T.S. Kelso
@TSKelso
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Operator of CelesTrak, the world's first source for orbital element sets and related software and educational materials.
Wailuku, HI, USA
Joined April 2009
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In case you missed it, 18 SDS just assigned NORAD Catalog Number 60011. As a reminder, we run out of 5-digit catalog numbers at 70000. CelesTrak will not be supporting Alpha-5, since all standards show these as integers. See to prepare now.
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We now have 230 pieces of cataloged debris from the 2020 May 8 Fregat fragmentation event. The debris has spread all over LEO due to differential precession. Yet one more reason not to leave upper stages in orbit after they have completed their mission: .
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45 days after the Indian ASAT test, 29 of 93 objects we have TLEs for have decayed, with another 5 likely reentered. With 59 still in orbit, that hardly supports India’s claim that everything would reenter in 45 days. And these are only the objects large enough to track.
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.
@SpaceX
has just posted an update (Feb 8) describing the current status of the satellites associated with the Group 4-7 launch of Feb 3 as a result of a recent geomagnetic storm:
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1/3 If you’ve been wondering why you can’t see the new
#Starlink
satellites in the Northern Hemisphere right now, here’s why. This shows the areas on the Earth where STARLINK-1194 is visible—more than 10 deg above the horizon, Sun below -6 deg, & satellite in sunlight--each day.
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We are excited to announce that
@CelesTrak
is now a 501(c)(3) non-profit! If you have been asking how you can help, here's your chance! Please go to to see how you can help us extend CelesTrak’s 36-year legacy!
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As I prepare to retire July 1 and devote my attention to CelesTrak, I thought I'd put together a brief history of the past 35+ years, starting with how the name and brand came to be. I hope you find it interesting!
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The Russian LUCH (OLYMP) satellite has inserted itself in a particularly busy stretch of the GEO belt at 1.1W. This type of uncoordinated behavior puts the entire GEO belt at risk, especially if a collision were to occur with a highly inclined object like SKYNET 4E.
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CelesTrak now has 8 more TLEs from the Indian ASAT test, bringing the total cataloged to 101 pieces (including the original). Of these, only 52 have decayed so far, 98 days after the test was conducted.
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I could not be more honored and humbled than to have been selected by SpaceNews for this year’s Space Stewardship award. What a privilege! And thanks to all of you who have helped me along the way and challenge me to find ways to do even more.
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CelesTrak has started a data set for today's Russian ASAT test against COSMOS 1408. I thought we had learned not to intentionally create debris on orbit, but this absolutely irresponsible action by Russia shows otherwise. This has to stop. NOW.
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Lest anyone think IS-29E is our only threat in GEO today, here is a view of everything tracked in that region of the GEO Protected Zone. Green are operational satellites, orange are dead ones, red are rocket bodies, yellow are other debris:
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CelesTrak now has TLEs for 48 objects from the SpaceX Starlink launch. Here’s what that looks like right now (0046 UTC on May 27): . OBJECT P is the leader at this point.
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Just a short clip of how the 2 space stations' (big green dots) orbits interact with the orbits of COSMOS 1408 (orange) and the 185 pieces of known debris (red) generated by the Russian ASAT test on Nov 15, over one rev.
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We now have SupTLEs for all but 2 of the latest Starlink satellites: . Wonderful to have this data so quickly! Screenshots show where the cluster is and how tightly packed the objects currently are.
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Food for thought: These Starlink satellites have 14 of the oldest 19 TLEs for active satellites. If 18 SPCS doesn’t know where they are for the past 5-14 days, satellite operators in this orbital regime probably don’t, either, which presents a serious threat to safety of flight.
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For those of you wondering why I was off the grid the past couple of weeks, I wanted to share this time-lapse of the eclipse...
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SOCRATES shows 95 conjunctions within 5 km with MICROSAT-R debris:
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It appears CZ-5B R/B came down on the last rev. We are awaiting confirmation of time and location.
Spoke with the team. We have indications the 🚀 is down. Once they get radar confirmation of nothing in orbit (after 0300UTC) they will release the final message with time. Y’all can stop hiding in your bunkers.
@SpaceTrackOrg
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1/2 It has been the honor of a lifetime to have the opportunity to play such a key role in the development of what we now call STM, particularly working with so many great people who are also passionate about safety of flight and protecting the space environment.
On behalf of your ohana at AGI, congratulations on your retirement,
@TSKelso
! Thank you for your outstanding service to the 🛰️aerospace community. We are happy to follow your continued expert analysis and tracking through
#CelesTrak
.
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Okay, we now have a permanent link for the data on the Current Data page () shown as Indian ASAT Test Debris. There is also an interactive table showing apogee/perigee. There are currently 46 pieces of debris with apogee above the ISS.
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1/3 It appears the US has decided to remove TLE data for objects like USA 253/254/270/271/283, which operate in GEO, from the public catalog.
