National Aeronautics and Space Administration

DAMPE

The Dark Matter Particle Explorer (DAMPE) satellite, also known as “Wukong” (a reference to the Monkey King hero in the Chinese story “Journey to the West”), is a Chinese Academy of Science mission to measure highly energic electrons and photons with high resolution in order to identify possible dark matter signatures.

The satellite was launched into a polar, sun-synchronous orbit with an altitude of 500 km on December 17, 2015. The Long March-2D rocket carrying DAMPE to orbit was launched from the Jiuquan Satellite Launch Center in China. At the start of operations, the mission was planned to have a three year service lifetime, but that was extended for a further two years in December 2018.

Mission Characteristics

Lifetime

Energy Range

Special Features

Payload

DAMPE is a single instrument mission. The detector contains multiple elements, stacked vertically atop each other along the Z (observational direction) axis of the spacecraft:

• The Plastic Scintillator Detector (PSD), which consists of a double layer of 1 x 2.8 x 82 cm staggered strips laid out in alternativing layers of X and Y orientation. with a 82 x 82 cm total area. The PSD detects the charge of cosmic rays and also serves as an anti-coincidence detector for energic photons. It has a position resolution of 6 mm and charge resolution of 0.25 for Z = 1 - 20. It also serves as a backup to the STK element.
• The Silicon-Tungsten Tracker (STK), which consists of multiple layers of silicon micro-strip detectors with interleaving tungsten converter plates. STK tracks the direction of gamma-rays by their conversion to charged particles in the tungsten plates, then tracking the particles through the instrument. STK has 6 tracking planes, each with two layers in X and Y planes, orthogonal to the intrument pointing. Cumulatively, this makes a sensor with 0.2° angular resolution at 10 GeV and the total silicon area is roughly 7 m².
• Bismuth-Germanium Oxide (BGO) calorimeter, which contains 308 bismuth germanate crystal bars, 2.5 x 2.5 x 60 cm, stacked in 14 layers in alternating X and Y direction orientations. A 0.5 mm gap around each crystal is filled with a silicone elastomer to hold each crystal in place and to prevent damage from launch vibrations. Incident particles interact with the crystals, generating a pulse of optical light which is detected by photomultipliers and each layer edge. The calorimeter is sensitive to energies between 5 GeV to 10 TeV.
• Neutral Detector (NUD), which consists of four large boron-doped plastic scintillation detectors, 30 x 30 x 1 cm in size. Each detector is equipped with a photomultiplier tube to measure light flashes causes by incident neutral particles exciting the boron and generating alpha particles and gamma-rays. The gamma-rays are converted to light pulses recorded by the instrument.