System Engineering Practices in Space projects

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Table of Contents

Introduction
A General Overview of Risk Assessment and Its Importance for Any Project
Risk Assessment in Space Projects
Risk Assessment in Small Satellite Projects
Conclusion
References

Introduction

Aerospace engineering is the field of engineering which is concerned with the production of spacecraft and aircraft; it involves using the discoveries of such fields as avionics, aerodynamics, materials science and engineering, and so on, due to the need for the spacecraft and aircraft to withstand exposure to various severe conditions such as those resulting from extreme changes in temperature and atmospheric pressure.

It should be stressed that aerospace engineering is also concerned with the production of artificial satellites. Artificial satellites play a critical role in today’s world; they are used for such purposes as research, observation, navigation, communication, weather forecasting, and so on. It is also noteworthy that nowadays, small satellites are often utilized for a wide array of purposes, due to their reduced cost and the relative ease of transporting them to the orbit in comparison to the large satellites.

One of the examples of small satellites is a CubeSat. A CubeSat is a small satellite made of one or several units sized 10x10x10 centimeters and weighing no more than 1.33 kilograms [1]. Their development began in 1999 when several professors from Stanford University and California Polytechnic State University at San Luis Obispo decided to design and create small satellites that would allow universities to better engage in cosmic science and exploration [1].

CubeSats, therefore, were often used for educational purposes. For instance, 7 CubeSats made by university students were launched into the orbit on the European Space Agency’s Vega Maiden Flight in the year of 2012 [2]. Another example of a large educational project involving CubeSats is called “Fly Your Satellite!” (FYS) [2].Students participating in this project receive a unique chance to create and launch their own satellite.

FYS is an ongoing project which comprises four main stages: the creation of a satellite, it is testing (including tests that involve exposure of a CubeSat to vibration, vacuum, and the temperature characteristic of the altitude in which they will be orbiting the Earth), preparation for the process of launch, and the execution of the planned operations once the satellite has been transported to its intended destination on the Earth’s orbit [2].CubeSats, therefore, have been pivotal as satellites used for educational purposes.

However, while creating satellites, it is also of great importance to take into account the issues of risk assessment and risk management. This paper is mainly concerned with the problem of risk assessment. A general overview of risk assessment is provided, and its roles in space projects on the whole and small satellite projects, in particular, are discussed.

A General Overview of Risk Assessment and Its Importance for Any Project

Risk assessment is one of the most critical parts of project planning, management, and implementation. The notion “risk” can be understood as the amount of “variability in the outcome or result of a particular action” [3, p. 82]. Furthermore, the term “risk assessment” can be defined as “a process that commences with hazard identification and analysis, through which the probable severity of harm or damage is established, followed by an estimate of the probability of the incident or exposure occurring, and concluding with a statement of risk” [4, p. 2]. Finally, risk management is a process aimed at avoiding or preventing undesirable happenings such as technical failures [3, p. 82].

Risk assessment can be of paramount importance in a wide array of projects, especially the ones the implementation of which might be associated with dangers to the individuals who take part in that project, the people who are not involved in it, or the property that can become damaged as a result [5]. The procedures of risk assessment permit the identification of the sources of the potential harm, which are called hazards, for the evaluation of the possible losses resulting from such harm, and the chances of such losses.

The damage that will be caused if the adverse situation occurs is adjusted by the estimated chance that this situation takes place, and is weighed against the cost of implementing risk management procedures, which allows for making a decision about whether it is worth carrying out these procedures [4].

Popov et al. provide a short generalized plan of the process of risk estimation and hazard analysis as it appears in a variety of standards; this plan is comprised of the following elements [4, p. 5]:

Choosing a matrix for risk assessment;
Determining the parameters for carrying out the analysis;
Identifying the hazards related to the situation which is being analyzed;
Considering the failure modes;
Estimating how serious and how costly the outcomes will be if the adverse situation takes place;
Calculating the likelihood of this situation occurring;
Determining the initial risk related to the given situation;
Choosing a hazard avoidance procedure or plan, or the ways to eliminate, decrease, or control the hazard;
Estimating the involved residual risks;
Making a decision pertaining to the degree of acceptability of the given risk;
Documenting the obtained results;
Providing follow-up related to the measures which were implemented [4].

