What are some more improvements for this report:

1.0	

1.1 Claim

Humans will never visit planets outside of our solar system.

1.2 Rationale

The claim “Humans will never visit planets outside of our solar system. 

1.3 Research Question

Are thermal nuclear rockets the most efficient form of space flight?

1.4 Background

Thrust is the force that moves aircraft such as space rockets. Thrust is created by propulsion systems that are implemented on the aircraft. There are multiple ways that thrust is developed in different propulsion systems but all use Newton’s third law of motion; for every action (force) in nature there is an equal and opposite reaction. In every propulsion system there is a working fluid that is accelerated by the propulsion system and the reaction to the acceleration produces a force. The amount of thrust generated depends on the mass flow through the engine and the velocity of the gas that exits the system.  The two main types of rocket engines are liquid and solid rockets. In a liquid rocket the propellants, fuel and oxidizer are stored separately as liquids and are pumped into the combustion chamber where it is then burned. In a solid rocket the propellants are mixed and then packed into a solid cylinder. The cylinder is then ignited the propellant is exhausted. (NASA, 2021)

Nuclear Electric Propulsion rockets convert thermal energy generated by a nuclear reactor into electricity, which then ionizes an inert gas propellant such as Xenon or krypton. The ionized propellant is then accelerated out the exit of the rocket by an electro-magnetic field, creating thrust. Though outperforming chemical rockets, the rockets become inefficient further from the sun because they are powered by solar arrays, making nuclear thermal propulsion systems the only reliable from of deep space travel. 

Nuclear thermal propulsion uses a liquid propellant such as liquid hydrogen, which is pumped through the reactor core of the propulsion system, where is heats up and turns into a gas, which is then forced out the exit of the rocket, creating a large thrust and accelerating the aircraft. Nuclear thermal propulsion is twice as efficient as chemical rockets and can short space flight times while carrying larger payloads. Shorter flight times also reduce a crew’s exposure to harmful radiation in space. (ANSTO, 2023)

2.0 Evidence


2.1.1 Figure 1
(Peakman, 2023)
 


2.1.2 Analysis

It can be identified that Nuclear electric propulsion has the greatest specific impulse (m/s) per thrust (N) exhausted from the rocket. The chemical rockets has the least amount of specific impulse per thrust exhausted and the Nuclear thermal rockets have the middle amount of specific impulse per thrust exhausted out of the three different types of rockets. Chemical rockets have around 1e+0.34 of specific impulse with around 1e+0.55 of thrust while Nuclear thermal rockets have around 1e+0.37 specific impulse with around 1e+0.045 of thrust. Nuclear electric rockets are the most efficient with around 1e+0.45 of specific impulse with around 1e+0.1 thrust.

2.1.3 Interpretation 

The data indicates that the most effective form of propulsion system is the Nuclear electric propulsion rocket in terms of specific impulse per thrust and the worst being the chemical propulsion system. The Nuclear Thermal propulsion system is slightly more efficient then the chemical propulsion system compared to the nuclear electric propulsion system. The nuclear thermal rocket has around 1e+0.03 more specific impulse and uses 1e+0.1 less thrust then the chemical propulsion system while the nuclear electric propulsion system has around 1e+0.11 specific impulse and uses 1e+0.45 less thrust then the chemical rocket. This means that the nuclear electric rocket is by far the most efficient form of space travel for travel near our Sun, since it uses the Suns solar rays to be powered, but the best form of interstellar travel would be nuclear thermal rockets as the nuclear electric rockets would be inefficient the further the rocket travels from our sun.


2.2.1 Figure 2
(Forsley, 2019)

 

2.2.2 Analysis

It can be identified that Uranium 238 is an efficient fuel source. The x-axis of the graph indicates the amount of incident energy generated and the y-axis is the surface area of the Uranium 238 used. The graph is a positive graph meaning that Uranium 238 is an efficient fission material that can be used in Nuclear thermal propulsion systems. The graph can be observed to slowly plateau. 

2.2.3 Interpretation

The data indicates that Uranium 238 is an efficient fuel source and fission material that can be used in Nuclear thermal propulsion systems. Because the graph plateau’s it means that after a certain amount of Uranium 238 surface area is used in the propulsion system the incident energy generated will have little effect. So from the graph it can be observed that the most efficient amount of Uranium 238 surface area that will be used in a Uranium thermal propulsion system is 10 mb for 20 MeV of energy. 

2.3.1 Figure 3
 

2.3.2 Analysis

By observing the graph the number of days that the thermal nuclear rocket is efficient for can be identified. The x-axis indicates the amount of days and the y-axis indicates the k effective of the nuclear reactions performed by the nuclear thermal rocket. If the k effective goes below 1.0 the nuclear reactions start to become inefficient. The graph shows a linear trend meaning that the k effective descends at the same rate over time. 

2.3.2 Interpretation

The data indicates that Nuclear thermal rockets will be efficient for 4000 days before the nuclear reactions in the rockets become inefficient and start to decline. Because the graph is linear it means that the k effective declines at the same rate over time and is critical for 4000 days before k effective drops below 1.0 and the nuclear reactions in the propulsion system becomes sub-critical and the nuclear reaction can no longer sustain a fission chain reaction. 


2.3 Limitations

Limitations that are evident in the data is the lack of other data that can be compared to it and a limited sample size of the data. In figure 2.2.1 and figure 2.3.1 there is a lack of other data that can be compared to it to successfully answer the research question “Are thermal nuclear rockets the most efficient form of space flight?” efficiently because the data that has been analysed and interpretated is only limited to one type of nuclear fuel the graph of the k effective of the nuclear thermal propulsion system. To make the data less limited the two graphs could be compared to other types of space flight propulsion systems like nuclear electric propulsion and chemical propulsion systems. In figure 2.1.1 the data is limited because of the small sample space used in the graph and the lack of a clear average of the data that can be observed so that the average does not need to be estimated of the data. 


2.4 Quality of evidence

The quality of evidence is very important to have a clear and reliable conclusion to the research question that is being investigated. The information collected for the report was secondary data sourced from online articles on the subject that may be bias or inaccurate, but were all heavily referenced and peer reviewed, so the chances of inaccuracy or bias is decreased. Data from three secondary sources were used for evidence that have been peer reviewed meaning that the data is likely reliable as it was reviewed by professionals of the topic. Data was also used to write the background of the report from government agency  NASA which may include bias or the information may have been selected or altered to fit the report written by the agency.

3.0

3.1 Evaluation of Claim

The claim “Humans will never visit planets outside of our solar system” was investigated by turning the focus of the report to the created research question of “Are thermal nuclear rockets the most efficient form of space flight?”. By researching this question it was found that nuclear thermal rockets are an efficient form of space flight and last for 4000 days for the k effective of the nuclear fission to become sub-critical. It was also found to be more efficient then chemical propulsion systems and less efficient then nuclear electric propulsion systems, but this is only for space flights in our solar system as nuclear electric propulsion systems and powered by the suns rays. Therefore, Nuclear thermal propulsion rockets are the most efficient from of deep space and interstellar space travel. 




3.2 Improvements

Possible improvements that can be made to the investigation are:
-Collecting more sources that include different types of propulsion systems to compare to the current data.
-More data that shows a larger variety of data

3.3 Extensions 

Possible extensions that can be made to the investigation are: