Space-track throttles API use in order to maintain consistent performance for all users. To avoid error messages, please limit your query frequency.
|CDM||3 / day||Once every 8 hours for all constellation Conjunction Data Messages (CDM)|
|CDM||1 / hour||Once every hour for a specific conjunction event (Note: The 18 SDS will continue to send Close Approach (CA) emails to satellite owners/operators)|
|TLE||1 / hour||Once every hour for TLEs. Please randomly choose a minute for this query that is not at the top or bottom of the hour.|
|SATCAT||1 / day||Once per day after 1700 (UTC) for SATCAT data|
|BOXSCORE||1 / day||Once per day after 1700 (UTC) for Box Score data|
|60-DAY DECAY||1 / week||Once per week, on Wednesdays after 1700 (UTC), for 60-Day Decay data|
With great power comes great responsibility...
The API Query Builder tool allows users a great amount of power and flexibility in creating queries. Your space-track account may be suspended if you violate the usage policy by querying data too often or by running queries that negatively impact the performance of the website. Repeat offenders may have their account suspended permanently.
If your account has been suspended you should receive instructions from us on what you need to do in order to have your account re-instated.
We're here to help...
We realize that it can sometimes be challenging to use our API to craft an efficient query to retrieve the data that you're looking for. Rest assured that we're here to help you! If you Contact Us and tell us what you are trying to accomplish, we can help you customize your queries to meet your needs.
For further information on orbital mechanics see: link
|AKM||Apogee Kick Motor|
|DoD||Department of Defense|
|GMT||Greenwich Mean Time|
|CFSCC||Combined Force Space Component Command|
|MM||Month or Minutes|
|PKM||Perigee Kick Motor|
|RCS||Radar Cross Section|
|SSA||Space Situational Awareness|
|TBA||"To Be Announced" in the future.|
|TBD||"To Be Determined" or unknown|
|TIP||Tracking and Impact Prediction|
|TLE||Two Line Element set|
|USG||United States Government|
|USSTRATCOM||United States Strategic Command|
|USSPACECOM||United States Space Command|
ISS (ZARYA) 1 25544U 98067A 04236.56031392 .00020137 00000-0 16538-3 0 9993 2 25544 51.6335 344.7760 0007976 126.2523 325.9359 15.70406856328906 ---------------------------------------------------------------------- 1234567890123456789012345678901234567890123456789012345678901234567890 reference number line 1 2 3 4 5 6 7
|1-24||ISS (ZARYA)||The common name for the object based on information from the Satellite Catalog.|
|3-7||25544||Satellite Catalog Number|
|19-32||04236.56031392||Element Set Epoch (UTC) *Note: spaces are acceptable in columns 21 & 22|
|34-43||.00020137||1st Derivative of the Mean Motion with respect to Time|
|45-52||00000-0||2nd Derivative of the Mean Motion with respect to Time (decimal point assumed)|
|54-61||16538-3||B* Drag Term|
|63||0||Element Set Type|
|3-7||25544||Satellite Catalog Number|
|9-16||51.6335||Orbit Inclination (degrees)|
|18-25||344.7760||Right Ascension of Ascending Node (degrees)|
|27-33||0007976||Eccentricity (decimal point assumed)|
|35-42||126.2523||Argument of Perigee (degrees)|
|44-51||325.9359||Mean Anomaly (degrees)|
|53-63||15.70406856||Mean Motion (revolutions/day)|
|64-68||32890||Revolution Number at Epoch|
The security classification of the element set. All objects on this site will have a classification of 'U' (unclassified).
This is another format for identifying an object.
"+", "-" or " " (space) are acceptable in the 34th character position on Line 1, and indicate positive or negative value for 1st Derivative of the Mean Motion. A space implies a positive value.
The checksum is the sum of all characters in the data line, modulo 10. In this formula, the following non-numeric characters are assigned the indicated values:
Alpha-5 is a stopgap object numbering schema from the United States Space Force that increases the satellite catalog’s capacity to display up to 339,999 objects in the GP/GP_History API classes using legacy fixed-width Two and Three Line Element Set (TLE/3LE) formats.
Replacing the 1st digit of the 5-digit object number with an alphanumeric character makes it possible to represent 240,000 more numbers. Objects less than 100,000 are unaffected by Alpha-5, as are users who download elsets from the GP and GP_History API classes in other formats like XML, JSON, KVN, and CSV. In order to preserve legacy operations that depend on 5-digit integers, our legacy API Classes tle, tle_latest, and tle_publish will not change to Alpha-5.
