jeudi 16 juin 2016

From Magnetic Levitation to Frozen Wax, Cargo Spacecraft to Carry Wide Range of Investigations












SpaceX / NASA - CRS-9 Dragon Mission patch.

June 16, 2016

Dragon spacecraft. Image Credits:SpaceX/NASA

SpaceX is targeting the launch of its Dragon spacecraft from Cape Canaveral Air Force Station in Florida in the early morning hours of July 16, marking the company’s ninth Commercial Resupply Services (CRS-9) flight for NASA. Dragon will deliver nearly 4,900 pounds of cargo, crew supplies, and research experiments to the International Space Station. These experiments include testing capabilities for sequencing DNA in space, regulating temperatures aboard spacecraft, understanding bone loss, and tracking ships around the world. Other investigations study how to protect computers from radiation in space and test an efficient, three-dimensional solar cell.

Biomolecule Sequencer

Image Credits: Oxford Nanopore Technologies

Determining the sequence of an individual organism’s deoxyribonucleic acid or DNA helps us understand how various environments may affect that organism. Currently, DNA sequencing can only be done on Earth, but the Biomolecule Sequencer investigation launching on the Dragon tests a miniature device that could make it possible aboard a spacecraft.

Crew members could use DNA sequencing to identify and monitor microbes and immediately determine appropriate remediation strategies, a capability that will be critical for exploration beyond our moon. Real-time DNA sequencing could help assess crew member health and determine the effectiveness of countermeasures during long spaceflights. It could be integrated into scientific investigations aboard the station and, in the future, analyze DNA-based life that may be found on other worlds. The device also could bring the benefits of DNA sequencing to people in remote and developing locations on Earth.

Phase Change Heat Exchanger

Image Credits: NASA

Space has no atmosphere to protect from temperature extremes of sunlight and shadow. Devices called phase-change material heat exchangers could help maintain critical temperatures inside a spacecraft by freezing or thawing a material. The Dragon launch will carry a new type of heat exchanger to the station for testing. This Phase Change Heat Exchanger Project (Phase Change HX) could lead to better temperature regulation on future missions.

Phase-change material heat exchangers store excess heat or energy by melting a material during peak loads then, when conditions allow, reject the energy through a radiator and freeze the material. The Apollo lunar rover and Skylab used wax as the material, with inconsistent results. Water stores more energy than wax, so a smaller volume of water could be used, but we don’t know how water-based exchangers function in microgravity. Also, water expands when it freezes. This investigation will test both wax and water to determine which would work better as a phase-change heat exchanger on spacecraft.

The investigation also will contribute to more efficient use of phase-change heat exchangers to control temperatures in chemical plants, power plants and other settings on the ground.

OsteoOmics

Image Credit: NASA

Astronauts on long-duration missions and bed-ridden people back on Earth have something in common: bone loss. Scientists study the mechanisms of this bone loss on Earth using a magnetic levitation device to simulate microgravity. The OsteoOmics investigation will test the accuracy of this simulation by comparing genetic changes in bone cells exposed to magnetic levitation on Earth with those exposed to real microgravity aboard the space station.

Improved understanding of the mechanisms behind bone loss could lead to better ways to prevent it during space missions. This also could contribute to better prevention of and treatments for bone loss as a result of diseases like osteopenia and osteoporosis or from prolonged bed rest. Should this investigation determine that ground-based magnetic levitation provides accurate simulation of microgravity, the technique could become an important tool for ground-based investigation of not only bone loss, but other effects of gravitational force on biological systems. OsteoOmics is sponsored by the National Institutes of Health as part of the U.S. National Laboratory, which is managed by the Center for the Advancement of Science in Space (CASIS).

Heart Cells

The Heart Cells investigation studies how microgravity changes the human heart and how those effects vary from one individual to another. This is a U.S. National Lab payload that is sponsored by CASIS. 

