Page 9 - Pakistan Link - October 18, 2019

OPINION OCTOBER 18, 2019 – PAKISTAN LINK – P9

Muslim Contribution to the NASA Hubble Space Telescope

n By Prof. Dr Nazeer Ahmed the truck or came from the outside!
Concord, CA In any case, the Main Ring had to
be vacuum-baked at 220 degrees F
uslims have enriched for several days to dry it out. Good
America. This is a story thing it was built of Titanium. If it
Mthat needs to be told, was any other material, the 8-mil-
and told loud and clear, especially lion-dollar item would have to be
in the current environment when scrapped. The lessons for scientists
vitriolic Islamophobia rages in the are obvious: No matter how careful
land and corrupts you are, you cannot avoid the intru-
the social land- sion of nature (the Divine Laws) or
scape. the frivolities of human behavior.
The story of a The Advanced Composites
group of Pakistani Metering Truss
doctors in Appala- The Primary Mirror, Second-
chian Virginia pro- ary Mirror, Focal Plane and the Fine
vides an example. About thirty-five Guidance Sensor have to be kept in a
years ago, I was invited to visit and stable configuration with respect to
speak in Roanoke, a town located one another. Thermal fluctuations
deep in the coal mining area of Ap- (the heat and cold of space) and
palachian Mountains that straddle launch dislocations can change the
the eastern states and extend into discussing such a highly specialized micrometer). The secondary mir- limits with which it can be designed, distance of one component from an-
southwest Virginia and Tennessee. subject. The illustrative pictures are ror is 14 inches in diameter and is manufactured and assembled. In the other. Weight, stiffness and stability
Poverty stalks the land. Most people from open source. ground to 1/700 th of a wavelength Hubble, all the “errors” from all the are major drivers. On the Hubble,
in the region subsist on coal min- The Hubble was one of the of red light. Why? The precision of components statistically add up to each pound of extra weight added
ing, although in recent years it has most precise instruments built in the mirrors is dictated by the wave- less than 1/18th of a wavelength of fifty thousand dollars in launch
attracted some white-collar jobs. the twentieth century. It expanded length of operation which is cho- red light. Management of the “er- costs at 1980 prices. A tubular Me-
According to available statistics, the the horizons of humankind and pro- sen depending on mission require- ror budget” is a major challenge in tering Truss, built of graphite epoxy
per capita income in the region is vided deep insights into the universe a complex project such as this as it advanced composites is used to keep
approximately $17,000 as compared that we are a part of. Specifically, it The Hubble runs across conceptualization, sys- the two mirrors in fixed configura-
to $35,000 in Northern Virginia. enabled us to know with greater cer- tems definition and analysis, design, tion (distance and tilt) with each
Until recent years, medical fa- tainty the location of black holes at was one of manufacture, assembly, test and other. The advantage of composites
cilities in the region were scarce. the centers of galaxies, improved the post-launch operations. is that you can “build” these ma-
People were dying of lung disease precision of the time of origin of our the most The Zero Gravity Float terials unlike the naturally occur-
from breathing the dust in the coal universe, enabled us to witness stars The next challenge is to grind ring materials such as metals. High
mines. In the 1970s a group of Paki- of magnitude 8 (formed as early as a precise the mirror so that it has the desired strength GY 300 fibers with tensile
stani doctors moved into the area, hundred million years after the Big shape in the weightlessness of space. strength in excess of 300,000 psi
providing much needed medical Bang) and provided us pictures of instruments When you polish a mirror on earth, were used on the Hubble. The com-
services to the poverty-stricken peo- distant stars and galaxies with awe- it will “sag” due to gravity. This sag posites were designed to have high
ple and building world class medi- inspiring resolution. built in the has to be corrected so that the mir- stiffness ratio, high specific strength
cal facilities. The health standards of Why the Hubble? ror has the correct shape after launch and very low coefficient of thermal
the region improved, and the people Astronomical observations twentieth in space where there is no gravity. expansion. The measurements re-
were grateful. It is a success story of depend on the signal to noise ratio The construction of a zero grav- quired for the characterization of
Muslim doctors serving the United (SNR). The higher the signal to noise century. It ity float was one of the responsibili- these innovative materials were so
States, transforming the health and ratio, the greater is the resolution ties of my group. An ultra-precise small (10 E-7 ins/in) that they ex-
welfare of an entire region and this (clarity) with which we can see the expanded the mechanism was designed to “float” ceeded the capability of interferom-
story needs to be told. stars and galaxies. The electromag- the mirror and achieve zero gravity eters then available and required the
Many are the doctors, engi- netic waves from the stars and deep horizons of on earth. The 1800 pound hogged invention of novel methods of mea-
neers, scientists, architects, artists, space objects constitute the signal. out (lightened) fused silica mirror surement.
professors, sportsmen and other All else is noise. The stray light from humankind was conceptually divided into 132 The advanced composite tubes
professionals who have enriched this earth and from the atmosphere are segments and the weight of each of were fabricated at Boeing Aircraft
great country. It is not just house- sources of noise that reduce the and provided these segments was precisely calcu- Company in Seattle. Do not be so
hold names like Mohammed Ali and SNR. Space-based telescopes are lated using finite element structural awed by these fascinating new ma-
Kareem Abdul Jabbar who have set free from earth-bound noise and of- deep insights analysis. An ultra-fine balance was terials. A visit to fabrication facili-