Only capital letters and numbers are used in Alpha-5. The letters “I” and “O” are omitted to avoid confusion with the numbers “1” and “0”.
Some example object numbers in Alpha-5 format, as they would be seen in the TLE:
|100000 => A0000||148493 => E8493|
|182931 => J2931||234018 => P4018|
|301928 => W1928||339999 => Z9999|
Even though TLE/3LE will support Alpha-5 format on output in lines 1 and 2, users need to specify NORAD_CAT_ID integer values to return specific objects. The API will not support filtering on Alpha-5 values or ranges like /NORAD_CAT_ID/T0000--V9999/.
If your propagation software cannot process alphabetical characters in the catalog number section of the TLE, you can eliminate the Alpha-5 range from your query by adding /NORAD_CAT_ID/<100000/ to filter them out as displayed in this example: https://www.space-track.org/basicspacedata/query/class/gp/NORAD_CAT_ID/%3C100000/decay_date/null-val/epoch/%3Enow-30/orderby/norad_cat_id/format/tle
The latest SGP4 propagator, Version 8.0, is compatible with the new Alpha-5 format shown in this graphic and is available at https://www.space-track.org/documentation#/sgp4:
|A => 10||J => 18||S => 26|
|B => 11||K => 19||T => 27|
|C => 12||L => 20||U => 28|
|D => 13||M => 21||V => 29|
|E => 14||N => 22||W => 30|
|F => 15||P => 23||X => 31|
|G => 16||Q => 24||Y => 32|
|H => 17||R => 25||Z => 33|
As the United States government agency responsible for Space Situational Awareness (SSA) information, United States Space Command (USSPACECOM), is committed to promoting a safe, stable, sustainable, and secure space environment through SSA information sharing. As more countries, companies, and non-governmental organizations field space capabilities and benefit from the use of space systems, it is in our collective interest to act responsibly and to enhance overall spaceflight safety. To achieve effective SSA, USSPACECOM seeks to increase cooperation and collaboration with partners and space-faring entities through the exchange of SSA data and provision of SSA services.
The Combined Force Space Component Command (CFSCC) provides SSA services through this website and the 18th Space Defense Squadron (18 SDS), located at the Combined Space Operations Center (CSpOC), Vandenberg Space Force Base, California. There are three levels of SSA services: basic, emergency, and advanced.
USSPACECOM provides space surveillance data to registered users through this public website, www.space-track.org. 18 SDS routinely updates the website with positional data on more than 16,000 satellites in orbit around the Earth. Users can build customized API queries to pull specific data from historical records, and automate the retrieval of new data.Available products:
Redistribution of basic SSA information retrieved from Space-Track.org requires an approved Orbital Data Request. Redistribution includes, but is not limited to, the use of Space-Track.org data to support public websites, web applications, software programs, written publications, and any other means of sharing Space-Track.org data with the general public.Available products:
Anomaly Resolution consists of actions taken by an owner/operator in response to a launch or on-orbit anomaly or non-nominal condition affecting a spacecraft bus, telemetry subsystem or communications payload, onboard sensor(s), or any other operating payload or subsystem.Available products:
On-Orbit Conjunction Assessment (CA) is the process for determining the point and time of closest approach of two tracked orbiting objects. 18 SDS screens all active satellites against the satellite catalog several times per day to identify close approaches. If a close approach meets emergency reportable criteria, 18 SDS will notify the satellite's owner/operator by email and through Space-Track.org's Operator Panel. This service is provided at no cost to promote spaceflight safety, and does not require an SSA Sharing Agreement or an ODR.Available products:
If a satellite owner/operator receives a close approach notification email from 18 SDS, the owner/operator may submit their proposed maneuver plan and ephemeris for screening against the space catalog. Results that meet emergency reportable criteria will be provided. Collision avoidance is the responsibility of the satellite owner/operator, but 18 SDS will support their collision avoidance efforts by screening their predictive ephemeris and providing results in the Conjunction Data Message (CDM) format.Available products:
Launch Conjunction Assessment (CA) identifies potential conjunctions that may result in a collision between launching objects and on-orbit objects. Using information provided by the customer prior to launch, via the Form 22 , 18 SDS screens the launch vehicle against the space catalog and provides conjunction information for each associated launch time. Screening begins at an altitude of 150km or greater and continues through the duration of the launch trajectory provided by customer. The Launch CA screening results identify periods during the launch window which may put the rocket and payload at increased risk for collision.Available products:
