NASA Technical Reports Server (NTRS) 20100030582: Athena: Providing Insight into the History of the Universe

28 Pages·6.2 MB·English

by  NASA Technical Reports Server (NTRS)

Executive Summary
The American Institute for Aeronautics and Astronautics has provided a Request for
Proposal which calls for a manned mission to a Near-Earth Object. It is the goal of Team
COLBERT to respond to their request by providing a reusable system that can be implemented
as a solid stepping stone for future manned trips to Mars and beyond. Despite Team COLBERT
consisting of only students in Aerospace Engineering, in order to achieve this feat, the team must
employ the use of Systems Engineering. Tools and processes from Systems Engineering will
provide quantitative and semi-quantitative tools for making design decisions and evaluating
items such as budgets and schedules. This paper will provide an in-depth look at some of the
Systems Engineering processes employed and will step through the design process of a Human
Asteroid Exploration System.
Team COLBERT (from left): Josh Eggleston, Kris Walbert, Eric Buckenmeyer, Umair Surani,
Andrew Lyford, Katie Rybacki
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ApplIcable Documents
Document TItle DescnptIOn of Document
2009-2010 AIAA FoundatIOn Undergraduate ProvIdes the problem defimtIOn and lIsts
Team Space TransportatIOn CompetItIon Request many of the mISSIOn reqUIrements
for Proposal (1)
111
Table of Contents
1 IntroductIon 1
1 1 Background 1
1 2 Problem DefimtIOn 1
2 Systems Engmeenng Process 2
2 1 Systems Engmeenng Process Plannmg 2
2 1 1 Major Products and Results from Process 2
2 1 2 Upper Level System Needs, Alterables, and Constramts 2
2 1 3 Resource AllocatIOn 3
2 1 4 VenficatIOn Plannmg 3
2 1 5 ObjectIve Hierarchy Chart and AnalytIcal HIerarchy Process 4
2 2 FunctIonal AnalysIs and AllocatIOn 5
23 ReqUIrements AnalYSIS and ValIdatIOn 5
23 1 AsterOId AnalYSIS 5
2 3 2 MISSIOn ArchItecture 6
2 3 3 Power System 6
2 3 4 CommumcatIOns, Command, and Data Handlmg 7
235 Human Systems and Safety 7
2 3 6 RelIabIlIty and MamtamabilIty 7
2 4 System SyntheSIS 8
241 CommercIal off the Shelf (COTS) or Developmental Items 8
242 Reuse 8
2 5 System AnalYSIS and Control 8
25 1 Trade StudIes 8
252 Budget Forecastmg 12
2 5 3 RIsk Management 12
2 5 4 Interface Management 12
2 5 5 ReqUIrement TraceabIlIty l3
3 TransitIonmg Cntical TechnologIes l3
3 1 ActIVItIes l3
3 2 Cntena for Use 13
33 RISk 14
4 IntegratIOn of Systems Engmeenng Effort 14
4 1 Use of Concurrent Engmeenng 14
4 2 OrgamzatIOn of DeSIgn DiscIplmes 14
4 3 ExpectatIOn and Frequency of ReVIews 14
5 ImplementatIOn Tasks 15
5 1 Team Schedule 15
5 2 System ImplementatIOn Schedule 15
AppendIX 16
IV
LIst of FIgures
FIgure 1 OrbItal Diagram 2
FIgure 2 AHP WeIghted Values 4
FIgure 3 Spacecraft at 1991 JW 11
FIgure 4 ObjectIve HIerarchy Chart 16
FIgure 5 FunctIOnal AllocatIOn 17
FIgure 6 Full Assembly m Space Transport ConfiguratIOn 17
FIgure 7 Gantt Chart displaymg Team COLBERT schedule 20
FIgure 8 Gantt Chart displaymg MIssIOn Timeime 21
LIst of Tables
Table 1 Needs, Alterables, and Constramts for the HAES 3
Table 2 AHP WeIghts of Lower Level ObjectIves 5
Table 3 Techmcal Data for MISSIon ArchItecture Trade Study 9
Table 4 SelectIOn MatrIx for MIssIOn ArchItecture 9
Table 5 Power Trade Study 10
Table 6 SelectIOn MatrIx for Structural ConfiguratIOn 11
Table 7 Budget for ImtIal Cost and Each Subsequent MISSIon 18
Table 8 Sample ReqUlremnt Checkhsts 19
v
Nomenclature
NASA NatIOnal AeronautIcs and Space AdmmistratIOn
NEO Near Earth Object
COLBERT Close Object Landmg By an Earth Research Team
HAES Human AsteroId ExploratIOn System
NEA Near Earth AsterOId
!1V Delta VelocIty
EVA Extra-VehIcular ACtIVIty
AHP AnalytIcal HIerarchy Process
PT&E Power, Thermal & EnVIronment
CC&DH CommUnICatIOn, Command & Data HandlIng
LEO Low Earth OrbIt
COTS Commercial Off The Shelf
VASIMR Vanable SpecIfic Impulse Magnetoplasma Rocket
VCRlMHD Vapor Core Reactor coupled WIth a Magnetohydrodynamic power generator
VI
Athena ProvIdIng InsIght Into the HIstory of the UnIverse
