(tense music)
Arguably the most significant
scientific instrument in history
has been the Hubble Space Telescope.
It has changed our understanding of the universe,
yet it has posed serious new questions
about the nature of matter itself.
Hubble has confirmed the widespread distribution
of black holes.
And has viewed light from galaxies
more distant than anything previously seen.
As well as its scientific discoveries,
are this stunning images.
(upbeat music)
In 1609, Galileo built an early telescope.
And soon turned it to the night sky.
The telescope was a powerful tool
that led to a complete re-evaluation
of the Earth's place in the universe.
In 1668, Newton invented the reflecting telescope
to eliminate the problem of uneven refraction
of the different wavelengths of light.
The reflecting telescope became the design of choice
for astronomers.
And in 1781, William Herschel used an instrument
he had built himself to discover the planet Uranus.
The Newtonian telescope was scaled up
to immense proportions.
And in 1924, it was with the 2.5 meter Hooker Telescope
at the Mount Wilson Observatory
that Edwin Hubble realized the Milky Way
was not the universe, but just one of countless galaxies.
But there was still a problem.
No matter how mathematically perfect a telescope is,
it's images are distorted by the Earth's atmosphere.
And some wavelengths cannot reach the ground.
In 1946, astrophysicist Lyman Spitzer
proposed the telescope in orbit
above the Earth's atmosphere.
The idea clearly outstripped the technology of the time,
but by 1966, NASA began launching a series
of orbiting astronomical observatories.
(rocket engine roaring)
Only two were successful,
but the telescopes in low earth orbit
were the first to see the night skies
in the ultraviolet part of the spectrum.
In the 1970s plans were drawn up
for a large orbiting telescope.
Part of its brief was for it to be visited regularly
by maintenance crews.
Something that would become possible
when the Space Shuttle went into service.
The design called for a 2.4 meter primary mirror
ground within very fine tolerances.
Because it was required to function
well into the ultraviolet spectrum.
Originally known as that large space telescope,
it was slated for launch in 1979,
but delays in construction led to several postponements
and the Challenger disaster led to more delays.
In 1983, the name Hubble Space Telescope
was adopted in honor of the man
who confirmed that the universe was expanding.
(helicopter whirring)
Finally, in April, 1990, Hubble was ready for launch.
Sound suppression water system has started.
T minus 13 seconds.
T minus 10, go for main engine start.
We are go for main engine start.
T minus 6,
five, four, three, two, one
and lift off of Space Shuttle Discovery
with the Hubble Space Telescope.
Our window on the universe.
Hubble has a unique relationship
with the Space Shuttle.
Which would revisit the telescope
on five different occasions.
At this stage,
nobody understood just how vital these missions would be.
To deploy Hubble, the Shuttle Discovery
set a new altitude record of more than 600 kilometers.
Release of the telescope was routine.
It took several weeks
methodically checking Hubble's control
and communication systems, before astronomers working
at the Space Telescope Science Institute
in Baltimore could see Hubble's first images.
Results were disappointing.
Images were blurred.
The telescope's mirror had been accurately ground,
but to the wrong shape.
An incorrectly assembled test instrument
had been relied upon during manufacture
and nobody had double-checked.
Soon a fix was proposed.
Because the error was understood,
a corrective device could be fitted to the telescope.
A series of small mirrors would compensate
for the primary mirror's defect.
It was called COSTAR.
Another of those cumbersome NASA acronyms.
Training astronauts for the job
of accurately installing COSTAR began.
The High Speed Photometer would be scrapped
to make room for it.
(water bubbling)
In addition to correcting the optics,
a number of other modifications were set in train.
A new wide field planetary camera would be installed.
The original was obsolete.
The telescopes' solar panels would be replaced.
There would be a new electronics processor,
extra magnetometers, and two gyroscopes would be replaced.
(water bubbling)
Ten, nine
and we have a go for main engine start.
(rocket engine roaring)
Five, four, three, two, one
and we have lift off.
Lift off of the Space Shuttle Endeavour
on an ambitious mission to service
the Hubble Space Telescope.
Finally in December, 1993
the mission to repair Hubble began.
(rocket engine roaring)
Rodger roll Endeavour.
It took the Endeavour three days
to catch up with Hubble.
And it was clear from the beginning
that one solar panel was damaged.
The work on the telescope was considerable,
and there were five space walks scheduled.
Firstly, the shuttle's robotic arm grabbed the Hubble
so it would remain stable while the work was carried out.
The work would be shared
between two teams of two astronauts.
Over five days, the allocated tasks were carried out.
With the space telescope operations control center
monitoring the Hubble's performance
as each new component came online.
Most of the parts replaced were stowed in the cargo bay
for return to Earth.
The one exception being the damaged solar panel
which was set adrift in space.
All five space walks went according to plan,
with the only major problem
being the difficulty involved
in closing the telescopes' doors.
On the ninth day of the mission, Hubble was released.
It would take controllers on the ground another month
to fully check the telescopes' new systems.
