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NOAA-2
	NOAA 2 lifts off
Mission type	Weather
Operator	NOAA
COSPAR ID	1972-082A
SATCAT no.	6235
Mission duration	2 years and 3 months
Spacecraft properties
Manufacturer	RCA Astrospace
Launch mass	306 kilograms (675 lb)
Start of mission
Launch date	October 15, 1972, 17:17 UTC
Rocket	Delta-300
Launch site	Vandenberg SLC-2W
End of mission
Disposal	Decommissioned
Deactivated	January 30, 1975
Orbital parameters
Reference system	Geocentric
Regime	Low Earth; Sun-synchronous
Eccentricity	0.00032
Perigee altitude	1,448 kilometers (900 mi)
Apogee altitude	1,453 kilometers (903 mi)
Inclination	101.8°
Period	114.9 minutes
Epoch	October 15, 1972
Instruments
	SPM, SR, VHRR, VTPR
	ITOS ← ITOS-B ITOS-E →

NOAA-2, also known as ITOS-D was a weather satellite operated by the National Oceanic and Atmospheric Administration (NOAA).^[4] It was part of a series of satellites called ITOS, or improved TIROS.^[5] NOAA-2 was launched on a Delta rocket on October 15, 1972. The launch carried one other satellite: AMSAT-OSCAR 6.^[3]

Mission of NOAA-2

NOAA 2 was the first in a series of reconfigured ITOS-M satellites launched with new meteorological sensors on board to expand the operational capability of the ITOS system. NOAA 2 was not equipped with conventional TV cameras. It was the first operational weather satellite to rely solely upon radiometric imaging to obtain cloud cover data. The primary objective of NOAA 2 was to provide global daytime and nighttime direct readout real-time cloud cover data on a daily basis. The Sun-synchronous spacecraft was also capable of supplying global atmospheric temperature soundings and very high resolution infrared cloudcover data for selected areas in either a direct readout or a tape-recorder mode. A secondary objective was to obtain global solar-proton flux data on a real-time daily basis.

Composite image of Northern hemisphere derived from NOAA-2 scanning radiometer visible-spectrum image.

The primary sensors consisted of Very High Resolution Radiometer (VHRR), a Vertical Temperature Profile Radiometer (VTPR), and a Scanning Radiometer (SR). The VHRR, VTPR, and SR were mounted on the satellite baseplate with their optical axes directed vertically earthward.

The nearly cubical spacecraft measured 1 by 1 by 1.2 meters (3.3 ft × 3.3 ft × 3.9 ft). The satellite was equipped with three curved solar panels that were folded during launch and deployed after orbit was achieved. Each panel measured over 4.2 meters (14 ft) in length when unfolded and was covered with approximately 3,500 solar cells measuring 2 by 2 centimeters (0.79 in × 0.79 in). The NOAA 2 dynamics and attitude control system maintained desired spacecraft orientation through gyroscopic principles incorporated into the satellite design. Earth orientation of the satellite body was maintained by taking advantage of the precession induced from a momentum flywheel so that the satellite body precession rate of one revolution per orbit provided the desired Earth-looking attitude. Minor adjustments in attitude and orientation were made by means of magnetic coils and by varying the speed of the momentum flywheel.

The spacecraft operated satisfactorily until March 18, 1974, when VTPR failed. NOAA 2 was then placed in a marginal standby mode from March 19 to July 1, 1974. It was then used as the operational NOAA satellite until October 16, 1974, when it was again placed in a marginal standby mode. The spacecraft was deactivated on January 30, 1975.^[1]

Current status

The satellite's ITOS imaging system has been heard transmitting a sync signal containing no image, on March 13, 2021, by Scott Tilley,^[6] confirmed shortly after by Derek OK9SGC^[7] and again later by Derek on September 25, 2022.^[8]

As of January 11th, 2023 the satellite continues to broadcast this sync signal,^[9] and software made by Alexandre Rouma ON5RYZ/KE8SUI and Jacopo IU1QPT is available for decoding.^[10]