Release No. 96-13

For Release: March 1996

STS-76 Mir Environmental Effects Payload (MEEP)

Understanding the Effects of Space Debris on Space Station Materials

What Are The Objectives Of MEEP?

MEEP will be attached to the outside of the Russian space station Mir to study the effects of impacts from space debris. MEEP, made up of four separate experiments, will study the frequency and effects of space debris striking the station. MEEP will study both human-made and natural space debris, capturing some debris for later study. MEEP will also expose selected and proposed international Space Station materials to the effects of space and debris.

How Will MEEP Be Attached To Mir?

MEEP will be attached to the Mir shuttle docking module during a spacewalk by mission specialists Linda M. Godwin and Michael (Rich) Clifford. After the four MEEP experiment containers are attached to Mir, Godwin and Clifford will open the containers to expose the experiment materials to space and orbital debris.

Why Fly MEEP Aboard Mir?

The international Space Station will be placed in approximately the same Earth orbit as Mir. Flying MEEP aboard Mir will give researchers an opportunity to test materials for the international Space Station in a comparable orbital position. MEEP will remain attached to Mir until late 1997, when the four experiment containers will be retrieved by another space shuttle crew (STS-86) and returned to Earth for study.

How Will MEEP Study Orbital Debris?

The NASA Langley Research Center's Polished Plate Micrometeroid and Debris (PPMD) experiment is designed to study how often space debris hit the station, the sizes of these debris, the source of the debris, and the damage the debris would do if it hit 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 experiment is recovered.

How Will 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, consist 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.

How Will the MEEP Data be Used?

The debris which is brought back to Earth, after approximately a year and a half of being on orbit, 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. The data will be studied to determine what kind of debris hit the space station and how those contaminants can actually collect on some of the different surfaces of a space station, affecting its surfaces and long-term performance. After the data from all four MEEP experiments is analyzed, the data will be placed into an electronic archive which 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 attachment to the payload bay of Atlantis (STS-76), a handrail clamp for attachment to the Mir shuttle docking module, and the experiment container to house the individual experiment. The four PEC handrail clamps will be stored in a Spacehab locker aboard Atlantis and will be used to orient the MEEP experiments during the spacewalk. The PECs were designed and built at NASA Langley Research Center. NASA Langley, which manages the MEEP project, was also responsible for ensuring that the MEEP experiment was properly integrated aboard both the Space Shuttle Atlantis (STS-76) and Mir.

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For more information on MEEP, please contact the NASA Langley Office of Public Affairs at (757) 864-6123. Photos of the MEEP Passive Optical Sample Assembly II experiment (L-95-6412) and astronaut Godwin testing the MEEP attachment hardware ( L-95-6370) are available. Video of the MEEP hardware being examined and tested by astronauts at NASA Langley and in the Johnson Space Center Weightless Environment Training Facility is also available, as is an interview with the MEEP Project Manager.

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