a mark of excellence in their fields fer ideal platforms for astronomical built to apply an upward thrust on ties in one of these big name com-
and have brought honor to their observations with a high SNR. into the each individual segment, precisely panies reminds one of grandma’s
country. There are literally hun- The proposal for a space tele- equal to the calculated weight of that kitchen. Their fabrication is still
dreds, perhaps thousands of others, scope was advanced as early as universe segment. It was a major achieve- more of an art than a science. De-
some well-known, others obscure the 1950s by the physicist Lyman ment to so balance the large mirror fects in manufacture are common-
who have made their contributions Spitzer (1914-1997) and others. that we are and attain zero gravity on earth. place and have to be patched up or
and have made America richer, safer In the 1970s, when the American The Main Ring they have to go through a Materials
and a better place to live. The stories space program was at its zenith, the a part of. The Optical Telescope Assem- Review Board for acceptance. The
of these contributions must be col- US Congress allocated the funds to bly of the Hubble is divided into Hubble advanced the state of the art
lected and told again and again so conceptualize and build the Hubble four major subsystems: The Primary in advanced composites. The lessons
that future generations remember (named after the astrophysicist Ed- ments. In general, you can tell a Mirror Assembly, the Secondary learned about the limits of compos-
and are inspired to excel and serve. win Hubble). The thrust was the great deal about a telescope or a sen- Mirror Assembly, the Focal Plane ite material usage under various
This article is about the NASA advent of the Space Shuttle which sor just from the wavelength of its Assembly and the Fine Guidance load conditions, their stability when
Hubble Space Telescope. As Senior offered new means of deployment of operation. The long wave infrared Sensor. All of these systems are sup- subject to temperature variations,
Staff Project Manager at Perkin El- payloads like the Hubble. telescopes are used for surveillance ported on the Main Ring, a dough- moisture (water and volatile con-
mer Corporation in Danbury, CT, I The Concept and tracking. The short wave infra- nut shaped titanium structure. densable matter) and the environ-
had the privilege of being a member The core of the Hubble is the red telescopes are used for hom- Let me tell you a story here. ment, were used in other advanced
of the core team that designed, built, Optical Telescope Assembly (OTA) ing devices and missiles. The vis- The Main Ring was manufactured in systems in later years.
assembled, tested and delivered the with which I was associated. The op- ible and ultraviolent telescopes are Upstate New York and was shipped The Strain Free Mounts of the
Hubble. I was responsible for de- tics is a Ritchey–Chrétien reflector used for celestial observations. The to Danbury, Connecticut, a distance Mirrors
livering diffraction limited perfor- (invented as early as 1910) . Light shorter the wavelength, the greater of about two hundred miles. This The mounting of the mirrors
mance for the Secondary Mirror As- from far field (deep in space) is col- the precision of the mirrors and kind of specialized hardware is spe- without distorting their fine shape
sembly at 1/700 th of a wavelength lected by a convex primary mirror the greater the stress on design. The cially packed and sealed in air bags is a specialized research issue. The
of light in the visible (0.63 microme- which reflects it onto a concave sec- other reason is cost. The greater the to prevent damage in transporta- Secondary Mirror, for instance,
ters). It included the Metering Truss, ondary mirror. The reflection from precision, the higher the cost. The tion. On the way, the truck carrying which is ground to 1/700 th of a
the Secondary Mirror and its Strain the secondary mirror passes through mirrors of the Hubble are ground to the Main Ring ran into severe rain wavelength of light is so sensitive
Free Mount, the stray light Baffles, a hole in the primary mirror and is operate from 0.35 to 0.75 microm- storms and had to pull out of the that it changes its shape when a per-
Figure Control Actuators, the Ad- “seen” by a focal plane located at the eters. In other words, they operate highway. Accelerometers attached to son walks into the room in which it
vanced Composite Structures as well focus of the secondary mirror. Light in the ultraviolet to the short-wave the truck showed 5g loads, meaning is kept, due to the breathing of the
as the Zero Gravity Float. Each one shields are used on both mirrors to infrared spectrum. the trucker had hit big pits on the off person. The strain-free mounting of
of these was a research project in it- minimize stray radiation. The performance of a space ramp. In any case, the truck arrived the Secondary Mirror was entirely
self that stretched the limits of tech- The primary mirror of the telescope is limited by the diffrac- at our facility in the early hours of my contribution which resulted in
nology. The lessons learned were lat- Hubble is 2.4 meters in diameter. tion of space particles. As a rule of the morning and I was one of the awards of multiple US patents.
er used in advanced systems both in Why? This size is dictated by the size thumb, diffraction limited perfor- team asked to receive it. When we The Focal Plane Structure
the civilian and other sectors. This of the bay in the Space Shuttle which mance is about 1/18 th of the select- opened the truck door, water came houses the bays for the Scientific
is a brief non-technical note on that carried the telescope into space. The ed wavelength. Each of the compo- gushing out of the truck and with it Instruments (SI). It is built of ad-
exciting project although some tech- primary mirror is ground to 1/70 nents of a telescope contributes an there was a little frog. To this day I vanced composites, except
nical jargon is unavoidable while th of a wavelength of red light (0.63 “error” (inaccuracy) because of the do not know if the frog was inside HUBBLE, P24
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