Early Orbit Determination (EODET) is the process by which the Space Surveillance Network (SSN) tracks a launch and/or separation of an object and sends observation data to 18 SDS for the calculation of initial orbit(s), entry into the space catalog, identification and naming of the object(s), and continual generation of element sets. 18 SDS uses information provided by the launch entity or satellite owner/operator to inform the tracking, cataloging, and identification process.Available products/services:
Early Orbit Conjunction Assessment (CA) includes the screening of owner/operator-provided ephemeris against the satellite catalog to facilitate the safe maneuvering of a newly launched object into its final orbit. Expanded screening volumes and propagation are used to identify possible close approaches. Operators may provide more than one ephemeris file for each maneuver to allow analysis of multiple scenarios.Available products:
Advanced On-Orbit CA uses expanded screening volumes and propagation to provide more results than Basic Emergency CA.Available products:
Advanced Collision Avoidance may be provided to assist owners/operators in relocating a satellite, or to avoid self-identified close approaches. Both situations allow an owner/operator to submit maneuver and non-maneuver ephemeris for expanded screening against the satellite catalog.Available products:
Disposal/End-of-Life Support consists of planning for proper upper stage disposal and spacecraft end-of-life operations. If provided maneuver planning and on-orbit Information, 18 SDS may support a satellite owner/operator’s plans for disposing of an object by providing conjunction assessment and collision avoidance using expanded screening volumes and propagation.Available products:
Deorbit and Reentry Support includes reentry assessment, reentry confirmation, and assistance in deorbit operations. Reentry assessments are predictions of the time and location where an uncontrolled object will reenter the atmosphere (not where the object will impact the ground). If a satellite owner/operator decides to perform the controlled deorbit of a satellite or rocket stage and provides relevant on-orbit information, 18 SDS will provide related conjunction assessment and collision avoidance support using expanded screening volumes and propagation, and confirmation of reentry after the owner/operator’s deorbit procedures are performed.Available products:
All customers (non-U.S. government, commercial, and USG) should request advanced services using the Orbital Data Request (ODR) form. To submit an ODR, follow the directions on page 1 of the form and send it to 18SPCS.email@example.com.
18 SDS’s SSA Sharing Team processes all requests, which undergo security, legal, and resource assessments before the final 18 SDS authority approves or disapproves the request. In the event of disapproval, the SSA Sharing Team will work with the customer to revise their request for reconsideration. If a request is approved by 18 SDS, but the customer is non-USG and does not have an SSA Sharing Agreement, the request will be forwarded to USSPACECOM for further review.
After approval, the SSA Sharing Team will provide an estimate of when the data will be delivered, or when the ongoing service will be initiated. In some situations this will take more time than others, but the customer will be notified accordingly. ODRs are valid for one year from the date of approval.
Customers may request information not included in standard services, but this will lengthen the review process and the time required to deliver the data or service, if the request is approved.
Whether you are putting your first satellite on orbit, or adding to an existing constellation, we encourage you to register your asset with 18 SDS so that we can plan for optimal tracking and identification, and provide you with conjunction assessment services as soon as possible. As soon as you register, a member of 18 SDS will contact you to discuss the details of your mission and coordinate conjunction assessment and other required support.
Due to the dynamic nature of space operations, 18 SDS relies on information from operators, launching agencies, and the overall space community to maintain space situational awareness. Even if you do not require direct support from 18 SDS, we welcome the following information:
Maintaining spaceflight safety and space situational awareness is a cooperative activity and responsibility. The information you provide advances these goals and ensures equal access to space for all global users. If you have questions about USSPACECOM services or suggestions on how we can improve any aspect of our SSA Sharing process, we encourage you to contact the 18 SDS SSA Sharing Team at 18SPCS.firstname.lastname@example.org.
USG entities and their contractors may be eligible to receive additional data and services not listed above depending on their mission requirements and security clearance. For more information, please email 18SPCS.email@example.com.
18 SDS SSA Sharing Team
Please direct all initial inquiries to 18 SDS SSA Sharing Team. The SSA Sharing Team will respond to your inquiry, or put you in contact with the appropriate 18 SDS personnel.
Phone: +1-805-606-2675 or DSN 276-2675
18 SDS Orbital Safety Team
Please contact 18 SDS Orbital Safety Team for routine conjunction assessment support. They are manned 24 hours a day, 7 days a week.
