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Robert J. Sawyer's First Science Article
Copyright © 1982 by Robert J.
All Rights Reserved.
I'm posting this in the summer of 2017, thirty-five years
after the article below first appeared in print.
As I mentioned on the page about
my first-ever fiction sale, my family
had a vacation condominium on Canandaigua Lake, near Rochester,
New York, and because of that I became aware of the activities of a
group of students in the area ... and their ambitious plan to build
an orbiting space telescope years before Hubble, to be launched from
a space shuttle.
As a budding freelance writer I was all of 22 years old
I pitched one of my favorite magazines,
Sky & Telescope, and got the go-ahead to write
this 2,000-word article. I didn't get my first computer until a year
and a half later, so the version here has been OCR'd from a hardcopy
of the magazine. (And you can read a PDF of the article, with the
Sadly, the explosion of the space shuttle Challenger in 1986 and
subsequent flight moratorium put an end to their project, but I had a
blast writing the article, and still remember fondly the time I spent with
and the thrill of seeing an article written by me on sale at magazine
And, indeed, this article led to the first time I was ever recognized as
an author by a stranger. Over Labor Day weekend 1982, I attended my first
World Science Fiction Convention, Norwescon 2, in Boston, and while
riding up an elevator, wearing a convention ID badge that said,
"Robert J. Sawyer, Ontario, Canada," a man said,
"Hey, did you write that article in Sky & Telescope?"
I was also touched to find my piece fondly remembered by physicist
Andrew LePage, who, in a
2014 blog post,
recalled it as "an excellent, detailed article."
Eventually, in my nonfiction career, I produced over 200 feature article
before transitioning in the early 1990s to writing science fiction novels
full-time. But this piece, from thirty-five years ago, will always hold
a special place in my heart.
An Amateur Space Telescope
by Robert J. Sawyer
Cracking open a new frontier is everyone's business. The North
American West was discovered, explored, and finally settled as
much through the efforts of private parties as by government and
industry. Homesteaders, prospectors, adventurers all were
pioneers. Today, private citizens are joining the ranks of those
who will explore that final frontier, limitless space. Major
among these is a group that has sprung up in the idyllic
countryside of upper New York state, a land known for finger
lakes, vineyards, photography, glassworks, and now, an orbiting
The Independent Space Research Group is an international,
nonprofit organization formed in early 1980 by students at
Rensselaer Polytechnic Institute in Troy, New York. At present,
the ISRG has 250 members in the United States, Canada, and 10
other countries around the globe. The group's first project will
be to build an Amateur Space Telescope (AST) and to have it
placed in orbit by late 1984. Last year, all optical work was
transferred to the University of Rochester, 400 km west of RPI,
where a second group of student teams (under faculty advisers)
Once the AST reaches orbit, anyone with receiving equipment
(costing about $300) will be able to obtain pictures and data
directly from the satellite and display them on a standard
television set or photographic printer. Armchair astronomers
will be able to tune in a show with real stars from their living
ISRG's members are not the first fans to stop being mere
spectators in the sport of spaceflight. Amateur radio operators
("hams") have built and operated their own radio communications
satellites since 1961. A dozen of these devices, affectionately
known as OSCAR's (for Orbital Satellites Carrying Amateur Radio),
have hitched free "piggyback" rides on various NASA and European
The hams discovered that they could build simple satellites for
two percent of the cost to NASA or private industry. The savings
are attributed to skilled volunteer labor, off-the-shelf parts,
and proven system designs. In addition to the hams and the ISRG,
at least four other nonprofit organizations are working on
Though details continue to be refined, the size, shape, and
internal layout of the ISRG's first AST have been firm since
1980. It will measure 50 cm in diameter and 1-1/4 meters long,
weighing in at about 80 kg. The actual telescope will be a 45-cm
Ritchey-Chrétien system. Images across a considerable
range of wavelengths will be available from 1900 angstroms
in the ultraviolet to 10,000 angstroms in the near infrared
with resolution near the respective diffraction limits of
about 0.02 and 0.35 arc second. By applying computer enhancement
to the images, these theoretical limits may actually be obtained.
