Project Sail propulsion ship

[perseus]

Sail propulsion, based on the Pioneer anomaly, similar to the Solar Sail film.

Photons, which are "particles" of light, bounce off the reflective material of the sail. (Newton's Third Law of Motion states that for every action there is an equal and opposite reaction.) The reaction here causes a change in momentum, pushing the sail and accelerating the spacecraft. A photon reflecting off the mirror-like surface of a solar sail gives the sail a double kick -- a push equal to twice the photon's momentum (one push from the sail stopping the photon and one from it reflecting the photon and accelerating it away).

But the real advantage of solar sailing is that, unlike a chemical rocket that applies a lot of thrust but only for an instant, sunlight hitting the sail applies thrust continuously. In 100 days a sail could reach 16,000 kilometers per hour (10,000 miles per hour); in one year it could reach 58,000 kilometers per hour (36,000 miles per hour). In just three years, a solar sail could reach a speed of over 160,000 kilometers per hour (100,000 miles per hour). At that speed you could reach Pluto in less than five years. In comparison, the New Horizons misson to Pluto, using chemical propulsion and a gravity-assist from Jupiter, is planned to take nine years to reach its target. Still, 160,000 kilometers per hour (100,000 miles per hour) is still only 0.00015 the speed of light. It would take about 1,000 years for a solar sail to reach one-tenth the speed of light, even with light shining on it continuously.

Tron.

the Pioneer anomaly,: Researchers want to determine whether heat from Pioneer probes' electronics or two nuclear power sources—known as radioisotope thermal generators (RTGs)—could be emitting infrared photons that then smack into the spacecraft's dish-like main antenna, causing a recoil effect that Turyshev likened to sunlight striking a solar sail.

Analysis and modeling of how the Pioneer 10 spacecraft emits heat from various sources, including its RTG, found that they account for between 55 percent and 75 percent of Pioneer Anomaly, said Gary Kinsella, a group supervisor for spacecraft thermal engineering and flight operations at JPL. "

Assuming that the error bars are small enough that the above diagram (especially the "Stochastic Acceleration" portion) is reasonably accurate, it looks to me like the acceleration curve flattens out to an asymptotic value of about 7 x 10^-10 ms^-2.

The most obvious cause, in my opinion, would be an exponential decaying acceleration with a half-life of about 3-4 years (declining due to radioactive decay in the RTG?) plus a steady acceleration of unknown origin of about 7 x 10^-10 ms^-2

The Solar Sailer is a simulation of a futuristic bulk transport vehicle, that was used by Tron, Flynn and Yori to escape from the Game Grid and reach the MCP.

When idle, its sails are translucent, however, for faster speeds, the sails turn
opaque and give the solar sailer a tremendous boost in speed.

 

[Pipcard]

Tron!

 

[Izack]

A photon reflecting off the mirror-like surface of a solar sail gives the sail a double kick -- a push equal to twice the photon's momentum (one push from the sail stopping the photon and one from it reflecting the photon and accelerating it away).

It doesn't work that way... You're forgetting another basic law: conservation. You can't "add" momentum to a system that way. It must come from somewhere and go somewhere, never vanish or materialise.

Edit: By the logic in the OP shining a torch on a card gives unlimited energy.

But the real advantage of solar sailing is that, unlike a chemical rocket that applies a lot of thrust but only for an instant, sunlight hitting the sail applies thrust continuously. In 100 days a sail could reach 16,000 kilometers per hour (10,000 miles per hour); in one year it could reach 58,000 kilometers per hour (36,000 miles per hour). In just three years, a solar sail could reach a speed of over 160,000 kilometers per hour (100,000 miles per hour). At that speed you could reach Pluto in less than five years. In comparison, the New Horizons misson to Pluto, using chemical propulsion and a gravity-assist from Jupiter, is planned to take nine years to reach its target.

One caveat of solar sails is that sunlight comes from only one direction: from the Sun. Force is diminished as the angle between the sail's normal and the direction of the Sun increases, though you can get lateral 'thrust' this way. You can't apply force towards the Sun, though.

Also, sunlight intensity (and thus propulsive effectiveness) drops off with greater distance from the centre of the solar system. This also happens to solar electric arrays (the very reason Pioneer has an RTG in the first place.)

I'll leave it to others to critique the Tron-inspired sail design...

 

[Jarvitä]

It doesn't work that way... You're forgetting another basic law: conservation. You can't "add" momentum to a system that way. It must come from somewhere and go somewhere, never vanish or materialise.

