 |
 |
 |
|
|
|
|
|
|
||||||||||||||||||
|
|
|||||||||||||||||||
|
|
|||||||||||||||||||
|
|||||
|
|
 Previous: Amateur Groups to Attempt Transatlantic 2-Meter Contact |  Next: In Brief |
NEWINGTON, CT, Jun 22, 1999--The next Space Amateur Radio EXperiment mission--set to launch in July--will field test a digital signal processing box NASA is looking at to improve the quality of shuttle communications audio.
Word from NASA is that the next SAREX mission has been scheduled to launch on July 20 at 0436 UTC aboard shuttle Columbia mission STS-93. The shuttle mission, which will deploy the Chandra Observatory into orbit, already has been delayed several times.
The STS-93 Mission Commander is Eileen M. Collins, KD5EDS. Also aboard will be Mission Specialist Michel Tognini, KD5EJZ, and Mission Specialist Catherine G. Coleman, KC5ZTH.
Students at five schools--in Texas, Rhode Island, Virginia, and Florida--are on the list to talk to the STS-93 crew via Amateur Radio. And that's where the DSP experiment comes into play. NASA's SAREX Principal Investigator Matt Bordelon, KC5BTL, says the agency's contractors have been exploring ways to make improvements to the aging shuttle fleet. Among the possibilities was improving the intelligibility of shuttle communications audio by using DSP.
But Bordelon says making and testing these kinds of changes on the astronauts' communication system gets expensive and involved, so it was decided to first try out a DSP box by Quintronix on the less-critical SAREX payload aboard STS-93 to see how it performed under actual spaceflight conditions.
"They wanted an easy way to determine if this would clean up the audio," Bordelon explained. The SAREX Amateur Radio gear uses standard interfaces, so it was an easy match from a hardware standpoint. Bordelon says he thinks SAREX will provide a good test of the DSP hardware/software package.
"It's a box with a headset connection on one end and the connectors to the equipment on the other," he explained. "It's got a couple of switches on it, and it's battery-powered," so it doesn't need to take power from the shuttle itself.
Bordelon says the two-channel DSP box tailors both the transmit and receive audio, but it is not adjustable. The only thing the operator can do is turn the box on or off and either enable or disable it.
"For anything in spaceflight, you want to keep it as simple as possible," he said.
The Quintronix DSP box will interface with one of the old reliable Motorola MX-360 H-Ts that NASA has been using for SAREX flights for nearly two decades now--the same type of transceiver that astronaut Owen Garriott, W5LFL, used to make the first Amateur Radio contacts from space in 1983.
NASA has dubbed this particular SAREX hardware configuration as "Configuration CQ." Bordelon explains that SAREX is comprised of several different configurations of hardware, each one designated by a letter of the alphabet. "We typically use Configuration C on most shuttle missions," he said. Add the Quintronix DSP box to the mix, Bordelon says and "you could either say that we merged the two together for a purely coincidental name or, that it embodies the true spirit of Amateur Radio for this mission."
STS-93 will mark the 25th time that the Space Amateur Radio EXperiment has flown. It's also the only SAREX flight scheduled for 1999 and the last one scheduled to take place from the shuttle fleet. Bordelon says future shuttle missions will be "way too busy" to accommodate SAREX. The Amateur Radio on the International Space Station program is working toward establishing a permanent Amateur Radio presence in space aboard the ISS. An interim Amateur Radio station should be operational from the ISS by early next year.
The SAREX program is a cooperative venture of NASA, AMSAT, and the ARRL. For more information on SAREX, contact Jean Wolfgang, WB3IOS, e-mail jwolfgang@arrl.org.
| Previous: Amateur Groups to Attempt Transatlantic 2-Meter Contact | Next: In Brief |
