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  Mission Chronicles :: Flight Day 5-6

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Mission Chronicles
Where Is Hubble Now?

A more informal perspective - members of the Hubble Project give their reactions and thoughts about Hubble and the SM3B mission.

Skip to any page in the chronology of events.
Pre-Launch Flight Day   1-4   5-6   7-8   9-12 Post-Landing

March 6, 2002
One Hubble Girl's View by Ann Jenkins
Mission Control, Houston

EVA 3 and the Next Morning

Astronaut reflectionWAITING TO EXHALE
After a long, nerve-wracking night, we finally got word minutes ago: Hubble has a heartbeat once again! Last night was the spacewalking surgery that stopped our baby's heart and kept it stopped for more than 6 hours. But now, with the aliveness and functional tests complete, we're happy to report that our telescope's new electric heart is once more beating strong and steady.

The aliveness test came at the end of an arduous spacewalk, but before the astronauts returned to the Shuttle. They stood by (well, floated) while controllers sent power into Hubble. And Hubble responded by coming back to life!

I really expected to hear cheers at that news. I figured that the the sense of happiness and relief would be uncontainable. But up here in the Payload Control Center at Mission Control, the mood was far more serious. My co-workers noted the moment, but--ever the engineers--they did it with extreme caution. I think they were waiting for the more thorough functional test to be performed.

Well, hours later, the test is finally finished--and Hubble's new heart is alive and healthy! But the group that worked through the night is now sleeping so they will be fresh for tonight's spacewalk. The day shift is in, but they're off on other tasks to prepare for this evening. Anyway, they weren't here through the rollercoaster ride that was last night. When the word finally came, of course they cheered. But I wish all those folks who had endured the long and agonizing night could have been here to cheer with us. I bet the astronauts would have heard us in orbit!

March 6, 2002, 12:00pm CST
Dr. Edward Cheng (different Ed)
HST Development Project Scientist
Johnson Space Center

Astronaut reflectionWhat a relief! The Power Control Unit (PCU) changeout last night went about as flawlessly as can be expected, and HST is waking up after taking a 4 hour nap. (Well deserved after 12 years of continuous work advancing the frontiers of knowledge!) The PCU functional tests have been successfully completed, and most of the subsystems will be back on-line after a few more hours of commanding and checkout. Needless to say, the team has worked exceptionally hard on this aspect of the mission, and this is a great achievement. HST now has a new and fully functional power system to take it to the end of its mission. The net result is that we have about 30% more power on the spacecraft now, compared to before SM3B.

How does this stack up? We now have about 3 kilowatts (orbit average) available from the solar arrays. (Previously, this number was more like 2.3 KW, so we gained about 0.7 KW.) A quiescent HST that is doing nothing consumes about 1.9 KW. So in terms of available power to do science, we went from something like 0.4 KW to 1 KW, over a factor of 2! This increase in power capability is one of the things that makes it possible to put up new generation instruments like the Advanced Camera for Surveys (ACS), the NICMOS Cooling System (NCS), and two more new instruments for SM4.

Last night's activities were not without some high drama though. Before the astronauts started decompression of the airlock, Grunsfeld's backpack for his spacesuit started leaking water. This was just at the point where we had stopped "warming up" the HST in preparation for turning its power off. Controllers at GSFC immediately resumed the heating, and postponed the power off sequences until the issue was resolved. The leak was isolated to a valve which should not have opened until the astronauts were in vacuum. The conjecture is that a power glitch in the umbilical that powers the suit in the airlock caused this problem. As a result, the astronauts will be using battery power instead of the umbilical for future EVAs. The crew did a superb job of switching over to another suit, resulting in a EVA start delay of only around 2 hours.

The astronauts worked for a total of 6 hours and 48 minutes (24.485 Ksec). Everything on the Shuttle and on HST is normal, and ready for the fourth day of EVA. We'll be getting to the first of two "science oriented" EVA days tomorrow, with the installation of the ACS instrument.

The headache metric today reads:
Excedrin: 1 + 4 = 5
Tylenol: 4 + 1 = 5
Bayer: 0
Aleve: 2 + 1 = 3
Advil: 3 + 4 = 7
Clearly, we had an exciting day.

March 5, 2002
One Hubble Girl's View by Ann Jenkins
Mission Control, Houston

Flight Day 5 and the next EVA

Astronaut reflectionAs of this morning, Hubble now sports two beautiful new rigid arrays and a fresh and healthy reaction wheel. The mission's first two nights of spacewalks went exceedingly well, with the astronauts successfully completing all scheduled tasks--and even managing to squeeze in two extra "get-ahead" tasks. We couldn't be happier!

Now it's time for shift handover, with the mission's two teams huddled around consoles discussing the flight day's events. We split the day into two 13-hour shifts to allow for continuity and smooth transfer of information. I sit here in the Payload Control Center and watch my colleagues with a reverence I generally reserve for childhood heros. These are just ordinary people. But I've watched them prepare for this mission for years, working long days and nights, sacrificing so much time they could have spent in other, more enjoyable ways. All to get to this point, and to cheer like a crowd at a football game when they hear the good news from the aliveness tests. I love to just sit like a fly on a wall and watch.

