8/9/2019 USA TODAY Collegiate Case Study: The Hubble Legacy -
Part 3
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In collaboration with NASA Goddard Space Flight CenterPage 2
The Hubble Legacy
Part Three: The Solutions and the Stakes
Those setbacks dampened the euphoria rom the lastshuttle
rendezvous - the dramatic rescue in May 1992 o an Intelsat
satellite that required a scripted, on-the- ygrab by three
spacewalkers.
Two crewmembers o that ight - Tom Akers, who helpedmake the
grab, and Kathy Thornton, who was on a di er-ent spacewalk - are
aboard Endeavour or this rescue.
A Hubble success now also is a critical con dence-builderor
another, even riskier program: NASAs planned spacestation, to be
launched and assembled in orbit this decade.The station, as with
Hubble, will be designed or routineservice and repair jobs by
spacewalkers.
When the space station is built, this sort o thing will haveto
be done all the time, says Webb. So this will plainlydemonstrate i
we have the capability or not.
Hubbles problems began shortly a ter it was dropped o in space
by a shuttle in April 1990.
Scientists ound to their horror that the telescopes 8- ootmirror
had been ground too at around the edges, caus-ing starlight to
spread out on the mirrors sur ace in auzzy halo instead o being
ocused to a point. The result isblurred images.
Only through computer enhancement has NASA been ableto provide
the tantalizing photos o distant stars and gal-axy clusters
ground-based telescopes cant see becauseo Earths atmosphere. Hubble
has difculties seeing verydim stars or ocusing on those in crowded
elds.
You wont nd a group o people who are more angrythan the
astronomers, says William Keel, an astronomerat the University o
Alabama. Weve been able to see justenough to know what were
missing.
The curvature was o by 1/50th the width o a human hair- a gaping
margin in optical terms. Contractors Perkin-
Elmer Corp. and Hughes Danbury Optical Systems agreedthis
October to pay the ederal government $ 25 millionor the de ect.
The servicing mission is costing taxpayers $ 251
million,including $ 86 million to x the mirror. In addition,
justlaunching the shuttle costs $ 500 million to $ 650 million.
There were more troubles: The delicate solar panels shud-dered
as Hubble moved into and out o sunlight, making it
difcult to steady the telescope. Over time, uses and
magnetic sensors wore out, computer so tware ailed and- worst o
all - three o six gyroscopes ailed.
With gyroscopes needed to point and align Hubble, havingthree
working ones is essential or the health o the tele-scope, says
Musgrave. I we lose one more, were downto a no-science mode.
The solution or Hubbles shaky health and myopic vision isa risky
one. A ter replacing the gyroscopes and solar pan-els, spacewalkers
Musgrave, Akers, Thornton and Je Ho -
man will try to install two bulky, corrective optical units:
A 610-pound, wedge-shaped camera with built-in mirrorsreplaces
the wide- eld camera in Hubble that now ren-ders blurry images.
A 600-pound phone booth-size device with mirrors willbounce
starlight rom the awed primary mirror ontothree other instruments.
Each has to t just right or theoptics to work.
Graphic by Marty Baumann, USA TODAY