Taking these steps permits for effectively estimating the risks related to a particular project or situation, for deciding whether or not measures should be taken to address these risks, and, if the answer is positive, for choosing which measures exactly should be employed [4].

It should also be pointed out that the procedure of risk assessment is usually followed by measures aimed at managing the identified risks [5]. There are two main ways to manage the risks which were identified as important ones: to lower the likelihood of the occurrence of the adverse event during the project implementation or to reduce the possible adverse impact of that event on the project [4]. Depending on the severity of the possible adverse consequences of the risk, one or both these ways may be utilized in order to address the risk that has been identified for a project [6].

There exist a number of reasons which make the processes of risk assessment and risk management ones of crucial importance [6]. The most obvious of these reasons is that it helps to prevent large disasters from taking place during the project, possibly saving the lives of individuals who would have been affected, as well as the property which would have been damaged.

Next, it allows for preventing large expenses that might be needed in order to mitigate the adverse consequences of a disaster or other negative circumstances should they occur during the process of the project implementation; therefore, it permits for increasing the overall revenues of the project as well. It also considerably increases the chances of successfully finishing the project, therefore reducing the probability of failure, and provides those who implement it with a competitive advantage over their rivals. In addition, it may aid in discovering additional opportunities related to the project which would have gone unnoticed otherwise [5].

Finally, it enhances the feeling of accountability and responsibility and delivers considerable psychological benefits such as mental satisfaction and an increased feeling of safety, which also provide confidence and help all those who take part in the project to successfully complete it [6]. It should also be noted that without risk management, it is difficult for an organization to properly define its objectives for the future due to the fact that if these risks become a real situation, the company is likely to suffer a great setback and might not be able to recover [4].

Risk Assessment in Space Projects

Risk assessment is a necessary condition of any risk management procedures, and it is stressed that “effective risk management is critical to program and project success and affordability” [7, p. xv]. It is stated that there exist two main dimensions of risk related to space projects, namely, the probability of the undesired outcome, and the degree of its severity [3, p. 82]. It is also pointed out that the decisions pertaining to the risks involved in these projects are managerial decisions due to the fact that risk can only be accepted or not accepted (so that measures are taken to minimize or avoid it, or the project is adjusted/canceled).

However, to make such a decision, it is of utmost importance to gather as much information about risk as possible, so that the decision is well-informed and results in outcomes which are maximally appropriate [3].

A serious challenge related to the projects involving space missions is that these projects are associated with a considerable degree of risk due to the fact that satellites are, in most cases, few in numbers and high in cost, and there is practically no way to test them “in the field” prior to launching them to space; so, all the hypotheses about their functioning are first verified only when they are already in space, and at this point, there is almost no opportunity to implement changes in the software utilized by the satellite, and no chance at all to carry out any changes in the hardware or the technical parts of the apparatus [3].

In order to address this challenge, thorough scrutiny of possible risks related to each of these projects is strongly required at all the phases of mission designing, including the earliest ones [3]. Carrying out such scrutiny might permit for making an informed decision about the given project, whether this decision is an approval of a given project or its cancellation [3].

The techniques of risk assessment in space projects usually involve several main aspects: the identification of possible risks related to the given project, the assessment of the severity of the aftermath of the identified dangerous events, as well as the estimation of the probability of these events taking place [3].

