The
Mengtian experiment module is equipped with expanded in-orbit experiment capacity, including eight research cabins. It provides a pressurized environment for researchers to conduct science experiments in freefall or zero gravity which could not be conducted on Earth for more than a few minutes. Experiments can also be placed on the outside of the modules, for exposure to the
space environment,
cosmic rays, vacuum, and
solar winds. It has its own airlock. The axial port of
Mengtian is fitted with rendezvous equipment and will first dock to the axial port of Tianhe. A mechanical arm known as the indexing robotic arm, similar to the
Lyappa arm on the Mir space station, then moves
Mengtian to a portside port of the Tianhe Core Module. In addition to this arm used for docking relocation, the main robotic arm on
Tianhe core module can also be used as a backup in place of the indexing robot arm.
Mengtian also carries a toolbox equipped with a dexterous robotic arm, installed to assist in cargo transfer and payload release, that can be used to launch
microsatellites, and an augmented-reality smart glass to assist astronauts with maintenance. Similarly to the
Wentian module,
electrical power is provided by two steerable
solar power arrays, which use
photovoltaic cells to convert sunlight into electricity. With a wingspan of over 55 m (180 ft), each array has an energy collection area of 110 m2 (1184 square ft). The energy is then stored to power the station when it passes into the Earth's shadow. Resupply ships will replenish fuel for experiment module 2 for station-keeping, to counter the effects of atmospheric drag. ==Aftermath==