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{tabsetup:1. The Requirement\|2. Rationale\|3. Guidance\|4. Small Projects\|5. Resources\|6. Lessons Learned}\\
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h1. 1. Requirements
Tabsetup
1. The Requirement
1. The Requirement
1
2. Rationale
2
3. Guidance
3
4. Small Projects
4
5. Resources
5
6. Lessons Learned
Div
id
tabs-1
1. Requirements
6.3.5
When
the
requirement
and
software
class
are
marked
with
a
"P
(Center),"
Centers
and
projects
shall
meet
the
requirement
with
an
approved
non-null
subset
of
the
"shall"
statement
(or
approved
alternate)
for
that
specific
requirement.
h2. {color:#003366}{*}
1.1
Notes{*}{color}
Notes
Note:
The
use
of
partial
Center
(i.e.,
"P
(Center)")
requirements
allows
for
local
adaptations
to
suit
Center
and
application
unique
needs.
Although
the
NASA
Headquarters'
Office
of
the
Chief
Engineer
is
the
review
and
concurrence
authority
for
the
Center
defined
"P
(Center)"
requirements,
this
approval
does
not
constitute
a
deviation
nor
a
waiver.
The
project
or
Center
is
responsible
for
flowing
down
all
applicable
NPR
7150.2
requirements,
including
"P
(Center)"
requirements,
to
contracted
software
development
activities.
"P
(Center)"
requirements
are
typically
documented
in
Center-level
directives.
h2.
1.2
Applicability
Across
Classes
This
requirement
applies
to
all
classes
and
safety
criticalities
{applicable:asc=1\|ansc=1\|bsc=1\|bnsc=1\|csc=1\|cnsc=1\|dsc=1\|dnsc=1\|esc=1\|ensc=1\|f=1\|g=1|h=1|}
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h1. 2. Rationale
The [NASA Governance and Strategic Management Handbook|http://nodis3.gsfc.nasa.gov/displayDir.cfm?t=NPD&c=1000&s=0A], NPD 1000.0A, provides the top level basis for establishing a non-null set of requirements in its paragraph
applicable
f
1
g
1
h
1
ansc
1
asc
1
bnsc
1
csc
1
bsc
1
esc
1
cnsc
1
dnsc
1
dsc
1
ensc
1
Div
id
tabs-2
2. Rationale
NPD 1000.0A, NASA Governance and Strategic Management Handbook,
sweref
261
261
provides the top-level basis for establishing a "non-null set" (a set that must contain at least one member) of requirements in its paragraph 3.4.2.2.2:
"Good
requirements
that
are
properly
managed
are
essential
to
any
successful
undertaking.
Part
of
establishing
the
proper
set
of
requirements
is
the
adjustment
of
prescribed
requirements
to
the
specific
task
(e.g.,
a
program
or
project)."
The
"P
(Center)"
approach
was
put
in
place
to
recognize
the
variety
of
NASA
projects,
applications,
and
existing
Center
directions
on
software
engineering
(
, e.g.,
"one
size
doesn't
necessarily
fit
all."
).
The
use
of
"P
(Center)"
allows
flexibility
in
the
implementation
of
over
sixty
60 per
cent
of
requirements
in
NPR
7150.
2A
2 for
one
or
more
classes
of
software.
The
flexibility
provided
by
these
locally
designated
subsets
of
Agency
software
requirements
enables
tailoring
of
the
original
SWE
requirements. The OCE expects this tailoring to be guided by "risks vs. resources" trades that are performed by the Center engineering organizations or by the Engineering Technical Authority. NPR 7150.2 Appendix D Requirements Mapping Matrix indicates which requirements can be tailored using the "P (Center)" approach.
The stipulation that the implementation include a 'non-null set' of the stated requirement indicates that projects are required to include some part of the requirement to assure the safe and efficient execution of software for the project. Because NASA projects' software products have wide variations in risk and scope, it is the responsibility of the Center's engineering organization or Engineering Technical Authority to develop and approve the best implementation of the non-null set. The Headquarters OCE reviews and concurs/non-concurs on a Center's P (Center) process approach and requirements subsets during periodic OCE surveys conducted at each Center. See [SWE-127|https://nasa7150.onconfluence.com/display/7150/SWE-127] and [SWE-129|https://nasa7150.onconfluence.com/display/7150/SWE-129] for guidance on the OCE concurrence process and appraisal surveys.
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h1. 3. Guidance
NPR 7150.2 provides general guidance for the implementation of the P (Center) concept, but delegates the development of the actual approach and process steps down to each Center. Because of this delegation Centers are able to develop subsets of requirements using the P (Center) approach that result in local adaptations to suit Center and application-unique needs. This general approach assures that Centers develop the requirements for their systems and work products to match the goals and objectives of their program and projects.
{panel}
!exclamation.gif! Centers are expected to document their approach for implementing the P (Center) requirements.
