Another failed deorbit of a Falcon 9 upper stage

Falcon 9 upper stage. Image: SpaceX

On 2 February 2026, SpaceX launched Starlink 17-32, with 25 new Starlink satellites, from Vandenberg SFB in California. The satellites successfully reached Low Earth Orbit, but something went wrong with the upper stage, and not for the first time. SpaceX stated on their website:

During today’s launch, the second stage experienced an off-nominal condition during preparation for the deorbit burn. The vehicle then performed as designed to successfully passivate the stage. The first two MVac burns were nominal and safely deployed all 25 Starlink satellites to their intended orbit. Teams are reviewing data to determine root cause and corrective actions before returning to flight.

This is not the first time a controlled Falcon 9 upper stage deorbit failed: this in fact was the fourth time in barely 1.5 years time. 

In July 2024, during the launch of Starlink 9-3, the upper stage failed to re-light, the engine destructing instead, leaving the payloads in a too low orbit. The upper stage later made an uncontrolled deorbit.

In September 2024, the upper staged used for the Crew Dragon 9 launch failed to do a proper deorbit burn, with the stage missing the designated deorbit area. 

In February 2025, after the launch of Starlink 11-4, the upper stage failed to do a deorbit burn. The resulting uncontrolled reentry 18 days later caused a spectacle in the NW European sky, with parts surviving and impacting in Poland (see this earlier blogpost).

And now something similar happened again with the latest, 2 Feb 2026 launch. The upper stage (2026-022AB, catnr. 67675) failed its controlled deorbit. Initially left in a 110 x 241 km orbit, it had an uncontrolled reentry twelve hours after the launch. 

Where it deorbitted is not exactly known. The US Space Force/CSpOC published a TIP for 3 February 2:29 ± 1h UTC. Our Tudat model suggests reentry one orbital revolution later, at 3:47 ± 1.5 h UTC. The maps below give the trajectory over the uncertainty window of respectively the CSpOC TIP, and our Tudat model. The uncertainties overlap each other.

trajectory over CsPOC TIP uncertainty window. Click to enlarge

 

trajectory over the Tudat uncertainty window. Click to enlarge

 

The controlled deorbit aimed for should have happened around 17:35 UTC, just after completion of the first orbital revolution (see map below of what the original plan was). Instead, the upper stage continued to orbit for some 7 more revolutions (or 10 extra hours).

original deorbit plan. Click to enlarge

USA 498, the NROL-69 payload, found

click map to enlarge

On 24 March 2025 at 17:48 UTC, a Falcon 9 blasted off from Cape Canaveral launch pad 40 in Florida as NROL-69, carrying the classified USA 498 payload to orbit for the National Reconnaissance Office (NRO).

About two hours later, the launch caused a spectacle in the skies over Europe, as a bright spiral-shaped cloud formed in the sky, moving along the track of the Falcon 9 upper stage from the launch. This was due to the Falcon 9 upper stage venting excess fuel, in preparation for reentry over the Indian Ocean about half an hour later, following a deorbit burn over the northern Atlantic. 

The cloud of fuel droplets vented by the rocket stage was at an altitude of about 1000 km, where it was still in sunlight, causing it to shine brightly in the sky. The spiral pattern is due to the rocket stage spinning around is major axis, in order to stabilize the orientation of the stage in space. This is very typical for Falcon 9 upper stages and has been seen quite a few times now.

 

 

Prior to launch, Navigational Warnings seemed to indicate an initial launch into a 51-52 degree inclined orbit for NROL-69, followed by a burn into an approximately 64.4 degree inclined orbit. 

Initially I interpreted the trajectory as featuring a 'dogleg' manoeuver into 64.4 degree inclination just after launch. I later revised that, following reports from observers in Poland that they saw the Falcon 9 during its first pass over Europe, 25 minutes after launch, in a trajectory more consistent with still being in a 51-52 degree inclination orbit. In addition, reports came from western Australia about a possible remnant exhaust cloud that might have been seen there about an hour after launch. 

