Fourth spacewalk on deck
Thursday, March 7, 2002 at 3 a.m. EST

Columbia astronauts Jim Newman and Mike Massimino are in their spacesuits and pre-breathing pure oxygen, nearly ready to begin the fourth spacewalk of this STS-109 mission to service the Hubble Space Telescope.

They are expected to officially begin the spacewalk around 3:30 a.m. EST.

Their chief task today: replace the Faint Object Camera -- the last of the original science instruments launched with Hubble in 1990 -- with the Advanced Camera for Surveys.

We'll offer updates every couple of hours on this page and you are invited to watch NASA TV coverage via our feed by clicking on the link above.

And again, we'd be happy to hear from you via e-mail this morning and answer any questions you might have.

Columbia astronauts Jim Newman and Mike Massimino have begun the fourth spacewalk of the STS-109 mission -- their second and final -- with the official start time marked at 4 a.m. EST, a half-hour later than planned but not beacause of any problems.

During the next seven hours the pair are scheduled to accomplish three basic tasks.

The first is to replace the Faint Object Camera with the Advanced Camera for Surveys. The FOC is the last of the original science instruments launched with Hubble in 1990. The new ACS promises to expand Hubble's imaging capabilities another order of magnitude, with the possibility of being able to image planets around stars beyond our solar system.

The two other tasks involve installing some equipment that will be used in concert with additional equipment to be installed Friday in reviving another Hubble science instrument, and the spacewalkers will do some clean up work associated with Wednesday's replacement of the observatory's electrical heart, the Power Control Unit.

Newman and Massimino were the spacewalkers for the second extravehicular activity performed Tuesday and were responsible for swapping out Hubble's port side solar array with a new, more powerful rigid solar wing. They are distinguished in pictures by the type of red stripe on their syuit. Newman's is a broken stripe while Massimino's is diagonally striped like a barber pole.

Their colleauges, John Grunsfeld and Rick Linnehan, performed spacewalks No. 1 and No. 3 and also will do No. 5 beginning about 3:30 a.m. EST Friday.

We will offer updates to this page about every two hours this morning, or as needed. Again, you are invited to watch NASA TV coverage via our feed by clicking on the link above, and we'd be happy to hear from you via e-mail this morning and answer any questions you might have.

After serving some 12 years as one of the original science instruments of the Hubble Space Telescope, the Faint Object Camera has been shut down and removed from the observatory's aft shroud.

Attached to the end of the shuttle's robot arm, Jim Newman removed the fasteners holding the instrument in place and then slowly pulled the large 850-pound box out of its socket beginning at 5:40 a.m. EST.

Newman will store the camera for its return to Earth and then he and fellow spacewalker Mike Massimino will work to install the Advanced Camera for Surveys.

Stay tuned to this page for updates.

The Advanced Camera for Surveys is installed inside the Hubble Space Telescope and ground controllers say it has passed its initial tests, known as an aliveness test.

The ACS occupies the volume inside Hubble's aft shroud where the Faint Object Camera used to be until it was removed and stowed in Columbia's cargo bay at the beginning of today's spacewalk.

Stay tuned to this page for updates.

Today's spacewalk, the fourth of the STS-109 mission, continues to move along the timeline and has been free of any trouble.

Things are taking a little longer than planned and spacewalkers Jim Newman and Mike Massimino are about 30 minutes behind schedule. As a result the spacewalk is expected to last until about 11 a.m. EST.

The major task of swapping out the Faint Object Camera for the Advanced Camera for Surveys is finished and Hubble Space Telescope ground controllers report the new science instrument is passing its initial tests. Full science operations with the new device aren't expected for another two months or so.

During the past hour the spacewalkers have been working to install an electronics package inside Hubble that will be used to help power a new cooling system that is to be installed during the fifth and final spacewalk on Friday.

Unless something unusual happens, our next update to this page will come at the conclusion of today's spacewalk in about two hours.

The fourth of five planned spacewalks for this STS-109 shuttle mission to the Hubble Space Telescope is complete and astronauts Jim Newman and Mike Massimino are safely inside Columbia's airlock, which is repressurizing after a seven-hour and 30-minute extravehicular activity.

Official end time of today's exercise outside: 11:30 a.m. EST.

Once again all of the major goals of this spacewalk to service Hubble were successfully completed, although the "deliberate" way in which the work was done put the whole operation behind schedule by about 30 minutes -- even though there were no technical problems to speak of.

The first task of this spacewalk was for Newman and Massimino to replace the Faint Object Camera science instrument with a new device, the Advanced Camera for Surveys. They then installed an electronics package that will be required to supply power to a new cooling system to be installed on Friday. Finally, the astronauts did some clean up work following the replacement Wednesday of Hubble's electrical hear, the Power Control Unit.

Tomorrow's spacewalk will be done by John Grunsfeld and Rick Linnehan and is set to begin about 3:30 a.m. EST. During this final spacewalk of the flight the pair are to install a new cooling system on the telescope in hopes of reviving a science instrument that can only be operated when it is supercold.