{panel}
The following paragraphs present two examples of approaches for implementing the P (Center) construct.
Centers may develop uniform interpretations (individual descriptions, process steps, and work product definitions) for P (Center) requirement for each class of software. Software engineering process groups (SEPG) may be assigned to develop the approach and/or the subsets of requirements. The process groups typically record their work products, i.e., the minimally acceptable subsets, in Center-level directives. The peer and senior management review of these directives assures a center-wide agreement and implementation of these P (Center) adaptations. This approach is well suited for Centers with a large number of similar software applications. A variation on this approach could involve the definition of specific P (Center) requirement subsets by major application area (e.g., Space based systems, Aeronautics, Facilities)
Other Centers may choose to assign the interpretation of P (Center) requirements to the Center Chief Engineer, the Engineering Technical Authority, or the software TA. The [NASA Space Flight Program and Project Management Requirements|http://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID=N_PR_7120_005D_&page_name=Chapter3#3_4] document lists many of the basic duties of a TA. Being involved in the determination of the non-null set of requirements should assist the TA in the performance of these duties: "The _Engineering Technical Authority_ establishes and is responsible for the engineering design processes, specifications, rules, best practices, etc., necessary to fulfill programmatic mission performance requirements." This approach is well suited for Centers with a large number of dissimilar projects. In a variation of this latter approach, Centers could have the software TA and the software team lead draft the P (Center) subsets together during the development of the project's compliance mapping matrix. This variation assures close and continuing interactions between the software TA and the software team lead. It also supports precise alignment between the project needs and the non-null subset of approved requirements. After a number of these software TA-software team lead interactions, the software TA will become more adept at matching non-null requirement subsets to projects. However, the approval of the P (Center) subset still resides with the software TA in this scenario, not the software team lead.
The use of the term "{color:#0000ff}non-null set'{color} indicates that the software team lead must consider the requirement as a whole but may implement a prudent portion of it on the project. The implementation may be the full extent of the stated requirement. It may be aspects related to safety only. It may reflect just the elements of the requirement for the project in question.
The use of the phrase "(or approved alternate)" refers to the potential change that may occur to a requirement of NPR 7150.2A through the use of [SWE-120] and [SWE-121] . If the OCE approves a request under SWE-120 for a specific alternate requirement, the intent of the 'non-null set' portion of this requirement will still apply.
The development of these non-null subsets of the P (Center) requirements for use on contracted efforts are also considered during the execution of the {color:#0000ff}"software acquisition process"{color}. (See the [Topic 7.7 - Acquisition Guidance |http://nasa7150.onconfluence.com/display/7150/7.7+-+Acquisition+Guidance] in Book 2).
Headquarters OCE will review each Center's P (Center) approach and documentation during periodic OCE surveys conducted at the Centers. The Center's approach should indicate if it uses the uniform interpretations Center directives approach, the individually tailored engineering TA approach, or a different locally developed approach. The description of the Center approach should be documented in the Center's Engineering Technical Authority Implementation Plan. Individual projects should be aware, however, that the OCE may review their compliance matrix and specific implementation of P (Center) requirements outside of these periodic surveys.
Note that projects frequently elect to go beyond the minimal subset of P (Center) requirements to address specific risks.
{panel}
!exclamation.gif! Consult Center directives, PALS, and Engineering Technical Authority Plans for information detailing local direction on implementing P (Center) subsets of the SWEs. Within a project, P (Center) subsets should be base lined in the software compliance matrix.
{panel}
{div3}
{div3:id=tabs-4}
h1. 4. Small Projects
The implementation of the P (Center) requirements might result in a very minimal set that is applicable to small projects. Documentation requirements from Chapter 5 in NPR 7150.2A are typical candidates for Center scrubbing on small projects.
{div3}
{div3:id=tabs-5}
h1. 5. Resources
# "[NASA Governance and Strategic Management Handbook|http://nodis3.gsfc.nasa.gov/displayDir.cfm?t=NPD&c=1000&s=0A]", NPD 1000.0A, 2008
# "[NASA Space Flight Program and Project Management Requirements|http://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID=N_PR_7120_005D_&page_name=Chapter3#3_4]", NPR 7120.5D, 2009.
# "[NASA Engineering and Program/Project Management Policy|http://nodis3.gsfc.nasa.gov/displayDir.cfm?t=NPD&c=7120&s=4D]", NPD 7120.4D, 2010
h2. 5.1 Tools
{toolstable}
{div3}
{div3:id=tabs-6}
h2. 6. Lessons Learned
There are currently no lessons learned identified for this requirement.
{div3}
{tabclose}
requirements. The OCE (Office of the Chief Engineer) expects this tailoring to be guided by "risks vs. resources" trades that are performed by the Center engineering organizations or by the Engineering Technical Authority (TA). NPR 7150.2, Appendix D, Requirements Mapping Matrix, indicates which requirements can be tailored using the "P (Center)" approach.
