Senate Approves Commercial Space Launch Competitiveness Act.Jurists to Convene for “Moot Court” On International Space Law.New Commander at US Air Force Safety Center.Top Space Traffic Expert and IAASS Member Joins University of Arizona.Dream Chaser's Affordable Space Missions For UN Member States.McGregor City Modifies SpaceX Rocket Testing Rules.Statement on FAA Oversight of Commercial Space Transportation.ISSF Announces Grants For Student Research On Space Safety.ISSF Graduate Student Fellowship Program 2017.Global Space Exploration Conference (GLEX) 2017.Will Space Exploration lead us to a Global Space Agency?.Results of 1st International SEAF Workshop.Arsenault Trust Fund Postdoctoral Research Fellowships “Safe Passage to Mars” Design Challenge.The Soyuz MS-09 Hole That Could Have Killed ISS.A Quality Issue Caused the Soyuz MC-10 Failure.10th IAASS Conference Keynote Speakers Announced.European Spacecraft Dodges New SpaceX Constellation Satellite.IAASS AWARDS 2021: Call for Nominations. Pam Melroy Sworn in as NASA Deputy Administrator.Tags Hadfield International Space Station JSC Light Gas Gun micrometeoride NASA solar array About the author Although the solar arrays on ISS were not badly damaged, given the 3567 square meter area of the arrays, it is perhaps lucky that these collisions are not more frequent.īelow, video showing hypervelocity tests on Whipple Shields at White Sands Test Facility: Some velocities in our solar system are estimated to be in the region of 70 km/sec, while fragments from deep space debris have been estimated to be travelling at an order of magnitude of 240 km/sec.Ĭritical areas of spacecraft, and the appropriate shielding to use, are decided by the probability of impact and by the geometry and size of the potential target area. Basic Whipple Shields are unsuitable for deep space, due to the extreme velocities experienced further into the solar system. NASA is currently developing more advanced shields for use on Mars and other deep space missions. Stuffed Whipple Shield, as used on ISS (Credits: NASA) The projectile is fired down the long barrel into the test subject, and high speed cameras record the effects of the particle on the shielding. For velocities of over 7 kilometers per second, NASA uses a Light Gas Gun, which is a 2 stage system comprising of a powder based first stage, and a compressed hydrogen second stage. Traditional powder projectiles, such as those found in firearms, generally can’t reach the hypervelocities achieved by micrometeoroids. JSC’s Hypervelocity Impact Technology Facility (HITF) design shields to be used on ISS and other spacecraft and send the test items to the Hypervelocity Group at White Sands, to be tested for flight certification. Most micrometeoroids impact at a velocity in excess of 11 kilometers per second, and simulating these velocities for testing shields on Earth can be a challenging task in itself.Įngineers from Johnson Space Center use a lab at White Sands Test Facility for testing hypervelocity impacts. Heavy metal! A monolithic shield (Credits: NASA) More advanced Whipple Shields contain multiple layers of materials such as Nextel and Kevlar, which serve to slow the shattered meteorite debris even further, and reduce the amount of impulse transferred into the hull. A Whipple Shield is made of different layers of material, which are separated by a gap allowing the debris particle to break up on contact with the outer aluminium layer, and dissipate over a wider area before striking the secondary layer, which in basic shields, is the spacecraft hull itself. One type of shield common on the ISS is the Whipple Shield, which was designed by Fred Whipple, an American astronomer who first suggested the idea in 1946. These naturally carried a heavy mass penalty, and were discontinued as shield designs became more advanced. The ISS contains over 200 types of shielding, varying in thickness and material type and are strategically placed over critical areas.Įarly spacecraft shields were known as “monolithic shields” and consisted of a solid, thick piece of aluminium to absorb the impact. Lucky indeed, although spaceship hulls are given some protection from such events, namely in the form of a layered skin, which contains different fillings within the layers. “Bullet hole – a small stone from the universe went through our solar array. The image was posted on 29 th April, and was accompanied by the following brief synopsis: International Space Station commander Chris Hadfield has posted an image to his Twitter account, showing a small hole in one of the station’s solar panels. Micrometeoroid hole, as tweeted by Commander Hadfield (Credits: Chris Hadfield).
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