Yaw steerling impact

After the selection of PEP, an issue on the possible yaw-steering operation of JUICE spacecraft popped up. (March 2013).

Background

Not very clear to me, but possible sun-illumination of the spacecraft may impact on power issues, so that a possible yaw-steering discussion has been initiated by ESA.

No matter what has been thought by ESA, we PI team is requested to investigate the possible impact on our science.

Frankly speaking, two possible impacts can be thought. JNA field of view and the pitch angle.

Impact on JNA field of view

The JNA field of view analysis is done in ../../../src/scripts/apps120816_flyover/flyover_mini.py, apps120816_flyover.flyover module.

On 130325, I have started to implement a new “yaw-steered” version of flyover, namely, apps120816_flyover.flyover_yaw.

Here the assumption of continuous steering with proportional to the latitude is made. Also, constant version is also added to get an idea.

A sample output is

../_images/flyover_yaw_70steer.png

A keynote summary is also made, but it is too big size. Therefore you can only ask to YF with referencing the file name as follows. 130324-YawSteeling/pyana.pep/src/scripts/apps120816_flyover/flyover_yaw_v1.key

Yaw-steering attitude

The attitude is calculated from self-developed module. See Frames. The pyana.pep.pep_attitude.NadirLookingSc provides the nominal nadir looking spacecraft coordinates. A new class, pyana.pep.pep_attitude.NadirLookingYawSteeringSc is implemented. This provides the yaw-steering nadir looking spacecraft.