I therefore revised my interpretation of the launch sequence. My revised interpretation features an initial insertion into a 51-52 degree coasting orbit, followed by an insertion burn into 64 degrees inclination near the ascending node, about an hour after launch, over the Indian Ocean near western Australia. Following that, and following orbit insertion of the payload, the deorbit burn for the Falcon 9 upper stage happened over the northern Atlantic just after completion of the first revolution, and next the fuel venting seen from Europe around 20 UTC (21 CET), some two hours after the launch, during the first part of the second revolution. Deorbit of the Falcon 9 was around 20:40 UTC, 1.5 revolutions after the launch, over the Indian Ocean southeast of Madagascar (see map in top of this post).

Below are the Navigational Warnings for the launch. The hazard areas from these warninsg are plotted in red in the map in top of this post.

191844Z MAR 25
NAVAREA IV 332/25(11,26).
WESTERN NORTH ATLANTIC.
FLORIDA.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
   241742Z TO 241824Z MAR, ALTERNATE
   251728Z TO 251810Z, 261714Z TO 261756Z,
   271700Z TO 271742Z, 281646Z TO 281728Z,
   291632Z TO 291714Z AND 301618Z TO 301700Z MAR
   IN AREAS BOUND BY:
   A. 28-38.31N 080-37.17W, 28-51.00N 080-14.00W,
      28-44.00N 080-03.00W, 28-30.00N 080-18.00W,
      28-27.40N 080-31.49W.
   B. 30-14.00N 078-53.00W, 31-58.00N 077-03.00W,
      32-18.00N 076-17.00W, 32-02.00N 075-57.00W,
      31-15.00N 076-21.00W, 29-55.00N 078-35.00W.
2. CANCEL THIS MSG 301800Z MAR 25.

190258Z MAR 25
HYDROPAC 711/25(61).
INDIAN OCEAN.
DNC 02, DNC 03.
1. HAZARDOUS OPERATIONS, SPACE DEBRIS
   1849Z TO 2058Z DAILY 24 THRU 30 MAR
   IN AREA BOUND BY
   23-06.00S 060-45.00E, 24-22.00S 058-21.00E,
   54-18.00S 084-05.00E, 53-02.00S 087-47.00E.
2. CANCEL THIS MSG 302158Z MAR 25.//

As 64.4 degrees is the typical inclination for a NOSS (Naval Ocean Surveillance System) duo of SIGINT satellites, and given the location and timing of the deorbit area for the upper stage, my initial suspicion was that this could be a new NOSS launch into a 900 x 1300 km 64.4 degree inclined orbit. I was wrong in this however.

Two days after the launch, in the evening of March 26, a number of European observers (Tomi Simola in Finland, Eelke Visser and me in the Netherlands, and David Brearley in the UK) managed to find the payload on-orbit, close to my search orbit. Only one object could be detected, indicating that it is not a NOSS but something else. Below is a stack of several video frames showing the object (video itself is at the end of this post):

click to enlarge

The payload, now named USA 498, was detected in a 64.1 degree inclined, ~700 x 1500 km orbit (but this is based on a very short arc so the exact orbital altitude is still up for revision). We have not seen something in this kind of orbit earlier, apart from NOSS satellites (the closest in orbital similarity otherwise is USA 327 (2022-040A), in a 1076 x 1135 km 63.4 degree inclined orbit).

The plot below shows its orbit and orbital position for the time of my March 26 observation: 

Click image to enlarge

Below is some of my video footage from March 26, showing the payload as an object of about magnitude +5 to +6 (the instrument was a WATEC 902H2 Supreme with 1.2/50 mm lens):

 

Preliminary orbit (McCants):

USA 498 (NROL-69)
1 63350U 25060A   25085.82507109 0.00000000  00000-0  00000-0 0    05
2 63350  64.0600 349.1636 0555412  27.6298 328.1938 13.37020084    05

The reentry of a Falcon 9 upper stage over NW Europe on 19 February [UPDATED]

In the early morning of February 19, 2025, near 3:45 UTC (4:45 CET) scores of people in the Netherlands, UK, Germany and Denmark saw a slow, fragmenting object move through the sky. The event garnered much attention. 

Above is a video of the event obtained by the camera of @dutchspace.bsky.social in the Netherlands.  Another stunning video, by the meteor camera of André Knoeffel in Brandenburg, Germany, is here. The video below is by Nick James from the UK, and shows the start of the reentry near 03:43 UTC and start of fragmentation.

