Boeing engineers
have provided a number of studies to help NASA keep the International Space
Station (ISS) viable for the foreseeable future, relying upon Russian
vehicles, Soyuz and Progress, to transport cargo to the station.

Engineers at Boeing NASA Systems in Houston, many from the ISS Vehicle
Integrated Performance and Resources (VIPeR) team, studied ways to maintain a
safe and operable ISS. The team was asked by NASA immediately after the space
shuttle Columbia accident to study a number of options, taking into account
the delay of the unique cargo ferrying capabilities of the space shuttle.

The Boeing ISS team’s primary assessment effort focused on a smaller ISS
crew size and assessed the consumables used by the station and its crew and
the need for spare hardware. The ISS team is relying upon the Russian
vehicles as the only means of transporting cargo to the ISS until the shuttle
returns to flight and/or the European Space Agency’s Automated Transfer
Vehicle is available.

The team tracked the primary consumables used by the station and its crew
and worked closely with NASA’s ISS Mission Integration group. Boeing
conducted various analyses to minimize ISS supply and return requirements
while optimizing the ISS vehicle performance and research.

The VIPeR team first focused on the issue of propellant on board the
station, which is used to keep the ISS in the proper orbit and orientation and
has been one of the most critical consumables in past studies. They concluded
that currently planned Progress launches would meet propellant re-supply
needs.

The next critical consumable is the water necessary to support the crew
and system needs. Each crewmember uses about two kilograms of water a day for
drinking, food and oxygen generation. The team looked at how water could be
brought up while also examining ways to reduce water needs. “We looked at how
long we could leave three crewmembers up there and when we would go to two
crew members,” said Neil Lemmons, senior systems engineer with the Boeing
VIPeR team.

“Without the space shuttle, it was quickly determined by all involved that
a three person crew could not be sustained,” said Bob Korin, manager of the
Boeing VIPeR team. Keeping a crew on the ISS was important, he added, because
it would “give us a set of eyes, hands and creative thinking capability to
respond to things that arise.”

Although there would be some limits, a two-person crew could also continue
to do scientific research. The Boeing teams, including a strong effort by the
safety community, looked at the risks associated with a smaller two-person
crew and concluded that there were no significant safety concerns. A two-
person crew not only keeps research going but also maintains support for
preventative and corrective maintenance, anomaly investigation and response,
and other ISS System Operations needs that can best be done by an on-orbit
crew.

Boeing and NASA engineers have studied the impact of a two-person crew on
future science research. “The focus has been on new samples and consumables
for the science and research apparatus already on board the ISS that require
minimal space and weight,” said Rick Golden, program manager of ISS payload
integration.

“Our group (Boeing and its subcontractors, Teledyne Brown Engineering and
United Space Alliance) ensures that interfaces between the science experiments
and the space station are compatible,” said Golden.

“A lot of our focus has been working the safety aspects to fly U.S.
payload hardware on Soyuz and Progress launches,” Golden explained. “We are
positioning a select number of payloads at the Baikonur launch site in order
to be able to take advantage of any space that becomes available on the
upcoming Progress flights.”

The Boeing ISS team reassessed the manifests for several planned shuttle
launches. “We had to support system maintenance which may have required
changing out filters, valves, bags and things along those lines or other items
to support system repair,” said Korin.

The team came up with a prioritized shopping list and looked at what they
could take up without the space shuttle. The NASA/Boeing ISS team evaluated
the amount of propellant, water, gas, and dry cargo that is needed to the
support the ISS and its crew. The ISS subsystem teams, including the
logistics and maintenance team, played a critical role in defining the
shopping list of needed items.

The Environmental Control and Life Support System group identified the
selector valve and filter for the Carbon Dioxide Removal Assembly and the
Internal Thermal Control System group identified the Pump Package Assembly as
essential spares to be manifested on the upcoming Russian Soyuz and Progress
flights.

The Soyuz is the ISS crew escape vehicle used in case of emergency and is
certified for 200 days of life and is rotated every 180 to 190 days. They are
normally taken to ISS by a “taxi crew” who then bring the “old” one back. The
Progress vehicle is unmanned and carries crew supplies and hardware spares to
help maintain the life of ISS. There are normally 3 Progress flights a year.

“The Russians have given us about 30 kg allocation for US items to be
launched on Soyuz 6S, so we have been working very hard with NASA to make sure
all these items are certified to be launched on a Russian vehicle, and the
Russians properly stow them for launch,” according to Ray V. Gonzales, Boeing
launch package manager for Russian vehicles. “We are also working to get
these items to Moscow and then to Baikonur, Khazakstan where they will be
launched.”

A unit of The Boeing Company, Boeing Integrated Defense Systems, is one of
the world’s largest space and defense businesses. Headquartered in St. Louis,
Boeing Integrated Defense Systems is a $25 billion business. It provides
systems solutions to its global military, government and commercial customers.
It is a leading provider of intelligence, surveillance and reconnaissance; the
world’s largest military aircraft manufacturer; the world’s largest satellite
manufacturer and a leading provider of space-based communications; the primary
systems integrator for U.S. missile defense; NASA’s largest contractor; and a
global leader in launch services.

For more information visit:
http://www.boeing.com/news/releases/2003/q2/nr_030424s.html