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Antares Rocket Launch Postponed; What is a Spacewalk?

December 19, 2013; 6:30 AM ET

NASA has postponed the Antares rocket for a launch date no earlier than mid-January. The reason is due to a faulty station pump module. Because of this equipment malfunction, a series of spacewalks are to occur Dec. 21, 23 and 25. Each of the three spacewalks will begin at 7:10 a.m. and is scheduled to last six and a half hours.

What is a spacewalk? A spacewalk is any period of time an astronaut is physically active outside of a spacecraft. The technical term for this activity is called an extravehicular activity or EVA, but spacewalk is the more common name due to the lack of gravity, there is no actual walking involved in the activity but in fact, floating.

On March 18, 1965, Russian astronaut Alexi Leonov performed the first spacewalk, lasting 10 minutes. Today, spacewalks last a bit longer, some five to eight hours! Currently, Russian astronaut Anatoly Solovyev holds the record for most spacewalks at 16, with more than 82 hours outside in space. The reason for most spacewalks today are for science experiments, though spacewalks also occur to test new equipment as well as make repairs to satellites or the spacecraft, which is the reason for this upcoming spacewalk. NASA astronauts Rick Mastracchio and Mike Hopkins will remove a pump module that has a failed valve. They must now replace this piece, which requires a spacewalk.

During these spacewalks, astronauts must wear spacesuits. These suits protect spacewalkers from spacedust, radiation as well as the extreme temperature changes in space which range from minus 250°F in the shade and 250°F in the sunlight. Another benefit of the spacesuit is that it gives the astronaut water and oxygen during missions. Astronauts must put on their suits several hours prior to a spacewalk since the suits are pressurized. The reasoning for this is because there is no pressure in space, and this will help keep the fluids in the body at a liquid state. There are many dangers that come with doing a spacewalk, but they are a necessary part of science and they help continue to advance our knowledge on so many levels.

We here at Accuweather Astronomy understand how dangerous a spacewalk can be, and although this has delayed the rocket launch, it is in the best interest of the brave astronauts currently stationed at the International Space Station. For more information on spacewalks visit here.

As for the updates on the spacewalk, and the Antares rocket launch, be sure to check back to AccuWeather Astronomy on Facebook periodically.

This blog was written by AccuWeather Astronomy Expert Gregg McCambley

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or


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Astronomy Blog
The astronomy blog, by Dave Samuhel, discusses stargazing, including how weather will affect viewing conditions of astronomical phenomenon.