TY - GEN
T1 - Defining software flexibility in space systems
AU - Nilchiani, Roshanak
AU - Hastings, Daniel E.
PY - 2004
Y1 - 2004
N2 - On-board software is a vital element in the operation and functionality of a space system. The functional requirements of space systems can change over time, and unforeseen failures can affect systems performance, thereby necessitating modifications to the on-board software. It is thus important to know in how far the possibility of remote software upgrades can help the system to maintain its functionality in an uncertain environment, or even use the uncertainty to its advantage by adding or improving functionality. In this paper, the concept of software flexibility for space systems is defined and a measure for its evaluation is introduced. The flexibility measure is designed such that it can incorporate monetary as well as non-monetary changes in the systems performance. Subsequently, the values of software flexibility for the Deep Space One mission, and the Galileo mission are evaluated. The case studies show how existence of this relative quantitative measure for software flexibility allows decision-makers to assess the extent of software flexibility their space systems can exhibit in the face of uncertainty. The case studies also indicate that the flexibility of a space system depends significantly on the relative cost of substituting the entire space system versus the cost of upgrading software. Given the fact that remote software upgrades are often far less expensive than on-orbit servicing and upgrading of hardware components, it becomes clear that software flexibility could be used as a first choice in flexibility to the extent that hardware limitations permit.
AB - On-board software is a vital element in the operation and functionality of a space system. The functional requirements of space systems can change over time, and unforeseen failures can affect systems performance, thereby necessitating modifications to the on-board software. It is thus important to know in how far the possibility of remote software upgrades can help the system to maintain its functionality in an uncertain environment, or even use the uncertainty to its advantage by adding or improving functionality. In this paper, the concept of software flexibility for space systems is defined and a measure for its evaluation is introduced. The flexibility measure is designed such that it can incorporate monetary as well as non-monetary changes in the systems performance. Subsequently, the values of software flexibility for the Deep Space One mission, and the Galileo mission are evaluated. The case studies show how existence of this relative quantitative measure for software flexibility allows decision-makers to assess the extent of software flexibility their space systems can exhibit in the face of uncertainty. The case studies also indicate that the flexibility of a space system depends significantly on the relative cost of substituting the entire space system versus the cost of upgrading software. Given the fact that remote software upgrades are often far less expensive than on-orbit servicing and upgrading of hardware components, it becomes clear that software flexibility could be used as a first choice in flexibility to the extent that hardware limitations permit.
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U2 - 10.2514/6.2004-5857
DO - 10.2514/6.2004-5857
M3 - Conference contribution
AN - SCOPUS:18844461935
SN - 1563477203
SN - 9781563477201
T3 - A Collection of Technical Papers - AIAA Space 2004 Conference and Exposition
SP - 375
EP - 386
BT - A Collection of Technical Papers - AIAA Space 2004 Conference and Exposition
T2 - A Collection of Technical Papers - AIAA Space 2004 Conference and Exposition
Y2 - 28 September 2004 through 30 September 2004
ER -