Edit: By the logic in the OP shining a torch on a card gives unlimited energy

You're not adding momentum. The photon's momentum is either annihilated (if they're absorbed into the sail) or reversed (if they're reflected). And the energy isn't unlimited, it comes from the sun (which isn't really "renewable", no matter what the eco-nuts would have you think).

 

[jedidia]

Well, the OP claims that the sail gains twice the momentum energy of the photon, because the photon gets reflected. That would indeed be energy from nowhere. The sail could catch the photon and accelerate it back again, but it has to provide the energy for the acceleration part from somewhere.

One caveat of solar sails is that sunlight comes from only one direction: from the Sun. Force is diminished as the angle between the sail's normal and the direction of the Sun increases, though you can get lateral 'thrust' this way. You can't apply force towards the Sun, though.

You don't really have to. All you have to do is loose orbital velocity, the sun will get you down all by itself.

At that speed you could reach Pluto in less than five years.

Your data results in an acceleration of 0.00051 m/s^2, which seems about realistic. The problem is, of course, that you needed three years to reach that speed that allows you to reach Pluto in five years, and you'll have to give it some years to break... I don't know if it will end up any faster in the end, but it's certainly a cool project for Orbiter.

 

[grid4dante]

IMHO, I think some Tron-based addons would be a great addition to the Orbiter universe... maybe some UCGO bikes and quad runners, 1 and 3 man jets, even maybe the command ship... one thing I think would be really cool about these addons is how some of the developers (for instance, the one who did NX-425 and NX-426) can add the "glowy bits" to their vessels... Alas, I have not been blessed by the with the gift of addon development

 

[T.Neo]

Tron!

No, wait... not the same Tron. :dry:

And the energy isn't unlimited, it comes from the sun (which isn't really "renewable", no matter what the eco-nuts would have you think).

It lasts for billions of years and it emits nearly 400 million exawatts. That's enough for me to consider it unlimited.

 

[perseus]

Originally Posted Izack "by It doesn't work that way... You're forgetting another basic law: conservation. You can't "add" momentum to a system that way. It must come from somewhere and go somewhere, never vanish or materialise.

Edit: By the logic in the OP shining a torch on a card gives unlimited energy.

In principle, the law appears to violate conservation of momentum, but the system is emitting radiation outside.

But there is the Pioneer anomaly, and studies that attempt to explain what the phenomenon is possible to the Thermal radiation pressure:

A real deceleration not accounted for in the model could result from asymmetrical thermal radiation pressure of the heat from the spacecraft (the effect cannot be from the radiation pressure of sunlight or the spacecraft's radio emissions as it is too small at this distance, and points in the wrong direction).but there is the anomaly, and studies that attempt to explain what the phenomenon is possible

Possibilities include the asymmetrical radiation of heat from the RTGs (See Radioisotope rocket) or the spacecraft electronics. Even if the RTGs themselves radiate symmetrically, some of their radiation will reflect from the back of the spacecraft's dish-like main antenna, causing a recoil like sunlight striking a solar sail.

The asymmetrical radiation of heat remains a prime suspect, as presented at the second ISSI meeting in Bern, February 2007. A presentation at the APS April 2008 meeting suggests that differential heating may account for as much as one third of the observed acceleration.[33]

A research team from Portugal has proposed that previous modelling used to predict the directions of radiation pressures was incorrect. By using the Phong reflection model to model diffusive and specular reflections they believe that the observed and theoretical results no longer diverge. This proposed explanation finds most of the diverging thrust in the heat from the main equipment compartment reflecting off the back of the main antenna, which would tend to produce a thrust in the direction of the sun.[34] The Jet Propulsion Laboratory is currently attempting to confirm this explanation by studying their own thermal data.[35]

And test their explanations confirms that the momentum be changed by radiation, relativity things, someone could clarify this physically and scientifically?

 

[n0mad23]

When the anomalies first were reported I remember there was some speculation about it being due to encounters with dark matter. Personally, I'd love to see exactly where these episode occurred as I suspect they could be explained (at least partially) by harmonic orbital frequencies.

In terms of "solar sailing", the technology really isn't "one-way" only away from the sun. If the sail is turned 45 deg (approx.) counter to the orbital trajectory, the photons will cause deceleration. It's also possible to turn the sail and "park" which could be really useful for Asteroid Belt exploration.

I considered making a solar ship addon, but my design needed a sail 120 km x 120 km. Made from 24 kt. Asteroid mined gold, and 3 atoms thick weighing 44 k kg, it would reflect golden sunlight from one side, and be translucent blue seen from the other.