Re:Small satellites are radically remaking space exploration
by keanebean86 on Wednesday July 15, 2020 @12:18PM
(#23847424)
What about a cubesat solar system relay system? Each with a few directional antennas pointed at the nearest neighbor in the grid. Maybe offset from the solar system plane to avoid impacts. It would take a few billion sats to blanket the whole solar system but they're cheap. If we built them in space we could have spares all over waiting to fill gaps.
I tried to do the math but failed. Pluto's orbital diameter, according to wikipedia, is about 4.4 billion km. That means the main solar system has a circumference of about 27 billion km. Starlink cubesats orbit at about 550km. Relay sats wouldn't need to punch through atmosphere so they could be farther apart.
I pictured a series of circles. The close to the sun the smaller. I'm sure if I'd listened in cal 1 I could use a summation to figure this out.
Losing a few sats periodically isn't a big deal and it won't bring down the whole network.
It might slow signals down to propagate through the mesh but communication is already slow in space. If a probe/ship needs to communicate quickly it can use its own high power dish or laser.
The article imagines what we could do with 100 mini Curiosity rovers, but the reality is not much. A rover is a completely different proposition from a cubesat. The instruments Curiosity carried can't just be scaled down 100 times. Similarly if we're going to put a lander on Europa, there's a minimum size such a thing would need to be to work at all, be able to carry useful instruments and have enough power to transmit data back, and it's not tiny.
The fact is you build the probe and mission around the instruments you want to send, and that sets quite high minimum vehicle design parameters for many missions. The MarCO cubesats barely carried any instruments at all, they were mainly communications relays for the InSight probe. On their own they could do practically no science. Yes I know they were mainly a demo mission, but lets keep things in proportion. Add more instruments and you need more power so bigger solar panels, more powerful computers, more capable antennas, bigger batteries, more powerful thrusters, a bigger launcher and all of a sudden it's not a cubesat any more.
So I do apologies for pouring all that cold water. The stuff is really exciting and is genuinely opening up new and exciting opportunities, but let's not kid ourselves that the old way of doing things is over. It really isn't. If these new technologies created the impression that flagship missions are a waste of money and not worth doing, it would be a terrible shame. This isn't an SLS vs Starship type contest where one solution essentially deprecates the other. Micro-missions are a fantastic complement to traditional exploration models, but not a replacement.