Project Hermes: New horizons in satellite communications
Suppose it were possible for a seismologist to open a mobile phone app and command a satellite to take pictures of an earthquake in progress many miles away.
Such scenarios could become a reality in the future, as a result of new approaches to satellite communications being pioneered at Capitol College by astronautical engineering professor Risabh Maharaja and a team of students.
Their endeavor, dubbed Project Hermes (“High Elevation Remote Elevation Messenger”), aims to develop a system that uses TCP-IP – the same protocol used on the internet – to communicate and control high-altitude payloads. Such an approach allows for web-based telemetry and command systems; any device that can connect to the internet can be used.
In April and May, the concept was tested during two high-altitude balloon flights supported by the University of Maryland Space Systems Laboratory, with funding from the Maryland Space Grant Consortium.
“The first flight, on April 12th, took us up to 70,000 to 78,000 feet,” Maharaja explains. “The idea was to send commands to our payload and take a picture. Due to certain app issues, we weren’t able to take the picture, but our device did receive all the commands that we sent it. We came back with some ‘lessons learned’ and then flew again on May 3rd. On that second flight, where we launched to 82,000 feet, we were able to send 346 commands and take 346 pictures.”
The team’s next milestone will be to conduct tests at suborbital levels, to see if the system works at the altitude reached by Alan Shepard during his historic 1961 flight. Eventually, the research will move from balloon launches to actual satellites.
On-demand, real-time interaction with satellites has a wide range of potential applications, not only in science but in fields such as aviation, according to Maharaja.
At NASA, he said, mission operations have currently have to wait for a satellite to come within view of their own ground or relay satellites in order to communicate or receive data. “But if they use our Capitol College research, they could maintain communication using commercial satellites with ordinary internet TCP/IP, with potentially higher bandwidth and quicker response times than conventional methods," he said.
System could make flying safer
Similar capabilities could help fix holes in airline security of the kind highlighted by the March disappearance of a Malaysian jetliner bound for Beijing. Malaysia Airlines Flight 370’s transponder went offline less than an hour after takeoff, and the airline subsequently flew out of radar range. Although it is thought to have crashed in the southern Indian Ocean, not a shred of wreckage has been found to this date.
Clues to the airliner’s trajectory came from a satellite data link that continued to transmit automated “pings” after the transponder went off. Inmarsat, the British satellite company that operates the system, has since offered a free tracking service to all airlines, capable of sending out key information at 15-minute intervals.
According to Maharaja, the system being developed at Capitol College provides even more robust monitoring.
“Firstly, we can do it faster than in 15-minute intervals,” he said. “Secondly, because we have commanding involved, and it's a completely separate system, the pilot can't turn it off.”
With such capabilities at their disposal, airlines can conduct flight tracking at their own facilities, without relying on services such as Inmarsat, or on air traffic controllers, Maharaja said. At any time, they can send a command to photograph what is going on inside an airplane; with the right equipment installed, they can then downlink the image in real time.
“Our research can provide more services than are available at present, thus boosting safety and providing airlines with greater independence and increased options,” he said.
Getting Project Hermes off the ground would not have been possible without a dedicated team of student researchers from the astronautical and computer engineering technology programs at Capitol. The college emphasizes in-the-field experience as a cornerstone of its approach to training, and students are encouraged to become fully involved in both the conception and execution of new technological approaches.
For the April and May launches, James Aaron Bush and Jeff Williams worked on configuring satellite communications gear pairing. Edwin Boateng programmed smartphone devices, while Jamie Hassett focused on programming the TASKER app, which translated the commandsfor taking photos. Several team members were involved in building the structures used in the project.
In addition to its use of internet protocols, the project also included a standard communications method – low bandwidth UHF frequencies – as a backup should the main system be disabled, as well as to highlight the vast performance gains achieved using the TCP/IP channel. The radio backup was developed and operated by a fifth team member, Carl Hansen.
During the balloon launches, Hansen used ham radio transceivers to operate a subsystem that carried a UHF “heartbeat signal” capable of being detected from the balloon during its flight. “It worked flawlessly,” he said. “However, it was only transmitting one half bit per second.”
“The plan down the road, as Hermes gets closer to becoming a satellite, is to actually implement coding so we can communicate via the backup is needed,” Hansen said.
Photos: 1) A view from the earth taken by Hermes during its May launch; 2) team member James Aaron Bush, 3) view of the Hermes payload (second object from lower left).