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Handprints on Hubble -
presented by Science@NASA
It's funny, the things you notice
hanging upside down in space.
Astronaut John Grunsfeld
remembers a quirky discovery back in 1999.
He had just arrived at the Hubble Space Telescope,
and climbed out of the airlock of shuttle Discovery
to begin a servicing mission.
Clinging to a handrail
running down the side of Hubble's gleaming exterior,
he ran his eyes over the blue planet 350 miles below
and tried not to think too hard about the yawning
starry expanse behind him.
The astronaut, Hubble, and Discovery, connected together,
raced around Earth at 17,000 mph.
That's when he noticed the handprints.
'Hubble, having been designed to be human-serviced
means that it has handrails,
places for people to crawl around, you know,
things-human-scale latches...
there's a big handle that you swing to open
these big doors.
And, well, all the doors are hinged,
and the 'handprints', if you will,
are kind of concentrated around these interfaces.'
Astronauts have visited the orbiting telescope
five times since it was launched in April 1990,
conducting 23 spacewalks to repair and improve it.
The 'handprints' come from oil and silicon
on the astronauts' gloves,
which make an impression on Hubble's exterior foil.
The prints Grunsfeld saw
are more than chemical scuff marks, though.
They are a symbol of a unique
human-robotic partnership.
Hubble's designers
intended for astronauts to lay hands on Hubble.
The telescope is festooned with knobs and handrails,
hinged doors,
and crawl spaces fit for astronauts
to visit and tinker.
This has allowed Hubble to do something
no other spacecraft has done before-
evolve.
When Hubble left Earth 25 years ago,
it was equipped with reel-to-reel data recorders,
1980s-era microprocessors,
and some of the earliest digital cameras.
Fast forward to the present:
Almost every scientific instrument onboard the telescope
has been replaced at least once.
Hubble now has solid-state recording devices,
upgraded computers,
and astronomical detectors
that far outperform the older technology
it originally took to space.
Astronauts have also replaced the telescope's aging solar arrays,
batteries, gyroscopes,
some reaction wheels and fine guidance sensors.
Keeping pace with technological advances on its home planet,
Hubble is very much a creature of the 21st century.
The servicing missions were crucial.
Without them
'we wouldn't have necessarily measured the age of the universe,
we wouldn't have validated black holes,
we wouldn't have discovered dark energy.'
In May of 2009,
as the shuttle program neared its end,
Atlantis blasted off for one last mission
to the great observatory.
Grunsfeld, who has visited Hubble
more often than any other person,
was on board.
'I did everything that I could
to make sure that we'd be successful-designing new tools,
new training,
new techniques,
and we really upped the game on what it took to do the mission.'
The astronauts had to invent new procedures
to do the unprecedented-
like removing hundreds of tiny screws in bulky space suits.
They replaced batteries,
swapped out all six gyros,
installed a new Fine Guidance Sensor,
repaired two scientific instruments
and completely replaced two others.
Mindful that astronauts might never visit Hubble again,
the spacewalkers installed a soft-capture mechanism
that would allow a future robotic spacecraft
to grapple Hubble to ensure a safe conclusion
to its operational lifespan.
For one last time,
Grunsfeld saw the marks of those
who performed spacewalks to repair Hubble,
the handprints of Story Musgrave,
Jeff Hoffman,
Kathryn Thornton,
Thomas Akers,
Mark Lee,
Steve Smith,
Greg Harbaugh,
Joe Tanner,
Mike Foale,
Claude Nicollier,
Rick Linnehan,
James Newman,
Mike Massimino,
Andrew Feustel,
Michael Good,
and Grunsfeld himself.
'I didn't know whether I'd be extraordinarily sad
deploying the Hubble,
knowing it was the last shuttle mission to service Hubble...
And at the end,
the sense of the whole crew was,
it was thrilled that we achieved all of our goals
and a little bit more,
sending Hubble off in the best shape it had ever been in.'
Current estimates
suggest that Hubble will continue doing great science until 2020,
and possibly longer.
All thanks to the human touch.
For more news from Hubble,
and other space telescopes,
stay tuned to science.nasa.gov.