QUOTE (djellison @ Aug 24 2020, 02:18 AM)
I'm afraid some extreme bubble bursting is required here.
Fair enough, these are ideas, not CAD drawings.
QUOTE (djellison @ Aug 24 2020, 02:18 AM)
How are you going to pay for, operate, communicate with and build these?
-Funding the science is supported by mapping the billions of dollars in metals that reside in the asteroid belt; same way that the science of geology piggybacks off oil/natural gas drilling and locating ore deposits. Funding might also reflect the need to have a "repeater" for the Deep Space Network to relay signals, where a mesh of satellites with radios provides redundancy for deep space data, and a VLA the size of the asteroid belt.
-Communication would not be to any one satellite, but to a "mesh network" probably leave a trio of larger, smarter "repeaters" in orbit around Mars to provide 3x throughput and tridundancy for talking to the "mesh". Basic cubesats would be similar to the concept of SpaceX's Starlink, although each Starlink is much larger, 260 kg or roughly 200 cubesats. I had not based the idea on Starlink, but those basic specifications are a good place to start: 4 phased array RF antennas, standardized solar panels, ion propulsion for station keeping, a star tracking camera, and collision avoidance/database of objects in orbit.
-Initial operation would be a 3d version of the "picket fence" that detected that Arrokoth was a contact binary using 21 occultation observations over time. Sometimes the LACK of data and for how long, IS the data your looking for. This is comparable to router firmware "load balancing" that detect data dropouts- except here the data dropouts would be loss of visual signal as an asteroid passes between a cubesat and the tracking stars, or loss of radio signal as an asteroid passes between two cubesats. This builds up a 3d map of occultations, which gives you asteroid locations.
After you build up a basic map, you'd move to an extended mission of trying to actively "ping" a specific asteroid and have other cubesats listen in to triangulate position like GPS. Then ping from different cubesats to build a 3d map of interesting asteroids, and finally ping at different frequencies to build up a texture map of really interesting asteroids.
-Building would be by the lowest qualified bidder. There would probably be a mix of cubesat sizes, 1x, 2x, 5x, 10x. Starting with 200 to 400 units, you would trade performance for redundancy.
QUOTE (djellison @ Aug 24 2020, 02:18 AM)
The Delta IV heavy you propose using is a $400M launch vehicle. You can't just replace its second stage - that's required to even reach LEO. A Delta IV heavy WITH it's second stage can't even get a Black Arrow to GTO, let alone a trans lunar injection.
Good point, IIRC, the early specs indicated they could do LEO by throttling down the center core after lift off to conserver fuel, then throttling up after the outer 2 separated. This might have needed a vacuum nozzle for the center core and been unstable at sea level.
Better solution would be, since the 1st & 2nd stages of the "Black Arrow" have the same 2.6km/s but the 1st is heavier, use a pair of the lighter 2nd stages for the "Black Bolt" to get a lighter craft with the same specific impulse, that would meet lunar payload limits.
QUOTE (djellison @ Aug 24 2020, 02:18 AM)
You're definitely going a bit beyond blue sky thinking here. The way to do Cubesats beyond the EM system is to piggy back a couple at a time on a larger dedicated missions as MarCO did with InSIGHT - or to pay for a dedicated ride with someone like Rocket Lab whose upgraded Electron rocket can now deliver Cubesats beyond the EM system.
Yes, that's the traditional way to do cubesats. But not the only way. I'm thinking in NK, number of nodes, number of connections. Since NASA/ESA/JAXA will need more deep space bandwidth, a distributed communications network further out isn't unprecedented, and using data dropouts to map the asteroid belt, is, admittedly thinking counter to expectations.