Critical ISS EVA Now Planned For Saturday

The EVA is now planned for Friday morning, delayed a day to give the support team more time to prepare.

The ISS head said that Dragon or Cygnus could carry the pump module to ISS. Dragon has an external cargo bay,so an easy operation with the RMS.With Cygnus that would be quite an operation.I guess he is saying the ports and interior has enough room. Trough the docking port,down the halls,back out of another port.Maybe Kibo?I wonder how many of the other ORUs could be done this way?How is external cargo going to be transferred from Dragon.Through Kibo?Or only stuff that is needed outside will be carried on Dragon?

It is a little hard to tell from the NBL videos, but it looks like the Pump Modules are too big for an ordinary hatch. The CBM (Common Bething Mechanism) hatch, maybe, but they are really huge ORUs. Anyone know the exact dimensions?

I'm certain someone's going to pipe up and mention that we need the shuttle to stick around another few years to resupply the space station. It would be nice if the shuttle would fly once or twice a year for the next decade; especially since nothing else will be going up there except 40 year old Soyuz's.

Anyone got 190 Million a month on hand to donate to NASA?

I wonder if anyone has done a study of the cost of new ORUs VS refurbishment? And as concerns downmass, absent Shuttle it's vilch.

Good luck astronauts. Hope the repair goes smoothly.

Bill Harwood on SpaceFlightNow says the pump is "5-and-a-half feet long, 4 feet wide and 3 feet high".

Folks:

There is no option to pass a new pump unit through the interior of the ISS. Although it would fit through the Common Berthing Mechanism hatch it would not fit through the quest airlock hatch. There are four spare ammonia pump units stashed around the exterior of the station. They won't need one from the ground for a while.

The Spacex Dragon capsule will probably be the best choice for bringing up orbital replacement units. It's trunk is twelve feet (almost four meters) in diameter. The trunk is just the interface between the second stage and the Dragon capsule. Spacex decided to drag it along when they realized that their solar panels were not going to fit in the nose of the capsule. The trunk also houses the capsules radiator loop for cooling. I can see their point about not wanting to throw anything away. But since the trunk is there, they decided to use it for external cargo like the Japanese HTV has. I like the idea of not having a service module. Dragon is virtually self contained. If they can reuse it they will recover 80% of their capsule by weight and over 90% of their systems (solar panels and radiator loops thrown away with the trunk). Once the Shuttle Program retires, Dragon will be in a class of it's own.

tinker

The importance of this EVA cannot be overestimated, especially as it occurs amid so many transitional currents in space operations. If we're ever going to do really big things in space in the coming years, such hardware replacements and related supporting maintenance will be an essential element of such in-space operations. How this task comes off will illuminate much, probably good and bad, for the road ahead.

While one can mourn the loss of the shuttle and its capabilities (as I did here last week: http://www.thespacereview.com/article/1669/1) or, contrarily, cheer its end and offer alternate avenues of approach, that we must discuss such matters in the most concrete and practical terms in light of such a vital repair task brings home and makes real the issues that so many of us have been rambling on about as so much ether on the blogs for years.

Continued (and hopefully expanding) operations in space will require certain enabling capabilities that we must recognize and/or identify, and not all of them involve exotic propulsion or even ISRU. Without doing so and then ensuring the continuing presence of such "mundane" technologies or abilities, we may cripple ourselves such that our hopes and dreams, built on high-level political philosophies instead of concrete engineering, will become moribund for lack of ability to implement such hopes and dreams.

We must be careful.

"I wonder if anyone has done a study of the cost of new ORUs VS refurbishment?"

I don't think there has been a comprehensive study but for each subsytem failure on orbit the responsible hardware board reviews and decides on the most cost effective approach, i.e. refurbishment, replacement, or do nothing (got enough spares to meet future needs). Most of the time they go for refurbishment since most of the hardware isn't widely used elsewhere, the spare parts to do the refurbishment were bought as part of the original lot that built the existing hardware, and restarting component production is cost prohibitive or impossible.

Thanks.I could not find Cygnus hatch size.Assuming that the DragonLab 50"x50" is standard,they could do it with 2" to spare.