While science and technology develops, we’re requesting our space missions to deliver additional benefits. This fact is exhibited by the MSL Curiosity as well as Perseverance rovers of NASA. Perseverance is an amazingly exquisite assemblage of technologies. These cutting-edge rovers require a huge amount of power, which means they require a great deal of bulky and costly power sources.
The exploration of space is becoming more and more energy intensive. At least as far away as Jupiter, orbiters as well as fly-by missions are able to use solar power to carry out their missions. And ion drives could send spacecraft to distant places. To comprehend distant worlds, including the moons of Jupiter and Saturn, or even distant Pluto, we will need to eventually land a rover and / or lander on them, just like we do on Mars.
For these missions, missions call for more energy, which usually means MMRTGs (Multi-Mission Radioisotope Thermoelectric Generators). But they are expensive, heavy and bulky, three attributes that are not good for spacecraft. Each one costs more than 100 billion dollars. Could there be a better option?
Stephen Polly believes that there is.
Polly is a scientist in the NanoPower Research Laboratories in the Rochester Institute of Technology. His work focuses on something that the majority of us have not actually heard of: Development, growth, description and integration of III-V components through metalorganic vapour phase epitaxy (MOVPE).
While that may seem complicated to non space enthusiasts, space enthusiasts could readily connect with what his work has led to: Operating space missions in a possibly new fashion.
In another area, Polly is focusing on an innovative way to power spacecraft on lengthy trips to the outer worlds. It is similar to an MMRTG, and it is known as a thermoradiative cellular (TRC). Its source of energy happens to be a radioisotope.
Polly employs a method called Metalorganic vapour phase epitaxy (MOVPE). It produces thin polycrystalline films by using chemical vapors. It’s an industrial process which is used in optoelectronics to produce things like LEDs (light emitting diodes). In her work, Polly uses MOVPE to create thermoradiative cells (TRCs).
TRCs use a radioisotope much like MMRTGs, and are derived from heat generated by radioactive decay, but there is a difference. The decomposition of the TRC heats it up and then emits light. Then the light enters a photovoltaic cell which produces electricity. It operates like a hybrid of solar power and an MMRTG.
But Polly is idea is so much smaller and that’s a holy grail for spacecraft engineering. “This device, driven by a radioisotope heat source, will allow an order of magnitude increase in mass-specific power (~30 vs ~3 W/kg) and also a three orders of magnitude decrease in volume (~0.2 vs ~212 L) as compared to a standard multi-mission radioisotope thermal generator (MMRTG),” Polly explained in a small press release.
“these devices could help revolutionize our space exploration pursuits,’ Polly wrote. It could result in a proliferation of small spacecraft which don’t need to carry heavy MMRTGs or unfurl big solar arrays. Because technological advancements continue to shrink scientific payloads, CubeSats will become a lot more useful if the power source is able to shrink together with it.
“This will immediately enable small-sat missions to the outer planets in addition to operations in permanent shadows, for example polar lunar craters,” said George Polly, a NASA planetary scientist. The technology is usually utilized in the first mission to Uranus. “We are going to evaluate a thermoradiative converter to provide power to a CubeSat (or fleet of CubeSats) that may ride along with a Flagship Uranus mission, doing such things as serving as info relay for atmospheric probes, and obtaining a parallax view of the world and moons.”
We’re all along for the ride—or at least our intellects and imaginations are—when we send spacecraft out into the Solar System to explore nature. If Polly’s work comes to fruition, and spacecraft can be built with smaller, more effective energy sources, the ride will get even more interesting.
Polly’s idea is a Phase One Selection in NIAC, the NASA Innovative Advanced Concepts Program. He’s received funding to develop the idea further.