Scholars speak of three main levels of severity of the event’s aftermath: high (if the adverse event would make it impossible to achieve the goals of the project in question), medium (if the hazardous event would significantly lower the observed level of achievement in comparison to the expected one, thus resulting in the need to spend considerable amounts of time (e.g., months) and finance in order to mitigate the situation and achieve the performance the commitment to which had been made), or low (if the event would impact the expected distribution of labor, cost, or other resources, would require several weeks to restore the situation to an acceptable state, and might need the project resources to be redeployed) [3, p. 83].

Similarly, the probability that the adverse event will take place can also be divided into three levels: high (the situation is highly likely to happen, and preventive measures are unavailable or cannot be properly utilized so as to avert the aftermath of the event), medium (the situation is rather probable to take place, and/or the existing preventive measures are not considered reliable enough so as to avert the negative effects of the event’s occurrence, so additional actions are needed), and low (the situation still can happen, but it is unlikely, and/or the existing controls are estimated as sufficient to appropriately prevent the event or its negative results from taking place) [3].

Based on assessments of the severity of the event’s adverse consequences and of the probability of the latter, a decision is made about the cancellation of the project, its modification, or alternative ways to deal with the risk [4].

It should also be emphasized that in accordance with the standards of NASA, risk analysis is an integral part of risk-informed decision making, and is carried out with taking into account such dimensions of a project as its safety, schedule, and its technical and financial aspects [7, p. 8]. Risk analysts discuss the risks involved in a given project, taking into account the objectives as set by various stakeholders of that project (including internal and external stakeholders) and comparing the given project to performance models as supplied by subject matter experts. The decision of risk analysts is taken into account in the process of deliberation carried out for the given project [7, p. 8].

Risk Assessment in Small Satellite Projects

When it comes to projects related to launching small satellites, risk assessment and management procedures play a critical role in increasing the chance of their success. This is due to the fact that satellites are highly sensitive pieces of technology that can easily be damaged, and once a satellite is in orbit, it is impossible to conduct any repairs, so in case of any emergency, the whole project might immediately become failed [8]. It is also important that the risks related to the transportation, assembly, etc. of satellites need to be assessed and addressed as well, for if the satellites are damaged during these processes, and the damage goes unnoticed, they might be launched and suffer from a failure shortly after that [8].

It is stated that the risks involved in satellite projects can typically be characterized as follows:

only a small number of risks exist;
there is a considerable technological diversity;
insured values vary greatly, and total losses are often a threat;
total losses may accumulate when a number of satellites are launched simultaneously;
there exists a risk of serial losses resulting from faults in a line of satellites [8].

It is also noteworthy, however, that because a variety of types of satellites are launched, the risks related to them often may be rather heterogeneous [8].

With regards to the projects using small satellites, it is emphasized that rather often, the procedures of risk analysis and management are not carried out; on the contrary, the plans of risk management are usually created and implemented for larger and more expensive satellites [9].

It is also stressed that to be created, the risk management plans in organizations involved in satellite projects in most cases require the work of several highly experienced members of risk management staff, as well as a considerable amount of time for carrying out the analysis [9]. When these facts are taken into consideration, it might be possible to state that a current problem related to the use of small satellites is the need for the creation of systems of risk analysis and management that would allow for cheaper and more effective risk assessment for projects involving these satellites.

While addressing the problem of the dearth of risk assessment and management procedures of small satellites, it is paramount to take into account several challenges that are often faced when launching such satellites. It is pointed out that while small satellites are usually cost-effective, there exist a number of specific problems that are related to their use [10].

For instance, the desire to make them cost-effective sometimes results in designs of satellites with low reliability; such satellites, however, are usually formation-controlled, and, therefore, the low reliability of every single satellite is compensated by the overall reliability of the whole system, which often uses the so-called “constellation design” [10, p. 43]; it is clear that in this case, the procedure of risk assessment is of crucial importance if a good decision related to the choice of design and the quality of a single satellite is to be made and a project is to be successful.

