A Cheap Satellite with Large Fuel Tank Could Scout For Interplanetary Missions

A spacecraft that can provide the propulsion necessary to reach other planets while also being reproducible, relatively light, and inexpensive would be a great boon to larger missions in the inner solar system. Micocosm, Inc., based in Hawthorne, California, proposed just such a system via a NASA Small Business Innovation Research (SBIR) grant. Its Hummingbird spacecraft would have provided a platform to visit nearby planets and asteroids and a payload to do some basic scouting of them.

Large space missions are expensive, so using a much less expensive spacecraft to collect preliminary data on the mission target could potentially help save money on the larger mission’s final design. That is the role that Hummingbird would play. It is designed essentially as a propulsion system, with slots for radiation-hardened CubeSat components as well as a larger exchangeable payload, such as a telescope.

The key component of the Hummingbird is its propulsion system. It uses a rocket engine that runs on hydrazine fuel. More importantly, it holds a lot of that fuel. A fully assembled system is expected to weigh 25 kg “Dry”—meaning without propellant installed—whereas a fully fueled “Wet” system would weigh an estimated 80 kg. 

That would give Hummingbird plenty of “oomph” – enough to bring its orbital speed up to an estimated 3.5 km/s delta-V, which is required for getting to hard-to-reach objects like some near-Earth asteroids. However, it could also reach other, larger places, like Mars or even Venus, the various Lagrange points, or even Mars’ moons.

When it got there, the prototype of Hummingbird described in a paper presented back in 2013 would take images of its target world using an Exelis telescope. The manufacturer of this telescope has since been bought by Harris Systems, which was then rolled into L3Harris Technologies, the owner of Aerojet Rocketdyne. However, the authors stress that the payload itself was interchangeable and could be tailored to the mission that it was meant to scout.

The Hummingbird bus was also the fuel tank, and it had additional slots for CubeSat components. These components could be used for further data collection or data analysis. However, the paper doesn’t necessarily mention how Hummingbird would handle standard CubeSat operations, like attitude control or communications back to a ground station.

Those could likely have been worked out in future iterations. Additionally, the final design was published before the dramatically reduced cost of getting to orbit, which is now available – the authors don’t even mention a “Falcon” as a potential launch service. A lot has changed in the space industry in the last 11 years. Still, the idea behind Hummingbird, an inexpensive, adaptable platform for preliminary scouting missions to interesting places in the inner solar system, has yet to see its day in the Sun – the project did not appear to receive a Phase II SBIR grant, which could have continued its development. But maybe, someday, it or a similar system will see the light of interplanetary space.

Learn More:
C. Taylor et al – Hummingbird: Versatile Interplanetary Mission Architecture
UT – What Happened to those CubeSats that were Launched with Artemis I?
UT – A CubeSat Mission to Phobos Could Map Staging Bases for a Mars Landing
UT – We Could SCATTER CubeSats Around Uranus To Track How It Changes

Lead Image:
Computer-generated mockup of the Hummingbird spacecraft
Credit – C. Taylor et al.