23940 - TOMS-EP

TOMS-EP (Total Ozone Mapping Spectrometer-Earth Probe; also known as TOMS-EP96) is an American Earth science spacecraft that was launched by a Pegasus XL rocket from an L-1011 airplane over southern California at 00:48 UT on 2 July 1996. The 248-kg (fuel-free) and 103-W spacecraft carries a single instrument: a modified Ebert-Fastie polychromator with fixed exit slits at six near-UV wavelengths, which will monitor and store full-orbit data and downlink them over one or two ground stations. The initial parameters of the circular, Sun-synchronous orbit were period 97.6 min, altitude 500 km, and inclination 97.4 deg.

The goal of the Total Ozone Mapping Spectrometer (TOMS) Earth Probe mission (part of NASA's Mission To Planet Earth (MTPE) Phase I program) was to continue the high-resolution global mapping of total ozone on a daily basis (begun with the Nimbus 7 SBUV/TOMS) as well as to detect global ozone trends to verify depletion predicted by atmospheric chemistry models.

The TOMS-Earth Probe (TOMS-EP), the first of a series of NASA Earth Probe missions, was one of three TOMS missions which included METEOR 3/TOMS2 (launched 1991) and ADEOS/TOMS (launched 1995). The TOMS-EP carried only one instrument: the Total Ozone Mapping Spectrometer (TOMS).

The TOMS-EP spacecraft was based on the TRW/DSI Eagle bus developed under the USAF STEP program. The spacecraft was three-axis stabilized so that the TOMS instrument was nadir-pointed with about 0.5 degree control and about 0.1 degree knowledge from measured altitude data. The TOMS-EP spacecraft bus was designed to accomodate all of the TOMS instrument requirements to support a two-year lifetime with a three-year lifetime goal.

Alternate Names

SMEX/TOMS-Earth Probe
Small Explorer/TOMS-Earth Probe
TOMS-EP96
TOMS-Earth Probe

Facts in Brief

Launch Date: 1996-07-02
Launch Vehicle: Pegasus XL
Launch Site: Vandenberg AFB, United States
Mass: 248.0 kg