Phone: +1-805-605-3533 or DSN 275-3533
|Satellite Registration Form||Register your asset with 18 SDS for optimal identification, tracking, and conjunction assessment services.||docx|
|Orbital Data Request||Request all advanced services||docx pdf|
|Form 22||Provide detailed parameters on launch collision avoidance requirements||docx|
|R-15 Form||Provide detailed parameters on an upcoming launch and/or satellites to achieve orbit||docx|
|Early Orbit Maneuver Plan||List maneuver schedule and screening requirements for satellite(s) as they transfer from spacecraft separation to final orbit||xlsx|
Please read the following terms and conditions of the User Agreement carefully! This website permits access to U.S. Government space situational awareness information to approved users only. To obtain access, all users must abide by the following terms and conditions:
The User agrees not to transfer any data or technical information received from this website, or other U.S. Government source, including the analysis of data, to any other entity without prior express approval. See, 10 USC 2274(c)(2).
The User agrees to pay an amount that may be charged. The present U.S. Government policy is not to charge for website access. The website will provide notification should this policy change. See, 10 USC 2274(c)(1).
The User agrees to hold harmless the U.S. Government, any agencies and instrumentalities thereof, and any individuals, firms, corporations, and other persons acting for the United States. Such shall be immune from any suit in any court for any cause of action arising from the provision or receipt of space situational awareness services or information, whether or not provided in accordance with 10 USC 2274, or any related action or omission. See, 10 USC 2274 (g).
The User agrees he or she will only enter this site utilizing his or her own username and password. The User agrees not to share, assign or transfer his or her username or password to another. Each individual user or entity is required to obtain a separate account. See, 10 USC 2274(c)(3).
The User agrees to provide a valid and working email address at registration and for the duration of Account usage. This ensures effective communication with and delivery of services to the User. As part of the registration process, the User will be asked to provide and verify his/her email address.
The User agrees these terms and conditions shall be governed by and construed in accordance with U.S. Federal law.
Approved access must be renewed periodically. The U.S. Government may unilaterally terminate this agreement for any reason.
The agreed upon terms and conditions above do not alter in any way those of any other written agreement with the U.S. Government for space situational awareness services and information. The U.S. Government reserves the right to change or modify these terms and conditions at any time, and without prior notification.
TWO-LINE ELEMENT (TLE) SET IS THE MEAN KEPLERIAN ORBITAL ELEMENT AT A GIVEN POINT IN TIME FOR EACH SPACE OBJECT REPORTED. A TLE IS GENERATED USING THE SIMPLIFIED GENERAL PERTURBATIONS THEORY AND IS REASONABLY ACCURATE FOR LONG PERIODS OF TIME. A TLE AVAILABLE TO THE PUBLIC SHOULD NOT BE USED FOR CONJUNCTION ASSESSMENT PREDICTION. SATELLITE OPERATORS ARE DIRECTED TO CONTACT THE 18TH SPACE DEFENSE SQUADRON AT 18SPCS.firstname.lastname@example.org FOR ACCESS TO APPROPRIATE DATA AND ANALYSIS TO SUPPORT OPERATIONAL SATELLITES.
THIS SITE MAY BE INACCESSIBLE FOR SHORT PERIODS OF TIME FOR ROUTINE MAINTENANCE AND UPDATES. THE U.S. GOVERNMENT RESERVES THE RIGHT TO LIMIT BOTH ACCESS DURATION AND DATA AMOUNTS FOR ANY USER.
U.S. GOVERNMENT DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THIS WEBSITE OR THAT THE WEBSITE WILL BE UNINTERRUPTED, ERROR FREE, THAT DEFECTS WILL BE CORRECTED, OR THAT THE WEBSITE OR SERVER WILL BE FREE OF VIRUSES, OR OTHER TECHNICAL PROBLEMS.
Current as of 1 August 2019.
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For detailed questions regarding the satellite data, ephemeris, or decay information presented on this website, please email the data provider (18th Space Defense Squadron) at 18SPCS.email@example.com.
For permission to redistribute space-track data, information outside of what space-track provides, requests for launch support, and requests for Conjunction Assessment, please submit an Orbital Data Request.
For problems with Laser Clearinghouse procedures or documents, please contact the LCH team.
For problems with www.space-track.org website functionality, please email firstname.lastname@example.org.