Shield Development
One of the main functions of the HyperVelocity Impact Technology is the
development of advanced shielding concepts to protect spacecraft on orbit.
Much of our shield development activities have been in support of the
International Space Station (ISS), which will be covered with meteoroid
and orbital debris shields.
The HVIT has been responsible for developing many of the advanced shielding
concepts that will be used on the ISS. The goal is always to develop a shield
that is effective, while being lightweight. Spacecraft shield designers must
work carefully to produce shielding solutions which are within the allocated
mass, volume, and cost budgets of the spacecraft.
Basic Concepts
Monolithic
This Monolithic Shield is the brute force approach and does
not win any points for ingenuity. It's simply a slab of
aluminum capable of absorbing the entire force of an impact.
This shielding method is mostly relevant as a comparison to
equivalent mass advanced shields. Also, the monolithic shield
can be used to represent the "default shielding" (a simple
aluminum wall) against meteoroid and debris impacts.
Whipple
The Whipple Shield is the first spacecraft shield ever implemented.
It was introduced by Fred Whipple back in the 1940s, and is still
in use today. Simply, it consists of placing a sacrificial bumper,
usually aluminum, in front of the spacecraft, thus allowing it to
absorb the initial impact.
The Whipple bumper shocks the projectile and creates a debris cloud
containing smaller, less lethal, bumper and projectile fragments.
The full force of the debris cloud is diluted over a larger area
on the spacecraft rearwall.
Stuffed Whipple
The Stuffed Whipple Shield is a variation of the simple Whipple Shield.
Layers of Nextel and Kevlar are inserted in between the bumper and
rearwall. These additional layers further shock and pulverize the
debris cloud such that any fragments reaching the rearwall are benign.
Multi-Shock
The Multi-Shock Shield is a popular shielding desgin. It consists of
staggering layers of Nextel at specified standoff distances. The multiple
layers of Nextel repeatibly shock the projectile and debris cloud until
the remainig fragments are too harmless to breach the rearwall.
Mesh Double Bumper
The Mesh Double Bumper Shield consists of a double layer bumper of
aluminum mesh, followed by an aluminum rearwall.
Honeycomb Panel
Many spacecraft are designed using Aluminum honeycomb sandwich panel
structures. The panels are tested and evaluated for their MMOD
shielding capabilities.
Foam Panel
Metallic foam sandwich panels provide stuctural support similar to
honeycomb panels, but have improved MMOD shielding capabilities.
Metallic foam panels are being tested and evaluated for future
spacecraft designs.
Transhab
The Mars Module Shield is a prototype shield developed for a
future manned mission to Mars. The shield consists of layers of
Mylar, Nextel, Kevlar, and foam. The foam is cored out inside in
order to reduce mass. The foam design is used because it is
desired that the shielding be compressible for launch.