Earth Probe TOMS (Total Ozone Mapping Spectrometer)

Mission Description
TOMS-EP will contribute to NASA's long-term daily monitoring of the global distribution of the Earth's ozone layer. The satellite was built by TRW for NASA's Goddard Space Flight Center (GSFC). Launch failures of the first two Pegasus XL vehicles have caused a 2 year delay in the launch of TOMS-EP. These delays have caused the mission to be altered. EP/TOMS will now be placed into a lower orbit in a effort to achieve higher resolution measurements and to study UV-absorbing aerosols in the troposphere more thoroughly. The lower orbit will therefore complement measurements taken from ADEOS TOMS which is scheduled for launch in mid-August.

Specifications:

Attitude Control
Type	Three axis
Pointing Knowledge	+/- 0.25 deg/axis
Pointing Control	+/- 1.0 deg Yaw +/- 0.5 deg Roll +/- 0.5 deg Pitch
Command and Data Handling
Command Rate	2 Kbps
Station Compatibility	DSN, GSTDN
Telemetry Rate
Real Time	1.024 Kbps
Playback	50 and 202 Kbps
Storage Capability
Megabytes	16 MBytes
Hours	24 Hours
Country of Origin	United States
Designed Lifespan	2 years
Dimensions
Height	1.73 m (68 inches)
Diameter	1.11 m (43.76 inches)
Launch	July 2, 1996 (12:46 am PDT) onboard a Pegasus XL rocket.
Manufacturer of instrument	Perkin Elmer (Purchased by Orbital Sciences Corp.)
Manufacturer of spacecraft	TRW
Mass (Total launch mass)	294.8 kg (650.0 lbs)
Instrument Mass	34.3 kg (75.6 lbs)
Spacecraft Mass	187.5 kg (413.4 lbs)
Propellant Mass	73.0 kg (161.0 lbs)
Orbit	500 km (310.7 miles) (Originally planned to be 950 km), circular, sun synchronous
Orbit Inclination	97.36 deg.
Power
Load Power, Avg.	103 W
Solar Array Power, Max.	275 W
Battery Capacity	10.0 A-Hr
Propulsion System	Hydrazine propulsion system with eight thrusters.
Spacecraft in TOMS Series	TOMS-EP is the 3rd in a series of 5 satellite missions to carry the TOMS instrument. 1. Nimbus-7 (1978-1993) 2. Meteor-3 (1991-1994) 3. TOMS-EP (1996-?)