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中圖分类号：TP129 文献标识码：A 文章编号：1009-914X（2018）10-0368-02
Introduction
One of the questions which humanity has been discussing for millennia is whether there is life in the universe beyond our planet. Although this question may prove very difficult to answer， scientists have identified that Mars could potentially show evidence， through study of its geology， that it once contained water- a prerequisite for life. The SRC at the University of Leicester is currently running projects which are investigating this possibility， through analysing samples from comets and meteorites which come from Mars， and by developing equipment and instruments to perform relevant experiments. One such project is the SPLIT （Small Planetary Linear Impulse Tool）， a tool which applies force to the outside of a rock in order to cleave it in two， thus exposing the inside surface without contaminating it by direct contact with scientific equipment.
This device is designed for use on the surface of Mars， for which it would need to be mounted to a planetary rover. The idea of a remote-controlled， unmanned， planetary rover which could be sent into space to provide data about a planet or other body has been around for a long time， and the first successful rover mission was the Soviet Union’s Lunokhod 1， sent to the moon in 1970 [1]. Since then， rovers have been used to explore Mars， as its hostile conditions and distance make it impractical for manned mission currently. The Mars Exploration Rover （MER） mission， run by NASA， sent two rovers to Mars with the goals of exploring the planet’s surface and geology. Spirit， the first of the two， was in operation for about 6 years， while Opportunity， the second， is still in operation to this date. NASA has since sent another rover， called Curiosity， to Mars and it is also still functioning [2]. Curiosity had a more expanded set of goals， which were more focused on biological and geological investigations into the possibilities of life being possible on the planet. To accommodate this， it also featured a more comprehensive scientific test-bed and greater computing power. These designs have been used as inspiration for this project in many instances.
Project Progression
During the project defining and planning stage， an initial project plan was created to reflect the timeline throughout and to order tasks required to complete the project. The plan was both vague in some respects due to not knowing the full scope of tasks that would be needed but also contained very specific tasks in subsystems that team members had more experience in. The plan also contained initial estimates for resource distribution， with lead engineers designated for each sub-system and support engineers assigned so that members had someone to consult whilst overcoming design challenges and checking work. Following conversations with the Space Research Centre， it was determined from an early stage that the workshop deadline was not applicable to the project due to an alternative manufacturing solution in the Physics workshop， where manufacturing could take place with much shorter notice. The deadline was still included as a target to aid with timeliness of the project as opposed to a requirement for project success in order to motivate the team to produce a suitably developed design in the early stages of the project.
The initial plan was created using rough estimates from the team of what tasks would be required and how long they would take to complete. This also included initial resource allocation to foresee who would be loaded heavily at which points of the project. From this initial exercise of determining how much work each sub-system required， initial design restrictions were made to ensure project completion such as the simplification of steering design. Odometry was also planned but set to a low priority. This was due to time pressures being highlighted within the project where suitably qualified team members would not have enough availability to ensure the systems would be completed sufficiently， if at all.
Throughout the early stages of the project， the team continued working with the initially proposed Gantt chart with little evolution of it until the management review with Martin Rhodes. At this point， it was suggested that an unmaintained project plan hampered project progression as opposed to keeping track of it. As a result of this， the team realised that the project plan must be a living document which is maintained and updated throughout the project to ensure it aids with project progression instead of impeding it. Therefore， the plan was reworked with greater task detail and more realistic timeline calculations to allow for easier management of the project.
The initial plan contained tasks accounting for research within the individual sub-systems， however there was initially a small amount of disagreement between the Space Research Centre and the team as to the amount of time that should be spent on research. The team wanted to press ahead with design development stages of the project and had planned to do so， conscious of the time restrictions in place with pressures mounting in the manufacturing stages of the project； whereas the Space Research Centre wanted the team to spend a greater amount of time researching and preparing for designing. For the first parts of the project， progression was mostly to schedule with only minor delays relating to the mechanical parts of the project. However， towards the end of semester 1， it became clear the initial plan was not an accurate representation of the requirements of the project and delays were arising particularly in the mechanical aspects of the project. Ample mechanical development had not been performed， highlighting the Space Research Centre’s previous concerns regarding initial research and requirements gathering. Therefore， development was extended， causing delays to the planned timeline. Although delays pushed the project off of the initial timeline， the developments allowed for a better and more suitable design， which also improved manufacturability and ease of assembly， which eased time pressures in the latter stages of the project. A factor which acted in favour of easing these time pressures was that as the workshop deadline target was not completely applicable to the project， this delay was not critical. Therefore， the deadline imposed by the team was not a critical milestone and could cope with a limited amount of delay.
