I hear it again and again: ‘we aren’t even past the Moon yet.’ And by “we,” they mean “the uninformed.”
Here’s a loaf of bread: approx. 4x4x12 inches HWD. You’re looking at the future of space exploration: CubeSats in particular, and miniaturized craft in general. That’s right, probes that (in most cases) you can balance on your hand. The future will be discrete, scalable, and efficient. I said this the last time I got asked about space exploration. His response was ‘that’s not what I think is cool.” Sorry dude, the future made up its mind while you were uninformed.
~4x4x12 is actually a “3U” CubeSat; each “U” is defined as 10x10x10 cm, or 1 liter. Besides 1U birds flying right now, there are in fact sub-U designs for sale. That’s right, future space gets down to loaf leftovers, and at times a thick slice (0.2U).
So far, all these CubeSats have been in Earth orbit: no deep-space missions. That is about to change. One mission, INSPIRE (Interplanetary NanoSat Pathfinder In Relevant Environment), is being built by the Jet Propulsion Laboratory, the University of Michigan, and private contractors. INSPIRE will slowly creep to the Moon using ion thrusters. As there are no humans onboard (ridiculous), the highly-efficient electric propulsion can take its time. With no one eating, drinking, breathing, and excreting, electric propulsion runs its efficient course. Electric thrusters are an order of magnitude more mass-efficient than conventional, chemical-fueled thrusters. But they generate low thrust levels, so maneuvers and missions stretch from hours and days to weeks and months. INSPIRE is a 3U design, since surface area is needed for solar arrays to power the electric thrusters.
For other missions, 1U is okay and cheap, and sometimes even smaller. Private companies, government organizations, and universities have inexpensively launched experiments and cameras in 1U. (You thought the GoPro was extreme?) Some field tests of space electronics will take place in 0.2U “Cube slices.” After the INSPIRE field tests, future probes to the Moon and beyond will more likely be 6U- imagine two loaves of bread side by side. Many things can be shrunk, but some can’t, so 6U gives room for the more interesting missions. The same 1U boards and components will slot into larger sizes just fine. Still, most builders prefer 2U or 3U. That’s the beauty of the CubeSat platform: it’s a scalable platform, not a single design. It’s more like a beige-tower PC than a tightly-integrated smartphone, in more ways than one. You can build your own desktop, by ordering the standardized components cheaply. The same principle works for miniaturized spacecraft. After the platform specifications were released, other groups proposed sizes like 1.5U and 6U- one good idea, released into the engineering ecosystem, will then attract others.
CubeSats are hardly alone here. The US government has designs going down to this size class, of which the average person is uninformed. As have the Canadians and British and French, plus private firms. The future is coming, quietly and efficiently. Ever wonder what else is coming while you weren’t looking? Next: ChipSats or Sprites, essentially flying SOCs (Systems On a Chip). Yup, satellites and probes you can balance on your finger, carried and deployed by CubeSats, for a lot less bread.