NASA Technical Reports Server (NTRS) 19950018145: Issues in NASA program and project management

68 Pages·4.4 MB·English

by  NASA Technical Reports Server (NTRS)

NASA SP-6101 (08)
ISSUES IN
NASA PROGRAM
AND PROJECT
MANAGEMENT
edited by
Dr. Edward J. Hoffman
Program Manager
NASA Program (cid:0)Project Management Initiative
National Aeronautics and SpaceAdministration
Office of Management Systemsand Facilities
Scientific and Technical Information Program
Washington, DC 1994
This publication is available from the NASA Center for Aerospace Information,
800 Eikridge Landing Road, Linthicum Heights, MD 21090-2934, [phone],
NationalAeronautics and
Space Administration
Hudquarl_'s
Washington, DC 20546-0001
Reply toAttn of:
Dear Readers,
Inordertosatisfytheneeds ofourcurrentreadersand properlyexpand the
distributionofIssuesinNASA Program and ProjectManagement, we would
liketohear fromyou. Thispublicationisprintedtwiceayear and collects
currenttopicsand lessonslearnedinNASA program and projectmanagement.
Ifyou no longerwant toreceiveIssues,pleaseletusknow. Ifyou know of
anyone who would liketostartreceivingIssues,pleasefillintheappropriate
areaon theback ofthispage. Also indicateifyou areinterestedinwritingan
articlefora futurevolume ofIssues.
Pleasecomplete theform on theback and faxtoDebbie Johnson at
[phone] assoon aspossible.
Thank you forhelpingusupdate our mailinglist.Ifyou have any questions,
pleasecallDebbie on [phone].
Sincerely,
Edward J. Hoffman
PPMI Project Manager
Please continue to send updated volumes of Issues in NASA Program and Project
Management to my current address.
Name and Address:
Number of copies I would also like a back copy of Issues.
of Issues, Vol. 8: (Please circle volume number.)
#1 #2 #3 #4 #5 #6 #7
I am interested in writing an article for
publication. Please contact me at: ( )
I do not wish to continue
receiving Issues.
Please send a copy of
Issues, Vol. 8 to:
Please fax this form to Debbie Johnson, TADCORPS, 202/863-1664.
Issues in NASA Program and Project Management
A Collection of Papers on Aerospace Management Issues
National Aeronautics and Space Administration Winter 1994
PAGE TITLE AUTHOR
1 Power Sources for the Galileo and Ulysses Missions Gary L. Bennett
DOE's Director of Safety and Nuclear Operations and past manager ofAdvanced Propulsion Systems in
the Transportation Division of OACT shows how a check-and-balance approach met mission require-
ments forthe radioisotope power sources on the Galileo voyage toJupiter and the Ulysses exploration of
the Sun's polar regions.
11 Managing Requirements Ivy F. Hooks
After two decades ofmanaging requirements on the Shuttle program, the author, now with Compliance
Automation Inc., offers valuable advice on spotting the major problems in requirements management
and improving the process through awareness of necessary, verifiable and attainable requirements.
19 Program Control on the Tropical Rainfall Dorothy J. Pennington
Measuring Mission & Walt Majerowicz
The Tropical Rainfall Measuring Mission (TRMM), an integral part ofNASA's Mission to Planet Earth,
is noted for its comprehensive Project Control System which covers schedules, budgets, change control
and risk assessment.
36 The Project Management Method Thomas G. Johns
The head of Business Management Consultants (BMC), which specializes in project management devel-
opment and training, emphasizes the concepts of customer, ownership, system and teamwork.
41 Career Development for Project Edward J. Hoffman, Dale Crossman,
Management Deborah Duarte & Andrea Lewis
The Program/Project Management Initiative (PPMI) team examines career paths for existing project
management personnel and makes career recommendations. Job requirements are identified, as well
as training and developmental experiences.