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CelesTrak is now back online. Most everything is rebuilt after a major hardware failure and significant file corruption. Special Data Requests are still offline pending data restoration. LMK if you see any problems and thanks for your patience! Off to bed!
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1/ I am very excited to finally release a new feature on CelesTrak that I think you are all going to love! Together with our partners at Digital Arsenal, we have been working hard for months to provide interactive orbit visualization that is literally one click away.
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If you're a software developer still using 5-digit catalog numbers, you might note that we're already at 50983. With 105+ objects launched today, we have already used 5.4% of what's left since hitting 50000 on Dec 13--just one month ago. At this rate, you're running out of time.
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After what marks the last expected launch of 2019, it looks like we’ve had another busy year, with 97 total launches of 434 satellites. The view of the past 30 days’ launches—with 17 of those launches—seems to have been especially busy:
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No IDs yet for any of 60 Starlink satellites, launched May 24. And 9 have TLEs more than 5 days old. We also have no IDs for 7 objects from the Chinese sea launch from June 5, or even the 3 Radarsat Constellation Mission satellites, launched June 12. We need some data sharing!
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1/With 112 launches, 2018 saw the most launches since 1990. While 1984 still holds the record with 129 launches, that was for 170 payloads, compared to 413 for 2018--an all-time record. That does not include another 25 payloads deployed from the ISS.
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We could probably ID all Starlink satellites quickly (at least those with current TLEs) if
@SpaceX
followed the lead of
@planetlabs
in providing supplemental TLEs (operator-generated) or ephemerides to the public. If anyone knows of an online source, please LMK!
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CelesTrak is moving to a new server Friday, 2020 May 8, at ~1600 UTC. The move should provide much better bandwidth and improved overall performance.
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That was ABSOLUTELY AMAZING! Just watched the Starlink train as it passed over Maui. With thin clouds and just past civil twilight, they were barely visible to the naked eye but easily seen in binoculars. Tenth object very bright. Right where they were expected to be.
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3/3 These actions are a step backwards for transparency in the interest of safety of flight.
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We need better ways to identify and track things launched into orbit. There are currently 171 unidentified objects in Earth orbit from the past 5 years--5 of those deployed from the ISS. And there are 21 payloads & 15 rocket bodies on the Lost List. We can do better.
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.
@SpaceX
's plan to deorbit 100 older Starlink satellites is well underway with 42 of those reentering in the past 60 days: .
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1/5 CelesTrak has completed the transition of the Current Data page from only supporting legacy TLE formats to supporting all GP formats. The default is still TLE format, but when you are ready to use one of the new formats, we've got your back: .
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CelesTrak now has TLEs for 3 objects from the SpaceX Starlink launch (2019-029). I’ve added those to the previous links () so you can see how they compare to TLE from
@cgbassa
(TRAIN A) &
@Marco_Langbroek
(TRAIN B) at current time (2025 UTC). Progress!
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Wondering how we are going to handle data requiring catalog numbers beyond the current 5-digit format in TLEs? Be sure to check out the article "A New Way to Obtain GP Data (aka TLEs)": .
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China reports reentry of the Long March-5B rocket body that launched TIANHE at 0224 UTC over the Maldives.
@18SPCS
reports reentry at 0214 UTC at the same location. Here is what the latest TLE from 18 SPCS showed at 0224 UTC (over the Maldives) on the CelesTrak visualization.
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It appears LUCH (OLYMP) is once again making things difficult for Intelsat, by performing uninvited ‘prox ops’ with IS-20 & IS-36. We need to work together to ensure these types of situations don’t result in unanticipated behavior that adversely impacts safety of flight.
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Updated TLEs for Starlink (). STARLINK A is from
@cgbassa
and STARLINK B is new from
@Marco_Langbroek
. Orbit visualization () shows good agreement, as expected. Will continue to update as more data becomes available.
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Finally completed long overdue overhaul of CelesTrak's EOP & space weather data, as discussed in 2013 paper. Space weather now relies on primary sources (to eliminate irregularities) and both data types now have CSV versions: .
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My experiment taking a time-lapse of the total lunar eclipse from Maui using the iPhone 12 Pro Max. The lens flare (blue) gives a good sense of overall progress. Mid-totality occurs as the Moon moves out of frame and the clouds roll in.
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CelesTrak has TLEs for 8 more pieces of debris from the Indian ASAT test, bringing the total to 93 objects—22 of which have decayed to date. That still leaves 71 pieces in orbit—37 days after the test.
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2018 Year in Review. 2018 has been an interesting year for Space Situational Awareness (SSA). Here are some of the highs and lows for the year.
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I’m off to the Cubesat Workshop at Cal Poly this week with the hope of finding others who can help us improve our ability to track and ID newly launched objects. Seems we have lots of examples of how we could do this better.
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We need to find a way to work together to better ID objects in orbit. As of today, we show 118 (125 on
@SpaceTrackOrg
) unidentified objects—44 from 2019 alone. Jeopardizes safety of flight when you don’t know what you’re conducting with, who it belongs to, or if it can maneuver.
