DS 1 [NASA]
DS1 (Deep Space 1) was a mission to test high risk technologies like an ion-engine and autonomous operation. It was the first mission funded by NASA under the 'New Millennium' program.
As part of the technology demonstrations, the probe carries the Miniature Integrated Camera-Spectrometer (MICAS), an instrument combining two visible imaging channels with UV and IR spectrometers. MICAS is used to study the chemical composition, geomorphology, size, spin-state, and atmosphere of the target objects. It also carries the Plasma Experiment for Planetary Exploration (PEPE), an ion and electron spectrometer which measures the solar wind during cruise, the interaction of the solar wind with target bodies during encounters, and the composition of the cometary coma.
The Deep Space 1 spacecraft is built on an octagonal aluminum frame bus which is 1.1 x 1.1 × 1.5 m in size. With instruments and systems attached, the spacecraft measures 2.5 m high, 2.1 m deep, and 1.7 m wide. The launch mass of the spacecraft is about 486.3 kg, which includes 31.1 kg of hydrazine and 81.5 kg of xenon gas. The probe is powered by batteries and two solar panel "wings" attached to the sides of the frame which span roughly 11.75 m when deployed. The solar panels, designated SCARLET II (Solar Concentrator Arrays with Refractive Linear Element Technology) constitute one of the technology tests on the spacecraft. A cylindrical lens concentrates sunlight on a strip of GaInP2/GaAs/Ge photovoltaic cells and acts to protect the cells. Each solar array consists of four 160 cm × 113 cm panels. The array will furnish 2500 W at 100 volts at the beginning of the mission, and less as the spacecraft moves further from the Sun and as the solar cells age. Communications are via a high-gain antenna, three low-gain antennas, and a Ka-band antenna, all mounted on top of the spacecraft except one low gain antenna mounted on the bottom.
Propulsion is provided by a xenon ion engine mounted in the propulsion unit on the bottom of the frame. The 30 cm diameter engine consists of an ionization chamber into which xenon gas is injected. Electrons are emitted by a cathode traverse discharge tube and collide with the xenon gas, stripping off electrons and creating positive ions. The ions are accelerated through a 1280 volt grid at to 31.5 km/sec and ejected from the spacecraft as an ion beam, producing 0.09 Newtons (0.02 pounds) of thrust at maximum power (2300 W) and 0.02 N at the minimum operational power of 500 W. The excess electrons are collected and injected into the ion beam to neutralize the electric charge. Of the 81.5 kg of xenon, approximately 17 kg were consumed during the primary mission.
Other technologies which will be tested on this mission include a solar concentrator array, autonomous navigation plus two other autonomy experiments, small transponder, Ka-band solid state power amplifier, and experiments in low power electronics, power switching, and multifunctional structures (in which electronics, cabling, and thermal control are integrated into a load bearing element).
Doing science was only a secondary focus on this mission, but it yielded good results on fly-bys with Asteroid 9962 Braille on 29.07.1999 and with comet 19P/Borrelly on 22.09.2001.
|Type / Application:||Technology Experiments, Asteroid & Comet Flyby Probe|
|Equipment:||MICAS, PEPE, SCARLETT 2|
|Propulsion:||1 × NSTAR ion thruster|
|Power:||2 deployable solar arrays, batteries|
|Mass:||486 kg (373.7 kg spacecraft, 31 kg hydrazine, 81 kg xenon)|
|DS 1||1998-061A||24.10.1998||CC SLC-17A||Delta-7326||with SEDSat|