in February 2003 caused a
reexamination of the capabilities of the Space Shuttle. As a
result of this, the
was made in January 2004 to not service HST any longer
with a human crew, but to allow it to decay gradually out of a
operational state. After much behind-the-scenes work, in
October
of 2004, NASA changed directions slightly, and we formed a team
consisting of MDRobotics,
and the Hubble
Project to build a
robotic vehicle to service the Hubble Space Telescope.
This major event was preceded by several months of effort on the part
of our team to convince NASA that this mission could be done with
available technology. Prior to the loss of the Columbia, it
was
already the plan to launch an unmanned spacecraft to deorbit HST into
the Pacific Ocean to prevent an uncontrolled reentry of
Hubble.
This is because Hubble is so big and heavy that it will not burn up
completely in the atmosphere. It is possible that a part
would
fall out of space and hit land. As a result, a Shuttle or a
rocket vehicle was always planned for retrieval of Hubble. It
seemed feasible to us to include a robot on this mission along with
new replacement hardware so that the telescope's life could be extended
and it could be safely deorbited at the end of the mission.
Concept graphic of the HRSDM. A new vehicle would fly up with
a
robotic system to grapple and
service HST. The brown part is called the Ejection Module
(EM),
and contains the new instruments,
and the robotic system. This part would be ejected and only
the
blue part would remain. This latter
Deorbit Module (DM) will have a rocket motor to push Hubble out of
Earth's orbit when it is
time to end its life.
One of the investigations by our team was to decide what the best
robotic technology would be that we could readily fly in our mission
and that would be most suitable for our application. The two
leading contenders were the Robonaut system from the NASA Johnson Space
Center and the Special Purpose Dexterous Manipulator from MDRobotics in
Canada.
Visit to the robonaut lab at the Johnson Space Center (click for more)
Due to our extremely short schedule, the SPDM robot from MDRobotics was
chosen as the Dexterous Robot on our robotic servicing mission.
Having selected a robot arm, we performed feasibility test with mockups
of Hubble hardware at
MDRobotics in Canada working along with our team. We hoped
that
these tests would show that the tasks formerly performed by humans
could be done with manageable risk by a robotic system.
Showing success, the above tests were continued back home at the
Goddard Space Flight Center. At this phase, we handled
mockups of
science instruments and more tools. Specifically, we removed
and
inserted a mockup of an instrument I have been working on called
Wide Field Camera 3,
and I became
involved with the changeout of a large bulky instrument called the
Cosmic Origins
Spectrograph (COS).
These feasibility studies were so successful that it convinced the NASA
Administrator and the rest of the agency that it would be possible to
service the Hubble with a robotic system. As mentioned above,
we
found out in October that we were approved to
pursue the mission until our Critical Design Review in September
2005. This put our project into high gear. NASA
considers
this mission to be the first exploration mission in relation to the
President's
vision for the Exploration of the Universe. This
exploration
will need large spacecrafts to be assembled in space using robotics
controlled from the ground. In addition to gaining useful
experience with this activity, we have the chance to save the Hubble
Space Telescope, the most useful space observatory ever.
One of our next activities was to meet with past Hubble Astronauts to
benefit from their personal experience during their mission.
Technical Interchange
Meeting with past
Hubble Astronauts at the Johnson Space Center (click for more)
Meanwhile, the number of newspaper articles were growing,
such as
these:
Washington
Post article (11/12/04)
Chemical
& Engineering News (11/29/04).
In December 2004, we proceeded with our System Requirements Reviews,
and by
then the design matured to the concept shown above. As you
can
see in the above figure,
the Solar Arrays have been added to the 'bottom' part to form a sun
shield to prevent
the entry of solar energy into the exposed parts of the
Telescope.
The Hubble Robotic
Vehicle consists
of two parts. One part, called the Ejection Module (EM),
holds
the robot arm, the new instruments that will be replaced, and the tools
that are required. Once servicing is complete, it will be
ejected
from the system, leaving only the Deorbit Module (DM) behind on the
Hubble Space Telescope. The DM is the white faceted object
just
below HST in the picture above. By minimizing the amount of
mass
that is left behind in the DM, we can better allow HST to point and
'slew' across the sky. The DM will contain a large rocket
engine
that will allow the HST to be 'deorbited' once its mission has been
complete to ensure safe disposal of the Telescope in the Pacific Ocean.
Due to the cost of launching heavy items into space, robots used in a
micro-G environment tend to be very flexible and are unable to lift
themselves in the presence of gravity on the surface of the
earth. As a result, it is not feasible to train the robot
operators with them, and we need to rely on computer simulations
instead. In order to learn about the current advances in
simulation and training facilities, we visited the Canadian Space
Agency, who has produced the robots used on the Shuttle and the Space
Station.
Visit to the Canadian Space
Agency. Click
on image for more.
Back home at Goddard, we have set-up the Dexterous Robot Ground Trainer
to
perform tasks and to test tools.
In March 2005,
Miles
O'Brien from CNN came to interview some of our team members.
In January 2005, we were dismayed to learn that about the
Decision
by the White House to drop Hubble Servicing from 2006 budget (1/05)
Undaunted, we press on buoyed by:
Statement
by Senator Barbara Mikulski supporting Hubble Servicing (3/05)
Statement
by Congressman Steny Hoyer (3/30)
and by the National Academy of Science's
Final
report for Assessment of Options to recommend the extension
of
the life of Hubble (3/05)
On March 21 2005, we held our Preliminary Design Review (
click for more).
The review was extremely successful, and we impressed the rest of NASA
about
our ability to pull this mission off. Nevertheless, current
plans
are to not perform a
robotic servicing mission.
Article
on CNN.com.
A quote from Mark Borkowski (NASA's Program Executive for the HRSDM) :
"
Last week’s preliminary design
review for Hubble
servicing was one of the better ones I’ve seen"
"a super job".
Article
on space.com
Fight continuous to save Hubble:
Article
in washingtonpost.com (free registration needed).
On 4/29/2005, Dr. Mike Griffin, the NASA Administrator made the
decision to stop development of the
Hubble Robotic Servicing and De-Orbit Mission, and resume work on a
Shuttle Servicing Mission.
Transcript
of press conference.
As covered in the press:
Baltimore
Sun
Space.com
Nature.com
(subscription needed)
Bangor
News
Houston
Chronicle
Florida
Today
Christian
Science Monitor
This means stop work on the De-Orbit Module, and the Ejection
Module.
However, due to the progress we have made with the robotic system,
the Administrator has also decided to continue
our group's work in the robotic area.
The President's Vision for Space Exploration will need robotic technology,
and our
group may have a role in that future. As a result, I
am continuing my work with the
Contact
Dynamics
Lab.
These days much of space related
research and development
is done in the private
sector by companies like SpaceX. Such private
enterprises need to be knowledgeable
about
IRC Section 41, which is the IRS
code for calculating R&D tax credits.