1 Introduction
1 1 Background
The Umted States has been the leader of manned spaceflIght smce 1962 when PresIdent
Kennedy challenged NASA to reach the moon by the end of the decade The excItement over
human spaceflIght shIfted m the 1980's to the Space Shuttle program, WhICh was desIgned as a
hftmg rocket to put space statIOns mto orbIt rather than to explore new worlds hke Kennedy's
Apollo program The shuttle has been the focus for nearly three decades but now wIth an agmg
space shuttle fleet, a new dIrectIOn for manned space flIght must be developed
In 2009, a panel of 10 sCIentIsts was assembled to determme a solutIOn to thIS problem
The panel, known as the Augustme CommIssIOn, outhned vIable optIOns for the future of
manned spaceflIght wIth an end goal of sendmg humans to Mars A dIrect mISSIOn to Mars was
found to be mfeasible however, due to unproven technologIes and mISSIOn desIgns The
commISSIOn determmed that before a manned mISSIOn to Mars could be pursued, It would be
more practIcal to send manned mISSIOns to the Moon, the MartIan moons, or a Near-Earth Object
(NEO) (2) The goal of thIS project IS to develop a prehmmary desIgn for a mISSIon to a NEO
ThIS project wIll serve as a steppmg-stone for a future manned mISSIon to Mars and WIll help to
extend humankmd's knowledge ofthe solar system
1 2 Problem DefimtIOn
The Amencan InstItute for AeronautIcs and AstronautIcs (AIAA) released a Request for
Proposal (RFP) detaIlmg theIr desIre for a manned excursIOn to a NEO It IS the mISSIOn of
VIrgmia Tech's Team COLBERT (Close Object Landmg by Earth Research Team) to respond to
the RFP and develop a Human AsteroId ExploratIOn System (HAES)
Accordmg to AIAA, a reahstic mISSIOn to a NEO would have the followmg ObjectIves
The HAES must be capable of transportmg two or more astronauts to a Near Earth AsterOId
(NEA) and have them return safely to Earth The mISSIOn and technology should be feaSIble for a
mISSIOn tImehne between the years 2018 to 2030 The HAES must prOVIde all of the crew
accommodatIOns and hfe support systems for safe travel and It must be capable of human
exploratIOn of the asterOId surface as well as the observatIOn of the asteroId wIth sCIentIfic
eqUIpment AddItIonally, the system must be capable of extractmg and returnmg to Earth at least
100 kg of asterOId matenal
The target asterOId for the Athena mISSIOn as determmed by Team COLBERT from a
prevIOUS desIgn process IS 1991 JW ThIs asterOId was chosen pnmanly due to ItS abundance of
launch opportumtIes, ItS earthhke orbIt, and ItS clasSIficatIOn as a ' PotentIally Hazardous NEO"
(3) Lambert's problem was solved through an IteratIve process m order to optImIze total
mISSIOn ~ V for speCIfied launch and arnval dates ~ V IS the net change m velOCIty needed to
enter a dIfferent orbIt and therefore can be used as a gauge for mISSIOn feaSIbIlIty by specIfymg
the amount of propellant needed After performmg the reqUIred calculatIOns, the optImal ~ V
was found to be 8 79 kmls WhICh corresponds to Earth launch and arnval dates of
September 28,2027 and March 7, 2028, respectIvely FIgure 1 shows the orbItal dIagram of
1991 JW wIth respect to the orbIt of the Earth along wIth the arnval and departure dates
1
SUmmtny
aJ79.I5 (19911'N) 201().M.,.28 17 1946 To[a/4V_1I.7B6 km/_
Duration _160.0 tItIys
JHIJWDe".t"tMrW ,H, Arrl'"
0'5 _---------:..= . ...: l.:.Z:.: /: .:. l:.:.Z: .:/.:.-l.:O .:.:.:l .'. . .. JW
.dV. f .• 71Ima/~ lZ/lZ/lOl'
0' .................. ~ -_....~::v~ ~O.UJ It",/NC
...........................
-0'
., .,
-08 -06 -02 02 O' 06 08
'.'"
Figure 1: Orbital Diagram. This diagram shows the orbits of the Earth (blue) and 1991 JW (red)
as well as the dates and 11 V requirements for the two arrivals and departures. The
dotted black line corresponds to the transfer orbit that the the spacecraft will follow.
2. Systems Engineering Process
This section describes the systems engineering process implemented to develop the
spacecraft design. It will highlight how the mission requirements were developed and validated.