Further mechanical delays were encountered relating to design development and procurement when required parts became unavailable around the Chinese New Year period， making a prime source of components unavailable for a couple of weeks. This delay was negated during the manufacturing stage where mechanical assembly progress was limited， allowing the components to be delivered during the waiting period for manufacturing to be completed.
The vision system was completed on schedule but only after resources were reallocated to provide additional support after decisions made over the Christmas break caused a major setback in its development. The original support engineers to fan， George and Qinyuan， could not spare the time required to fully provide support. Therefore， Ben was reallocated as support engineer for the vision system， resulting in its timely completion.
The main control hub was completed in its most part on schedule， albeit additional hours were worked per week to ensure timely completion. This was due to an initial underestimation of the amount of work required to complete the system， with several additional aspects added later. As a result of this oversight， several aspects of the main control hub remain incomplete， however other factors have also hindered the system’s progress such as issues relating to the drive system. The drive system was completed to schedule throughout most of the project， however system assembly and testing proved extensive， causing delays and postponing whole system tests. Additional resources were allocated to this system in an attempt to mitigate this effect however the delays caused project completion to be delayed.
Conclusion
Overall， the project was completed largely to schedule within the early parts of the timeline， however inaccuracies in the early task duration estimates meant delays became inevitable within the middle parts of the project on some sub-systems. The management review highlighted errors in the initial plan and timeline recalculations were performed once it had been restructured. The delays present in the initial plan were later negated by recalculations in the second half of the project in the most part， whilst mechanical design developments initially causing delays were negated by improved ease of assembly. The combination of these factors ensured the majority of the project was completed on time.
References
[1]https：//www.space.com/35090-lunokhod-1.html （last accessed 3/05/18）
[2]https：//www.space.com/37722-mars-rover-curiosity-five-years-anniversary.html （last accessed 3/05/18）
Introduction
One of the questions which humanity has been discussing for millennia is whether there is life in the universe beyond our planet. Although this question may prove very difficult to answer， scientists have identified that Mars could potentially show evidence， through study of its geology， that it once contained water- a prerequisite for life. The SRC at the University of Leicester is currently running projects which are investigating this possibility， through analysing samples from comets and meteorites which come from Mars， and by developing equipment and instruments to perform relevant experiments. One such project is the SPLIT （Small Planetary Linear Impulse Tool）， a tool which applies force to the outside of a rock in order to cleave it in two， thus exposing the inside surface without contaminating it by direct contact with scientific equipment.
This device is designed for use on the surface of Mars， for which it would need to be mounted to a planetary rover. The idea of a remote-controlled， unmanned， planetary rover which could be sent into space to provide data about a planet or other body has been around for a long time， and the first successful rover mission was the Soviet Union’s Lunokhod 1， sent to the moon in 1970 [1]. Since then， rovers have been used to explore Mars， as its hostile conditions and distance make it impractical for manned mission currently. The Mars Exploration Rover （MER） mission， run by NASA， sent two rovers to Mars with the goals of exploring the planet’s surface and geology. Spirit， the first of the two， was in operation for about 6 years， while Opportunity， the second， is still in operation to this date. NASA has since sent another rover， called Curiosity， to Mars and it is also still functioning [2]. Curiosity had a more expanded set of goals， which were more focused on biological and geological investigations into the possibilities of life being possible on the planet. To accommodate this， it also featured a more comprehensive scientific test-bed and greater computing power. These designs have been used as inspiration for this project in many instances.
Project Progression
During the project defining and planning stage， an initial project plan was created to reflect the timeline throughout and to order tasks required to complete the project. The plan was both vague in some respects due to not knowing the full scope of tasks that would be needed but also contained very specific tasks in subsystems that team members had more experience in. The plan also contained initial estimates for resource distribution， with lead engineers designated for each sub-system and support engineers assigned so that members had someone to consult whilst overcoming design challenges and checking work. Following conversations with the Space Research Centre， it was determined from an early stage that the workshop deadline was not applicable to the project due to an alternative manufacturing solution in the Physics workshop， where manufacturing could take place with much shorter notice. The deadline was still included as a target to aid with timeliness of the project as opposed to a requirement for project success in order to motivate the team to produce a suitably developed design in the early stages of the project.
