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Catherine E. Watson
(757) 864-6122

Sept. 9, 1997

Release No. 97-111

STS-86 Mir Environmental Effects Payload (MEEP) Retrieval
Understanding the Effects of Space Debris on Space Station Materials

What Was The Objective Of MEEP ?

MEEP was attached to the outside of the Russian space station Mir in March 1996 (during STS-76) to study the long-term effects of the space environment on selected and proposed International Space Station materials, and to study the effects of impacts from space debris. MEEP, made up of four separate experiments, was designed to determine the frequency and effects of both human-made and natural space debris striking the station, and determine the reactions of materials in the space environment.

How Will MEEP Be Retrieved From Mir?

MEEP will be retrieved from the Shuttle/Mir docking module during a spacewalk by shuttle mission specialists Scott Parazynski and Vladimir Titov (Russian Space Agency). After the four MEEP experiment containers are removed from Mir, Parazynski and Titov will secure the four containers in the payload bay of Atlantis for the return to Earth.

Why Was MEEP Flown Aboard Mir?

The International Space Station will be placed in approximately the same Earth orbit as Mir. Flying MEEP aboard Mir gave researchers an opportunity for long-term testing of materials for the International Space Station in a comparable orbital position. When the four MEEP containers are retrieved, they will have been attached to Mir for 18 months.

How Did MEEP Study Orbital Debris?

The NASA Langley Research Center's Polished Plate Micrometeoroid and Debris (PPMD) experiment was designed to study how often space debris hit the Mir station, the sizes of these debris, the source of the debris, and the damage the debris inflicts on the station. The PPMD is made up of gold, zinc and aluminum plates. The NASA Johnson Space Center's Orbital Debris Collector (ODC) experiment is designed to capture orbital debris and return them to Earth to determine what the debris are made of and their possible origins. The ODC uses a material called aerogel, developed by the Jet Propulsion Laboratory, which is a silicon dioxide compound. The aerogel will capture debris and hold them in place until the ODC experiment is recovered and returned to Earth.

How Did MEEP Study International Space Station Materials?

The Passive Optical Sample Assembly (POSA) I and II experiments, from the NASA Marshall Space Flight Center and the Boeing Defense and Space Group in Seattle, Wash. respectively, consisted of various materials that are intended for use on the international Space Station. These materials include paint samples, glass coatings, multi-layer insulation and a variety of metallic samples. Researchers will analyze how these samples held up for the 18 months they were attached to Mir.

How Will The MEEP Data Be Used?

The debris which are brought back to Earth will be analyzed using several techniques. These techniques include a scanning electron microscope and spectroscopy to determine what the debris are made of and their relative sizes. This data will be studied to determine what kind of debris hit the space station and how those contaminants collected on some of the different surfaces, affecting the surfaces and their long-term performance. After the data from all four MEEP experiments is analyzed, the data will be placed into an electronic archive that will be accessible via the Internet.

What Hardware Components Make Up MEEP?

The four MEEP experiments are contained in four separate Passive Experiment Carriers (PEC). Each PEC consists of a sidewall carrier for reattachment to the payload bay of Atlantis (STS-86), a handrail clamp that was used for attachment to the Shuttle/Mir docking module and the experiment container that housed the individual experiment. The four PECs were designed and built at NASA Langley Research Center. NASA Langley, which manages the MEEP project, will be responsible for ensuring that the four MEEP experiments are analyzed and the data disseminated.

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For more information on MEEP, please contact the NASA Langley Office of Public Affairs at (757) 864-6123. A photo of the MEEP Passive Optical Sample Assembly II experiment (L-95-06412) is available from NASA Langley. Electronic images of STS-76 astronauts deploying the MEEP hardware on Mir are available via the Internet. Video b-roll of the MEEP hardware being deployed on Mir, and tested by astronauts at NASA Langley and in the Johnson Space Center Weightless Environment Training Facility is also available. Also visit the MEEP homepage.


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