We will post a wrap-up story on this page following the daily status briefing, and then our next update in this space will come about 3 a.m. EST Friday. See you then.

The fifth and final planned spacewalk for this STS-109 mission is expected to begin about 3:40 a.m. as John Grunsfeld and Rick Linnehan switch their spacesuit power to internal batteries.

We will update this page again when the spacewalk begins.

Stand by!

Columbia astronauts John Grunsfeld and Rick Linnehan officially began the fifth and final planned spacewalk of this STS-109 mission at 3:46 a.m. EST, switching the source of their spacesuit's electricity to internal batteries and becoming, in effect, two independent spaceships.

The outer hatch of the airlock is open and they will begin moving outside momentarily.

Their primary goal is an interesting one: install a new system that will make one of the Hubble Space Telescope science instruments so cold that it can once again be used to make observations. The work will require running coolant and electrical lines, connecting a turbopump and neon supply tank, as well as attaching a 13-foot-long heat radiator to the side of the observatory.

Components of the system were tested during the 1998 shuttle mission that flew John Glenn on his second spaceflight, so there is a good deal of confidence the system will work. Nevertheless, it still is considered an experiment and no one is really sure what will happen.

The instrument in question is the Near Infrared Camera and Multi Object Spectrometer, or NICMOS. The only way this instrument will work is if it's chilled to supercold temperatures. Its original supply of liquid nitrogen was lost soon after the instrument was installed because of a problem with a storage tank.

During totday's spacewalk Grunsfeld will be in the suit with red stripes, while Linnehan's is pure white.

You are invited to follow the spacewalk on NASA TV by clicking on the link above. And you can stay up-to-date by checking back to this page every couple of hours.

Efforts to install a new cooling system for a Hubble Space Telescope science instrument are going well this morning as the fifth and final spacewalk is just shy of two hours old.

Spacewalkers John Grunsfeld and Rick Linnehan are working in Columbia's cargo bay to install an experimental cooling system for the Near Infrared Camera and Multi Object Spectrometer, or NICMOS.

The heart of this system is a so-called "cryo cooler," which contains a supply of supercold neon gas and a turbopump that spins at 400,000 rpm. It has been removed from its carrier box and is being installed in the same Hubble bay that holds NICMOS.

As of this writing the cooler is being placed in the bay by Linnehan, who will soon begin turning the bolts that will mechanically attach the device. Power and coolant lines then will be connected as Linnehan works from the end of the shuttle's robot arm.

During totday's spacewalk Grunsfeld will be in the suit with red stripes, while Linnehan's is pure white.

You are invited to follow the spacewalk on NASA TV by clicking on the link above. And you can stay up-to-date by checking back to this page every couple of hours.

Astronauts John Grunsfeld and Rick Linnehan have been working outside in shuttle Columbia's cargo bay for four hours now and all is going well with the spacewalk moving along right on the timeline.

Today's principal task is to install an experimental cooling system that pumps neon gas to chill a Hubble Space Telescope science instrument so it will work again.

So far the main "cryo cooler" has been mechanically installed near the Near Infrared Camera and Multi Object Spectrometer, or NICMOS, science instrument and a 13-foot-long radiator -- which will shed heat generated by the pumping system -- has been attached to the side of the observatory.

Electrical connections to the cooler are being made right now, and then other connections and lines must be hooked up and snaked through the telescope between the radiator and the cooler.

Today's spacewalk, which officially began at 3:46 a.m. EST, is expected to last about seven hours.

You are invited to follow the spacewalk on NASA TV by clicking on the link above. And you can stay up-to-date by checking back to this page every couple of hours.

The spacewalking pair are nearing the end of their extravehicular activity for today and are cleaning up Columbia's cargo bay in anticipation of entering the airlock and repressurizing.

With the spacewalk now more than six hours in duration, everything appeared to go fairly well as John Grunsfeld and Rick Linnehan installed a new experimental cooling system to chill one of the instruments inside the Hubble Space Telescope.

We are standing by for the official conclusion of the spacewalk and will post another update shortly.

The fifth and final spacewalk of the STS-109 is concluded with astronauts John Grunsfeld and Rick Linnehan safely inside Columbia's repressurizing airlock. Official end time is 11:06 a.m. EST, making the duration of today's sortie seven hours and 20 minutes.

Before heading inside the two spacewalkers offered a tribute to the many people who helped prepare and execute their mission, with Linnehan even poking fun at a former physics teacher who once told him all he would ever be good for is taking up space.

During this final extravehicular activity the pair installed an experimental cooling system on the Hubble Space Telescope. If the device works, astronomers will be able to reactivate a science instrument. Early indications are that the cooling system is passing its initial tests.

The work wraps up a week-long series of spacewalks in which two pairs of astronauts conducted a total of five spacewalks to overhaul the observatory's electrical system, install a new science instrument and recover the use of another.

Next up for Columbia is a 36-minute maneuver today that will boost Hubble's altitude by three statute miles. That will set the stage for the crew to deploy Hubble early Saturday morning at 5:03 a.m. EST.