Ka-Band: The Future of Space Communications

JAXA astronaut Akihiko Hoshide performs maintenance work on the International Space Station during an Expedition 32 spacewalk. 

Antennas in the background include those being used for the SCaN Testbed's testing of software defined radios in S-band and Ka-band. 

Image courtesy NASA. 

Imagine you're in a restaurant and it's nearly empty.

You can talk to your companions, low-volume, easy and relaxed. But then more patrons start arriving and it gets more and more crowded.

The noise level rises; you have to shout to be heard. There's no room to move.

That's a picture of the demands on the world's communication frequency bands. Cellular phones, streaming entertainment, data communications, civil and commercial providers; they are all placing incredible strains on available spectrum bandwidth.

SCaN Testbed

In the electromagnetic spectrum, many NASA missions use what is referred to as S-band, and commercial businesses are putting pressure on the government to free up other bands within the electromagnetic spectrum.

NASA saw this trend years ago and started opening up a new part of the electromagnetic spectrum called Ka-band.

With the need to speed up transmission of high-rate science data from space missions, Ka-band, at 26 GHz, is now considered the spectrum of the future for NASA communications.

Compared with S-band, Ka-band has data transmission rates that are hundreds of times faster.

It's like the difference between the television antennas perched on houses decades ago that used transmission frequency called VHF or Very High Frequency and the satellite antenna dishes used today that use a much higher frequency, 50 times higher than VHF.

Those old antennas worked on frequencies that delivered one channel at a time whereas the TV antenna technology of today uses higher frequencies to deliver hundreds of shows to viewers.

But operating in Ka-band requires new hardware and software. Engineers at NASA's Glenn Research Center in Cleveland and the Harris Corporation developed a radio that uses software to leverage the vast resources of Ka-band. R and D Magazine recognized this design in 2013 with its R and D 100 Award.

Richard Reinhart

"Every mission has a different set of needs," says Richard Reinhart, principal investigator for NASA's Space Communications and Navigation SCaN Testbed, where these radios are being put through their scientific paces aboard the International Space Station.

The testbed is being used to test and demonstrate NASA'S cutting-edge communications, networking and navigation technologies in the challenging environment of space.

"Software defined radios (SDR) allow us to upload new software to hardware already deployed in space. We can extend missions, solve problems and even adapt to new science opportunities by changing and adapting new software," adds Reinhart.

"Because these are signal processing platforms, or computers with an antenna, we can upload new software from the ground to change what the radio does," explains Reinhart.

"It still operates within Ka-band, but we can move the signal around because the electronics enable both signal and frequency flexibility and, for the SCaN Testbed system, we can change the data rate to anything we want between zero and 400 megabits-per-second."

"Why would we want to do that? When a mission goes up, it's generally designed to run at the same data rate throughout the whole mission but what if the transmitter starts to degrade or we detect interference?

We can back the signal rate down to whatever our communications system gives us and maybe extend the mission.

Maybe an antenna doesn't deploy enough; we can figure out what is left and change the software to accommodate whatever the system gives us," says Reinhart.

While there are a few missions sending data on Ka-band direct to Earth stations, the SCaN Testbed's radios are the first NASA mission to transmit through the Tracking and Data Relay Satellite (TDRS) system, a constellation of NASA communications satellites.

The advantage of this system is that data can be communicated from space to Earth 24 hours a day; whereas direct to Earth can only occur when receiving stations come in line with a direct satellite signal.

SETI Live: Online Project Lets ‘Citizen Scientists’ Help Search for Aliens

SETI (Search for Extraterrestrial Intelligence) Institute, has launched a new website, which invites anyone to log on and help analyze signals from space that could provide evidence of intelligent alien life in the universe.

SETI Live provides data gathered by the Institute's Allen Telescope Array, which scans sections of space for radio frequency signals.



Web users can log on to the site and help analyze the data, sifting through signals for evidence of an extraterrestrial civilization.

"There are parts of the spectrum where our sophisticated signal processing system is overwhelmed because there are so many signals," said astronomer Jill Tarter, director of the Center for SETI Research, in an interview. "I'm hoping to put together this army of citizen scientists to help figure out which signals to follow up on."

Essentially, human eyes are needed to pick up on subtle patterns that might be overlooked by SETI computer algorithms.

"The people that will do the best at this are going to be people whose pattern skills are such that they can ignore the bright pattern that's so easy to detect and look to see that there's something else there, something fainter, and see if they can in fact discover this needle that's buried under the hay," Jill Tarter stated.

SETI Live came out of the TED Prize program, which awards $100,000 every year to an "exceptional individual" with "One Wish to Change the World."

Jill Tarter won the prize in 2009, revealing her wish to "to empower Earthlings everywhere to become active participants in the ultimate search for cosmic company." Her wish developed into SETI Live.

SETI Institute scientists have been searching for signs of intelligent alien life since the 1960s, but have yet to find anything. With the discovery of 700 extra-solar planets, the search for extraterrestrial life has become much more targeted in these regions of space.

SETI: Astronomers Resume Search for Intelligent Alien Life

Allen Telescope Array

CREDIT: SETI.org

Astronomers have rebooted their search for intelligent life on alien planets, and they've got thousands of targets to scan.

After hibernating for more than seven months, a set of radio telescopes run by the SETI (Search for Extraterrestrial Intelligence) Institute has once again begun listening for signals from the many alien planet candidates discovered by NASA's Kepler space telescope, researchers announced Monday (Dec. 5).

