C/NOFS, or Communications/Navigation Outage Forecasting System was a USAF satellite developed by the Air Force Research Laboratory (AFRL) Space Vehicles Directorate to investigate and forecast scintillations in the Earth's ionosphere. It was launched by an Orbital Sciences Corporation Pegasus-XL launch vehicle at 17:02:48 UTC on 16 April 2008 and decayed on 28 November 2015. The satellite, which was operated by the Space Test Program (STP), allowed the U.S. military to predict the effects of ionospheric activity on signals from communication and navigation satellites, outages of which could potentially cause problems in battlefield situations. C/NOFS had a three-axis stabilization system equipped with seven sensors. It was placed into low Earth orbit with an orbital inclination of 13.00°, a perigee of 405 km and an apogee of 853 km. It carried the CINDI experiment for NASA. Launch had been scheduled for 2003, but was delayed for a number of reasons.

Scientific instruments on board

The spacecraft payload consists of the following instruments:

Experiments

C/NOFS Occultation Receiver for Ionospheric Sensing and Specification (CORISS)

The C/NOFS Occultation Receiver for Ionospheric Sensing and Specification (CORISS) is a Global Positioning System (GPS) dual-frequency receiver that measures the total electron content (TEC) along the line-of-sight from C/NOFS to GPS satellite. TEC measurement can help to constrain C/NOFS ionospheric models. Limb profiles of TEC obtained during occultations can be inverted to produce vertical profiles of electron density. It may be also possible to measure L-band scintillations caused by electron density irregularities.

Coherent Electromagnetic Radio Tomography (CERTO)

The Coherent Electromagnetic Radio Tomography (CERTO) is a tri-band (150, 400, 1067 MHz) radio beacon that permits direct measurement of ionospheric scintillation parameters at several frequencies by ground receivers. CERTO measurements can also be used for tomographic reconstruction of electron density profiles.

Coupled Ion-Neutral Dynamics Investigation (CINDI)

The Coupled Ion-Neutral Dynamics Investigation (CINDI) payload is funded by NASA as an Explorer Mission of Opportunity. CINDI consists of two instruments: the Ion Velocity Meter (IVM) and the Neutral Wind Meter (NWM). The IVM instrument includes an ion drift meter and a retarding potential analyzer. IVM measure the ion drift vector, the ion temperature, and the major ion composition with a spatial resolution of about 4 km along the satellite track; the ion drift meter also provides vertical and horizontal ion drift components at 500 m resolution. The NWM consists of a cross track wind sensor and a ram wind sensor providing a direct measure of the neutral wind vector with a spatial resolution of about 8 km along the satellite track.

Planar Langmuir Probe (PLP)

The Planar Langmuir Probe (PLP) is a dual-disk probe designed to provide in situ measurements of plasma density and density fluctuations. Low time-resolution density measurements are intended as inputs for background ionosphere models and high time-resolution density irregularity measurements to specify disturbance conditions. PLP also monitors the spacecraft surface potential.

Vector Electric Field Instrument (VEFI)

The Vector Electric Field Instrument (VEFI) consists primarily of three orthogonal 20 m tip-to-tip double probe antennas. It measures the alternating current (AC) and Direct current (DC) electric fields related to plasma drift and irregularity development. The VEFI instrument package also includes a fluxgate magnetometer, an optical lightning detector and a fixed-bias Langmuir probe.

Scientific data

C/NOFS science data is available online for general use. VEFI and PLP data are available through NASA Goddard's Coordinated Data Analysis Web. CINDI data are available through the William B. Hanson Center for Space Science at the University of Texas at Dallas.

Timeline

C/NOFS related publications