Paraphrase

Hi, I would like you to paraphrase only the answers not the questions.

1) What is involved in mission characterization?
Ans) Mission characterization is the initial process of selecting and defining a space mission.
The aim is to select the best overall approach from the available wide range choices to
successfully complete a space mission. Typically, the most cost-effective approach is
selected which provides a traceable rationale that is intelligible to the decision makers.
Mission characterization mainly involves following steps
a. Define a concept of operation
b. Identify alternative mission architectures
c. Identify system drivers of each architecture
d. Characterize mission concepts and architectures
Define a concept of operation: This involves data delivery between missions and
housekeeping, communication among various components of the system, task scheduling
and control, and program scheduling.
Identify alternative mission architectures: This deal with trade study of eight mission
elements namely controllable subject, passive subject, payload, spacecraft bus, lunch
system, orbit, ground system, communication architecture and also includes trade study
of mission concept and mission operations. At this stage option for construction of trade
tree is available. After trade tree is available it is pruned by eliminating unrealistic trade
combinations. Other alternatives which could substantially influence the mission
accomplished are also considered.
Identify system drivers of each architecture: This include identifying parameters which
measures cost assessment, risk assessment, and mission performance.
Characterize mission concepts and architectures: At this stage preliminary mission
concept and subject characteristics are defined. Also the orbit or constellation, payload
size and performance are determined. This also involves selection of mission operations
approach like communication architecture, operations and ground system.
2) Describe the principle trade studies that must be considered for any 3 of the architectural
elements shown in class?
Ans) Architectural elements consist of mission concepts, subject, payload, spacecraft bus,
launch system, orbit, ground system, communication architecture and mission operations.
Among all the architectural elements mission concept, payload, spacecraft bus, launch
system, orbit ground system and mission operation are tradable.
Payload trade study: Payload trade study depends on frequency bands like communication
can be made over normal bands, type of observation IR, visible or microwave, kind of radar
used L, C, S bands or UHF. Trade studies can also be made depending on the complexity of
band single or multiple bands and single or multiple instruments employed. Further trade
study can be performed depending on small aperture with high power or large aperture with
low power consumption. Launch system trade study: It depends on type of launch vehicle like SSLV, Atlas, Delta,
STS, Titan, Pegasus, Ariane, etc, upper stage Pam-D, IUS, TOS, Centaur, Integral propulsion
etc and launch site like Kennedy, Vanderberg, Kourous etc.
Orbit trade study: Many different orbits are available such as special orbits like None,
geosynchronous, Sun-synchronous, frozen, Moiniya, repeating ground track; depending on
0 altitude Low-Earth orbit, mid-altitude and geosynchronous, depending on inclination 0 ,
00000 28.5 , 57 , 63.4 , 90 , 98 etc.
3) What are system drivers? Why is it necessary to quantify them?
Ans) System drivers are the principal mission parameters which influence performance, cost,
risk, or schedule and which the user or designer can control. Correctly identifying the key
system drivers is a critical step in the mission analysis and design. Misidentifying system
drivers is one of the most common causes of mission analysis error. System drivers are
identified by area of interest, parameters which measure the area of interest, develop first-
order algorithms, examine the factors, and look for possible hidden drivers. Most important
system drivers include size, on-orbit weight, power, data rate, communications, pointing,
number of spacecraft, altitude, coverage, scheduling and operations. Defining system drivers
depends in-part on physical and technical nature of the problem and in-part on the constraints
imposed on the mission analyst.
4) Read the FireSat Mission Statement document posted in this lesson. Using that statement
as an example, write a mission statement for space system that "will, on a worldwide
basis, search for, detect, track, identify and report on all ships in all oceans and seas." The
customer is the US Navy and Homeland Security.
Ans) Security and safety has always been in top priority for any country. Therefore, it
becomes necessary to monitor movements of all the ships in sea and oceans. US needs a
more efficient space system to search, detect, track identify all ships in oceans and sea. The
information collected will be used by US Navy and Homeland Security to report on all ships
in all oceans and seas to take proper measures in case of any threat situation. The
communication between the groups must be coded and on special band so that other cannot
detect and interpret it