LOFTI-1 was an American satellite which was launched in 1961 and operated by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

and

Naval Research Laboratory The United States Naval Research Laboratory (NRL) is the corporate research laboratory for the United States Navy and the United States Marine Corps. It was founded in 1923 and conducts basic scientific research, applied research, technological ...

. It was used to conduct research into the propagation of

very low frequency Very low frequency or VLF is the ITU designation for radio frequencies (RF) in the range of 3–30 kHz, corresponding to wavelengths from 100 to 10 km, respectively. The band is also known as the myriameter band or myriameter wave a ...

radio signals in the ionosphere, and to investigate if these signals could be received by submarines. A 136.17 MHz transmitter was used for this investigation. The launch of LOFTI-1 was conducted at 03:45 UTC on 22 February 1961, using a Thor DM-21 Ablestar rocket flying from Launch Complex 17B at the

Cape Canaveral Air Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

. It was a secondary payload aboard the rocket, with the primary payload being the Transit 3B prototype navigation satellite. The rocket and upper stage used had the serial numbers Thor 313 and Ablestar 007 respectively. The launch resulted in a partial failure, with the spacecraft being placed in a more eccentric orbit than planned, and failing to separate from the upper stage. LOFTI-1 was a spacecraft, which was powered by six groups of solar cells charging a nickel-cadmium battery. It ended up in a

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

with a

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ell ...

of , an

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ell ...

of , and 28.3 degrees of

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

. It had an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 96.4 minutes. Due to the low perigee of its orbit, LOFTI-1 decayed quickly, and reentered the atmosphere on 30 March 1961, less than 37 days after launch. Despite being in the wrong orbit and operating for less time than had been planned, some useful data was returned from the mission. Together with data returned by later satellites, the data returned by LOFTI-1 proved that very low frequency signals were not suitable for satellite communications with submarines.

References

Spacecraft launched in 1961 Satellite launch anomalies Spacecraft which reentered in 1961 {{US-spacecraft-stub

See also

References