Another challenge is related to several types of satellites working at the altitude of 600-800 kilometers, namely, to the debris mitigation; this is due to the relatively high density of various objects that are considered debris at that altitude, as well as to the relatively long periods of time that satellites or their parts survive after the mission is finished; i.e., these satellites or parts do not naturally de-orbit during the currently recommended period of 25 years after their mission ends [10, p. 43].

This means that when creating new satellites that are to orbit at this altitude, it is of increasingly great importance to pay attention to the issue of prevention of collision of these satellites with the debris that is present there; the risks of collision need to be calculated carefully (which, clearly, requires a large number of calculations and very qualified personnel), therefore resulting in the need for highly professional risk assessment and management to decide e.g. whether on-board propulsion systems are needed so as to enable these satellites to conduct collision avoidance maneuvers [10].

It has already been noted that scholars speak of a lack of practices aimed at careful scrutiny of risks related to the small satellites [9]. This may be in part due to the fact that there exists a relatively small number of techniques and tools which could easily be utilized for the purpose of such scrutiny. It should be noted, for instance, that universities very often use rather simple techniques for assessing the risks involved in satellite projects; these include such methods as top risk list (identifying the greatest risks and addressing them), team review, intense guidance, etc. [11].

On the other hand, in projects created by aerospace corporations, as well as in projects run together by such companies and universities, several methods for risk assessment and management are usually used; however, it is emphasized that these methods often may be suboptimal [12].

In order to help solve this problem, several tools and methods have been offered. For instance, Gamble and Lightsey proposed an instrument which they labeled a CubeSat Decision Advisor; it employs certain elements of decision theory, multi-attribute utility theory, as well as utility elicitation techniques for the purpose of identifying the possible benefits of offered mitigation methods aimed at addressing the risk of a mission involving a small satellite [9]. It appears clear, however, that further development of methods and tools for efficacious risk assessment and management related to projects involving small satellites may be required if the risks involved in these projects are to be addressed at an optimal level.

Conclusion

On the whole, it should be stressed that risk assessment is a part of the process of risk management, which is of vital importance for most projects if these projects are to be affordable, successfully implemented, and if the possible high-risk hazards are to be neutralized, and profoundly adverse outcomes are to be averted. However, risk assessment requires professional, temporal, and other resources so as to be carried out at a high level. In small satellite projects, the procedures of risk assessment that often take place are suboptimal. In order to more efficaciously identify and address the hazards faced by these projects due to a variety of reasons, it is paramount to further develop the methods of risk assessment and management specifically designed for such projects.

References

ISIS. (n.d.). CubeSats. Web.

European Space Agency. (n.d.). CubeSats and education: The Fly Your Satellite! programme. Web.

M. A. Aguirre, Introduction to Space Systems: Design and Synthesis. New York, NY: Springer, 2012.

G. Popov et al., Risk Assessment: A Practical Guide to Assessing Operational Risks. Hoboken, NJ: John Wiley & Sons, 2016.

M. Rausand. Risk Assessment: Theory, Methods, and Applications. Hoboken, NJ: John Wiley & Sons, 2011.

M. Majeed. (2012). Risk management: an important part of project management. Web.

H. Dezfuli et al. (2011). NASA risk management handbook. Web.

Munich Re. (n.d.). Risk assessment improves the entire project’s chance of success. Web.

K. B. Gamble and E. G. Lightsey, “Decision analysis tool for small satellite risk management,” J Spacecr Rockets, vol. 53, no. 3, pp. 420-432. 2016.

R. Sandau. International Study on Cost-Effective Earth Observation Missions. London, UK: Taylor & Francis Group, 2006.

E. Deems, “Risk management of student-run small satellite programs,” M.S. thesis, Dept. of Aeronautics and Astronautics, Massachusetts Inst. of Tech., Cambridge, MA, 2007.

S. Nag et al., “Cost and risk analysis of small satellite constellations for Earth observation,” IEEE Aerosp Conf Proc, pp. 1-16. 2014.

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