(bright music)
Hubble had been repaired in December, 1993,
yet it would take close to two months for technicians
on the ground to run through
a complex series of optical alignments
before they could be certain that the telescope
was performing correctly.
When astronomers finally saw results,
they were stunned at the quality it was delivering.
(people cheering)
The repair mission had been successful.
With the services of a powerful new tool
finally at their disposal,
astronomers at the Space Telescope Science Institute
began addressing a pressing list of demands
for time on Hubble.
(dramatic music)
In March, 1993 a comet had been discovered orbiting Jupiter.
Its path suggested that it had only recently
been captured by Jupiter's gravitation.
And that it would soon crash into the planet.
No one had ever seen a collision between bodies
within the solar system,
and opinions differed about how visible
the impact would be.
(dramatic music continues)
Soon Hubble captured this image of a chain of fragments.
Comet Shoemaker-Levy 9 had been shattered
by Jupiter's gravitation.
The fragments ranged in size from the several hundred meters
to several kilometers across.
Over six days in July, 1994,
Hubble observed the pieces crash into Jupiter's unlit face.
As the planet revolved,
the impact region showed a series of black swirls.
Some of the dark shadows were as large as the Earth,
and they persisted in Jupiter's atmosphere for months.
Spectral analysis from Hubble
revealed diatomic sulfur and carbon disulfide.
These had never been seen at Jupiter,
yet the amounts detected were too great
to have come in with the comet.
They had been stirred up from the planets' interior.
Scientists learnt so much from observing these impacts.
Yet the observations almost didn't happen.
Just days before the first impact was due,
Hubble began acting unpredictably
and then went into safe mode.
It would not execute any of its instructions.
Technicians suspected a memory problem,
and took measures to switch across to new memory installed
on the recent service mission.
Things started to improve,
until the spacecraft reported
it had entered zero gyro sum point.
It appeared that two gyroscopes had failed,
and the situation had dramatically deteriorated.
The problem was traced to a counter
that had run out of numbers with which to count.
The issue was understood and quickly resolved.
The incident underlined just how complex
the operations of the Hubble would be.
And that the ground engineers
still had to learn how to operate the new hardware.
Though Hubble functions as a telescope,
it is also a spacecraft
that must be controlled with exquisite accuracy.
Unlike other spacecraft, it has no thrusters.
Chemical residue from rocket engines
would quickly contaminate the precision optics.
To enable it to move,
Hubble has four reaction control wheels.
As they spin,
the telescope will rotate in the opposite direction.
Each one has a mass of 45 kilograms,
and they are controlled
by the telescopes' computer.
Combinations of spin in any three wheels
will allow the telescope to point accurately
in any direction.
They are mounted in angled pairs
around Hubble's center of gravity.
In 1997 on the space telescope second servicing mission,
one of the reaction control wheels was replaced.
It had developed an electrical fault.
So that Hubble can remain pointed accurately,
three fine guidance sensors
positioned toward the back of the telescope
will lock onto any of a series of bright guide stars.
Hubble only needs two guidance sensors
to point with accuracy.
They are so sensitive,
they can detect wobble in the motion of closer stars.
The third vital aspect
of the telescopes' pointing system
is its ability to detect the rate
and direction of it's movement.
Hubble is equipped with six gyroscopes
that register its orientation.
These are essential when pointing the telescope
in a new direction.
The gyros spin at 19,200 RPM and they do wear out.
This is why there are six units,
even though when designed Hubble only needed three
to function properly.
With new algorithms,
Hubble can now point with only two gyros,
though less accurately.
Work has been done to enable it to work
at reduced capacity with only one gyroscope.
Hubble can point with an accuracy
better than two millionths of one degree.
This ability to stay fixed
on one narrow region of the sky for a very long time,
led astronomers to perform a unique observation.
For 10 days in 1995,
they pointed Hubble at a small empty region of the sky
near the constellation Ursa Major.
To some this was folly,
a waste of valuable observation time.
The results astounded everyone.
This empty part of the sky
was packed with irregular shaped galaxies.
Some were as old as 13 billion years.
Hubble had looked back in time
at the formation of new galaxies
in a range of shapes not seen closer to our own Milky Way.
It became known as the Deep Field Survey.
It was the first of a series of similar explorations
of areas of the sky in which nothing
had previously been seen.
Animators have added depth to these images
by using spectral information known as red shift,
which indicates a body's distance from Earth.
This was a completely new area of astronomy
and it was one reason why Hubble had been built.
But the space telescope
was already running into design constraints.
Engineers began work on equipment
that would upgrade the telescopes' performance
in the near-infrared part of the spectrum.
This would be fitted during the next servicing mission
along with updated support equipment,
such as a solid state recorder,
which would replace the original reel-to-reel recorder.
Yet even at this early stage of Hubble's life,
astronomers were realizing its limitations.
The distant galaxies it had seen were approaching
the extent of its view in the infrared end of the spectrum.
Even with enhancements,
the telescope could not be kept cold enough
to observe the large redshift wavelengths
revealing very old, very distant objects.
Plans were drawn up for a new larger telescope
known as the Next Generation Space Telescope
that could explore the most distant parts of the universe.
