Aqua (satellite)

Aqua

Artist's rendering of the Aqua satellite
Names	EOS PM-1
Mission type	Earth observation
Operator	NASA
COSPAR ID	2002-022A
SATCAT no.	27424
Website	aqua.nasa.gov
Mission duration	6 years (planned) Elapsed: 22 years, 8 months and 6 days
Spacecraft properties
Bus	T330 (AB-1200)
Manufacturer	TRW
Launch mass	3,117 kilograms (6,872 lb)
Dimensions	4.81 m × 16.7 m × 8.04 m (15.8 ft × 54.8 ft × 26.4 ft)
Power	4.444 kilowatts
Start of mission
Launch date	May 4, 2002, 09:54:58 (2002-05-04UTC09:54:58Z) UTC
Rocket	Delta II 7920-10L D-291
Launch site	Vandenberg SLC-2W
Contractor	Boeing
End of mission
Last contact	2026-2027 (planned)
Decay date	2046 (planned)
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Semi-major axis	7,080.6 kilometers (4,399.7 mi)
Eccentricity	0.0000979
Perigee altitude	702 kilometers (436 mi)
Apogee altitude	703 kilometers (437 mi)
Inclination	98.1987°
Period	99 minutes
RAAN	95.2063°
Argument of perigee	120.4799°
Mean anomaly	351.4268°
Mean motion	14.57116559
Epoch	02 June 2016, 10:25:37 UTC
Revolution no.	74897
Logotype of the mission. Large Strategic Science Missions Earth Science Division ← Terra ICESat → Earth Observing System ← GRACE ICESat →

Aqua (EOS PM-1) is a NASA scientific research satellite in orbit around the Earth, studying the precipitation, evaporation, and cycling of water. It is the second major component of the Earth Observing System (EOS) preceded by Terra (launched 1999) and followed by Aura (launched 2004).

The name "Aqua" comes from the Latin word for water. The satellite was launched from Vandenberg Air Force Base on May 4, 2002, aboard a Delta II rocket. Aqua operated in a Sun-synchronous orbit as the third in the satellite formation called the "A Train" with several other satellites (OCO-2, the Japanese GCOM W1, PARASOL, CALIPSO, CloudSat, and Aura) for most of its first 20 years; but in January 2022 Aqua left the A-Train (as Cloud Sat, CALIPSO and PARASOL had already done) when, due to its fuel limitations, it transitioned to a free-drift mode, wherein its equatorial crossing time is slowly drifting to later times, from its tightly controlled orbit.^[1]