The stipulation that the implementation include a non-null set of the stated requirement indicates that projects are required to include some part of the requirement to assure the safe and efficient execution of software for the project. Because NASA projects' software products have wide variations in risk and scope, it is the responsibility of the Center's engineering organization or Engineering TA to develop and approve the best implementation of the non-null set. The Headquarters' OCE reviews and concurs/non-concurs on a Center's P (Center) process approach and requirements subsets during periodic OCE surveys conducted at each Center. See SWE-127 and SWE-129 for guidance on the OCE concurrence process and appraisal surveys.
Div
id
tabs-3
3. Guidance
NPR 7150.2 provides general guidance for the implementation of the P (Center) concept but delegates the development of the actual approach and process steps down to each Center. Because of this delegation, Centers are able to develop subsets of requirements using the P (Center) approach that result in local adaptations to suit Center- and application-unique needs. This general approach assures that Centers develop the requirements for their systems and work products to match the goals and objectives of their program and projects.
Panel
Image Added Centers are expected to document their approach for implementing the P (Center) requirements.
The following paragraphs present two examples of approaches for implementing the P (Center) construct.
Centers may develop uniform interpretations (individual descriptions, process steps, and work product definitions) for P (Center) requirement for each class of software. Software engineering process groups (SEPGs) may be assigned to develop the approach and/or the subsets of requirements. The process groups typically record their work products, i.e., the minimally acceptable subsets, in Center-level directives. The peer and senior management review of these directives assures a Center-wide agreement and implementation of these P (Center) adaptations. This approach is well suited for Centers with a large number of similar software applications. A variation on this approach could involve the definition of specific P (Center) requirement subsets by major application area, e.g., space-based systems, aeronautics, facilities.
Other Centers may choose to assign the interpretation of P (Center) requirements to the Center Chief Engineer, the Engineering Technical Authority (TA), or the software TA. NPR 7120.5, NASA Space Flight Program and Project Management Requirements
sweref
082
082
, Chapter 3, lists many of the basic duties of a TA. Being involved in the determination of the non-null set of requirements aids the TA in the performance of these duties, as stated in section 3.3.6 of NPR 7120.5: "The Engineering Technical Authority establishes and is responsible for the engineering design processes, specifications, rules, best practices, etc., necessary to fulfill programmatic mission performance requirements." This approach is well suited for Centers with a large number of dissimilar projects. In a variation of this latter approach, Centers could have the software TA and the software team lead draft the P (Center) subsets together during the development of the project's compliance mapping matrix. This variation assures close and continuing interactions between the software TA and the software team lead. It also supports precise alignment between the project needs and the non-null subset of approved requirements. After a number of these software TA-software team lead interactions, the software TA will become more adept at matching non-null requirement subsets to projects. However, the approval of the P (Center) subset still resides with the software TA in this scenario, not the software team lead.
The use of the term "non-null set" indicates that the software team lead must consider the requirement as a whole but may implement a prudent portion of it on the project. The implementation may be the full extent of the stated requirement. It may be the aspects related to safety only. It may reflect just the elements of the requirement for the project in question.
The use of the phrase "(or approved alternate)" refers to the potential change that may occur to a requirement of NPR 7150.2 through the use of SWE-120 and SWE-121. If the OCE approves a request under SWE-120 for a specific alternate requirement, the intent of the non-null set portion of this requirement will still apply.
The development of these non-null subsets of the P (Center) requirements for use on contracted efforts are also considered during the execution of the software acquisition process. (See the Topic 7.3 - Acquisition Guidance in Book C).
The Headquarters' OCE will review each Center's P (Center) approach and documentation during periodic OCE surveys conducted at the Centers. The Center's approach is expected to indicate if it uses the uniform interpretations Center directives approach, the individually tailored engineering TA approach, or a different locally developed approach. The description of the Center approach is documented in the Center's Engineering Technical Authority Implementation Plan. For an individual project, the OCE may review its compliance matrix and specific implementation of P (Center) requirements outside of these periodic surveys.
Note that projects frequently elect to go beyond the minimal subset of P (Center) requirements to address specific risks.
Note
Consult Center directives, PALs (Process Asset Library), and Engineering Technical Authority Implementation Plans for information detailing local direction on implementing P (Center) subsets of the SWEs. Within a project, P (Center) subsets are baselined in the software compliance matrix.
Div
id
tabs-4
4. Small Projects
The implementation of the P (Center) requirements might result in a very minimal set that is applicable to small projects. Documentation requirements from Chapter 5 in NPR 7150.2 are typical candidates for Center scrubbing on small projects.
Div
id
tabs-5
5. Resources
refstable
toolstable
Div
id
tabs-6
6. Lessons Learned
No lessons learned have currently been identified for this requirement.