Jul 3, 1997

Putting Science on the EXPRESS Track





July 4, 1997 09:30 a.m. CDT
Flight Day 4 of Migrogravity Science Laboratory-1 Science Activities aboard STS-94


interior module view
Simply moving a box of plants from one shelf to another might seem like a minor effort, but it represents a major step for scientists planning research aboard the International Space Station.

Thursday morning, astronauts aboard Space Shuttle Columbia moved the Astro Plant Generic Bioprocessing Apparatus (Astro-PGBA) from its storage location in the middeck to the EXPRESS rack in the Spacelab module, and plugged it to electrical power and a data connection. In a few years, this should be a routine way of getting experiments to Space Station and results back.

EXPRESS stands for EXpedite the PRocessing of Experiments to the Space Station. The name reflects the philosophy that will be followed in using it to put payloads aboard the Space Station. Up to eight EXPRESS racks will be aboard Space Station in addition to dozens of International Standard Payload Racks that will be used by large science facilities on the station.

"This is supposed to be a test bed," said Bill Telesco, an engineer with Teledyne Brown Engineering in Huntsville, Alabama, said of the EXPRESS rack board MSL-1. Telesco is one of several engineers monitoring operations aboard EXPRESS (seen at midpoint on the right side of the picture above). Having the astronauts move the Astro-PGBA from the middeck and plug it into to the rack in the module demonstrated how future crews will install new experiments in EXPRESS racks.

Astro-PGBA contains plants being grown to understand the role gravity plays in plant structures. Already mounted in EXPRESS was PhaSE, the Physics of Hard Spheres Experiments which uses miniature plastic beads as large models of how molecules form crystals.

Designing and building experiments for Spacelab missions like MSL-1 has been a demanding process and culminating in extensive assembly and tests at Kennedy Space Center. EXPRESS rack, by comparison, will let scientists design equipment to "plug and chug," said Greg Day, an engineer with Boeing Co., the Space Station's prime contractor. Boeing is developing EXPRESS rack for NASA's Marshall Space Flight Center.

"Giving developers an easier, generic interface will shorten development time," he said. "That's why they call it EXPRESS rack - to get scientists' experiments up there faster than we have in the past." Faster means in 10 to 12 months, compared to an average of 36 months for Spacelab experiments. In particular, this will help graduate students who need to complete an experiment program in a year or two so they can earn their degrees. EXPRESS rack will serve as an extension of their laboratory.

"The rack itself is just the facility," Telesco said, "and you just plug in your equipment."

"Plug in" is the key phrase. Equipment slides into the rack and screws are tightened to secure it in place. Then the apparatus is connected to rack utilities, including Ethernet, serial, and military-standard computer interfaces, video, and electrical power, and water cooling; two racks will also have fluids and vacuum lines, and a few will have electromagnetic shock absorbers. Experiments can be controlled by astronauts using a PC-compatible laptop computer attached to the rack, or by scientists working in the comfort of their offices and linked through the Space Station's data system.

Day said that EXPRESS developers held a lot of meetings with potential users to make sure that the rack's design would meet most of their needs. It's not possible to design a system that would be ideal for every investigator, especially with so many demands being placed on Space Station resources. EXPRESS rack offers eight slots, each equivalent to a locker in the shuttle middeck. That's about the same size as a salesman's catalog case that can fit under an airline seat.

Yet, scientists and engineers have proved to be innovative in designing experiments that take advantage of such a small volume, even as early as the second shuttle mission in 1981.

Typical payloads will be like the refrigerated enclosures, the glovebox, the Droplet Combustion Experiment, and other gear now aboard MSL-1. An experiment can fill a standard drawer, half the size of a lockers, or could take up to four locker spaces, depending on the importance of the investigation.

The EXPRESS philosophy extends beyond the racks inside the station modules. Telesco added that NASA is building EXPRESS pallets that will be mounted to the outside of Space Station so scientists will have a place where small telescopes, scanners, and other instruments can be easily attached (and later removed) to observe the Earth and sky. One payload scheduled already is KidSat which will support Earth observations by grade-school students.

For the next 13 days, you can follow along and learn about the science being performed on the mission through activities on this WWW site, as well as the "Liftoff" Mission Home Page, and the Shuttle Web Site.

  • Check out the twice daily Mission Status Reports prepared by Marshall's Public Affairs Office.
  • More Science Updates


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Author: Dave Dooling
Curator: Bryan Walls
NASA Official: John M. Horack