| Methods of microgravity experiments | Microgravity level | Duration | Information, Examples |
| International Space Station | 10-4～10-6G | Weeks to several years | |
| Aircraft | 10-2～10-3G | 10 to 25 seconds | Weeks to Months |
| Drop Tower | 10-3～10-4G | one to ten seconds | Weeks to Months |
| Space shuttle | 10-3～10-5G | One to two weeks | |
| Free flyer | 10-5g or over | Depends on mission duration (about six months) | Weeks to Months |
| Small rockets | 10-2～10-3G | Several minutes | Space experiments by launching small rockets |
| Mir | 10-3～10-5G | Weeks to Months | Russia’s Mir Space Station |
SSTL is Singapore’s sole administrator for the utilisation of the Japanese Experiment Module (JEM) on the International Space Station (ISS) for education and technical development.
JEM, also known as Kibo (the Japanese word for “hope”) is the Japanese science module of the ISS and the largest ISS module.
A wide variety of scientific, medical, and educational experiments are conducted on the JEM. These includes experiments to be conducted by Japanese astronauts, in-orbit testing of new technologies in actual space environments, as well as launching of cubesats and microsats.
Features of the space environment
Why conduct experiments in space?
The space environment has features which cannot be easily obtained on the ground, such as microgravity, high level of vacuum, excellent visibility, and space radiation. A variety of fields of research and experiments or observations is expected to utilise these features.
Microgravity environment
- Since there is almost no buoyancy in the space environment, light materials and heavy materials can be mixed uniformly.
- Defect-free crystal structures can be formed because there is almost no weight or depth pressure.
High-level vacuum
Space provides a large-scale high-level vacuum environment. At the ISS altitude about 400km (250mi), the pressure of the environment is about one 100,000th of 1Pa, which is about 0ne 100 milllionth of the pressure on the ground.
Excellent visibility
Visibility for observing space is excellent since there is almost no atmosphere and no meteorological effects in space close to the Earth. The whole Earth can be observed from outside of the atmosphere. Abundant, constant, and high-density solar energy is also available.
Space radiation
The space radiation environment is composed of various types of particles. These include a radiation belt consisting of particles captured by the Earth’s magnetic field and surrounding the Earth like a donut; protons with energies ranging from 10 through 1016 Mev; galactic radiation composed of many types of nuclei such as helium, carbon, oxygen, and iron; and high levels of particles generated by solar flares.
Ideal for long-term microgravity experiments
Experiments in an exposed space environment
In the past, opportunities for conducting experiments in the exposed environment was limited since it requires onboard crew’s Extravehicular Activity (EVA) for installing and retrieving the experiment equipment.
However, Kibo’s unique facility, the ExHAM, increases experiment opportunities in the exposed environment.
Exposed Experiment Handrail Attachment Mechanism (ExHAM)
The ExHAM, JEM’s Exposed Facility, is a cuboid mechanism equipped with a grapple fixture on the upper surface for the Kibo’s robotic arm. It provides an easy way
- To see how materials or parts actually change in space.
- To see how materials or parts degrade over a period of time.
- To search what kinds of particles are floating in space.
The number of loadable experiment samples is 7 on the upper surface and 13 on the side surfaces. Experiment objects can be exposed for a few months or up to 3 years and then sent back to Earth for analysis.