Future exploration of an asteroid or Mars will require long periods of space travel, which creates increased risk of health problems such as muscle atrophy, including possible atrophy of the heart muscle. For this investigation, scientists induced human skin cells to become stem cells, which can differentiate into any type of cell, and forced them to grow into human heart cells. These heart cells will be cultured aboard the space station for one month and analyzed for cellular and molecular changes. This will provide insight into how microgravity affects the heart. Results could advance the study of heart disease and the development of drugs and cell replacement therapy for future space missions and people with heart disease on Earth.

Maritime Awareness

A world-wide Automatic Identification System (AIS) tracks most ships on the oceans, but the curvature of the Earth blocks signals when ships are far from shore or each other. The U.S. National Lab Maritime Awareness investigation is sending an AIS receiver to the space station for a 12-month test of its ability to continuously monitor ships from above.

Because nothing will block the signal, the system on the station could provide more complete information about world shipping traffic by collecting continuous, real-time information on the identity, position, course, speed, and cargo of ships. These data can improve shipping safety and security, enable monitoring of trade agreements and business interests, and improve enforcement of environmental protections.

NanoRacks – Gumstix

Image Credit: NASA

Radiation bombarding computers in space can interfere with processors and cause malfunctions or loss of data. The lengthy process of testing computers for use in space often puts them two or three generations behind those on Earth. This investigation, NanoRacks-Gumstix, in coordination with CASIS, will place commercially available computers called Gumstix modules on the exterior of the space station to see how the radiation environment affects them. Gumstix modules use processors with tiny gaps between transistors, which make it possible for the computers to be very small. Their small size, however, makes the modules vulnerable to radiation.  

A watchdog circuit will keep track of any radiation-related errors during the six-month test. Depending on the results, future miniature spacecraft could use Gumstix to conduct communications and remote sensing research, lowering the cost of access to space.

NanoRacks – Nano Tube Solar Cell

Image Credit: NASA

The NanoRacks-Nanotube Solar Cell investigation launching to the station will study a next-generation, three-dimensional solar cell that absorbs sunlight more efficiently. The US National Lab investigation, sponsored by CASIS, will examine its response to the continually changing sun angles on the space station and the harsh environment of space.

The 3-D, carbon nanotube-based photovoltaic (3DCNTPV) devices are lightweight, flexible, and cost efficient. They also produce more power when the sun isn’t hitting them directly, which eliminates the need for bulky and expensive tracking machinery. In addition, these cells use a copper-zinc-tin-sulfide photoabsorber that has all the traits of an ideal material, including low-cost and abundant chemical elements and compatibility with existing technologies, structures and materials. This technology could improve the efficiency of solar panels on both the space station and on the ground.

These investigations represent just a sampling of science conducted aboard the orbiting lab and the wide range of benefits the research offers both future space exploration and life on Earth.

Related links:

Dragon spacecraft: https://www.nasa.gov/mission_pages/station/structure/launch/spacex.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Biomolecule Sequencer investigation: http://www.nasa.gov/mission_pages/station/research/experiments/2181.html

Phase Change Heat Exchanger Project (Phase Change HX): http://www.nasa.gov/mission_pages/station/research/experiments/2077.html

OsteoOmics investigation: http://www.nasa.gov/mission_pages/station/research/experiments/1284.html

Center for the Advancement of Science in Space (CASIS): http://www.iss-casis.org/

Heart Cells investigation studies: http://www.nasa.gov/mission_pages/station/research/experiments/1914.html

U.S. National Lab Maritime Awareness investigations: http://www.nasa.gov/mission_pages/station/research/experiments/1915.html

NanoRacks-Gumstix: http://www.nasa.gov/mission_pages/station/research/experiments/1873.html

NanoRacks-Nanotube Solar Cell investigation: http://www.nasa.gov/mission_pages/station/research/experiments/1874.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

Images (mentioned), Text, Credits: NASA’s Johnson Space Center/Kristine Rainey/International Space Station Program Science Office/Melissa Gaskill.

Best regards, Orbiter.ch

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