After a flawless launch, an unmanned Russian Progress resupply ship used a new expedited technique to reach the International Space Station in hours instead of days. Progress 48 was loaded with almost three tons of food, fuel and supplies for the six crew members, and it docked successfully to the Pirs docking compartment on August 1, just six hours after the launch from the Baikonur Cosmodrome in Kazakhstan at 19:35 UTC (3:35 p.m. EDT, 1:35 a.m. Aug. 2 Baikonur time). The fast trip and rendezvous was designed to test a method for conducting additional firings of the Progress engines early in its mission to expedite the time required for a Russian vehicle to reach the complex.
Russian officials say the technique could be applied to manned Soyuz vehicles in the future to improve crew comfort and extend the life of the Soyuz return vehicle.
Russian cosmonaut Gennady Padalka has been quoted as saying it is every cosmonaut’s dream to only have a 6-hour flight in the cramped Soyuz!
Russian engineers and managers are still assessing the new technique, but by all appearances the quick trip seemed to be a great success. This Progress vehicle will stay at the ISS until December.
During the docking, NASA also tested a new technique of attitude control for the ISS which will save fuel, requiring 10 times less fuel to put the station in the proper orientation relative to Earth for the unpiloted cargo vehicle’s arrival.
According to Pooja Jesrani, lead attitude determination and control officer (ADCO) for this expedition at the Mission Control Center in Houston, the new maneuver is called the optimal propellant maneuver, or OPM. OPM is an improvement on the standard zero propellant maneuver, or ZPM, also developed by Draper Laboratory. The OPM takes into account the need to make the orientation, or attitude, changes to the space station faster than the ZPM. This speed avoids thermal concerns on the exterior of the station’s modules.
“Maneuvers such as the OPM will increase the International Space Station’s efficiency by using less propellant,” Jesrani said. “Additionally, the reduction in thruster firings during an OPM results in the station enduring lower structural loads. These benefits, among others, will help increase the longevity of the station.”
The maneuvers to and from the docking attitude are expected to save more than 90 percent of the fuel typically used when a Russian cargo spacecraft docks with the orbiting outpost.
Source: NASA
I’m glad to see this. I’ve always wondered why it took a few days to rendezvous with the ISS. After all, if you launch at the right time and the right speed it shouldn’t be that complicated. Easy for me to say, I suppose. But I’ve never seen a good explanation for the delay. Maybe, in the case of manned missions, they want to give the people on board time to adapt to a space environment, time to stop barfing.
It is not that simple. The orbit must match perfectly and also the same inclination. But when you launch your inclination is wrong for starters.
Why launch at the wrong inclination? Wouldn’t it be easier to launch at the correct inclination than change it in orbit?
The problem is that you don’t have a launch pad at such a correct location 😉
Recall if you can, that the International Space Station is in a compromise orbit meant to allow access from most of the nations involved, at least the ones in the northern hemisphere. Had it only been built by the U.S. matching the orbit would have been much easier for us, but quite difficult for any other nation’s launch sites. When the Shuttle had to match MIR”s highly inclined orbit it had to launch a lighter load to have enough fuel for the maneuvers to reach it.
Yes but,,, launching from the cape to an equatorial orbit gains advantage from the earth’s rotation. And the ISS orbits at a significant inclination to an equatorial orbit. But you *could* launch from the cape to a polar orbit if you wanted to. With a lighter payload becacuse you would lose the earth rotational advantage. Wouldn’t it still make more sense to launch directly to a polar orbit than launch to an equatorial orbit and then correct it to a polar one?
So why not launch directly to the ISS inclination?
Wasn’t it you that recently asked the question – “Why does it take so long to reach the ISS?” Apparently, timing is everything.. if you don’t launch at exactly the right instant, which was hard to do in the past with so many unpredictable variables, then you would have to either wait until the same orbital configurations were matched or recalculate everything and/or use up fuel. The Russians have had a whole lot of practice doing this and it shows!
My response to that question was that I thought it was Space X who had proposed this technique.. but I couldn’t find the link. I was looking in the wrong place!
What about it Universe Today? Is Space X up to similar?
this sounded like the development of the 1865 locomotive act into the 1896 act.
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The 1865 locomotive act required someone with a flag running 60yards in front of a car with set speedlimits of 4mph in country and 2mph in town. In other words, a dangerous oddity on the road.
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the 1896 act accepted vehicles now the norm for transportation
(Think Benz 1885, Daimler & Maybach 1889, FW Lanchester 1895)
One thing comes to mind:
Why would the flagbearer have to run in front of the car? At 4mph (country) he could just have a brisk walk 😛
I was also hoping to get some explanation on how the manouvers work. I assume its time vs fuel use compromise for Progress. I am wondering if the ISS is using the new test (ion?) propusion system for altitude control and if that’s where part of the fuel savings came from.
“NASA plans to test a 200-kilowatt VASIMR engine on the International Space Station, reportedly in 2013.” Follow this link to Nancy’s coverage…
Read more: http://www.universetoday.com/87425/zubrin-claims-vasimr-is-a-hoax/#ixzz22Qy1TRcw
and again, one big point more for the russians…
It’s there in six hours or the pizza’s free!