The initial plan was created using rough estimates from the team of what tasks would be required and how long they would take to complete. This also included initial resource allocation to foresee who would be loaded heavily at which points of the project. From this initial exercise of determining how much work each sub-system required， initial design restrictions were made to ensure project completion such as the simplification of steering design. Odometry was also planned but set to a low priority. This was due to time pressures being highlighted within the project where suitably qualified team members would not have enough availability to ensure the systems would be completed sufficiently， if at all.
Throughout the early stages of the project， the team continued working with the initially proposed Gantt chart with little evolution of it until the management review with Martin Rhodes. At this point， it was suggested that an unmaintained project plan hampered project progression as opposed to keeping track of it. As a result of this， the team realised that the project plan must be a living document which is maintained and updated throughout the project to ensure it aids with project progression instead of impeding it. Therefore， the plan was reworked with greater task detail and more realistic timeline calculations to allow for easier management of the project.
The initial plan contained tasks accounting for research within the individual sub-systems， however there was initially a small amount of disagreement between the Space Research Centre and the team as to the amount of time that should be spent on research. The team wanted to press ahead with design development stages of the project and had planned to do so， conscious of the time restrictions in place with pressures mounting in the manufacturing stages of the project； whereas the Space Research Centre wanted the team to spend a greater amount of time researching and preparing for designing. For the first parts of the project， progression was mostly to schedule with only minor delays relating to the mechanical parts of the project. However， towards the end of semester 1， it became clear the initial plan was not an accurate representation of the requirements of the project and delays were arising particularly in the mechanical aspects of the project. Ample mechanical development had not been performed， highlighting the Space Research Centre’s previous concerns regarding initial research and requirements gathering. Therefore， development was extended， causing delays to the planned timeline. Although delays pushed the project off of the initial timeline， the developments allowed for a better and more suitable design， which also improved manufacturability and ease of assembly， which eased time pressures in the latter stages of the project. A factor which acted in favour of easing these time pressures was that as the workshop deadline target was not completely applicable to the project， this delay was not critical. Therefore， the deadline imposed by the team was not a critical milestone and could cope with a limited amount of delay.
Further mechanical delays were encountered relating to design development and procurement when required parts became unavailable around the Chinese New Year period， making a prime source of components unavailable for a couple of weeks. This delay was negated during the manufacturing stage where mechanical assembly progress was limited， allowing the components to be delivered during the waiting period for manufacturing to be completed.
The vision system was completed on schedule but only after resources were reallocated to provide additional support after decisions made over the Christmas break caused a major setback in its development. The original support engineers to fan， George and Qinyuan， could not spare the time required to fully provide support. Therefore， Ben was reallocated as support engineer for the vision system， resulting in its timely completion.
The main control hub was completed in its most part on schedule， albeit additional hours were worked per week to ensure timely completion. This was due to an initial underestimation of the amount of work required to complete the system， with several additional aspects added later. As a result of this oversight， several aspects of the main control hub remain incomplete， however other factors have also hindered the system’s progress such as issues relating to the drive system. The drive system was completed to schedule throughout most of the project， however system assembly and testing proved extensive， causing delays and postponing whole system tests. Additional resources were allocated to this system in an attempt to mitigate this effect however the delays caused project completion to be delayed.
Conclusion
Overall， the project was completed largely to schedule within the early parts of the timeline， however inaccuracies in the early task duration estimates meant delays became inevitable within the middle parts of the project on some sub-systems. The management review highlighted errors in the initial plan and timeline recalculations were performed once it had been restructured. The delays present in the initial plan were later negated by recalculations in the second half of the project in the most part， whilst mechanical design developments initially causing delays were negated by improved ease of assembly. The combination of these factors ensured the majority of the project was completed on time.
References
[1]https：//www.space.com/35090-lunokhod-1.html （last accessed 3/05/18）
[2]https：//www.space.com/37722-mars-rover-curiosity-five-years-anniversary.html （last accessed 3/05/18）