The event was caused by the reentry of a SpaceX Falcon 9 upper stage, object 2025-022Y (cat nr 62878) . This upper stage, from the Starlink group 11-4 launch from Vandenberg, California, on 1 February 2025 23:02 UTC, 18 days prior to the reentry event, failed to deorbit in a controlled way after launch and payload insertion. It was supposed to do a deorbit burn after releasing the payloads, and deorbit over a specified area in the Pacific Ocean around 00:45 UTC on Feb 2, near the end of the first revolution (see map below). With the deorbit failed, it however stayed on orbit for almost 3 weeks, and then had an uncontrolled deorbit over NW Europe on February 19.

 

click map to enlarge

The general character of the Feb 19 event (slow, fragmenting) as well as time and location fit well with the Falcon 9 upper stage reentry. The CSpOC final TIP for this reentry (which we suspect is based on a satellite observation of the reentry fireball) is 19 February 3:43 UTC ± 1 min, near 52.8 N, 5.6 W. The reentry trajectory runs over the British Isles, the northern Netherlands, northern Germany and Poland.

Below is the ground-track for the last orbit up to reentry, and a detail of the approximate final reentry track over Europe, with the Netherlands indicated in red:

click map to enlarge

 

click map to enlarge

A possible piece of debris has been found at Komorniki near Poznan in Poland, media reports. The object on the photograph looks like a Composite Overwrap Pressure Vessel, a component of the Falcon 9 upper stage that has survived reentry before, e.g. in March 2021 when a Falcon 9 upper stage reentered over Washington. The location of the find matches well with the reentry trajectory, as can be seen in the map above. [update: reportedly another one of these composite-wrapped pressure tanks was subsequently found in Poland]

The event caused a lot of media attention: I did several media interviews on the reentry, amongst others with two Dutch national tv channels.

 

A covert launch on June 19? [UPDATED]

 

click map to enlarge

On 19 June 2022 at 4:27 UT, SpaceX launched a Falcon 9 from Cape Canaveral pad 40 ostensibly carrying a Globalstar block II communications satellite, Globalstar-2 FM15. 

However, something was odd about this launch, and rumour has it that it covertly launched a second unacknowledged payload for the US Government. [UPDATE: now confirmed. And it are actually 4 payloads!]

This payload, if it exists, was seemingly released into a lower orbit than the Globalstar payload eventually was, possibly (as suggested by Cosmic Penguin on Twitter) at ~535 km (the Globalstar satellite was subsequently released at a much higher  ~1125 km altitude). It likely is in the same 52-degree inclined orbital plane as the Globalstar satellite. 

At ~535 km and with ~52 degree orbital inclination, this means the covert payload is hiding near the forest of Starlink satellites, which orbit at around ~550 km in 53-degree inclined orbits, only slightly higher in orbital altitude and 1 degree higher in orbital inclination.

The oddities with the launch that gave rise to the rumour are listed in this Spaceflight.com article. Given the mass of a Globalstar satellite and capacity of a Falcon 9, there was no need to have the first stage land on a droneship downrange in the Atlantic Ocean, rather than have it return to land at Cape Canaveral. This suggests it might have carried a heavier payload (e.g., because a second covert payload was on board), which lead to the rumours.

And then, just before the Globalstar deployment, live in-flight footage was shown (screenshot below) that showed something odd: the Globalstar satellite (still attached to the payload adapter on top of the rocket stage) and what looks like a second, empty payload adapter.

 

click image to enlarge

So this gives credence to the suspicion of a covert deployment of a second satellite in a lower orbit, before deployment of the Globalstar payload into a higher orbit.

The live webcast made no mention of such a second payload: after initial orbit insertion of the Falcon 9 some 10.5 minutes after launch, merely a long 'coasting phase' was suggested (with no live footage during this coasting period), before an orbit raising burn 1 hour 5 minutes after launch (~5:33 UT) , followed by a circulation burn 1 hour 47 minutes after launch (~6:14 UT) and deployment of the Globalstar satellite at 1h 53 minutes after launch (6:20 UT).

