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EVA4

EVA 4
February 17, 1997

Daily Updates from NASA

Space Walkers: Harbaugh and Tanner    

Summary:

  • Today's Highlight - working on the MSS

On FD 7, the final scheduled EVA will feature the replacement of the Solar Array Drive Electronics-2 (SADE-2) and the new upgraded Magnetic Sensing System Covers (MSS). These tasks, as well as the clean up and daily close out of the payload bay, are timelined for six hours.

In His Own Words
The mission as seen by
NASA Astronaut Steve Smith
STS-82 Mission Specialist

Overview

The fourth day, again, it's Greg and Joe. And they'll be out there doing the SADE task, the Sadie task. SADE stands for solar array drive electronics. There are 2 of those boxes. They're very small, about the size of a toaster. They control the solar arrays basically and the movement of the solar arrays to collect energy.

Replace SADE-2

The fourth day, again, it's Greg and Joe. And they'll be out there doing the SADE task, the Sadie task. SADE stands for solar array drive electronics. There are 2 of those boxes. They're very small, about the size of a toaster. They control the solar arrays basically and the movement of the solar arrays to collect energy.

On the first mission, SADE-1 was replaced because it had some transistors in it that failed. That box was brought back to earth and refurbished, and weÕre going to take it up and replace the other SADE which is working fine, but we're a little bit fearful that the same transistors that failed in the old box would fail on this SADE. So we're going to replace it, kind of preventively. It's much like DIU in that it's very hand-intensive. Greg will have quite a challenge.

DIU and SADE were not designed to be serviced in space, so, for example, the bolts that hold them to Hubble are not captive. By captive, I mean they don't stay with the box. As you back out the bolts and their washers, they are free-floating. So we have to be very careful when we pull these bolts to immediately put them into a retaining box so that they're not floating around. Something floating around Hubble can be disastrous.

Add On MSS Covers

MSS

The Hubble has 2 magnetometers that are used to measure the earth's magnetic field and help Hubble figure out where it is basically. And they have a covering on them thatÕs flaking off basically. That was installed on the previous flight. So we need to put a cover over those so that they don't continue to flake. You don't like flakes around the business end of a telescope.

Working on the MSS

It's unusual in that it's at very, very high other end of the Hubble space telescope. So it's an exciting task because you'll be 50 feet above the payload bay at this point looking back down at the shuttle. Among the crew, it's a very simple task but one that we all want to do to get the view basically.


Overview Launch EVA 1 EVA 2 EVA 3 EVA 4 Unscheduled Deploy & Return

* CALENDAR *

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