Sentinel-3B

{{Short description|ESA Earth observation satellite}}

{{Infobox spaceflight |auto=all

| name = Sentinel-3B

| image = Sentinel-3 spacecraft model.svg

| image_size = 275px

| image_caption = Vector drawing of the Sentinel-3

| mission_type = Earth observation

| operator = ESA{{·}}EUMETSAT

| COSPAR_ID = 2018-039A

| SATCAT = 43437

| website = {{url|http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-3|Sentinel-3 (ESA)}}

| mission_duration = Planned: 7 years
Elapsed: {{time interval|25 April 2018 17:57:51|show=ymd|sep=,}}

| spacecraft_type = Sentinel-3

| spacecraft_bus = Prima

| manufacturer = Thales Alenia Space{{cite news |url=https://spaceflightnow.com/2018/04/25/european-environmental-observer-launched-by-russian-rocket/ |title=European environmental observer launched by Russian rocket |work=Spaceflight Now |first=Stephen |last=Clark |date=25 April 2018 |access-date=25 April 2018}}

| launch_mass = {{convert|1250|kg|lb|0|abbr=on}}{{cite web |url=https://directory.eoportal.org/web/eoportal/satellite-missions/c-missions/copernicus-sentinel-3 |title=Copernicus: Sentinel-3 |work=eoPortal |publisher=European Space Agency |access-date=25 April 2018}}

| dry_mass = {{convert|1150|kg|lb|0|abbr=on}}{{cite web |url=https://www.wmo-sat.info/oscar/satellites/view/401 |title=Satellite: Sentinel-3B |publisher=World Meteorological Organization |access-date=25 April 2018}}

| dimensions = {{convert|3.9|xx|2.2|xx|2.2|m|ft|abbr=on}}

| power = 2,300 watts

| launch_date = {{start-date|25 April 2018, 17:57:51}} UTC

| launch_rocket = Rokot/Briz-KM

| launch_site = Plesetsk Cosmodrome, Site 133

| launch_contractor = Eurockot Launch Services

| entered_service =

| disposal_type =

| deactivated =

| last_contact =

| decay_date =

| orbit_reference = Geocentric

| orbit_regime = Sun-synchronous

| orbit_semimajor = {{convert|7180.77|km|mi|abbr=on}}

| orbit_eccentricity = 0.0001027

| orbit_periapsis = {{convert|801.90|km|mi|abbr=on}}

| orbit_apoapsis = {{convert|803.38|km|mi|abbr=on}}

| orbit_inclination = 98.6276°

| orbit_period = 100.93 min

| orbit_RAAN = 183.84°

| orbit_arg_periapsis = 96.39°

| orbit_mean_motion = 14.26 rev/day

| orbit_repeat = 27 days{{cite web |url=https://sentinels.copernicus.eu/web/sentinel/missions/sentinel-3/overview/mission-summary |title=Sentinel-3 › Mission Summary |publisher=European Space Agency |access-date=30 January 2016}}

| orbit_epoch = 25 April 2018, 20:50:15 UTC{{cite web |url=http://heavens-above.com/orbit.aspx?satid=41335 |title=Sentinel 3B - Orbit |work=Heavens Above |date=25 April 2018 |access-date=25 April 2018}}

| apsis = gee

| trans_band = S band (TT&C support)
X band (science data)

| trans_bandwidth = S band: 64 kbit/s uplink, 1 Mbit/s downlink
X band: 2 × 280 Mbit/s

| instruments_list = {{Infobox spaceflight/Instruments

| acronym1 = OLCI | name1 = Ocean and Land Colour Instrument

| acronym2 = SLSTR | name2 = Sea and Land Surface Temperature Radiometer

| acronym3 = SRAL | name3 = Synthetic Aperture Radar Altimeter

| acronym4 = MWR | name4 = Microwave Radiometer

| acronym5 = DORIS | name5 = Doppler Orbitography and Radiopositioning Integrated by Satellite

| acronym6 = LRR | name6 = Laser Retro-Reflector

| acronym7 = GNSS | name7 = Global Navigation Satellite System

}}

| programme = Sentinel-3

| previous_mission = Sentinel-3A

| next_mission = Sentinel-3C

}}

Sentinel-3B is a European Space Agency Earth observation satellite dedicated to oceanography which launched on 25 April 2018. It was built as a part of the Copernicus Programme, and is the second (after Sentinel-3A, launched 16 February 2016) of four planned Sentinel-3 satellites.