"This morning, at 6:18, we began re-observing the Kepler worlds," Jill Tarter, director of the Center for SETI Research at the SETI Institute, said Monday during the Kepler Science Conference here at NASA's Ames Research Center. "We're just extremely excited to be back on the air today."

SETI's Allen Telescope Array (ATA) is a set of 42 radio dishes located about 300 miles (500 kilometers) northeast of San Francisco. It began scanning the heavens for "technosignatures" — electromagnetic signals that could betray the presence of an intelligent alien civilization — in 2007.

SETI researchers recently started using Kepler's discoveries to guide the ATA's activities. Kepler launched in March 2009 on a mission to hunt for Earth-size planets in their parent stars' habitable zone, that just-right range of distances where liquid water — and perhaps life as we know it — could exist.

In January of this year, Tarter said, the SETI team started training the Allen array on the 54 planet candidates Kepler had detected in the habitable zone to date.

The work didn't last long, however. SETI had to shut the ATA down in April after budget problems forced the Institute's former partner, the University of California, Berkeley, to withdraw from the project.

SETI launched a crowdfunding site, www.setistars.org, in an attempt to get the array back up and running. And the public came through, donating enough money to take the ATA out of mothballs. As of Monday, citizens had chipped in more than $230,000.

Some funding help has also come from the United States Air Force, which is interested in using the array to track satellites and space debris, SETI officials said.

Many new worlds to scan
On Monday, the Kepler team announced the discovery of 1,094 new exoplanet candidates, bringing to 2,326 the total number of potential alien worlds the instrument has detected in its first 16 months of operation.

Researchers have confirmed only about 30 of these candidate planets to date, but Kepler scientists have estimated that at least 80 percent of them will end up being the real deal.

The ATA will take special interest in Kepler's candidates in the habitable zone, Tarter said. But SETI researchers hope to scan every last one of the potential planets to minimize the chances that we're blinded by our assumptions about where life "should" be.

"What we think we know actually might be a barrier to finding what is actually out there," Tarter said. "We intend to systematically explore all of these candidates."

The search of the Kepler candidates will involve scanning 9 billion different channels in a broad window of microwave frequencies. It should take two to three years, at $1.2 million per year, to search for signals from every potential alien world from the study, Tarter said.

It's exciting to focus the ATA on likely alien solar systems rather than just point the dishes toward stars and hope for the best, she added.

"We now know where to look for planets," Tarter said. "We're going to take the public's quest for technosignatures to the next level."

ISRO refuses to part with minutes of Space Commission meetings

The Indian Space Research Organisation has refused to make public the minutes of meetings of the Space Commission where the controversial Antrix-Devas deal was discussed.

Replying to an RTI application, ISRO said the minutes of the Space Commission meetings where the deal between its commercial arm Antrix Corporation and Devas Multimedia over the leasing of scarce S-band spectrum was discussed cannot be provided as they relate to national security.

Last July, the Commission had recommended annulment of the contract with Devas under which the private firm, floated by ex-ISRO officials, was to get on lease 90 per cent of the S-band transponders on two satellites - GSAT 6 and GSAT 6A for its novel Digital Broadcast Audio Service.

After uproar over the issue, the Cabinet Committee of Security headed by the Prime Minister decided to annul the deal on February 17.

The RTI applicant had sought to know from the Department of Space the minutes of all Space Commission meetings since 2005 where issue of the Devas-Antrix deal, which has now been annulled, had figured.

Section 10 of the RTI Act has severability clause which allows a public authority to remove the information, which is exempted from disclosure under the transparency law but the Central Public Information Officer of the ISRO did not apply the clause and summarily rejected the application saying, "Information is related to security and scientific interests of the State."

Antrix had signed the contract in January 2005 and had got sanction of the Space Commission and the Union Cabinet for the two satellites without informing them that bulk capacity would be leased to Devas Multimedia.

In December 2009, the ISRO ordered a review of the deal, and subsequently, the Space Commission recommended its annulment on July 2, 2010.

NASA Working to Boost Speed of Space Communications

View of the Canberra Complex showing the 70m (230 ft.) antenna and the 34m (110 ft.) antennas. The Canberra Deep Space Communications Complex, located outside Canberra, Australia, is one of the three complexes which comprise NASA's Deep Space Network. The other complexes are located in Goldstone, California, and Madrid, Spain

Rovers and deep space probes can forget about quickly posting cool high-definition videos to YouTube, given the painfully slow data transfer rates for most of today's space missions.

But NASA wants to change that by fusing together three aged space communication networks into a much faster, more efficient data network worthy of 21st century missions to the moon, Mars and beyond. And it hopes to do it all without costing taxpayers an extra cent.

NASA's overhaul aims to boost space communication by as much as 50 times faster than today's data transfer rates, so that a Mars mission squeaking by on a few megabits per second might someday get as much as 600 megabits per second, if not more. That could enable far more scientific payoff per mission in the long run.

"Imagine what you can accomplish with a single mission instead of several spacecraft flying over several years to collect the data," said Badri Younes, NASA's deputy associate administrator for Space Communications and Navigation.

An upgraded network might support the very quick upload or download of huge video files the size of an HD YouTube video, as opposed to current capabilities that would struggle to transfer mp3 music files.

Younes worked at NASA's Goddard Space Flight Center for a decade before leaving to join the U.S. Department of Defense. But the U.S. space agency hired him back in August 2007 for the purpose of revolutionizing its space communication networks.