But there was still plenty that Hubble could do
better than any other telescope.
And there appeared no reason
that it wouldn't continue being refitted
with the latest technology as it became available.
Early in 1997,
the Space Shuttle Discovery visited Hubble
for a second servicing mission.
Astronauts fitted new instruments
to improve its reach into the infrared.
In 1999, Discovery again visited Hubble.
This mission had been brought forward
as four of the gyroscopes had failed
and the telescope had gone into safe mode.
Four, three, two, one
and lift off of Space Shuttle Columbia
to broaden our view of the universe
through the Hubble Space Telescope.
In 2002,
Columbia lifted off with a new instrument,
the Advanced Camera for Surveys.
It would replace the Faint Object Camera.
The last of Hubble's original instruments.
When it departed,
Hubble was again in peak condition.
(soft emotional music)
Less than a year later,
at the close of its next mission
Columbia burnt up during re-entry.
Foam insulation had come loose during launch
damaging thermal protection tiles.
After an exhaustive search for debris,
and a thorough inquiry,
it was decided that the shuttle system was aging.
It would be retired upon completion
of the International Space Station.
All other missions were ruled out.
For the Hubble Space Telescope,
this was a death sentence.
In the corridors of power, Hubble had friends.
The sheer beauty of images from the telescope
gave it a public profile.
And key senators began campaigning
for one last servicing mission.
After a new administrator took charge at NASA,
a final shuttle flight to Hubble was re-instated.
Work began on what would amount
to a rebuild of Hubble's operational systems,
as well as another update of scientific instruments.
New fine guidance sensors would be fitted.
All gyroscopes would be replaced,
and a new set of batteries would replace the originals
that Hubble was still using.
Within the imaging spectrograph
a power supply had failed.
And training began to open up the unit
and replace an electronics board.
The Advanced Camera for Surveys had also malfunctioned,
and its repair work was seen as even more detailed.
Because the shuttle now had to operate with a backup,
and because Atlantis could not reach
the International Space Station from Hubble's orbit,
the Shuttle Endeavour was prepared for a rescue mission.
On the 11th of May, 2009
Atlantis sat on NASA's Pad 39A
ready for Hubble's finals servicing mission.
(rocket engine roaring)
This was to be the most complex servicing mission.
It had to deliver the longest possible life
for the orbiting telescope.
The 14 day operation went according to plan.
When problems arose,
they were solved.
And Hubble was eventually released
as the best telescope it had ever been.
On the ground astronomers
from the Space Telescope Science Institute
waited for the first pictures
from Hubble's new more sensitive instruments.
This means the telescope can operate more efficiently,
needing less observing time than earlier incarnations.
(group applauding)
The team was quick to release examples
of the new generation images.
In the Eagle Nebula,
the pillars of creation,
thousands of light years from Earth.
Immense clouds of hydrogen and dust
are giving birth to new stars.
The five galaxies of Stephan's Quintet
in the Pegasus constellation.
Four of these are colliding.
(bright music)
16,000 light years from Earth,
Omega Centauri in the constellation Centaurus
is a globular cluster.
Stars here are so densely packed,
that on average, there is just one 10th of a light year
between them.
While Hubble has been adding to its list of discoveries,
everyone understands that without further servicing,
the telescope will eventually die.
That slow death has already started.
And it's the gyroscopes that are failing.
Engineers have been careful,
operating just three gyros.
Keeping the other three as spares.
By mid 2018, three of the units had ceased functioning.
As the last of the three gyroscopes held in reserve
was brought online.
It misbehaved and all science operations
of the telescope were suspended.
By recycling power to the unit,
a measure akin to switching it off and back on,
normal function resumed.
As further gyros fail,
the telescope will use its star trackers
to help it point accurately.
Hubble is expected to function well into the 2020s.
By which time a new space telescope should be in orbit.
The next generation space telescope
is now called the James Webb Space Telescope
named after NASA's Apollo era administrator.
The telescope has been completed
and is undergoing exhaustive checks before it is launched.
It has a giant mirror of 18 hexagonal segments
that is folded before deployment.
Compared with Hubble,
it is huge yet the complete spacecraft
weighs considerably less than Hubble.
NASA built the Webb Telescope
in collaboration with the European
and Canadian Space Agencies.
And it will launch on an Ariane 5
from the European Spaceport in Kourou, French Guyana.
It will orbit at the second Sun Earth Lagrangian point
a place 1.5 million kilometers
from the night side of the Earth,
where the telescope can maintain a stable position.
A large, very thin sun shield will protect the James Webb,
allowing the optical components of the telescope
to cool to around 50 degrees Kelvin.
It's operational temperature must be very low
to allow it to see deep into the infrared end
of the spectrum.
The Mid-Infrared Instrument needs to be colder still,
a cooler using helium as its refrigerant
will enable a sensor to function
at just seven degrees Kelvin.
The Webb Space Telescope is designed
to build on the work of Hubble
by seeing further back to the earliest emergence
of galaxies, stars and exoplanets.
(bright music)