Can you write me improvements and extensions using this information (Rationale
This future spacecraft would be targeted in space by Earth-based lasers and accelerate to 20 percent the speed of light (The Planetary Society, 2019). The pursuit of interstellar travel has captivated the human imagination for generations, inspiring both scientific inquiry and speculative fiction. The claim, “Humans will never visit planets outside our solar system” can be broken down into various aspects to obtain an answer for a specific part of the claim.

The first aspect is the amount of fuel needed for travel to an exoplanet. For interstellar travel, the amount of fuel needed for spacecrafts other than a solar sail, is significant and impossible for a spacecraft to carry that amount of weight for fuel. To resolve this significant issue is the use of solar sails, the sun supplies the necessary propulsive energy, solar sails also require no onboard propellant, thus reducing payload mass (NASA, 2005).

The second aspect is the speed of the spacecraft for the ability to reach an exoplanet in a human lifetime. Solar sails have been found to have a maximum speed, which is 10% the speed of light, which equates to 18,600 miles per second. Solar powered spacecrafts are able to travel faster than conventional rocket fuelled spacecrafts due to constant light pressure being applied to the sail propelling it forward (Exploring Solar Sails).

The third aspect is the amount of distance for travel between the planets outside of our solar system. The closest exoplanet to us is Proxima Centauri B is approximately 4.2 light years away from Earth. (NASA, 2021). The distance chosen for this investigation is 5 light years, this distance was chosen because of Proxima Centauri B being around 4.2 light years away and 5 being a round whole number that provides leniency for a trip to Proxima Centauri B. 

Research Question
From breaking down the claim into three aspects, a research question has been devised to incorporate all parts of the claim, “Can a solar sail travel at high speeds for interstellar travel?”

Background Information
Light is made up of particles called photons. Photons don’t have any mass, but as the travel through space they do have momentum. When light hits a solar sail – which has a bright, mirror-like surface – the photons in that light bounce off the sail (i.e. they reflect off it, just like a mirror). As the photons hit the sail their momentum is transferred to it, giving it a small push. As they bounce off the sail, the photons give it another small push. Both pushes are very slight, but in the vacuum of space where there is nothing to slow down the sail, each push changes the sail’s speed. (The Planetary Society, 2019).

An astronomical unit (AU), a unit of length effectively equal to the average distance between Earth and the Sun, defined as 149.597,870.7km or 92,955,807.3 miles (Britannica, 2013).

Solar Radiation Pressure (SRP) is the force produced by the impact of sunlight photons on the surface of the spacecraft. SRP is the fourth most relevant perturbation after the gravitational attraction of Earth, Sun and Moon (Zardain, L).

An exoplanet is any planet beyond our solar system. Most orbit other stars, but free-floating exoplanets, called rogue planets, orbit the galactic centre and are untethered to any star (NASA, 2021).

Evidence
Graph 1.1 (Montgomery, E., Garbe, G. and Heaton, A.)
 
Analysis
It can be identified that the closer the distance to the sun, the higher the solar pressure. This is justified from the peak of solar pressure (1000N/Km^2) being 0.1 AU’s from the Sun and the decline of Solar Pressure the larger distance to the Sun. The graph shows once you begin to get further from the Sun, there is a large, significant decline of solar pressure as from 0.1 AU to 0.3 AU the Solar Pressure drops from 1000N/Km^2 to 100N/Km^2 and at 3.0 AU the Solar Pressure flatlines at a pressure of 1.0N/Km^2 and stays at that constant pressure.


Graph 1.2 (Bolonkin, A (2008).

 
Analysis
The graph shows various initial starting accelerations for Solar Sails, and the effect on their speed (km/s) the further they travel from the Sun (in intervals of million km’s). It is shown that after the Solar Sail exceeds 2 million kilometres from the sun the speed starts to slow down and around 7-10million kilometres from the sun the speed does not increase or decrease. The faster initial acceleration shows a higher final speed with shown by a starting acceleration of 10m/s^2 peaks at around 140km/s and another starting acceleration of 100m/s^2 peaking at around 430km/s.

Table 1.3 (Andrew J Tang and Xiaofeng Wu 2020)
 
Table 1.3 offers a comparative overview of various solar sail projects based on key performance metrics. The table presents data on sail area, areal density, acceleration due to solar radiation pressure (aSRP), and the non-dimensional parameter beta (β). Notable trends emerge from the data. For instance, IKAROS showcases a sizable sail area with relatively low areal density, resulting modest aSRP and beta parameter values. NanoSail-D2, with a smaller sail area and higher areal density, exhibits a comparable pattern. Conversely, SunJammer’s significant sail area combined with a low areal density results in notably higher aSRP and beta parameter values. Hailey’s Comet Sail, boasting an enormous sail area, demonstrates the highest aSRP and beta parameter values among all the projects.

Limitations
Graph 1.1, the analysis of the graph illustrating the relationship between solar pressure and distance from the Sun suggest a direct correlation. The graph doesn’t include the different solar activities that can heavily impact the solar radiation pressure. Variations in solar activity, such as solar flares and other events, could impact the accuracy of solar pressure predictions. Graph 1.2 presents a simplified relationship between initial accelerations and final speeds. Factors such as sail degradation, gravitational perturbations and changing solar radiation intensity could complicate this relationship. Other factors that affect are solar sail performance, sail material properties, mission trajectory and interactions with other celestial bodies are not accounted for. Table 1.3 primary focuses on quantitative metrics, neglecting qualitative aspects like mission success and adaptability to different scenarios.

Interpretations
The data indicates that there is a relationship between Solar Pressure and Solar Sail’s speed. In Graph 1.1 it is clearly identified that there is a significant drop in Solar Pressure the further you are from the Sun and in Graph 1.2 there is a significant drop in solar sail speed the further you are from the sun. This shows that the higher the solar pressure, the faster your solar sail will accelerate and move. This relationship is further supported as solar radiation pressure is created when radiation from the Sun acts on an object. The light from the sun can be thought of as in the form of packets of energy or photons. These photons from the Sun impact the solar sail and transfer momentum (Mesloh, M, 2007). Because of this relationship between Solar Radiation Pressure and the speed of your solar sail, for the mission of 5 light years it would be best for the Solar Sail to be as close as possible to the sun so it can gain the most momentum giving it the greatest speed for a mission of 5 light years. Table 1.3 compares various different Solar Sail Projects which help us determine which Solar Sail would be most useful and beneficial for the 5 light year mission. The solar sail project that would reach the exoplanet the fastest would be Hailey’s Comet Sail with an acceleration of 1.01m/s^2 as its enormous Sail Area experiences the most force of the Sun. For practicality, the NanoSail-D2 and the LightSail Project would the best option as its more manageable for certain missions due to their mass and size constraints.


Quality of Evidence
The quality of the evidence collected is highly reliable. Data and evidence used from three peer-reviewed journals were used accounting for the reliability due to the data being reviewed and cited by various scientists relevant to the topic. The authors of all 3 journals are experts in their field and work for respective organisations such as NASA that are only specialists in the field of space. Outside sources sufficiently backup the main data collected from the 3 journals.

Evaluation of Claim
The clam, “Humans will never visit planets outside our solar system” was investigated throughout this research investigation by creating a specific research question, “Can a solar sail travel at high speeds for interstellar travel?” Using this research question, it was discovered that Solar Sails were an effective and fast way of interstellar travel as it harnessed solar radiation pressure to accelerate it through space and with super light solar sail spacecrafts being able to travel at very high speeds. )