49 Resources for NASA Managers William M. Lawbaugh
A PPMI Listserv has been created to provide an interface with the NASA project management commu-
nity, withinstructionosn how tosubscribetovariouslistsanddiscussiongroups.Plus,book reviewsof
threenew projectmanagement handbooks and otherselectedtitlesofinterestforprogram and project
managers.
SP-6101(08) Issues in NASA Program and Project Management is eighth in a series from NASA's Pro-
gram and Project Management Initiative. This series is collected and edited by Dr. Edward J. Hoffman
and Dr. William M. Lawbaugh with Francis T. Hoban, editor emeritus. Statements and opinions are
those of the authors and do not represent official policy of NASA or the U.S. Government. Useful and en-
lightening material is welcome, and diversity ofideas is encouraged.
Inquiries should be directed toDr. Edward Hoffrnan, Program Manager, Office of Training and
Development, Code FT, NASA Headquarters, Washington, D.C. 20546-0001.

Power Sources for the Galileo and Ulysses Missions
by Gary L. Bennett
The Galileo mission to Jupiter and the In selecting a power source for Galileo and
Ulysses, several daunting challenges had
Ulysses mission to explore the polar re-
to be overcome: the solar energy flux at Ju-
gions of the Sun presented a series of tech-
piter is about 25 times less than it is at
nical challenges to the design, develop-
ment and fabrication of spacecraft power Earth (making solar power impractical);
the temperatures are quite low (_-130 K);
sources. Both spacecraft were designed to
and the radiation belts are very severe.
fly to Jupiter. Ulysses, which was launch-
ed from the Space Shuttle Discovery (STS- Fortunately, the successful flights of the
41) on October 6, 1990, used the immense Pioneer 10 and 11 spacecraft and the Voy-
ager 1 and 2 spacecraft to Jupiter and be-
Jovian gravity to twist its trajectory out of
yond had shown that radioisotope thermo-
the plane of the ecliptic and into a polar
electric generators (RTGs) could easily
path around the Sun in February 1992.
overcome these challenges. (An RTG con-
Launched from the Space Shuttle Atlantis
(STS-34) on October 18, 1989, Galileo will sists of a radioisotope heat source that
arrive in December 1995 to conduct a 20- provides thermal power from the natural
radioactive decay of the radioisotope fuel to
month exploration in orbit of the largest
a converter that converts the thermal
planet in the solar system.
PLASMA-WAVE
ANTENNA
LOW.GAIN HIGH-GAIN ANTENNA
(COMMUNICATIONS AND
ANTENNA /RADtO SCIENCE)
MAGNETOMETER
SENSORS
STAR
ENERGETIC
PARTICLES DETECTOR
PLASMA SCIENCE
OUST DETECTOR
RETROPROPULSION MODULE
THRUSTERS ABOVE: SPUN SEC11ON
,,,,,,,,, BELOW: OESPUN SECTION
LOW.GAIN
,ANTENNA
PROBE
RELAY SCAN PLATFORM. CONTAINING:
ANTENNA •PHOTOPOLARIMETER RADIOMETER
JUPITER •NEAR-INFRAREO MAPPING SPECTROMETER
RADIOISOTOPE ATMOSPHERE • SOLID,STATE IMAGING CAMERA
THERMOELECTRIC PROBE • ULTRAVIOLET SPECTROMETER
GENERATORS
Figure 1. Diagram of the Galileo Orbiter and Probe showing the two general-purpose heat source radio-
isotope thermoelectric generators (GPHS-RTG) mounted on the two booms. The length of a GPHS-RTG is
113 centimeters (about 45 inches). Galileo is a NASA spacecraft mission to Jupiter, designed to study the
planet's atmosphere, satellites and surrounding magnetosphere. Fully loaded with rocket fuel, the Orbit-
er has a mass of about 2400 kilograms (weight of about 5230 pounds). The Probe, which is designed to en-
ter the atmosphere of Jupiter, has a mass of340 kilograms (weight ofabout 750 pounds).