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1/Catalog Number 49999 was just added to the SATCAT. We have 20,000 to go before we run out of 5-digit ones (at 70000). It took 7.4 years to go from 30000 (2007-02-02) to 40000 (2014-06-14), as a result of the Chinese ASAT test and Iridium-Cosmos collision.
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CelesTrak has GP data for 2 objects from the launch (2023-179) of Wangli-1 atop a Chollima-1 rocket from Sohae Satellite Launching Station on Nov 22 at 1342 UTC: . Data for the launch can be found at: .
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After many requests, I created a TLE list of all active satellites. Automatically updates with other TLEs, with link on Current Data page (). Now you can get all active satellites with a single download.
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1/ CelesTrak is continuing to deprecate the use of the legacy static TLE text files, in no small part to limit abuse by a growing number of users who download files—which are only updated every 2 hours—hundreds or even thousands of times a day.
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Watched nervously this morning as IS-29E & TDRS 3 had what we consider a ‘nightmare scenario’ in GEO—a high-speed encounter (~1 km/s). Let’s wish Intelsat luck on getting IS-29E back under control.
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CelesTrak has pre-launch SupGP data for 36 objects in the initial deployments of the
#Transporter
-7 mission, set to launch from Vandenberg SFB on 2023-04-11 at 06:48:25.990 UTC. Deployments will occur from 07:49:31.010 UTC to 09:23:43.870 UTC.
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I’ll just say it: I’m very concerned about what I’m hearing for the deployment process for 70+ satellites on the upcoming SSO-A launch on Nov 19. Recommend all passengers read this paper to get prepared for what’s ahead:
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Confirmation of launch of Razbeg reconnaissance satellite on a Soyuz-2.1v rocket from Plesetsk Cosmodrome on Sep 9 at 1959 UTC: .
CelesTrak has TLEs for 2 objects from what appears to be a launch (2021-081) from Plesetsk Cosmodrome on Sep 9 at 2005 UTC. Cannot find any open-source confirmation at this time.
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2/2 I am deeply grateful to
@AGItweets
and
@COMSPOC
for all of their support while I was on this part of my journey. I am looking forward to being able to devote my full attention to enhancing the services provided on CelesTrak--stay tuned!
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1/5 Using a pre-launch state vector provided by SpaceX, we used STK's HPOP to propagate the orbit and fit Supplemental TLEs (SupTLEs) for the first 8 hours following deployment. Data can be found at .
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It appears that COSMOS 2473, launched 2011-09-20, may have failed around the end of June and is now drifting uncontrolled in GEO.
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A month ago we announced CelesTrak as a non-profit--thanks to all of you who already stepped up and supported us! But to implement our vision, we are going to need a lot more help. Just a little from each of you would mean a world of difference. Please consider donating today!
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And it looks like USA 107 (DSP 17) may have just failed in GEO, too. Noticed when drift rate went above 0.1 deg/day. Monitoring.
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Starlink-7 launch is set for 2020-04-22 19:30 UTC with deployment at 19:45:25.430 UTC.
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CelesTrak is proud to partner with
@AdrianWenz
to provide the ability to visually track the
#Artemis
I mission. You can find links to the latest NASA information on the mission, plus how to access BINARY SPACE's SpaceMissions Web-Edition to track it, at .
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A fascinating--if not disturbing--view of how debris events are affecting the Earth orbital environment. You can see how things decay over time, as apogee drops, as well as how bad initial data can be right after an event: . Great work!
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The
#Starlink
Group 6-1 launch has been move to Monday, Feb 27, with the launch window opening at 18:38:40 UTC. I will be updating CelesTrak next.
Targeting Monday, February 27 for launch of 21 second-generation Starlink satellites to low-Earth orbit from Florida →
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My best guess at this point would be MICROSAT-R, in a 260 x 282 km, 89.9 deg orbit. Would have been ascending over NOTAM area at ~0530 UTC, within the 0430-0830 UTC window. It should have been operational, facilitating tracking.
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1/ CelesTrak has pre-launch SupTLEs for the
@SpaceX
#Transporter
-3 launch scheduled for 2022-01-13 at 15:25:38.990Z UTC. SupTLEs are available for 82 objects from the initial deployments, which starts at 16:25:12.130 UTC: .
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3/ Satellite operators that have independent ephemeris based on their own tracking can help
@18SPCS
and CelesTrak make IDs by sharing that data, just like
@Planet
does. This can greatly expedite the ID process to the benefit of all
#Transporter
-3 passengers.
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@deepbluecea
@jeff_foust
@18SPCS
Good catch! Shows the current location but I forgot to add the label!
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For many years, TLE data on CelesTrak was entered by hand from Part I of the NASA Prediction Bulletins (received by mail). If you are curious about how they were used to allow manual calculations back before computers were widely available, check out: .
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