Subsequently, it will show how they were broken down into various systems and subsystems.
Due to report length restrictions, the development of several major systems, such as the Attitude
Determination System, was omitted.
2.1. Systems Engineering Process Planning
2.1.1. Major Products and Results from Process
The systems engineering process used for this design project will yield both a preliminary
spacecraft design and mission profile. The complete design will include both the launch vehicles
used and the spacecraft employed to transport crew and cargo to and from the asteroid. The
mission profile will consist of dates and propulsion requirements for transporting the spacecraft
to and from the asteroid.
2.1.2. Upper Level System Needs, Alterables, and Constraints
Based on the problem definition, the needs, alterables, and constraints of the upper level
system are identified and listed in Table 1. The needs, alterables, and constraints were used as an
initial step to determine the individual system requirements. The remainder of the section will
discuss this process in a more fastidious manner.
2
Table 1 Needs, Alterables, and Constramts for the HAES ThIS table IdentIfies all relevant
aspects of the mlSSlOn as part of the first step m determmmg system reqUlrements
Category Element
Needs • To perform sCIentific research
• Data storage and transnusslOn capabIhty
• System to control asteroId landmg
• AbIhty of astronauts to perform EVA s
Alterables • AsterOId selectlOn
• Transfer orbIt trajectory
• PropulslOn system
• Launch vehIcle selectlOn
• ReusabIhty of system
• RadlatlOn and thermal protectlOn systems
• Human hfe support systems
• Ground and space commUnICatlOn mfrastructure
• Earth reentry/landmg system
• Dnllmg technIque
• SCIentific analYSIS of asteroId
• Power system
Constramts • MlsslOn must be completed by 2030
• Must be capable of carrymg at least 500 kg of cargo to
asterOld
• Must carry at least 2 astronauts
• Must return at least 100 kg of asteroId sample
2 1 3 Resource AllocatIOn
The deSIgn team conSIsts of SIX Aerospace Engmeenng students at VIrgmIa Tech Each
student IS the lead on a partIcular system and aSSIsts on other systems when necessary ThIS type
of structure ensures that there are no holes m commumcatlon and allows each system deSIgn to
reach completlOn WIth no change m leadershIp, makmg the venficatlOn of reqUlrements process
SImpler and less prone to errors In order for a system leader to gam more resources, he or she
SImply needed to ask the team manager for help
214 VenficatlOn Plannmg
In order to venfy that all reqUlrements are met, each system wIll be overseen by two other
students specialIzmg m dIfferent systems These students wIll ensure that all necessary
reqUlrements for the system, as outlIned m the early stages of the deSIgn process, are completed
m a satIsfactory manner A benefit to usmg thIS style of venficatlOn process IS that by havmg
two students checkmg m on each system, the entIre deSIgn team wIll have a better understandmg
of the entIre proJect, thus minImIzmg commumcatlOn errors and maximIzmg team effiCiency
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2.1.5. Objective Hierarchy Chart and Analytical Hierarchy Process
Figure 4 displays the Objective Hierarchy Chart developed for the design problem. The
chart illustrates all major design factors and the criterion used to judge their effectiveness. There
are five major upper level objectives in this design. They are Scientific Analysis, Technology
Available, Performance, Cost and finally Safety. In the subsequent subsection, an analytical
hierarchy process (AHP) will be implemented to judge the importance of each objective with
respect to the others.
2.1.5.1. Analytical Hierarchy Process
An analytical hierarchy process was performed on the upper level objectives shown in the
Objective Hierarchy Chart in Figure 4. The AHP is a tool that ranks the importance of each
objective with respect to the others regarding importance to the mission. The process attempts to
eliminate bias by allowing the user to compare only two objectives at a time (4). An AHP was
also performed on the lower level objectives under each major category.
The chart shown in Figure 2 is the result of the AHP. These rankings show that the
safety of the astronauts is the top priority of this mission followed by the amount of scientific
analysis performed at the asteroid and the performance of the vehicle. Cost was second to last
and the amount of information and technology available was the least important of the upper
level objectives. This is appropriate because some of the technology that does not exist currently
will be available in 2018 when the launch window opens.
Science
Safety Performed
0.482 0.175
Technology
Available Cost
0.058 0.107
Figure 2: AHP Weighted Values. This graph shows the relative importance of each upper level
objective to mission success. Safety received the highest relative importance score and
the mission cost was least important to mission success.
The AHP results from the lower level objectives are shown in Table 2. The most
important lower level objectives are the system's ability to adapt to the asteroid's environment,
the launch cost and the system reliability. Mars capability was ranked third under the
performance objective; this measures the system's ability to carry over to a Mars mission which
is one of the major goals for a manned flight to a NEO. These rankings provided guidance for
the trade studies that were performed throughout our design process because they established a
minimally biased way of selecting the best design alternative for each system and subsystem.
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