ST5's (a.k.a. NCT - Nanosat Constellation Trailblazer)
objective was a mission to demonstrate and space-test the ability of "smart" satellites to
identify scientific events and implement cooperative data-taking strategies.
ST5 project also developed and build the spacecraft bus that enables the
mission's multiple nanosats to be launched into space from a single rocket and spun into
orbit approximately 4,500 kilometers above Earth. The spinning motion is
required for optimal use of sunlight. Sunlight is collected by the solar array panels and
transformed into energy for the satellite to use as power for all the internal components
and instruments.
Once deployed, the smallsats flew in various location points within the
magnetosphere, the region that surrounds our planet like a "suit of armor."
Magnetometers onboard each of these miniaturized satellites measured energetic
particles in the magnetosphere, The data was then forwarded to scientists on the
ground for analysis. Returned data aided in determining ambient radiation levels and
the spacecraft's subsystem response to this hazard.
Each smallsat be commanded individually from ground stations on the Earth, except for a
one-week period of "lights out." During this time, the smallsats will fly
"autonomously" with pre-programmed commands in a test to determine if ground
commanding (for 24 hours) is really necessary.
ST5's "maiden voyage" will pave the way for flying tens to hundreds of such
miniature craft in future missions. These missions can only be flown if they are capable
of responding to the changes in the charged particles and magnetic fields in the harsh
environment of Earth's magnetosphere.
Originally planned for a piggy back launch into geostationary transfer orbit, the ST5
spacecraft were finally launched on a dedicated Pegasus-XL
launcher, using a special dispenser.
The ST5 mission tested following technologies:
- Goddard Mission Services Evolution Center (GMSEC)
The Goddard Space Flight Center (GSFC) Mission Services Evolution Center (GMSEC) mission
is an integrated effort across multiple GSFC organizations to provide GSFC mission
services through the year 2010.
- Communications Components for Small Spacecraft
The X-Band Transponder Communications System was provided by AeroAstro. The transponder
system is a miniaturized digital communications transponder. It provides coherent
uplink-to-downlink operation that provides a ground-to-space command capability, space-to-ground telemetry capability, and a radio frequency tracking capability. The
X-Band weighs approximately 1/12th as much and is 1/9th the volume of communications
systems now used in other missions.
- Lithium-Ion Power System for Small Satellites
The Low-Voltage Power System uses a low-weight Li-Ion battery with triple junction solar
cells that can store up to four times as much energy as their Ni-Cad counterparts. The
Li-Ion rechargeable battery has a longer life and doesn't remember how much it has been
discharged prior to recharging.
- Ultra Low-Power Demonstration
The CULPRiT is a new type of microelectronic device that allows circuits to operate at 0.5
Volts. The technology will greatly reduce power consumption while achieving a radiation
tolerance of ~100kRad total dose and latch-up immunity.
- Variable Emittance Coatings for Thermal Control
The Variable Emittance Coatings, provided by AFRL and the Applied Physics Laboratory
(APL), are used for thermal control and consist of an electrically tunable coating that
can change properties, from absorbing heat when cool to reflecting or emitting heat when
in the Sun. The Microelectromechanical System (MEMS) chip is part of this technology.
- Propulsion Systems Components
A miniature microthruster that provides fine attitude adjustments on the spacecraft. The
Cold Gas Microthruster (CGMT) is a tiny electromechanical system designed by Marotta
Scientific Controls, Inc. to provide fine attitude adjustments on each of the micro-sats.
It uses 1/8th the power and weighs only half as much as attitude control systems being
used in other missions.
- Miniature magnetometer
- Miniature spinning sun sensor
- Spacecraft deployment mechanism
- Magnetometer deployment boom
- Nutation damper
