Tag: ISS

For the second time, a Progress freighter has launched and, after only four orbits, docked with ISS.

9:09 am

For the second time, a Progress freighter has launched and, after only four orbits, docked with ISS.

This was the fourth Progress launched this year, the second to follow an abbreviated four-orbit rendezvous with the space station. Russian flight controllers normally implement two-day rendezvous profiles, but they are perfecting procedures for single-day flights for possible use with manned Soyuz missions to shorten the time crews are forced to spend in the cramped ferry craft.

The Russians have used the leisurely two-day rendezvous path now for almost a half century. So, why are they suddenly trying to shorten the travel time to ISS to six hours? Though there are many good engineering reasons, I also suspect it is because they are now feeling the pressure of competition. The shorter travel time probably lowers their costs at mission control. It also makes using the Soyuz for manned flights more appealing. Dragon for example is presently using the two-day rendezvous path. And Dragon will soon become a direct competitor to Soyuz, when it begins flying humans in the next three to five years.

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It appears that NASA is at the moment unconcerned should the investigation into the Falcon 9 engine failure on October 7 cause a delay in the next Dragon supply mission to ISS.

9:06 am

It appears that NASA is at the moment unconcerned should the investigation into the Falcon 9 engine failure on October 7 cause a delay in the next Dragon supply mission to ISS.

The supply cache delivered to the station in early to mid-2011 by the now-retired space shuttle placed the six-person orbiting science lab on a firm footing well into 2013, according to Mike Suffredini, NASA’s space station program manager. “The launch date itself, in January, is not really critical to the program from a supply standpoint,” Suffredini told an Oct. 26 news briefing. “So we have some flexibility.”

In the short run a delay here would not be critical. A long delay, which is unlikely, would however not be good for operations on the station, and illustrates why it is very important to get the Orbital Sciences’ Cygnus cargo capsule up an running as soon as possible.

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A spacewalk November 1 will attempt to find and repair a coolant leak that could force a power reduction at the station.

5:34 pm

Construction workers in space: A spacewalk November 1 will attempt to find and repair a coolant leak that could force a power reduction at the station.

A slight 1.5-pound-per-year leak in the channel 2B cooling system has been present since 2007 and during a shuttle visit last year, two spacewalking astronauts added eight pounds of ammonia to the reservoir to boost it back up to a full 55 pounds. The plan at that time was to top off the system every four years or so to “feed the leak,” replacing the lost ammonia as required.

But over the past few months, engineers saw the leak rate suddenly quadruple, either because something changed at the original leak site or, more likely, because another leak developed somewhere else in the system.

Whether the leakage was caused by space debris or a component failure of some sort is not yet known. But the result is: If the leak continues at its current rate, the coolant will drop below a 40-pound safety limit and the system will shut down by the end of the year or shortly thereafter, taking power channel 2B down with it. While the space station can operate without the full complement of power channels, the loss of channel 2B would force flight controllers to power down equipment, eliminating redundancy and reducing the amount of research the crews could carry out.

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Orbital Sciences has delayed the first demo launch of its Cygnus cargo capsule until March 2013 at the earliest.

10:16 pm

Orbital Sciences has delayed the first demo launch of its Cygnus cargo capsule until March 2013 at the earliest.

The schedule for Antares itself has not been delayed. Launchpad tests are still scheduled to begin next week, with the first engine test set for early November, and the first launch of Antares set for December.

They don’t explain the reason for the Cygnus delay. I suspect they simply decided to be realistic. It was always unlikely that the first Cygnus launch would follow only a month after the first Antares launch, especially if there are any kinks in that launch.

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