Tilting TIROS II
Infrared Observation Satellite (TIROS) was the first platform for space-based
weather observation, both in visible and infrared wavelengths. All modern
satellites have attitude and orbit correcting capabilities via gas jets,
but there is only a limited supply of gas available so the lifetime
of a satellite is limited as well. Scientists who monitored the performance
of TIROS I noticed that the Earth's magnetic field affected the
satellite's attitude as it orbited. They reasoned that attitude control
coils could be installed and energized on TIROS II using electrical
power from its solar panels rather than the onboard fuel supply. This
article from a 1961 edition of Popular Electronics describes the effort.
February 1961 Popular Electronics
Table of Contents
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Tilting TIROS II
Magnetic "hand" tilts space satellite
The nation's latest "weather-eye" satellite, "Tiros II," has achieved
a major "first" in space. By means of a remote-control system, ground
observers can tilt the satellite in space for improved TV coverage of
clouds above the earth.
Spherical "cage" designed to produce magnetic fields resembling
those of the earth was used in pre-launching tests of Tiros II.
Here, Warren P. Manger, of the RCA Astro-Electronics Division, takes
reading of magnetic effect within the wired "cage," preparatory
to rotating the satellite on its mount for study of the orientation
Magnetic orientation system being tested at RCA's Space Center in
Princeton, NJ. Lights above and around the satellite are used to
check operation of solar cells which surround satellite.
Developed by the Radio Corporation of
America, the new orientation technique uses the effect of the earth's
magnetic field to alter the "attitude" of the satellite upon command
- without the need for special propulsion devices. This technique was
the outcome of studies by RCA and government scientists of an unexpected
gradual shift in the attitude of the first Tiros satellite under the
influence of the magnetic field surrounding the earth.
first Tiros, which returned nearly 23,000 useful TV cloud pictures to
earth following its launching last April, these magnetic forces caused
the satellite to tilt gradually away from the predicted position of
its axis in space. In Tiros II, the forces are being harnessed by a
controllable magnetic field generated around the satellite itself by
wire coils on the lower sides of the vehicle. Interacting with the earth's
magnetic field, this controllable field gives ground observers an invisible
"hand" to tilt the satellite on command, in order to obtain a more advantageous
Equipped with the orientation-control system and with
newly developed infrared instruments to measure the emission and reflection
of solar heat by the earth and its atmosphere, Tiros II represents the
second step in the experimental weather satellite program being conducted
by the National Aeronautics and Space Administration to study the feasibility
of regular satellite weather operations.
Among the major features
common to both the Tiros I and II satellites are electronic clocks that
control the timing of cameras, tape recorders, and infrared systems
during each orbit; more than 9000 solar cells on the top and sides of
the satellite to convert electrical energy for operation of the electronic
systems; "yo-yo" weights which slow the satellite's spin from 120 rpm
to 12 rpm as it enters orbit; and five pairs of solid-fuel spin-up rockets
to restore spin momentum.
Wide-angled television camera on Tiros II is checked
Sidney Sternberg, and Ralph Jordan at the RCA Space
Tiros II, mounted on its side in this photo, is
identical in external
appearance to Tiros I.