UoSAT-4

{{Short description|Failed British Low Earth Orbit Satellite}}

{{Use dmy dates|date=April 2022}}

{{Infobox spaceflight

| name = UoSAT-4

| image =

| image_caption = UoSAT-4 artist's concept

| mission_type = OSCAR

| operator = University of Surrey

| website =

| COSPAR_ID = 1990-005C{{cite web|title=Sat Cat|url=http://celestrak.com/satcat/1990/1990-005.asp|publisher=Celestrak|access-date=27 June 2012}}

| SATCAT = 20438

| mission_duration =

| spacecraft_bus =

| manufacturer = SSTL

| dry_mass =

| launch_mass =

| dimensions =

| power =

| launch_date = {{start-date|22 January 1990, 01:35:27|timezone=yes}} UTC

| launch_rocket = Ariane 40{{cite web|title=UoSat 3, 4, 5 (UO 14, 15, 22 / Oscar 14, 15, 22) / Healthsat 1|url=http://space.skyrocket.de/doc_sdat/uosat-3.htm|publisher=Gunter's Space Page|access-date=27 June 2012}}

| launch_site = Kourou ELA-2

| launch_contractor =

| disposal_type =

| deactivated =

| last_contact =

| decay_date =

| orbit_epoch = 15 April 2019, 20:59 {{cite web |url=http://heavens-above.com/orbit.aspx?satid=20438 |title=Oscar 15 - Orbit |work=Heavens-Above |date=15 April 2019 |access-date=16 April 2019}}

| orbit_reference = Geocentric

| orbit_regime = Sun-synchronous

| orbit_periapsis = {{convert|780|km|mi|abbr=on}}

| orbit_apoapsis = {{convert|796|km|mi|abbr=on}}

| orbit_inclination = 98.8074 degrees

| orbit_period = 100.6 minutes

| apsis = gee

| programme = OSCAR

| previous_mission = OSCAR 14

| next_mission = OSCAR 16

}}

UoSAT-4, also known as UO-15 and OSCAR-15, is a British satellite in Low Earth Orbit. It was built by a spin-off company of the University of Surrey, Surrey Satellite Technology (SSTL) and launched in January 1990 from French Guiana.

UoSAT-4 was launched on the same rocket as its sister satellite, UoSAT-3.