021Alt.: 2010 VT141, 2010 VX265 || |- id="2003 UM324" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.42 || data-sort-value="0.94" | 940 m || multiple || 2003-2024 || 30 Dec 2024 || 43 || align=left | — || |- id="2003 UY326" bgcolor=#E9E9E9 | 3 || || MBA-M || 18.9 || data-sort-value="0.70" | 700 m || multiple || 2003–2012 || 03 Nov 2012 || 20 || align=left | Alt.: 2012 UR39 || |- id="2003 UZ326" bgcolor=#d6d6d6 | 0 || || MBA-O || 17.6 || 1.7 km || multiple || 2003–2019 || 24 Dec 2019 || 41 || align=left | — || |- id="2003 UJ327" bgcolor=#d6d6d6 | – || || MBA-O || 18.4 || 1.2 km || single || 6 days || 23 Oct 2003 || 6 || align=left | — || |- id="2003 UC328" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.2 || data-sort-value="0.68" | 680 m || multiple || 2003–2020 || 18 Dec 2020 || 29 || align=left | — || |- id="2003 UW328" bgcolor=#E9E9E9 | – || || MBA-M || 19.1 || data-sort-value="0.45" | 450 m || single || 7 days || 24 Oct 2003 || 8 || align=left | — || |- id="2003 UM329" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.9 || data-sort-value="0.78" | 780 m || multiple || 2003–2015 || 28 Jul 2015 || 50 || align=left | — || |- id="2003 US330" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.42 || 1.8 km || multiple || 2003–2021 || 23 May 2021 || 45 || align=left | — || |- id="2003 UY332" bgcolor=#d6d6d6 | 0 || || MBA-O || 17.6 || 1.7 km || multiple || 2003–2019 || 21 Oct 2019 || 38 || align=left | Disc.: SDSSAdded on 22 July 2020 || |- id="2003 UG333" bgcolor=#d6d6d6 | 4 || || MBA-O || 17.6 || 1.7 km || single || 36 days || 23 Oct 2003 || 10 || align=left | Disc.: SDSSAdded on 29 January 2022 || |- id="2003 UR333" bgcolor=#fefefe | 0 || || MBA-I || 19.2 || data-sort-value="0.43" | 430 m || multiple || 2003–2019 || 01 Jun 2019 || 34 || align=left | Alt.: 2013 TR62 || |- id="2003 UW333" bgcolor=#E9E9E9 | 2 || || MBA-M || 18.5 || data-sort-value="0.84" | 840 m || multiple || 2003–2016 || 06 Oct 2016 || 51 || align=left | — || |- id="2003 UN334" bgcolor=#fefefe | 0 || || MBA-I || 19.0 || data-sort-value="0.47" | 470 m || multiple || 2000–2019 || 29 Jul 2019 || 60 || align=left | — || |- id="2003 UN335" bgcolor=#fefefe