The AST will yield resolution as fine as that seen by a visual
ground-based observer with a 45-cm telescope under "perfect"
conditions. Features as small as 130 km wide will be visible on
Mercury, and in the ultraviolet Venus will show atmospheric
details only 80 km across. Martian craters 70 km in diameter
will be resolved, as will structures in the clouds of Jupiter as
small as 700 km. Far Pluto and dark moon Charon will be separate
objects to the AST's eye.
Images will be fed to two General Electric CID (charge-injection
device) solid-state television cameras, providing both
narrow- and wide-field coverage. The cameras can take short exposures
repeatedly and integrate them in memory. This time-exposure
effect an electronic version of keeping a shutter open
will allow images of very faint objects to build up for as
long as 10 hours. Coupled with noise-cancellation procedures,
crisp images of objects down to the 23rd magnitude should be
obtainable. The field of view depends upon the number of
discrete picture elements (pixels) available at the focal plane.
The AST will likely be outfitted with a 256-by-256-pixel array,
although a unit with four times the area may prove feasible. The
telescope will also carry three photometers to measure the
brightness of stars in separate wavelengths and a small
AST has a projected minimum operational life of two years. If a
camera and supporting electronics worth $3,500 depreciate to
nothing over two years, then each day's operation costs about $5.
To raise funds to purchase the cameras, the ISRG is seeking
"sponsors" to contribute money for a day's, week's, or month's
The equipment bay, a 50-cm-long octagonal prism, forms the main
body of the satellite. Inside are five identical shelves (with
identical partitions) for mounting hardware. These
interchangeable components make structural analyses and
manufacturing much simpler, while maximizing the design
flexibility. The shelves are fabricated from a honeycomb
sandwich of graphite-epoxy and Nomex nylon. Sandwich
construction is very efficient in terms of stiffness to weight,
and it requires a minimum of skill and tooling to manufacture.
Solar panels will provide up to 60 watts of electricity, to be
stored in nickel-cadmium batteries. Once in orbit, the
spring-loaded panels should unfurl to a rigid 1.5-meter wingspan.
Attitude control of the satellite will be accomplished by a trio
of flywheels on mutually perpendicular axes. A fourth flywheel,
mounted at an angle, will be used as a backup in case one of the
others fails. An RCA 1802 microprocessor, combined with a series
of star sensors, will control the flywheels and most other
on-board systems and transfer ground commands into actions.
The satellite's communications will be handled by a receiver,
with a backup, plus a pair of transmitters each broadcasting with
500 milliwatts of power. One transmitter will serve as an
engineering beacon, continually broadcasting telemetry. The
other will act as a data beacon for pictures and other
astronomical information. All data will be sent in a digital
form that includes checksums and other means for detecting and
Because of their OSCAR program, amateur radio operators have
experience in controlling satellites from the ground. Therefore,
a network of ham stations will operate the AST, coordinated by a
similarly equipped ISRG facility. A number of advanced OSCAR
satellites are expected to be in geosynchronous and long-period
orbits by 1985; these should provide radio links between the AST
and ground stations over its horizon.
PROVING THE CONCEPT
Originally, a test satellite was planned to provide the ISRG with
experience in constructing and operating a satellite, to test the
attitude-control system proposed for the AST. and to give the
ground-based communications network practice in the deployment
and control of a device much like the AST. The test satellite
would have been the same size and shape as the AST. Yet. even
without astronomical optics, it would have cost $30,000 (compared
to an estimated $100,000 for the actual AST and its backup).
Fortunately, the simulation and logistics of modern
attitude-control systems are so precise that testing was deemed
unnecessary. Therefore, this spring the test satellite project
was scrapped and replaced with a more useful test flight of
critical components aboard the Space Shuttle. A great advantage
in sending materials on the shuttle, of course, is that they will
be returned to Earth for possible reuse on the AST itself.
Packed into one of the shuttle's small self-contained payload
canisters, the AST equipment package will be flown for a thermal,
vacuum, and launch-vibration stress test. The canister (also
called a "Getaway Special") is worth $10,000 and was donated to
the ISRG by the International Space Research Society of
Melbourne, Florida. The International Space Corp. contributed
another $5,000 to cover hardware development for the test flight.
Now 47th in the queue for room in the shuttle's cargo bay, the
test package should fly next summer.
