NIPPI equipments on HAYABUSA spacecraft

NIPPI joined JAXA HAYABUSA explorer project in developing components listed below.

・Extension spring for Sampler

・Spin ejection spring for Reentry Capsule

Fig.1.　HAYABUSA

One of notable configuration of HAYABUSA is the Sampler which protrudes from bottom of the explorer. The concept of sampling small stones or sands is shown in figure below. This concept was introduced to cope with micro gravity environment, and surface topology and condition of the asteroid, which had been unknown before landing.

As is the case with many other spacecrafts, deployable equipment should be retracted in small volume. The Sampler is stowed in compressed configuration during launch phase, and after launch it must be extended to required length.

And upon touch-down to the asteroid, the Sampler should be flexible enough to absorb shock, and to comply with surface shape.

In order to satisfy these requirements, “the extension spring (double reversed helical spring)” was developed. This is an application of Nippi’s “Coilable mast” technology.

Because straight longerons are deformed in helical coil shape, it works like a spring with very long stroke.

Fig.2. Touch-down to the asteroid

Fig.3.　Double Helical Spring for HAYBUSA Sampler

Another major mission of HAYABUSA is transporting samples of asteroid to researcher on the earth. In HAYABUSA, samples are contained in a capsule, and the capsule is separated and ejected from HAYABUSA, and finally capsule reenters the atmosphere of the earth. An equipment which gives relative velocity and spin to the capsule is “the spin ejection spring (helical spring)”. Height of this spring is shorter than the spring of Sampler, but principal mechanism is the same.

Fig.4. Separation of the Reentry Capsule

Fig.5. Helical Spring for Reentry Capsule

This spring is compressed in longitudinal direction and set in the explorer. The bent longerons together works like a spring.

There are some mechanisms which eject objects and give spin at the same time, with using normal coil springs and a spin table. But this helical spring performs the same function in quite simple mechanism, as well as contributing reliability and weight reduction. Such a mechanism in spring is the only one in the world.

The helical spring had been stowed for 7years after launch until it successfully separated and ejected the capsule.

Same type of the spring had been already installed to Engineering Test satellite “Micro –labsat” and to Selenological and Engineering explorer “KAGUYA”, and is planned to be also on board HAYABUSA -2.