The Total Ozone Mapping Spectrometer ( TOMS ) was a NASA satellite instrument, specifically a spectrometer , for measuring the ozone layer . Of the five TOMS instruments which were built, four entered successful orbit. The satellites carrying TOMS instruments were:
12-491: Nimbus 7 and Meteor-3-5 provided global measurements of total column ozone on a daily basis and together provided a complete data set of daily ozone from November 1978 to December 1994. After an eighteen-month period when the program had no on-orbit capability, TOMS-Earth Probe launched on 2 July 1996, followed by ADEOS I . ADEOS I was launched on August 17, 1996, and the TOMS-instrument onboard provided data until
24-488: A Taurus rocket from Vandenberg AFB , but did not achieve orbit. Since January 1, 2006, data from the Aura Ozone Monitoring Instrument (OMI) has replaced data from TOMS-Earth Probe. The Ozone Mapping and Profiler Suite on Suomi NPP and NOAA-20 have further continued the data record. Nimbus 7 Nimbus 7 (also called Nimbus G ) was a meteorological satellite . It
36-452: A binary output, indicating when the Sun is within the sensor's field of view . Analog and digital Sun sensors, in contrast, indicate the angle of the Sun by continuous and discrete signal outputs, respectively. In typical Sun sensors, a thin slit at the top of a rectangular chamber allows a line of light to fall on an array of photodetector cells at the bottom of the chamber. A voltage
48-476: The Sun . Sun sensors are used for attitude control , solar array pointing, gyro updating, and fail-safe recovery. In addition to spacecraft, Sun sensors find use in ground-based weather stations and Sun-tracking systems, and aerial vehicles including balloons and UAVs . There are various types of Sun sensors, which differ in their technology and performance characteristics. Sun presence sensors provide
60-628: The satellite which housed it lost power on June 30, 1997. TOMS-Earth Probe ( Total Ozone Mapping Spectrometer - Earth Probe , TOMS-EP , originally just TOMS , COSPAR 1996-037A) was launched on July 2, 1996, from Vandenberg AFB by a Pegasus XL rocket. The satellite project was originally known as TOMS, back in 1989 when it was selected as a SMEX mission in the Explorer program . However, it found no funding as an Explorer mission and transferred to NASA 's Earth Probe program, getting funding and becoming TOMS-EP. The small, 295 kg satellite
72-403: The spacecraft's orientation to be controlled to within plus or minus 1 degree in all three axes (pitch, roll, yaw). Eight experiments were selected, using the following instruments: These sensors were capable of observing several parameters at and below the mesospheric levels. Sun sensor A Sun sensor is a navigational instrument used by spacecraft to detect the position of
84-470: The torus provided mounting space for sensors and antennas . A box-beam structure mounted within the center of the torus provided support for the larger sensor experiments. Mounted on the control housing unit, which was located on top of the spacecraft, were Sun sensors , horizon scanners, and a command antenna. The spacecraft's spin axis was pointed at the Earth. An advanced attitude-control system permitted
96-401: The troposphere. The lower orbit was meant to complement measurements from ADEOS I enabling TOMS-EP to provide supplemental measurements. After ADEOS I failed in orbit, TOMS-EP was boosted to a higher orbit to replace ADEOS I. The transmitter for TOMS-Earth Probe failed on December 2, 2006. The only total failure in the series was QuikTOMS , which was launched on September 21, 2001, on
108-423: Was 954 kilometers (593 mi). The Nimbus 7 research and development satellite served as a stabilized, Earth-oriented platform for the testing of advanced systems for sensing and collecting data in the pollution , oceanographic , and meteorological disciplines. The polar-orbiting spacecraft consisted of three major structures: a hollow torus -shaped sensor mount, solar paddles, and a control housing unit that
120-492: Was built for NASA by TRW ; the single instrument was the TOMS 3 spectrometer. The satellite had a two-year planned life. TOMS-EP suffered a two-year delay to its launch due to launch failures of the first two Pegasus XL rockets. The launch delays led to alternations in the mission; the satellite was placed in a lower than originally planned orbit to achieve higher resolution and to enable more thorough study of UV-absorbing aerosols in
132-424: Was connected to the sensor mount by a tripod truss structure. Configured somewhat like an ocean buoy , Nimbus 7 was nearly 3.04 metres (10.0 ft) tall, 1.52 metres (5.0 ft) in diameter at the base, and about 3.96 metres (13.0 ft) wide with solar paddles extended. The electronics equipment and battery modules were housed in the sensor mount (torus) that formed the satellite base. The lower surface of
SECTION 10
#1732772725108144-519: Was the seventh and last in a series of the Nimbus program . Nimbus 7 was launched on October 24, 1978, by a Delta rocket from Vandenberg Air Force Base , California , United States. The spacecraft functioned nominally until 1994. The satellite orbited the Earth once every 1 hour and 34 minutes, at an inclination of 99 degrees. Its perigee was 941 kilometers (585 mi) and its apogee
#107892