Aug 01, 2016 14:44 Breakthrough Initiatives Posted on: Breakthrough Initiatives

Apr 13, 2016 03:51 Melih Çalıkoğlu Posted on: Breakthrough Initiatives
"I would suggest for a deliberative collision with a planet. Such an entry probe would enable us to analyze the atmosphere of exoplanets, and may be take a few picture of the surface features up close. If the problems with the speed would be solved by some kind of gravitational breaking procedure or may be using the light of the host star to slow down the craft that would lead to a possible successfull probing mission."


See above for detecting the impact results.
Gravitational breaking: Falling into the alpha Centauri system gravitational well will add kinetic energy and accelerate the probe, albeit by a tiny amount of the order of 1MJ as compared to the 2TJ of the probe. Of course a similar deceleration will take place during the exit from the solar system.
Star light breaking: Alpha Centauri has similar properties to the Sun. Even if we are at the surface of the star the power on the sail is only about 1 GW and decreasing with the square of the distance, as compared to the constant 15 GW on the probe, resulting in a final velocity of the order of 3,000km/sec or 0.01c before being slowed down by alpha Centauri. Travel time close to 1,000 years.

– Prof. Sasha Buchman, Breakthrough Initiatives

Aug 29, 2016 21:49 Joshua West Posted on: Breakthrough Initiatives

Having anything on board that could potentially serve as a catalyst for a catastrophic atmosphere ignition would be ill- advised. I would point it at the Star if at all possible, safety for a possible them should be even more paramount. I think the main concern given the above statement is the elements we are bringing onboard, if we bring a heavy foreign element that catalyzes the wrong sort of reaction we could annihilate a planet's ecosystem. The nature of solar systems being lots of collisions and periods of heavy bombardment I am not concerned with bumping into the planet or even fire, but the residue of what's left. Catalysts speed up reactions. Keep a careful eye on the elements on board, not all of them bind with O2 Ie: burn up. If they all do, what compounds do they form with what's there? What are the repercussions of those compounds being present? These questions should be answered before making an ethically sound StarShot.

Are there any effects at .2c that are seen in a particle accelerator that are not seen at slower speeds? What's probability of forming an element that was not originally present upon impact? The star is much older than our own, what does that say about the elements likely present on the surrounding planets?

I think a lot of this needs to be looked at if we decide shooting an interstellar gun at a planet we might want to live on or did not see is a "good" idea...

Nov 05, 2016 04:31 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"Aug 29, 2016 21:49Joshua WestPosted on: Breakthrough Initiatives
Having anything on board that could potentially serve as a catalyst for a catastrophic atmosphere ignition would be ill- advised. I would point it at the Star if at all possible, safety for a possible them should be even more paramount. I think the main concern given the above statement is the elements we are bringing onboard, if we bring a heavy foreign element that catalyzes the wrong sort of reaction we could annihilate a planet's ecosystem. The nature of solar systems being lots of collisions and periods of heavy bombardment I am not concerned with bumping into the planet or even fire, but the residue of what's left. Catalysts speed up reactions. Keep a careful eye on the elements on board, not all of them bind with O2 Ie: burn up. If they all do, what compounds do they form with what's there? What are the repercussions of those compounds being present? These questions should be answered before making an ethically sound StarShot.

Are there any effects at .2c that are seen in a particle accelerator that are not seen at slower speeds? What's probability of forming an element that was not originally present upon impact? The star is much older than our own, what does that say about the elements likely present on the surrounding planets?

I think a lot of this needs to be looked at if we decide shooting an interstellar gun at a planet we might want to live on or did not see is a "good" idea..."

Answer:
We plan to stay at least 1 AU from the planet. So there little chance of us colliding with the planet. Most particle physics accelerators bring single particles very close to 1 C. Our goal of reaching a speed of 0.2 C is significant lmore modest and we do not expect to create any new products.

- Avi Loeb, Breakthrough Starshot

Mar 22, 2018 01:36 Richard Boutilier Posted on: Breakthrough Initiatives

As opposed to impacting probes in the destination system, how about decelerating a single probe by reversing its orientation and reflecting light from the sails of a swarm of "nano"-crafts onto it as they pass by the star?

I think of this as a kind of hybridization of the original mission deceleration method proposed by R. L Forward (http://path-2.narod.ru/design/base_e/rit-1.pdf) and the one proposed by René Heller and Michael Hippke (https://arxiv.org/pdf/1701.08803v1.pdf).

Maybe the swarm of "nano"-crafts could be distributed such that as the decelerated craft moves backward relative to them, the faster moving craft successively act to further brake it. I imagine it would take a pretty large swarm though, to decelerate from 0.2c, but having even one probe remain in system, especially if it could be positioned favorably there, could be extremely beneficial to extend the scientific mission. And, it would take considerably less time then following Heller and Hippke's plan (141 years using 0.046c) to send swarms to all three stars, scout the systems with pass-through probes, and leave at least one (preferably several) probe stationed in each one.

May 14, 2018 22:43 Breakthrough Initiatives Posted on: Breakthrough Initiatives

Thank you for your comments. We will consider them as we build the system. The only slight challenge I see with this approach is our current sail material is most efficient in a limited range of 800 to 1060 nm frequency. In order to use the target star as a motive force to slow down the star chip, the sail would need to be responsive to broad band white light coming from the star. This may be a little more difficult however it is an intriguing idea.

- Pete Klupar, Breakthrough Starshot

Sep 13, 2018 16:28 Breakthrough Initiatives Posted on: Breakthrough Initiatives

Reply:

Aside from the additional technical complications this would entail, including, as Pete Klupar mentioned, the question of whether a sail tuned to the properties of the laser array could be used with a broad-band source (namely the light from a star), the added scientific benefit of being able to leave a starchip in the centauri system may make this idea worth pursuing. It may be that a careful analysis determines that the arrangement of other nanocraft would be implausibly difficult to arrange. For example, once the "second stage," in Robert Forward's language, begins to decelerate, it will rapidly move away from the other nanocraft reducing their effectiveness in decelerating it. As you suggest, this could be done in steps, though each time the wave of nanocraft will be effective for a shorter period of time. It's just a quantitative question of whether this procedure yields a large enough deceleration with a plausible number of assisting spacecraft. Regardless, great idea - someone should work it out!

- John Forbes and Avi Loeb (Harvard), Breakthrough Starshot