On February 14, geostationary communications satellite company Astranis announced that it had been awarded a contract with the US Space Force worth over $10 million. The contract is to first demonstrate a secure comms technique on the satellite hardware in a terrestrial test setting, and also includes the possibility of testing it in space.
Space remains a useful place for countries to place sensors that look down on other nations. Many of these satellites reside in low Earth orbit, or about 1,200 miles above the surface, which is easier for satellites to reach and lets satellites circle the globe rapidly. Geostationary orbit, which is 22,200 miles above ground, is harder to get to. Plus, satellites at all altitudes risk having signals jammed, or being disrupted by other objects in orbit, which has led the US military to pursue satellite constellations, or formations of smaller satellites, as a way to ensure that some functionality persists in the event of attack or disaster.
“We build small satellites for higher orbits, starting with geostationary orbit, which is quite a higher orbit,” says Astranis co-founder and CEO John Gedmark. “It’s the special orbit where you can park a single satellite over a part of the world or over a country and provide continuous service with just that one satellite.”
Over Alaska and Peru
Geostationary satellites have been used to provide communications and television broadcasts, and Astranis’ primary aim for both commercial and military customers is to use smaller geostationary satellites to provide continuous broadband-level internet connections. For two demonstrations of commercial uses, Gedmark points to upcoming launches placing satellites above Alaska (scheduled for early April), and one later this year that will put a satellite above Peru.
“This is a satellite that’ll go up over Peru and also provide some coverage in Ecuador. We will basically allow them to go and deploy and upgrade a number of cell towers out in some of the most remote parts of the country,” said Gedmark. “There’s a lot of parts of Peru where the terrain is just super rough and pretty extreme in the jungles, they have Andes mountains, they have a lot of things that make it very hard to get connectivity out to some of these remote areas.”
In both these places, the satellites will augment existing telecommunications infrastructure on the ground, letting remote towers connect through space instead of over land. Peru, like Alaska, contains vast stretches of varying terrain, where infrastructure such as wires, cables, or fiber internet connections can be hard to place. Freestanding cell phone towers can be set up, powered locally, and then route their communications through satellites instead of over-land wires, bringing 3G and 4G levels of internet to places people could not previously access it.
For military use
Those same traits, for connecting local rural infrastructure to wider data networks through space, are part of what makes Astranis satellites so appealing to the military.
“We realized that the military has this real problem right now for milsatcom and for some other capabilities around resiliency, right? They are really dependent on a small handful of these giant geo satellites, some of which cost billions of dollars. And those satellites are, as we like to quote General Hyten on this, big fat and juicy targets,” said Gedmark.
In 2017, Air Force General John Hyten was the head of US Strategic Command, and announced that he would no longer “support the development any further of large, big, fat, juicy targets,” referring to those types of satellites. Hyten retired in 2021, but the Department of Defense has continued to push for smaller satellites to fill the skies, as a more resilient option than all-in-one massive satellites of the present. Many of these constellations are aimed at low earth orbit.
“Without getting into specific pricing, we could put up about a dozen or more of our satellites for the cost of one of the big ones,” says Gedmark. Since 2018, Astranis has attracted venture funding on its premise to put satellites into geostationary orbit.
“It’s hard to design all the electronics for the harsh radiation environment of geo, you’re right in the thick of the Van Allen belts,” says Gedmark. The Van Allen belts contain charged particles that can damage satellites, so anything built to survive has to endure the heavy ion strikes and radiation dosages inherent to the region. “These higher orbits are harder to get to, so you have to solve that with some clever onboard propulsion strategies. We solve that by having an electric propulsion system, and having an ion thruster on board.”
When launched, the satellites are aimed towards geostationary orbit, and then use their own power to reach and maneuver in space. Gedmark says the satellites are designed to stay in geostationary orbit for between 8 and 10 years, with the ability to relocate up to 30 times in that period.
The speed at which the satellites can be maneuvered from one orbit to another depends on how much fuel the satellite operators are willing to expend, with repositioning possible in days, though Gedmark expects moving to a new location in weeks will be the more typical use case.
Once in orbit, the satellites need to communicate securely. The Protected Tactical Waveform is a communications protocol and technique developed by the US military, which Astranis aims to demonstrate can be run on the software-defined radio of its satellites. (A software-defined radio is a computer that can change its parameters for transmitting and receiving information with code, while a more traditional radio requires analog hardware, like modulators and amplifiers, to encode and decode information from radio signals.)
The Protected Tactical Waveform is “a set of techniques that are programmed into the radio so it can automatically avoid jamming and interference,” says Gedmark. “We’re gonna start by doing that as a demo in our lab, and then with the future satellites do that as an on orbit demo.”
Because this protocol will run on software radio, rather than hardware that is fixed on form once launched, it likely means that should the need arise, Astranis could adapt existing commercial satellites to carry the Protected Tactical Waveform, while it remains in orbit, facilitating the surge communications as events arise and to meet military need.
For now, the promise is that private investment in communication tech can yield a tool useful both for expanding internet connectivity across the globe, and for providing communications to US military forces in the field faster than it would take to set up ground-based infrastructure. For the Space Force, which is tasked with ensuring reliable communications across the heavens, more durable satellites that can be maneuvered as needed would allow it to redeploy assets across the skies to win wars on Earth.
Source : Popular Science