The image below intrigues me. It’s the first image of the Earth and the Moon together taken from a CubeSat, one of a pair of such tiny spacecraft NASA has despatched to Mars as part of a mission called MarCO (Mars Cube One), which will work in conjunction with the InSight lander. Taken on May 9, the photo was part of the process of testing the CubeSat’s high-gain antenna. But to me it’s a reminder of how far miniaturized technologies continue to advance.

Image: The first image captured by one of NASA’s Mars Cube One (MarCO) CubeSats. The image, which shows both the CubeSat’s unfolded high-gain antenna at right and the Earth and its moon in the center, was acquired by MarCO-B on May 9. Credit: NASA/JPL-Caltech.

As of this morning, we are 66 days away from InSight’s landing on Mars, at a distance of 65 million kilometers from Earth and 16 million kilometers to Mars. I don’t usually focus on Mars and lunar missions because this site’s specialty is deep space, which for our purposes means Jupiter and beyond, and of course the overall theme here is interstellar. But experimental technologies that bring us greater performance from very small payloads are certainly relevant.

Anything we can do to shrink payload size pays off as we look at ever more distant targets, and the cruise velocities and propellant needed to reach them. And CubeSats are a way of exploring small payloads. The standard 10×10×11 cm basic CubeSat is a ‘one unit’ (1U) CubeSat, but larger platforms of 6U and 12U allow more complex missions. With fixed satellite body dimensions, the CubeSat format creates a highly modular and integrated system.

What we have with the two MarCO spacecraft is the application of what had been a low-Earth orbit satellite technology to a planetary mission, with a useful goal. Trailing InSight by thousands of kilometers, they’ve already demonstrated their ability to operate in the interplanetary environment. At Mars, the intention is for them to relay data on InSight’s landing, a job consigned to Mars orbiters, but one this mission may show CubeSats are able to perform.

Image: Illustration of one of the twin MarCO spacecraft with some key components labeled. Front cover is left out to show some internal components. Antennas and solar arrays are in deployed configuration. Credit: NASA/JPL-Caltech.

Each of the MarCOs has its own high-gain antenna and the necessary radio equipment for data relay, with propulsion systems that have already made two steering maneuvers enroute. No one would claim the diminutive space travelers are as complex as conventional interplanetary craft, but I can see two goals here, the first of which leverages the ‘traditional’ CubeSat role of acting as low-cost entry-level ways to reach orbit.

“Our hope is that MarCO could help democratize deep space,” said Jakob Van Zyl, director of the Solar System Exploration Directorate at NASA’s Jet Propulsion Laboratory in Pasadena, California. “The technology is cheap enough that you could envision countries entering space that weren’t players in the past. Even universities could do this.”

Fair enough, as we’ve learned how satellites can be ‘piggybacked’ to open up access to space, lowering launch costs even as the cost of the CubeSats offers opportunities for inexpensive missions. Moreover, the fact that CubeSats can be built with standardized parts and systems, with key components provided by commercial partners, underscores their efficiency.

But let’s move beyond today’s current CubeSat. If we can build these craft strong enough to handle relay operations from Mars, we can contemplate future CubeSats capable of a wider range of science return and consider propulsion technologies like solar sails for ‘swarm’ missions to targets beyond Mars. Of particular interest is coupling CubeSats with solar sails for propulsion. Remember, for example, The Planetary Society’s LightSail-1, launched in 2015, which demonstrated sail deployment despite a series of major software glitches.

LightSail-2 is designed to demonstrate controlled solar sailing in the CubeSat format, with a sail of 32 square meters. A key goal of this mission is to raise the orbit apogee after sail deployment at 720 kilometers. I should also mention LightSail-3, which could take this technology out to the L1 Lagrangian point, where it would remain to monitor geomagnetic activity on the Sun.

NASA’s own future plans for CubeSat work take in BioSentinel, which would take living yeast (S. cerevisiae) into space to study DNA lesions caused by energetic particles, with operations expected to last 18 months at distances well beyond low Earth orbit. The NEA (Near-Earth Asteroid) Scout mission would take a CubeSat/sail to a small asteroid, exploring its rotational properties, spectral class, regional morphology and regolith, while Lunar Flashlight would achieve lunar orbit to study ice deposits on the Moon for the use of future explorers.

Image: Engineer Joel Steinkraus uses sunlight to test the solar arrays on one of the Mars Cube One (MarCO) spacecraft. Credit: NASA/JPL-Caltech.

I might likewise mention such European Space Agency efforts as GOMX-3, a CubeSat mission exploring the telecommunications capabilities of such craft. GOMX-3 was deployed from the International Space Station in October of 2015 and operated for a year before re-entering the atmosphere.

The list of upcoming missions under ESA’s In-Orbit Demonstration is extensive (you can see it here), and it’s noteworthy that the agency inserts at the top of its list of potential applications the fact that CubeSats can serve “As a driver for drastic miniaturisation of systems, ‘systems-on-chips’, and totally new approach to packaging and integration, multi-functional structures, embedded propulsion.”

So we can keep an eye on the MarCOs as a harbinger of CubeSat operations to come. All three of the future NASA CubeSat missions I’ve mentioned are designed to be launched as secondary payloads on a future Space Launch System (SLS) mission. But however we get such missions into space, they point toward further exploration of small payloads, a parameter space Breakthrough Starshot is pushing to the max in its plans for a centimeter-sized, gram-scale payload to be driven by laser propulsion at 20 percent of lightspeed to another star.