As for the AST itself, there are currently no firm policies for
launches of small satellites from the shuttle. The ISRG is
negotiating with NASA astrophysicists to determine how its
observations may augment or complement those to be performed by
the 2.4-meter Space Telescope. Such cooperative scheduling may
make it possible for the AST to be classified as a NASA payload
and thus to be launched for free. Other options include
piggyback flights on conventional rockets.
ISRG will have little say in the flight assignment it gets, but
it is ready to make the most of what's available. Ideally, the
AST would occupy a Sun-synchronous polar orbit, about 500 km
high, which possesses special characteristics. In a polar or
near-polar orientation, precession induced by the Earth will
cause the orbital plane to turn constantly. (If the orbit is
circular, the plane will turn like a spinning coin.) With the
right combination of altitude and inclination, the orbit will
turn at the same rate that the Earth revolves around the Sun
once per year. Moreover, if the AST circles directly
above the terminator, the satellite will never enter the Earth's
shadow, and the solar panels can then provide full power all the
time. This orbit will place the AST in a given ground-based
observer's sky at very nearly the same time every day.
APPLICATIONS OF THE AST
All sciences that depend on the day-today accumulation of data
count on legions of amateurs. Mineralogists rely on private
collectors. Psychologists use students to test behavior
theories. And so, too, with astronomers: there simply isn't
enough time on big telescopes to allow for the mundane but
necessary constant monitoring of the skies. Many amateur
observing networks, such as photometric observation of variable
stars, quasars, and Seyfert galaxies, could be facilitated by the
AST. The ISRG's eye-in-the-sky will regularly observe the
planets at high resolution and alert professionals to interesting
transient features worthy of closer examination.
The AST will be used for both scientific research and educational
projects. Individuals and groups wishing to perform observations
should submit proposals to the ISRG, which will then schedule
approved projects. There will1 be no charge for use of the
One application of the AST was suggested by a news item in this
magazine. The December, 1981, issue (page 545) report that a
possible moon may accompany the asteroid 9 Metis, based on a
slight bulge appearing on a photographic plate taken in China.
(See also page 164 of this issue.) If the presumed secondary is
real, its apparent separation of 1.2 arc seconds from Metis
represents an orbital radius of 1,100 km at the asteroid's
distance. The AST would have no trouble determining the real
situation; in fact, it could search for main-belt asteroid pairs
as little as 300 km apart.
What lies ahead for the ambitious ISRG members? Current
discussions revolve around what capabilities would be desirable
in a second AST, and three possibilities are now being explored:
- A diffraction-limited ultraviolet telescope of 1-meter
aperture or greater.
- A Schmidt telescope optimized for an ultraviolet survey of
the entire sky, comparable to the visible-light National
Geographic Society-Palomar Observatory Sky Survey. Both
wide-field coverage and high resolution would be required, a task
better suited to photographic film than television. Recoverable
film packages might be considered.
- A compact multiple-mirror telescope. Its weight- and
volume-to-aperture ratios make it a more reasonable payload than
a comparable single-mirror device. But an MMT design would
require great mechanical and structural complexity, making it a
potential but unlikely candidate for the second AST.
Farther into the future, a successful ISRG may wish to try other
kinds of missions. These might include an amateur lunar orbiter
(seed funding has already been donated by the International Space
Corp.) ; a solar-dedicated telescope; and a number of other
instruments for research at infrared, radio, and X-ray
Response to the AST concept from the aerospace community has been
excellent. The donation of funds ($6,000 from the Inter-Space
Society), materials (such as an aluminum "egg-crate" base for the
solar panels), expertise, and information have all been
gratefully received. Three optical companies have offered
assistance in manufacturing the telescope, and a division of
Hercules. Inc., is donating the graphite-epoxy composite to be
used for the equipment-bay structure.
Not everything comes free, of course, and the ISRG is actively
seeking new members. Individuals can obtain membership for as
little as $10, which includes a vote in the organization's
activities and a subscription to its bimonthly newsletter.
Inquiries should be addressed to the Independent Space Research
Group, P.O. Box 1246, Troy, NY 12180.
More Good Reading
PDF of the article as published
Rob's first SF publication
Rob's first SF sale
More nonfiction by Rob
Rob's 10,000-word autobiography
Rob's current curriculm vitae
Rob's short fiction
Oodles more about Rob
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