Researchers use liquid crystal to replace space motors

ScienceDaily (Sep. 22, 2011) — Researchers at the Institute of Electronics, Communications and Information Technology (ECIT) and the Northern Ireland Semiconductor Research Centre (NISRC) at Queen's University Belfast have devised a way to eliminate the need for motors in space borne radiometers by incorporating liquid crystals in their Frequency Selective Surface (FSS) antenna arrays.

The project has attracted funding of £0.5 million from the European Space Agency (ESA) and £100,000 from economic development agency, Invest Northern Ireland. It is expected to result in significant weight savings in satellite payloads and greatly reduced power consumption in weather monitoring instruments.

The technology has other important potential applications as well. These include eradicating the attenuation of mobile phone signals passing through energy efficient glass and creating buildings that can be locked down to block radio signals at the flick of a switch.

The innovative ECIT project addresses frequencies ranging from millimeter wave up to 1 THz. Measuring radiation in this waveband is a key technique used to study Earth's atmosphere to improve global weather forecasting and understanding of climate change.

Current generation remote sensing radiometers that collect this data incorporate a turntable-mounted mirror operated by an electric motor to calibrate the instrument before each scan by directing their field of view between cold and ambient targets.

The ECIT/NISRC research team however has devised a technique for making such motors redundant. This involves sandwiching layers of liquid crystals between the FSS's metalized quartz layers to act as an electronically controlled shutter. Applying a small voltage to the structure then enables the radiometer to be switched from calibration mode to signal detection mode without mechanical components.

The team believes that using this technique to replace the motor and turntable could produce potential weight savings of 10 per cent per radiometer. It would also greatly reduce power consumption requirements as a motor represents a radiometer's single biggest power requirement.

Prototypes are being built at Queen's University's Northern Ireland Semiconductor Research Centre with ESA support and the devices are expected to be used in space missions from 2025 onwards.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Queen's University, Belfast, via AlphaGalileo.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Plans for crewless space station underway

NASA astronauts Ron Garan (left) and Mike Fossum held a news conference from the space station Tuesday. NASA TV

Ground crews are making plans to possibly operate the International Space Station without crew for awhile, but preparations are not yet underway in space.

"The teams in Houston are in the preliminary stages of deciding everything from what ventilation we’re going to leave running, what lights we’re going to leave on, what condition of each particular experiment will be on, every tank, every valve, every hatch – there’s a lot to do," said NASA astronaut Mike Fossum at a news conference from the International Space Station with fellow NASA astronaut Ron Garan Tuesday.

The details will be shared with astronauts in the weeks ahead, he added, and they will have plenty of time to implement them.

In the meantime, the only preparations that the astronauts have been making so far is to document some of their space station work using video, in order to hand it over to the first crew to repopulate the space station. Up until now, all such handovers have been done face-to-face.

On Aug. 29, NASA had disclosed that following the crash of the Russian Progress unmanned cargo space ship on Aug. 24, some astronaut trips to and from the space station will be delayed.

The delays will give the Russian space agency time to investigate the accident and make sure the problem that caused it has been resolved. Following the retirement of NASA's shuttle fleet, astronauts are currently transported to the station aboard Soyuz spacecraft, which use the same rockets that failed during the Progress launch. U.S. and Russian space agency officials do not plan to make any manned launches until there have been at least one or two successful unmanned spacecraft launches with the rockets.

By the time that happens, all astronauts currently aboard the station may have already returned, leaving the space station crewless for the first time in more than 10 years.

Garan and two other astronauts are scheduled to return to Earth on Sept. 15, a week after their original planned return date of Sept. 8.

Fossum and the other two remaining astronauts on the space station are scheduled to return in mid-November.

Currently, the next Soyuz flight to the space station is scheduled to arrive on Nov. 2, before the return of Fossum's expedition.

But Fossum said the possibility that it will be delayed remains, as "there’s a lot of things that need to stack up to make that [flight] happen."

He noted that troubleshooting a rocket isn't easy and could take a long time if the problem doesn't involve obvious recent hardware, software or process changes.

If the space station does need to go crewless, the risk to the space station is low provided it remains crewless for a short time, Fossum said. The types of problems that are most likely to pose an issue without crew are things like the failure of a pump last year that knocked out half the station's cooling capability, which are not that serious in the short term but do reduce the station's ability to tolerate other failures.

"As that short gap turns into many months... it leads toward a greater possibility that we would have a problem up here that became very significant with nobody to take action."

Accessibility Links

View the original article here

Sharing Office Space

Sorry, I could not read the content fromt this page.

View the original article here