Cubesats for Solar System Exploration Options

[vjkane]

[ADMIN NOTE: New topic started using moved posts from Pallas telescopic observation topic. Please read and keep rule 1.9 in mind. Thanks!]


I was hoping that NASA would select the Athena mission to do a flyby of Pallas using a cubesat spacecraft under the SIMPLEx program. It selected the Janus mission to flyby two near Earth asteroid binary systems instead. The Athena team plans to submit again.

[HSchirmer]

Looks like the cubesat-solar sail is now in the extended mission...

https://spacenews.com/solar-sail-spacecraft...tended-mission/

The next size up seems to be CubeSail, designed by CU Aerospace (Champaign-Urbana Aerospace) and the University of Illinois, is a low-cost flight experiment based on the UltraSail concept. This experiment uses two CubeSat satellites to deploy a 20 sq. meter solar sail, which can play the same role as propellant on a conventional spacecraft.
https://www.cubesail.us/

[JRehling]

There are multiple reasons why the Sun is not an easy object for gravity assists.

Most compelling for the reason at hand, the Sun is not close in terms of delta-v; it is actually the single object in the universe that requires the most delta-v to reach. It is much less delta-v to reach Jupiter.

[HSchirmer]

There are multiple reasons why the Sun is not an easy object for gravity assists.

Most compelling for the reason at hand, the Sun is not close in terms of delta-v; it is actually the single object in the universe that requires the most delta-v to reach. It is much less delta-v to reach Jupiter.

Excellent points, as usual.

Here's a quick run from the excellent "Atomic Rockets" website...
http://www.projectrho.com/public_html/rock...on.php#oberthe0

The Sun increases the speed of the spacecraft during its run towards the solar surface, so that our ship, at rest far from Sol, will be moving at 600 kms/second as it sweeps past the solar photosphere. The kinetic energy of a body with velocity V is V2/2 per unit mass, so for an object moving at 600 kms/second, a 10 kms/second velocity boost increases the kinetic energy per unit mass by (6102-6002)/2 = 6,050 units. If the same velocity boost had been used to change the speed from 0 to 10 kms/second, the change in kinetic energy per unit mass would have been only 50 units. Thus by applying our speed boost at the right moment, when the velocity is already high, we increase the energy change by a factor of 6,050/50 = 121, which is equivalent to a factor of 11 (the square root of 121) in final speed. Our 10 kms/second boost has been transformed to a 110 kms/second boost.

All that the Sun has done to the spaceship is to change the speed relative to the Sun at which the velocity boost is applied. The fact that kinetic energy goes as the square of velocity does the rest.
...
The gain in speed is maximum if you fall in with zero velocity from a long way away. In the case of Sol, the biggest boost you can obtain from your 10 kms/second velocity kick is an extra 100 kms/second.

Fastest rocket yet was New Horizons using an Atlas/Centaur at 16km/s.
(For comparison, the Falcon Heavy tossed a Tesla at Mars at around 12km/s.)
So, an solar Oberth effect maneuver by an Atlas/Centaur should net ~10x that, about 160km/s.

[JRehling]

As a rule of thumb I keep in mind with orbital mechanics, escape velocity is sqrt(2) times the orbital velocity.

We're already orbiting the Sun. To send a rocket to the further point in the universe requires delta-v that is sqrt(2)-1 = 0.41 times the Earth's orbital velocity around the Sun.

To send a rocket to the Sun requires 1.0 times the Earth's orbital velocity of delta-v. So, roughly 2.5 the delta-v of a trip to infinity.

Of course, reaching Jupiter requires less energy than reaching infinity.