Announcement

Collapse
No announcement yet.

Magnetoshell AeroCapture.(shields UP, Scotty!)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Magnetoshell AeroCapture.(shields UP, Scotty!)

    aka: MAC, essentially an artificial magnetosphere for spacecraft, potentially usable during re-entry and against solar flares and planetary radiation belts.

    Yes, it's very serious (NASA is interested) and could be tested soon on a cubesat.



    Magnetoshell Aerocapture (MAC) Technology Background

    The two SBIR contracts mentioned above are both related to MSNW’s Magnetoshell Aerocapture (MAC) technology, so before I discuss those projects I would like to first give a layman’s introduction to how MAC works, and why the underlying technology is so fascinating. For more detailed explanations, you can refer to their NIAC Phase 1 Final Report and Presentation.

    At its simplest level Magnetoshell Aerocapture is a method for slowing a spacecraft by using interactions between neutral gas molecules in the atmosphere and a plasma magnetoshell you create around your spacecraft. Unlike other methods of using the atmosphere to slow down, which involve deflecting the gas particles around your spacecraft, plasma magnetoshells basically absorb incoming neutral particles and then reemit them later after they’ve been brought to the same speed as the spacecraft. As the absorbed particles are accelerated to the spacecraft’s velocity, the spacecraft’s momentum is decreased at the same time.

    The plasma magnetoshell is somewhat like a miniature planetary magnetosphere created around your spacecraft using a dipole electromagnet and a plasma generator. The dipole electromagnet is analogous to the earth’s magnetic field, and the plasma is injected and trapped by the dipole field. The plasma magnetoshell interacts with neutrally charged atmospheric particles via a charge exchange collision, where an electron jumps from the neutral molecule to an ion in the plasma that gets too close. At the typical velocities and densities for MAC charge exchange collisions dominate the other plasma effects, such as ionization.

    The slow moving atmospheric gas particle is now an ion inside a fast-moving magnetic dipole field, which will trap it and accelerate it. The now neutralized magnetoshell ion drifts off with a velocity that is on average equal to the velocity of the spacecraft. At the right altitudes (between about 85-150ish km), the “magnetization parameter” is optimal and with the right magnetoshell plasma density, and the right magnetoshell diameter, you can guarantee that every neutral atmospheric particle that passes through the magnetoshell will be charged, captured by the magnetoshell’s dipole magnetic field, accelerated to the spacecraft’s velocity, and then neutralized when hit by a subsequent atmospheric neutral particle or eventually lost.

    A couple of key benefits of plasma magnetoshells compared to other aero-deceleration approaches:

    * The effective diameter of the brake can be varied rapidly by changing the current flowing in the dipole electromagnet. This can allow closed-loop control of the drag force even in the face of unknown atmospheric density variations.

    * The effective diameter of the brake can be very large (up to 100 m in diameter) with respect to the spacecraft. This allows ballistic coefficients an order of magnitude or two lower than that of even inflatable entry systems and many orders of magnitude less than solid heat sheilds.

    * By providing very low ballistic coefficients the atmospheric density needed for effective braking can drop by one to two orders of magnitude, directly decreasing the dynamic pressure and heating felt by the spacecraft. Studies showed a potential 14,000X decrease in heating.

    * The spacecraft being aerocaptured or aerobraked does not necessarily need to be aerodynamically shaped.

    * Magnetoshell aerocapture does not require superconducting electromagnets, and can be performed using normal magnets powered off of a high power battery pack.

    * Plasma magnetoshells may also be useful for protecting a spacecraft from high-energy particle bombardment from planetary radiation belts and solar flares.
    >
    Concept art




    Jonathan A. Goff @rocketrepreneur
    Cool picture of a plasma magnetoshell prototype by our friends at MSNW: http://t.co/QYUETQa6GO


    >
    This is for a 6U cubesat tech demo @AltiusSpace is helping them develop for one of the SBIR Select contracts we're working on.
    >
    This picture shows the plasma injector in the middle injecting plasma that is being captured in the magnetic field created by the MAC coils.
    >
    In between altitudes of ~85-150ish km around Earth, that plasma bubble will ionize atmospheric molecules, and the coil then traps them.
    >
    In layman's terms, you're looking at a parachute whose "canopy" is made of plasma, whose "shroud lines" are magnetic fields. Super sci-fi.
    >
    Did I mention that I love getting to work on amazingly cool technology like this?
    >
    For comparison, here's what it looks like with the RF plasma generator on, but the electromagnet off: http://t.co/owcUgzuzoR

    Dr. Mordrid
    ----------------------------
    An elephant is a mouse built to government specifications.

    I carry a gun because I can't throw a rock 1,250 fps
Working...
X