As I mentioned in the post where I introduced our MIDAS SBIR Select Phase 1 project, one of the first steps in that project was to select an exciting and challenging reference mission that we can use as a basis for our performance and sizing analyses. After looking at several options, we’ve selected Titan (the largest of Saturn’s 53 named moons) as the destination for our reference mission.
Some Fun Titan Facts
Titan is the only moon in our solar system with a dense atmosphere, and is the only body in our solar system other than Earth with known stable bodies of surface liquid (albeit of liquid methane). Its nitrogen atmosphere is actually more massive than earth’s in spite of being much smaller. When combined with a surface gravity level of 0.14G (lower gravity than the Moon), Titan is one of the only places in the solar system where human-powered ornithopters would work (h/t xkcd what-if).
Another interesting fact is that a satellite in a 1000km altitude orbit around Titan would deorbit within less than a week. The lowest long-term stable orbit around Titan is nearly 1500km altitude (when the planet’s radius is only 2500km…), with an orbital velocity around 1.5km/s. Titan might also be a good planet for sample return, since the atmosphere is cold enough that you wouldn’t need to insulate or refrigerate a LOX/Methane or LOX/Propane stage, and the delta-V to orbit would be only a tiny bit higher than what my previous startup, Masten Space Systems, demonstrated with their Xoie lunar lander challenge vehicle…
The main reason we chose Titan as a destination for our reference mission was that it was an exciting destination for planetary science that would be otherwise very hard for a CubeSat to access. It’s also somewhat of an “acid test” of our rollable solar array concept due to getting only 1% as much sunlight per unit area as earth, and an “acid test” of our earth-return communication system due to having about -295dB of space losses. Basically if our system can close a useful RF communications link and provide enough power to operate out at in Saturn’s orbit, it should work wonderfully for destinations closer to the Sun such as Venus or Mars.
What About Other Destinations?
Just because we’re focusing on Titan for our Phase 1 reference mission that doesn’t mean we aren’t also interested in other destinations for MIDAS. Our hope is to design a system that can brake a satellite into orbit around any destination with an atmosphere this side of Saturn, and can provide enough power and comms to perform useful scientific missions.
- Venus orbiters
- Mars orbiters and Phobos/Deimos orbiters/landers
- Sample return missions to Earth that capture into LEO (for pickup by a Commercial Crew vehicle) instead of using direct return
Also, as I think was previously mentioned, MIDAS also isn’t limited to CubeSats–in fact it tends to scale up better than it scales down.
While we’ll be using Titan as our Phase 1 reference mission, we’ll also try to analyze MIDAS for those other destinations as time permits.