Gaia spots stars flying between galaxies

A team of Leiden astronomers used the latest set of data from ESA's Gaia mission to look for high-velocity stars being kicked out of the Milky Way, but were surprised to find stars instead sprinting inwards – perhaps from ...

Artificial brain helps Gaia catch speeding stars

With the help of software that mimics a human brain, ESA's Gaia satellite spotted six stars zipping at high speed from the centre of our galaxy to its outskirts. This could provide key information about some of the most obscure ...

How do stars go rogue?

Rogue stars are moving so quickly they're leaving the Milky Way, and never coming back. How in the universe could this happen?

Image: Hypervelocity impact test damage

An aluminium plate, ripped inwards by a single sand grain-sized fleck of aluminium oxide shot at it during hypervelocity testing.

Can super-fast stars unveil dark matter's secrets?

Zoom! A star was recently spotted speeding at 1.4 million miles an hour (2.2 million km/hr), which happened to be the closest and second-brightest of the so-called "hypervelocity" stars found so far.

Slingatron vision is to launch payloads into orbit

A Kickstarter project features Slingatron, the work of a seasoned team of scientists as a way to put cargo into orbit. The Slingatron is a mechanical, hypervelocity mass accelerator. The inventor of the Slingatron is Dr. ...

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Hypervelocity

The term hypervelocity usually refers to a very high velocity, approximately over 3,000 meters per second (6,700 mph, 11,000 km/h, 10,000 ft/s, or Mach 8.8). In particular, it refers to velocities so high that the strength of materials upon impact is very small compared to inertial stresses. Thus, even metals behave like fluids under hypervelocity impact. Extreme hypervelocity results in vaporization of the impactor and target. For structural metals, hypervelocity is generally considered to be over 2,500 m/s (5,600 mph, 9,000 km/h, 8,200 ft/s, or Mach 7.3). Meteorite craters are also examples of hypervelocity impacts.

Hypervelocity tends to refer to velocities in the range of a few kilometers per second to some tens of kilometers per second. It is especially relevant to the field of space exploration and military use of space, where hypervelocity impacts (e.g. by space debris or an attacking projectile) can result in anything from minor component degradation to the complete destruction of a spacecraft or missile. The impactor, as well as the surface it hits, can undergo temporary liquefaction. The impact process can generate plasma discharges, which can interfere with spacecraft electronics.

Hypervelocity usually occurs during meteor showers and deep space reentries, as carried out during the Zond, Apollo and Luna programs. Given the intrinsic unpredictability of the timing and trajectories of meteors, space capsules are prime data gathering opportunities for the study of thermal protection materials at hypervelocity (in this context, hypervelocity is defined as greater than escape velocity). Given the rarity of such observation opportunities since the 1970s, the Genesis and the recent Stardust Sample Return Capsule (SRC) reentries as well as the recent Hayabusa SRC reentry have spawned observation campaigns, most notably at NASA Ames Research Center.

Hypervelocity collisions can be studied by examining the results of naturally-occurring collisions (between micrometeorites and spacecraft, or between meteorites and planetary bodies), or they may be performed in laboratories. Currently the primary tool for laboratory experiments is a light gas gun, but some experiments have used linear motors to accelerate projectiles to hypervelocity.

The properties of metals under hypervelocity have been integrated with weapons, such as explosively formed penetrator. The vaporization upon impact and liquefaction of surfaces allow metal projectiles formed under hypervelocity forces to penetrate vehicle armor better than conventional bullets.

The White Sands Test Facility is a NASA facility that performs, among other tests, hypervelocity impact experiments to study the effect of micrometeoroid and orbital debris impacts on spacecraft, so that improved protection measures can be taken for its space missions. The facility uses two-stage light gas guns to accelerate projectiles to extreme velocities.

This text uses material from Wikipedia, licensed under CC BY-SA