I hope I hear those cheers tonight, because this is the night we've all been dreading. This is the night we turn off Hubble--our beloved Hubble--for the first time ever. What we're doing tonight has been compared to a heart-lung transplant. It's the changeout of the Power Control Unit, which pumps electricity throughout the telescope. This electricity powers all of Hubble's instruments and systems and is the very lifeblood of the telescope. And however irrational our anxiety is, we worry about what will happen when we try to turn Hubble back on.

We have a great astronaut crew--clearly the best of the best at NASA. We know them and trust them implicitly. But we still worry the way a parent would worry about a child going in for surgery. A surgery that will momentarily stop our baby's heart. We're already holding our breath...and we won't exhale till this task is through and Hubble's electricity is flowing again.

I'm off to TRY to get some sleep. Stay tuned.

March 5, 2002
Dr. Edward Cheung (Jackson & Tull)
HST Principal Engineer
Flight Day 5 Report

Hubble with new solar arraysThe mission has been progressing amazingly well, better than the previous one in 1999. We just finished our second space walk (EVA) day, and we now have two new powerful Solar Arrays on the Telescope. The Arrays' power is controlled by a pair of Diode Box Controllers, which I have spent the past two years building and testing. Their passing their functional test is a great feeling! HST now has plenty of power for the future. We also have a new Reaction Wheel, which is used to orient HST in space. I did not work on this latter piece of hardware.

Here at Johnson I work the console position named 'Systems Manager'. Three other colleagues and I staff this position. Our job here at the Systems Manager console is to monitor the Shuttle to HST combination. If there is a problem that involves the Shuttle to HST interface, one of us will be assigned to work it. Of course, since we are still HST engineers, if there is a problem we can assist with on the HST side, we will jump in.

Such it was yesterday when we saw a spike in current from one of the HST screens. I just came on shift then, and everyone was very high state of activity due to this unexpected current. The astronaut was just handling the Solar Array connectors, and we thought the current had something to do with what he did. Since there was nothing else happening, both Goddard and us started to work on this problem. It took a few hours, with telecons back to Goddard, but I finally figured out what the problem was, and the whole project was patting me on the back for that. Fortunately, this has been the only significant electrical anomaly. We had to solve this because the same circumstance would occur today when we install the second solar array.

I do not think that I am exaggerating when I say that tomorrow will be the most difficult space walk in history. We will be changing out the heart of HST's power system, which will require powering down all of the telescope. This will involve removing a box that was not meant for in space servicing, and that has many connectors. This has not been done before, but we are confident all will go well. It will be a great thrill when it is completed.

Since the telescope will be powered down for so many hours, we are currently performing what is called the 'preheat'. This is where we basically light up the Telescope like a Christmas tree, turning on every load we can to get everything good and warm. This allows us to remain unpowered for the longest amount of time so that the equipment does not cool below their allowable temperatures. Since we monitor the Shuttle to HST interface, we monitor the power usage, which is off the chart right now. To give you some real numbers, HST is drawing 2.5 kWatts from Shuttle at the moment.

More from Ed at:
Ed's Web page on the Diode Boxes:

Click here for more pictures of Flight Day 5...

March 5, 2002
One Hubble Girl's View
by Ann Jenkins
Mission Control, Houston
Some Photos of Our Team

At Mission Control in Houston, we work at consoles 24 hours a day throughout the mission. Most of us are split into two 13-hour teams that overlap for hand-off. The long days and nights require intense concentration, but we try to find time to enjoy the moment. The work is hard, we miss home, but we all know that being a part of this mission is the opportunity of a lifetime.

March 5, 2002, 12:00pm CST
Dr. Edward Cheng (different Ed)
HST Development Project Scientist
Johnson Space Center

Astronaut using toolsLast night, we successfully replaced the second of the two solar arrays. We also replaced a Reaction Wheel Assembly. All the replaced hardware has passed functional tests and are working fine. There was some time left over, so the astronauts replaced some torn insulation, and repaired a door hinge on the aft shroud. These "get-ahead" tasks are optional things to do to save time for subsequent EVA days or servicing missions.

The astronauts worked for a total of 7 hours and 17 minutes (26.204 Ksec).

Everything on the Shuttle and on HST is normal, and ready for the third day of EVA. Tonight, we'll change the Power Control Unit (PCU). This will be a stressful time, since it would be the first time that power is entirely turned off on the spacecraft since it was launched. (Individual systems are power cycled as needed, including during previous servicing missions.) We don't anticipate a problem, but it's not something one does lightly.

Life continues at a predictable pace in the control center. No great excitement ... just the way we like it. However, it is tiring all the same, with adrenalin running high for 12 hour shifts. We're getting our share of stomach aches from too many Krispy Kreme doughnuts and meatball sandwiches from Frenchies.

The headache metric today reads:
Excedrin: 1
Tylenol: 4
Bayer: 0
Aleve: 1 + 1 = 2
Advil: 1 + 2 = 3
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