[Python] Write AEM files with OREKIT

I am new to orekit and without a lot of knowledge about space physics. I am using orekit jpype to create an AEM file. No matter what I try, I get errors of the same format, something like:

in write_aem
writer.writeMessage(kvn_gen, aem)
org.orekit.errors.OrekitException: org.orekit.errors.OrekitException: frame EME2000 is not valid in this CCSDS file context


Also tried other frames.

My code is this:

def write_aem(attitudes_sequence: AttitudesSequence, states: list, filename: str, switch_date: AbsoluteDate):
start_time = states[0].getDate()
stop_time = states[-1].getDate()

# Header
header = AdmHeader()
header.setOriginator("SAFRAN SCSA")
header.setCreationDate(start_time) # Use start time as creation date

# Determine switch date from the attitude sequence and split states into two segments

states_segment_1 = [s for s in states if s.getDate().compareTo(switch_date) <= 0]
states_segment_2 = [s for s in states if s.getDate().compareTo(switch_date) > 0]

segments = ArrayList()
for segment_states in [states_segment_1, states_segment_2]:
if not segment_states:
continue # Skip empty segments

start_time = segment_states[0].getDate()
stop_time = segment_states[-1].getDate()

metadata = AemMetadata(1)
metadata.setObjectName("Satellite_name")
metadata.setObjectID("Sat_ID")
metadata.setCenter(BodyFacade("EARTH", CelestialBodyFactory.getEarth()))
metadata.setTimeSystem(TimeSystem.UTC)
metadata.setStartTime(start_time)
metadata.setStopTime(stop_time)
# TODO: Check this! which one is A and which is B???
metadata.getEndpoints().setFrameA(FrameFacade.map(states[0].getFrame()))
metadata.getEndpoints().setFrameB(FrameFacade.map(FramesFactory.getEME2000()))

aem_data = AemData()
for state in segment_states:
attitude = state.getAttitude()
timestamped = TimeStampedAngularCoordinates(
attitude.getDate(), attitude.getRotation(), attitude.getSpin(), attitude.getRotationAcceleration()
)
aem_data.addData(timestamped)

segments.add(AemSegment(metadata, aem_data))

# Create AEM file object
aem = Aem(header, segments, IERSConventions.IERS_2010, DataContext.getDefault())

# Writer
writer = WriterBuilder().buildAemWriter()
with open(filename, "w") as fp:
buffer = StringBuilder()
kvn_gen = KvnGenerator(buffer, AemWriter.KVN_PADDING_WIDTH, String("AEM file"), Constants.JULIAN_DAY, 60)
writer.writeMessage(kvn_gen, aem)
fp.write(str(buffer.toString()))


I of course want to choose the correct frames, but in a first moment, already creating the file would be great.

In here, example 4.3.1 they use 'SC_BODY', I tried creating this, but setFrameB only accepts FrameFacade input, and I have no idea how to create SC_BODY as it is not in the FramesFactory.

Why am I having this problem? And how can I solve it?

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