CubeSats are flying into space at a fairly regular rate. These are simplistic structures based on a standard “cube” structure measuring 10 centimetres on a side. That’s not a lot of volume, but as anyone who owns a smartphone knows, a lot of gear can be crammed into this space. Join several cubes together, and you can make larger satellites. Or you can go smaller. One recent mission used a CubeSat structure as a dispenser for a huge fleet of tiny satellites, each around 3.5 centimeters square, and less than a centimeter in depth!

More small satellites are planned for the future. More will be launched as constellations. The upcoming QB50 mission plans for 50 cubesats to launch simultaneously.

CubeSats and their cousins are making space more accessible than before. They use a lot of standard components and are cheap to build. They are helping students to gain apprenticeships in building satellites. Some technical projects wouldn’t make it to orbit in any other way. As financial austerity grips space activity around the world, we will probably find that these budget-friendly projects will become even more prominent.

Small satellites seem to have so many advantages, but are there any downsides? Admittedly, there are so many missions and projects that cannot be scaled down to these small proportions. Big birds will always fill our skies. The only potential problem that one could suggest for the small satellite revolution is the potential for more space junk. But will this really be a serious problem?

Let’s consider the orbits. Most CubeSats fly at fairly low altitudes. They will not stay in orbit for decades. Furthermore, their trajectories can be controlled from launch, and they can be tracked fairly easily with radar. We know where they are, and where they are going.

Most small satellites contain no propellants or explosive components. They will remain intact until they reenter. Fragmentation due to impacts with other objects is unlikely due to their small size.

In contrast to some other spacecraft, small satellites are normally deployed with a minimum of jetsam. They are often popped out of launch tubes with no other items released in the process. There will be fewer springs, bolts or rings to clutter nearby space.

When they return to Earth, they will be completely destroyed during reentry. There is no risk to people or property on the ground.

All things considered, the current revolution in small satellites probably poses less of a problem for space junk than many other space projects.

6 Responses

  1. KENNETH C JONES

    WHEN I FIRST HEARD ABOUT MICRO SATELLITES I IMMEDIATELY WAS CONCERNED WITH THEIR SMALL SIZE AND BEING MORE SPACE JUNK. HOWEVER THE AUTHOR STATES THAT WITH A LOW ORBIT THEY WILL EVENTUALLY BE SELF DESTROYING. INTERESTING

    Reply
    • Merryl Azriel
      Merryl Azriel

      At the moment CubeSats are launched into lower altitudes – without propulsive capability, their orbits degrade pretty quickly, from months to a couple years. So, for the moment at least, we probably don’t have to be too concerned. We will see what the future holds!

      Reply
  2. Larry J

    At 10cm on a side, cubesats are at the lower detection threshold for space surveillance network radars to track. Many of the existing radars have trouble tracking objects that small. Admittedly, their radar cross section may be higher than their physical size but don’t assume they’re easy to track. Fortunately, most will have their orbits decay within months to a few years after launch.

    Now, why is this site forcing me to type in all capital letters? I’m not shouting.

    Reply
  3. Hugh Lewis

    Nearly 40% of cubesats currently on orbit have lifetimes estimated to be greater than 25 years (I.e. are non-compliant with space debris mitigation guidelines). Cubesats appear regularly in conjunction lists. Discussion of the regulatory requirements for cubesats and engagement with the cubesat community are needed. I have to disagree with most of the opinions in this article.

    Reply
  4. Charles Pooley

    This problem disappears if it is realized that these LEO objects are not space exploration anymore, and addition of thousands of these is not likely to be tolerated. Thousands?

    If there is to be a “New Space Age” there must be accommodation for thousands of spacecraft. Consider the space between the orbits of Earth and Mars–literally a trillion times the volume of space compared to LEO.

    Microlaunchers is a plan to open large quantity low cost access in the form of very small spacecraft to, at first, photograph NEOs.

    Reply
    • Merryl Azriel
      Merryl Azriel

      LEO applications are critical to modern life on Earth. It may or may not be “exploration” (depends how you classify our many science missions) but we still need our weather satellites, telecommunication satellites, earth observation satellites…Somehow or other we’re going to have to figure out how to make LEO sustainable.

      Reply

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