MIT Develops Inflatable Antenna

Satellites the size of shoe boxes, which are expected to one day allow researchers to explore space more efficiently, will soon have greater range.

MIT researchers have built and tested an inflatable antenna that can fold into such a satellite, then inflate in orbit to enable long range communications — from seven times the distance possible today.

The technology will let the small satellites, called CubeSats, move further into space and send valuable information to scientists back on earth.

“With this antenna, you could transmit from the moon, and even farther than that,” said Alessandra Babuscia, a researcher on the inflatable antenna team at MIT, in a statement. “This antenna is one of the cheapest and most economical solutions to the problem of communication. But all this research builds a set of options to allow the spacecraft … to fly in deep space.”

The MIT effort comes as engineers at the University of Michigan work on ways to propel such small spacecraft into interplanetary space. The team is building a plasma thruster that could fit in a 10-centimeter space and push a small satellite-bearing spacecraft into deep space.

The university researchers using superheated plasma that would push through a magnetic field to propel a CubeSat.

The MIT researchers are seeking to solve the communications problems and enable far-afield CubeSats to send data to and receive instructions from Earth.

The CubeSat devices cannot support radio dishes that are used today to let spacecraft communicate when far from Earth’s orbit.

The inflatable antennas significantly amplifies radio signals, allowing a CubeSat to transmit data back to Earth at a higher rate, according to the university.

MIT engineers have built two prototype antennae, each a meter wide, out of Mylar, which is a polyester film known for its strength and use as an electric insulator. One antenna was a cone shape, while the other looks more like a cylinder when inflated. Each fits into a 10-cubic-centimeter space within a CubeSat.

Each prototype contains a few grams of benzoic acid, which can be converted to a gas to inflate the antenna, MIT noted.

In testing, the cylindrical antenna performed “slightly better” than the cone shaped device, transmitting data 10 times faster, and seven times farther than existing CubeSat antennae.

Source

Is Iridium A Friend Of Cellular Phones?

Cellular phones squashed Iridium once, but in its second coming the satellite phone maker and owner of the biggest satellite fleet is relying on them to resurrect their business.

For all their seeming ubiquity, cellular services cover only about 8 percent of the globe, leaving large regions where the only way to communicate is to use a satphone made by Iridium Communications Inc or one of its smaller competitors.

“The need for communication devices and services where terrestrial can’t be there is rising, and as bandwidth needs increase it’s surely helping Iridium,” Macquarie Research analyst Amy Yong said.

Investors have taken notice, pushing up the stock of the company nearly 50 percent over the past eight months.

“It’s a different company, with a prudent and successful financial model,” Raymond James analyst Chris Quilty said.

“They’re growing, they have extraordinarily high barriers to entry and some of the end markets and applications they’re targeting are vast and untapped,” he said.

Unlike its competitors, Iridium’s satellite constellation covers the entire globe, including the poles, and its array of 66 satellites dwarfs the fleets of its rivals. Inmarsat Plc has 11; GlobalStar has eight and is aiming to have 32 in orbit by the year-end; Thuraya has three, with one planned.

Source…