Labs from Chicago, Fall 1993 :
Dr. Jim Sweitzer
The Packsat Project.
Labs written for the CARA Space Explorers, Fall 1993
This is meant to be handed out to the students.
Satellite Communications: The Packsat Project
(We will also do a session up at Yerkes Observatory after Christmas.)
Satellite communications are vital to the workings of our modern world.
Many of your telephone calls and almost all of the TV you watch relies
upon a satellite at some point to relay the communications you receive. In
fact, satellite communications is probably the biggest benefit of all the
money we have spent in the space age.
In this short course you are going to become an expert in understanding
basically how satellites work and how they can be used for
communications. In fact, with a lot of hard work and a little luck, we
should be able to communicate directly with a Russian satellite.
We will also learn about two very advanced communications technologies.
Packet communications is where the information is sent in digital bursts.
This is how computers "talk" with one another. We will see first hand how
this technology works and try to listen to satellites talking with one
another using "packets" of information. Finally, we will learn how
cellular telephone communications work and even investigate a new
system of satellites that will be launched soon that is a big cellular
system that covers the entire Earth. It's called Iridium.
Part of the reason in doing this class is so that you will be prepared for
future work we will be doing with amateur radio and satellites. The Space
Explorers program has an application into NASA to contact an upcoming
Shuttle mission. You will be taking a ham radio class next year and this
will be useful for that class. The college is about ready to purchase a
radio that will allow us to communicate with satellites. We will also
probably be experimenting with satellite communications at both the
North and South Poles. Most of all, however, it is just an interesting way
to learn some physics you will need later in high school and college.
You will be evaluated for your performance in this course. Your
attendance is required at every session. If you can't attend you must bring
a note the following week from a parent or OSP to excuse your absence.
Even if you are unable to attend you will still be held responsible for doing
the homework. I will give you a yellow folder to keep the handouts and
work in for this class. You must bring this with you each time. If too many
people start forgetting their yellow folders, then I will require you to
bring it to class if you want to get credit for attending on that day.
You will team up with a couple of other students to do a project. Your
team will be graded on the final project and a couple of the project
milestones along the way. Your final score for the course will be figured
using the following percentages: attendance = 20%, homework = 40%, and
project = 40%.
Session Date Topic
1 October 27 Introduction, Circular Motion
2 November 10 Kepler's First Law
3 November 17 What Keeps a Satellite Up?
4 December 1 Satellite "Footprints"
5 December 8 Keeping a Date with a Satellite
6 December 15 Doppler Radio Waves
7 December 27/28 Packet Radio
8 January 19 Iridium System
9 January 26 Project Seminar
Note that there are a couple of Wednesdays when we won't be meeting.
We will also be going up to Yerkes Observatory after Christmas and will
use some of that time to work on research projects. Note below that you
will have some due dates in early January.
This class grade will be heavily weighted by projects that you and your
team members do in the course of the quarter. I will divide you into teams
during the first class. Below is a list of potential project subjects.
Between the first session (today) and next week, you and your team should
think about the projects you would most like to do. Rank them in order of
your preferences. When you come in next week we will all decide together
which group does which project.
All the projects are research projects. All members of a team will get the
same grade for the groups performance. This is a real research
collaboration! I will give you some references to get started next week.
Your team will be expected to contact an outside expert. I will track these
people down for you. The person listed as Advisor is the outside person
you must contact. (TBD means To Be Determined.) Below are the project
milestones (or due dates, if you like).
Each completed project must consist of three things:
Here are the due dates for the various milestones of your project:
- A term paper, of no less than 1,000 words. This should be done
using one of the Macs at OSP and should be a Teach Text file. Pictures or
illustrations are welcome and should be included in most of the projects.
- A transcript of an interview with your advisor concerning your
topic. This too must be typed into one of the Macs at OSP and given to me
as a Teach Text file.
- A 15 minute oral presentation to be delivered during the last
- November 10th ...... Topics chosen and /or assigned
- December 8th... Outline of paper & List of questions for
Interview due (They may be handwritten)
- January 12th .... Interview transcript file due at OSP
- January 19th ... Final term paper due
- January 26th ... Oral presentations delivered
- Project 1: Why use Satellites for Science?
- Advisor: Simpson
scientists use satellites and space probes to conduct their
research. Why can't they just use telescopes? What are
some of the most stunning discoveries that satellites have
made since they were first used? Dr. Simpson is a
pioneer in the business of using satellites. He's here at
the University and just a nice person. Currently he is
getting ready to launch a satellite to measure the dust and
debris around the Earth.
- Project 2: Russian Amateur Satellites
- Advisor: TBD
In class we will use
a Russian satellite as the one that we interact the most
via the radios. It's called RS10/11. There are a couple of
others, I think. This group is responsible for describing
the details about these satellites, their history and how
they work for us in writing and pictures. I am in the
process of trying to contact a person from the Moscow
Radio Club. He (or she) will be your advisor. You will
contact them over the computer network called Internet.
- Project 3: Packet Radio
- Advisor: Jendraszkiewicz
Computers, whether it is over a wire
or over phone lines or even with a satellite communicate
to each other using "packets." This group will describe
how packet radio communications work. We will
experiment a little with this in class. When you receive
your radio license next year, you will be doing lots of
packet radio. The contact person here is Gerry
Jendraszkiewicz. He is an engineer with the University
and a top-notch amateur radio person who has helped us
set up the station on campus.
- Project 4: How Cellular Telephones Work
- Advisor: Givens
Although cellular phones are really an Earth-based technology
(for now at least), they involve a form of digital
communications that are the wave of the future. This
group will write a paper that describes how the cellular
phone system works. Mr. Givens is a fascinating engineer
at a local company called Tellabs. They write the
computer programs to make cellular phones work.
- Project 5: Motorola's Iridium Project
- Advisor: TBD
By the time you are
in college, Motorola will have phones that you can put in
your pocket that will use satellites like a cellular phone
system. They will enable you to make a call from
anywhere on the Earth. This communications project is
called Iridium. This research group will write a paper
describing how Iridium will work. You should also
brainstorm in your group to think of unusual ways such a
global phone system will be useful. I will find an expert
at Motorola who will be able to help answer questions and
give you an interview.
- Project 6: Packet Satellites
- Advisor: Reeves
There is a type of satellite that is
about the size of a personal computer and flies very fast
in a very low orbit. In fact it is really just a computer
with a radio attached to it. When it talks back and forth to
computers on the ground it does so with packets. This
research group will research these small satellites,
describe them and tell how they are used. You might even
get to use one. The advisor for this class is a teacher in
California. He and his class, who use them all the time,
will help you. Your connection with them will also be
over the Internet, computer network.
Important Disclaimers and
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