1
Power Sources for the Galileo and Ulysses Missions
power into electric power by means of a Solar-Polar Mission; budget considerations
number of solid-state thermoelectric ele- forced NASA to drop its spacecraft, which
ments.) led to the cancellation of the requirement
for one of the GPHS-RTGs. Then the Gali-
After some design changes dictated by the leo spacecraft switched from a Voyager-
failure of a competing thermoelectric tech- class RTG to the GPHS-RTG, requiring a
nology and by modified user requirements, net gain of one GPHS-RTG to be produced
both missions settled on a common but plus a common spare that had to be com-
then unbuilt power source known as the patible with two spacecraft that operated
general-purpose heat source RTG or at different voltages.
GPHS-RTG. Performance requirements for
the GPHS-RTG were dictated by the space-
craft requirements and the launch vehicles
(Space Shuttle originally with Centaur up-
per stage). The principal requirements
were levied on power (at launch, at begin-
ning of mission and at end of mission);
structure (ability to withstand launch vi-
brations and pyrotechnic shock); magnetic
field strength (low enough to avoid inter-
fering with the science instruments); mass
properties (a low mass was desired and the
center of mass was tightly controlled be-
cause of spacecraft balance concerns--
particularly in the case of Ulysses, which
has the GPHS-RTG mounted directly on
the side); pressurization (ability to hold a
cover gas during ground operations); nucle-
ar radiation (as low as practical); and great
functional attributes.
Figure 2. Diagram of the Ulysses spacecraft show-
ing the general-purpose heat source radioisotope
thermoelectric generator (GPHS-RTG) mounted on
In outward appearance, the GPHS-RTG is
the side. Ulysses is a European Space Agency (ESA)
basically a cylinder of 42.2 centimeters
spacecraft mission that was launched by NASA and
across the fins and 114 centimeters in has some U.S. experiments designed to study the
length with a mass of about 56 kilograms polar regions ofthe Sun.
that provides about 300 watts of electrical
power at the time of assembly. As such it is The biggest impacts were the launch dates
the largest, most powerful RTG ever flown. and launch vehicles. Both kept shifting.
The Galileo spacecraft has two GPHS- While launch dates obviously drive deliv-
RTGs and the Ulysses spacecraft has one ery schedules, the launch vehicle drives the
GPHS-RTG [Bennett et al. 1986 and details of the design. All of these changes
Schock et al. 1979]. and the tight schedules (given the fixed
budgets) contributed to a very tense focus-
The overall mission schedule impacted the ing of the program. Fortunately, there was
GPHS-RTG program in a number of ways. an early agreement on the basic require-
Originally Ulysses was to be a two-space- ments for the GPHS-RTG which allowed
craft mission called the International some stability--at least in that areal
2
Power Sources for the Galileo and Ulysses Missions
A number of technical issueswere con- had been manufactured by what was then
frontedearly inthe program and success- theRCA Corporation.Afterthe completion
fullyovercome through focused team ef- of that program, RCA ceased itsthermo-
forts.The followingsectionsdescribesome electricactivitiess,owhen the GPHS-RTG
ofthese issues,followedby some personal program began, the system contractor,
observations on the process and lessons General ElectricCompany (GE) [laterMar-
learned. tinMarietta Astro Space],had toestablish
itsown thermoelectricproductionline.
Technical Issues
Small modules consistingof18 thermoelec-
The followingsubsectionsprovidea gener- tricelements each were manufactured and
alsummary ofsome ofthe major technical put on testtoevaluatethe GE product and
issuesencountered during theGPHS-RTG todetermine ifGE had been able todupli-
program. catetheRCA product.Differenceswere un-
covered thatledtothe formation ofan in-
Restarting Thermoelectric Production. vestigativeteam of representatives from
The thermoelectric elements used in the GE and several Department of Energy
GPHS-RTGs were of the same basic design (DOE) support contractors and laborato-
as the thermoelectric elements in use on ries.The team reviewed the process and
the Voyager power sources. However, dur- product requirements indetailand uncov-
ing the production campaign for the Voy- ered some material deficienciesthat were
ager program, the thermoelectric elements quicklycorrected.
