— Ch. 1 · Mission Origins And Selection —
Stardust (spacecraft).
~6 min read · Ch. 1 of 7
Scientists began seeking a dedicated mission to study a comet during the 1980s. Several missions to Comet Halley became the first successful missions to return close-up data in the early 1990s. The US cometary mission, Comet Rendezvous Asteroid Flyby, was canceled for budgetary reasons. In the mid-1990s, further support was given to a cheaper, Discovery-class mission that would study Comet Wild 2 in 2004. Stardust was competitively selected in the fall of 1995 as a NASA Discovery Program mission of low-cost with highly focused science goals. Construction of Stardust began in 1996 and was subject to maximum contamination restriction level 5 planetary protection. The risk of interplanetary contamination by alien life was judged low because particle impacts at over 5 kilometers per second were believed to be terminal for any known microorganism. Comet Wild 2 was selected as the primary target of the mission for the rare chance to observe a long-period comet that has ventured close to the Sun. The comet has since become a short period comet after an event in 1974 where its orbit was affected by the gravitational pull of Jupiter. In planning the mission it was expected that most of the original material from which the comet formed would still be preserved.
Engineering Design And Instruments
The spacecraft bus measured 3 meters in length and 2 meters in width adapted from the SpaceProbe deep space bus developed by Lockheed Martin Astronautics. The bus was primarily constructed with graphite fiber panels with an aluminum honeycomb support structure underneath. The entire spacecraft was covered with polycyanate Kapton sheeting for further protection. To maintain low costs the spacecraft incorporated many designs and technologies used in past missions or previously developed for future missions by the Small Spacecraft Technologies Initiative. The spacecraft featured five scientific instruments to collect data including the Stardust Sample Collection tray brought back to Earth for analysis. The probe was powered by two solar arrays providing an average of 330 watts of power. The arrays also included Whipple shields to protect the delicate surfaces from potentially damaging cometary dust while the spacecraft was in the coma of Wild 2. The solar array design was derived primarily from the Small Spacecraft Technology Initiative spacecraft development guidelines. A single nickel-hydrogen battery was also included to provide the spacecraft with power when the solar arrays received too little sunlight. The computer on the spacecraft operated using a radiation-hardened RAD6000 32-bit processor card capable of storing 128 megabytes of data.