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<div>Dear SLP WG,</div>
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<div>Yet another question for you!</div>
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<h5 style="margin: 12pt 0in 0.0001pt; text-indent: 0in; page-break-after: avoid; font-size: 14px;">
<span style="font-weight: normal;">The proposed NGSLP frame format has a </span><span style="font-weight: normal; font-size: 7pt; font-family: 'Times New Roman';"> </span>SPACECRAFT ID USE FIELD <span class="Apple-style-span" style="font-weight: normal;">field
that would identify mission phase in which the data contained in the transfer frame was generated. This proposed field is 2 bits long. </span><span class="Apple-style-span" style="font-size: 16px; font-weight: normal; font-family: 'Times New Roman';">This
field is not going to change after launch so: Is this field necessary? Or should ground data services provide an other method (e.g., SFDU header) to identify when the data was generated? Any Comments?</span></h5>
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<span style="font-weight: normal;">Rationale for inclusion of the field: </span></h5>
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<span style="font-weight: normal;">Currently missions request multiple SCID assignments to uniquely identify the environment in which the data was generated. This practice reduces the number of SCIDs that are available to CCSDS member agencies. Moreover the
SANA spacecraft ID registry is very limited: The number of possible SCIDs by Transfer Frame Version Number are: 1024 Version 1, 256 Version 2, 1024 Version 3 IDs. </span><span style="font-weight: normal;">The Spacecraft ID Use Field provides a mission unique
Spacecraft ID applicable for all pre and post launch phases while self-identifying the phase in which the data was generated. Three of the four values of this field (“00”, “01”, “10”) are mission defined. The fourth value, ‘11’ is reserved for post launch
data. </span><o:p></o:p></h5>
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Thanks!
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<div>Greg</div>
<div>Keeping an eye to the future </div>
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