PRESSURE "1
(-HEAT SOURCE / COOLING TUBES _- GAS MANAGEMENT VALUMINUM OUTER ACS -,_ RELIEF /
\ SUPPORT / J ASSEMBLY I SHELLASSEM_LY MAN,FOLD_ DEV,CE _
RTG
MOUNTING MUL'rI-FOIL GENERAL PURPOSE
FLANGE INSULA";ION SOURCE SUPPORt" HEAT SOURCE
Figure3.Cutaway drawing ofthegeneral-purposeheat sourceradioisotopethermoelectricgenerator
(GPHS-RTG). The GPHS-RTG consistsoftwo major components: the general purpose heat source
(GPHS) andtheconverterwhichconvertsthethermalpower generatedintheGPHS intoelectricaplow-
erby means of572thermoelectrieclementscalled"unicouples.T"he overalldiameteroftheGPHS-RTG
withfinsis42.2centimeters(about16.6inches).The mass oftheGPHS-RTG isabout55,9kilograms
(weightofabout123pounds).The GPHS-RTG producesover300wattsofelectricaplower atthetime of
assembly.The GPHS-RTG hasnomoving partsandshouldprovidepowerforover20 yearsafterlaunch.
3
Power Sources for the Galileo and Ulysses Missions
Perhaps more important was thediscovery Production ofthe radioisotopeheat source
thatactualRCA practiceshad gone beyond components ran intoa common problem:
documented specificationand process re- every time a component moved from the
quirements, which ledtotheexplicitwrit- laboratorytoproduction,defectswere dis-
ten incorporationofthese practicesalong covered. In each case, inter-laboratory
with more detailed instructions,tighter teams were established to discover the
limits,control of more parameters and causeofthedefects.
more detaileddescriptionsand controlof
the facilityconditions.Facilitychanges Developing the Assembly and Testing
and improved trainingwere completed and Facility. The GPHS-RTG program was
a real-timetrend analysissystem was im- operationallyconducted in a new way: a
plemented torecordand trackkey param- DOE laboratoryinsteadofthe system con-
eters,enabling prompt consideration of tractorhad responsibilityforthe assembly
processdeviations[GE 1991]. and testingofthepower sources[Amos and
Goebel 1992].In order to accomplish this
Developing a New Radioisotope Heat transitionintheshortestpossibletime and
Source. The radioisotope heat source that ensure the safetyoftheRTGs, a team com-
powered the GPHS-RTG was a new design prisedofrepresentativesfrom the system
that had improved safety features designed contractor(GE),theheat sourcelaboratory
to immobilize the plutonia fuel under all (DOE's Mound Plant) and other involved
credible accident scenarios, including im- contractorsand laboratorieswas employed
pact on Earth following a postulated atmos- towork the design,procedures and train-
pheric reentry from space [Snow & Zocher ing inreal-time.The use ofpracticehard-
1978, Snow et aL 1978, and Schock 1980]. ware, detailedprocedures,real-timecheck-
J f / _,,_ I _ "_ II
p
G i ._G _ t ll_l"l_I_" \ \ v .orSHOe_S,mol
......... L I|' '! LITL _ _ X-----PELLET 17B%SiGel
_. -COLD SHOE IW
- % PEDESTAl. (Cu)
\ ", \ "' ELECIRICAL CONNECIOR ICu|
• •
, "x , EIECIHICAL INSUI ATOR (AI2031
"_ _ COMPENSATOR (Mul
ilEAl SIIUNI ICIII -" ",PIIFSSURt PAD ISSI
Figure 4. An exploded view ofthe silicon-germanium unicouple (thermoelectricelement). 572 ofthese
unicouples are used ineach GPHS-RTG. The unicouple length is3.11 centimeters and the hot shoe mea-
suresalmost 2.3centimeters by 2.3centimeters.The hot shoeoperating temperature isabout 1305 K.
4