Project Title

Unified Space Data Link Protocol Green Book



Document Number



5.04 Space Link Protocols Working Group

Document Type


Description of Document

This work will describe the concepts, rationale, requirements, and operational scenarios envisioned towards a new generic CCSDS Data Link layer protocol, the Next Generation Space Link layer Protocol (NGSLP) examining all CCSDS space links i.e., Direct to Earth (DTE), Direct from Earth (DFE), and Proximity Environments). This project is the direct follow on result of the initial concept paper, which the WG produced as a prerequisite for the approval of this project. The NGSLP is targeted for agencies emerging missions, both human and robotic, which we anticipate will require higher performance (higher data rates and throughput) and operate with enhanced security. We define a new space data link layer protocol that is largely based upon the proven features of the existing CCSDS link protocols and adds options that can be used to tailor future mission link layer needs. In addition, the interfaces with other CCSDS working groups such as the emerging channel coding option of decoupling the transfer frame length from the code block size currently under study by the C&S WG will be investigated. This option would remove the constraint to align the transfer frame with the code block, allowing frame sizes to be explicitly tailored to mission requirements and enable future mission operational link layer modes. We believe this project should be immediately approved because of the long lead time required to develop standards, the emerging link layer requirements of the newly formed optical comm WG, and the changes to agencies space and ground link layer infrastructure required to support the emerging Space Data Link Security (SDLS) protocol and substantial increases in link data rates, provides an opportunity to introduce future link layer modifications. This Project is related to the NGSLP Blue Book Project described in the framework. This GB project extends past the BB project, because we envision that in the actual writing of the BB, some concepts identified in the GB may change, and there the GB might require an update before publication.

Applicable Patents

There are no patent issues for this technology that are known by the CCSDS community

Patent Comments

No patent issues.

Survey of Similar Standards
Documents or Projects
Undertaken in Other Bodies
and elsewhere in CCSDS


Book Editor


Book Editor Resources

NASA will provide the Book Editor. Assume 6MM required.

Prototype 1

Not Required

Prototype 1 Resources

Prototype 2

Not Required

Prototype 2 Resources

Prototype 3

Prototype 3 Resources



Monitor Only


Resource Comments


Legend for Schedule Milestones
Orange Bullet = Required for Orange Books
Green Bullet = Required for Green Books
Magenta Bullet = Required for Magenta Books
Blue Bullet = Required for Blue Books
Note - Red Books are Draft Blue/Magenta Books

Schedule Milestones
Orange BookGreen BookMagenta BookBlue Book
Original Completion Date
(Date in M/D/YYYY format.)
(Date in M/D/YYYY format.)
Project ApprovedOrange BulletGreen BulletMagenta BulletBlue Bullet10/31/2013CMC-P-2014-08-004 Confirmed by CNES delegate.
Project Start DateOrange BulletGreen BulletMagenta BulletBlue Bullet10/15/2014
Internal WG Review
First Draft Circulated to WGOrange BulletGreen BulletMagenta BulletBlue Bullet12/15/2013
First Draft Comments DueOrange BulletGreen BulletMagenta BulletBlue Bullet2/10/2014
Second draft circulated to WGOrange BulletGreen BulletMagenta BulletBlue Bullet4/21/2014Before Fall 2015 meeting
Second Draft Comments DueOrange BulletGreen BulletMagenta BulletBlue Bullet5/21/2014Before Fall 2019 meeting
Final WB Submitted to AD for Further ProcessingOrange BulletGreen BulletMagenta BulletBlue Bullet6/21/2014
External Milestones
Secretariat Document ProcessingOrange BulletGreen BulletMagenta BulletBlue Bullet9/15/2014Poll CESG-P-2020-04-004 started 30 April 2020
First Agency ReviewMagenta BulletBlue Bullet
RID ResolutionMagenta BulletBlue Bullet
Secretariat Document Processing 2Magenta BulletBlue Bullet
Final Agency ReviewMagenta BulletBlue Bullet
RID ResolutionMagenta BulletBlue Bullet
First Prototype DevelopmentBlue Bullet
Second Prototype DevelopmentBlue Bullet
CMC ApprovalOrange BulletGreen BulletMagenta BulletBlue Bullet3/22/2016Poll CMC-P-2020-06-004 closed 15 June 2020
Total Time to Complete
(in months)
Version: 386.0
Created at 10/22/2013 1:13 PM by Kazz Greg
Last modified at 7/2/2020 3:57 AM by Gian Paolo Calzolari