The Soil Moisture Active-Passive (SMAP) Project Spacecraft Flight Software controls all aspects of command and data handling (CDH) in the SMAP spacecraft. Required capabilities include uplink and command, telemetry and downlink, vehicle attitude control, science instrument control,...

The Wallops Arc Second Pointer (WASP) is a balloon-borne attitude control system capable of pointing a telescope or instrument with accuracy and stability down to the arc second, or 1/3600 of a degree of angular measurement. When a high-powered telescope is integrated with WASP, it provides a highly precise...

Small satellites, launched as secondary payloads, are increasingly being fielded. Advances in liquid rocket propulsion that enhance the on-orbit maneuverability, increase the on-orbit life, and decrease the time between identified need for and deployment of such spacecraft are of great...

Fuel slosh is excited during spacecraft maneuvers. The forces and torques exerted on the spacecraft by the slosh must be controlled by the attitude control system to maintain correct pointing and spacecraft orbit. In some rare cases, the attitude control system may excite the...

Satellite launches experience approximately one deployment failure every two years. These failures include a solar array or antenna that fails to deploy because it is stuck due to a mechanism failure, or is snagged by a cable or thermal blanket. Knowledge of the exact circumstances of the deployable...

Typical spacecraft thruster configurations are often unable to provide full six-degree-of-freedom control and may have unwanted interaction between their attitude control and trajectory control functions, have undesirably high instantaneous electrical power demands, and use more thrusters...

A micro-electrofluidic-spray propulsion (MEP) system was built on a micro scale, in which arrays of hundreds of nano-thrusters are etched on silicon wafers like ICs, only a centimeter on a side. Many dozens of these thruster chips can be...

Propellant mass gauging in microgravity has posed a challenge for decades. Various methods have been applied, including ultrasonic, capacitance probes, point level sensors, thermal detectors (thermistors, thermocouples, etc.), Michelson...

A paper describes a process for imposing safety constraints on a spacecraft trajectory design. The conventional process has the ACS (Attitude Control System) team define geometric constraints, then the NAV (Navigation) team produces a compliant thrust...

A new miniature fine Sun sensor has been developed that uses a quadrant photodiode and housing to determine the Sun vector. Its size, mass, and power make it especially suited to small satellite applications, especially nanosatellites. Its accuracy is on the order of one arcminute, and it...

A report describes a model that estimates the orientation of the backup reaction wheel using the reaction wheel spin rates telemetry from a spacecraft. Attitude control via the reaction wheel assembly (RWA) onboard a spacecraft...

This iPhone application, Space Junk Sammy, is intended to be an educational application designed for Apple iPhones and iPads. This new concept educates kids in an innovative way about how orbital debris affects space missions.

Rhenium, with its high melting temperature, excellent elevated temperature properties, and lack of a ductile-to-brittle transition temperature (DBTT), is ideally suited for the hot gas components of the ACM (Attitude Control Motor), and other hightemperature...

There have been a number of missions with spacecraft flying by planetary moons with atmospheres; there will be future missions with similar flybys. When a spacecraft such as Cassini flies by a moon with an atmosphere, the spacecraft will experience an atmospheric torque. This torque could...

The Miniature Variable-Speed Control Moment Gyroscope (MVS-CMG) was designed for small satellites (mass from less than 1 kg up to 500 kg). Currently available CMGs are too large and heavy, and available miniature CMGs do not provide sufficient control authority for use on practical satellites....

A patent disclosure document discusses a photonic method for connecting a spacecraft with a launch vehicle upper-stage telemetry system as a means for monitoring a spacecraft’s health and status during and right after separation and deployment. This method also provides an efficient...

A document discusses a method of controlling touch and go (TAG) of a spacecraft to correct attitude, while ensuring a safe ascent. TAG is a concept whereby a spacecraft is in contact with the surface of a small body, such as a comet or asteroid, for a few seconds or less before...