Introduction
Cubesats (or nanosatellites) represent an important chapter in the history of New Space that may have been eclipsed by more glamorous stories of SpaceX, Rocket Lab or other players in launch industry. Nevertheless, emergence of simpler and cheaper satellite designs allowed smaller teams with smaller budgets to participate in space exploration. Notably, the first cubesats were launched a year before the flight of SpaceShipOne in October 2004, the first major event of New Space epoch.
First missions
Original cubesat specifications were published in year 2000 by Space System Development Lab of Stanford University. But the first real cubesats were launched on June 30, 2003 on a Rokot launch vehicle (a converted ICBM) as a secondary payloads, while MOST, a Canadian space telescope was one of the primary ones. They all were deployed into relatively high-altitude circular orbits with altitude over 800 kilometers and therefore still in orbit as of 2020. The missions and fates of all those satellites were very different and illustrative of both capabilities and limitations of the early cubesats. Let’s have a look at each of those missions in more details, starting with less fortunate ones:
- CANX-1 was a 1U cubesat designed by University of Toronto, Canada. It was rather sophisticated for an early one, having an imaging camera, GPS receiver and proper attitude control and communication subsystems. Sadly, it never came alive after deployment and no signal was ever received from it. However it was not the last cubesat from University of Toronto Institute for Aerospace Studies and their later cubesat missions, starting with CANX-2, enjoyed more success.
- The next in the list of less-than-fortunate ones was DTUSAT cubesat, another 1U one from Technical University of Denmark. Its primary mission was a deployment of electrodynamic tether and the secondary mission was Earth observation, meaning it had an imaging camera. It could be a pretty interesting mission, but again the satellite was dead after deployment, with no signal ever received from them.
- The fate of AAUSAT-1, another Danish 1U cubesat from University of Aalborg was somewhat more fortunate. Its payload included an imaging camera as well. It became alive after launch and some radio signals were received from it. However, there were some problems with communications subsystem and those signals were very weak. Not much useful data were extracted on the ground. It was able to operate for two and a half months before its battery degraded. Still, it was a major step forward for cubesats in general.
- QuakeSat from already mentioned Stanford Space System Development Lab was a mission to detect Extremely Low Frequency electromagnetic waves for potential earthquake prediction. It was a considerably larger cubesat, in 3U form-factor, that is 30x10x10 centimeters. Its mission was a lot more successful than of previously mentioned ones. The satellite operated for a year and half, producing valuable scientific results (short-duration ELF emissions were indeed detected, but reliable monitoring of these events requires funding beyond the scope of a single satellite mission). Here is another interesting fact about it: the RF transmitting power of this satellite was approximately 1 Watt, same as the transmitting power of the first satellite launched ever, Sputnik-1, back in 1957.
- Next came two missions from Japanese universities. The first one to describe was named CUTE-1. It was designed by Tokyo Institute of Technology and its mission was testing transmission protocols for the space-to-ground communications. As with Quakesat before, this mission was also quite successful. It was fully operational at least until 2012, a very long time, considering the average cubesat lifetime is around two years. What is even more impressive is that CUTE-1 is still transmitting telemetry data, after almost 17 years of operations!
But another mission from Japanese team, 1U cubesat XI-IV has demonstrated even more impressive results. It was designed and built by University of Tokyo and had the primary mission of Earth Observation, meaning it had an imaging camera on board. And it was fully operational as late as June 2019, still able to produce the image with its CMOS camera and transmit it to the ground. Not bad for being also one of the first cubesats to reach orbit! Maybe we should learn a thing or two about satellite design from Japan.
And here is the image gallery from XI-IV. You can see gradual deterioration of camera instrument, but the images are still legible enough to see Earth’ cloud cover.
References
- University of Toronto UTIAS-SFL Home Page
- Gunter’s Space Program Page
- Earth Observation Portal Directory
- On-orbit Operation Results of the World’s First CubeSat XI-IV – Lessons Learned from Its Successful 15-years Space Flight. Ryu Funase, Satoshi Ikari, Ryo Suzumoto, et al. University of Tokyo, 2019. SSC19-WKIII-09.