At the moment the live feed cut out after reaching orbit, the Falcon 9 seemed to be in a coasting orbit at ~535 km altitude. If there was a covert second payload, it was likely released at this altitude, either just after orbit insertion of the Falcon 9 upper stage slightly over 10 minutes after launch, or just before the orbit raising burn at about an hour after launch. The latter burn, at about ~5:33 UT, was to raise the Falcon 9 plus payload to the orbital altitude of the Globalstar satellite. It was followed some 40 minutes later by a brief orbit circularization burn, at ~6.14 UT.

 

click map to enlarge

 

The orbit circularization burn at ~6:14 UT and deorbit burn after 6:20 UT happened over the central and eastern United States and caused a spectacle in the sky, with a 'smoke ring' (probably from the circularization burn) followed by a bright fuzzy cloud (probably the start of the deorbit burn).

This footage of the sky events related to the circularization burn and deorbit burn was made by Dan Bush in Albany, Missouri:

More images can be seen on the Spaceweather.com site here. Some very nice images which can be seen here were taken by Lick Observatory telescope operator Keith Wandry.

Spectacular views were also seen an hour later over New Zealand, where the Falcon 9 upper stage tank depressurization (fuel vent) in anticipation of the deorbit over the Pacific Ocean near Hawaii caused the by now familiar, spectacular bright 'spiral' cloud in the sky typical for Falcon 9 upper stage fuel vents (e.g. see an earlier similar event here, connected to the ill-fated Zuma launch in 2018). Imagery of the spiral cloud can be seen here.

In terms of the potential orbit of the covert payload, if it exists: a lot is uncertain, but I offer this very rough search orbit: [EDIT: updated orbits based on observations here]

UNKNOWN    launched with Globalstar FM15
1 70001U 22999A   22170.18541667  .00000000  00000-0  00000-0 0    02
2 70001 052.0000 230.1696 0001447 047.8547 325.7015 15.10393460    00

 

UPDATE 1 (20 June 20:45 UT):

The CSpOC catalogue list 4 (four) additional objects for this launch (all with orbital elements witheld):
USA 328, USA 329, USA 330 and USA 331 (catalogue nrs 52889 to 52892).

UPDATE 2 (23 June 10:00 UT):

We are tracking the objects from the launch, see this follow up post. One of the four payloads seems to be tumbling.

NROL-85: probably NOSS 3-9, a new pair of INTRUDER Naval SIGINT satellites

 

image: Wikipedia

 EDIT (15 & 16 Apr):  the launch of NROL-85 has been postponed by at least two days, 'due to technical difficulties'

EDIT (17 Apr): new launch date is 17 April 2022 13:13 UT

On 15 April 2022, at 13:41 UT (or later) according to a tweet by the NRO, SpaceX will launch NROL-85 for the National Reconnaissance Office (NRO). The launch will be from SLC-4E at Vandenberg SFB. [edit 16 Apr: launch was postponed to 17 April 13:13 UT]

NROL-85 is almost certainly a pair of NOSS satellites. NOSS stands for Naval Ocean Surveillance System; they are also known under the code name INTRUDER. If correct, the duo would become NOSS 3-9 (the 9th mission of block III). It will probably enter with the designation USA 327 in the CSpOC catalogue (with orbital elements witheld).

NOSS satellites are SIGINT satellites operated by the US Navy. They geolocate shipping on the high seas, by detecting their radio/radar emissions. They always operate in close pairs. The secondary object is usually listed (with orbital elements witheld) as "debris" in the CSpOC catalogue, but this is a ruse that fools nobody: it is a payload too that manoeuvres and keeps a careful constant close distance to the primary satellite.

Information from the launch contract tender for this launch reveals that the mission aims for a semi-major axis of  7500.5 km, an orbital eccentricity of 0.0131, an orbital inclination of 63.535 degrees and an argument of perigee of 190 degrees (i.e. perigee almost on the equator). The listed semi-major axis and eccentricity translate to a 1024 x 1221 km orbit. 

The combination of the 63.5 degree orbital inclination and 1024 x 1221 km orbit strongly points to a NOSS/INTRUDER mission. These typically have an orbital inclination of 63.4 degrees and a semi-major axis of 7485 km, values close to those quoted for NROL-85. If launch is indeed at 13:13 UT on April 17, the resulting orbital plane will be very similar to that of the existing NOSS 3-6 duo (2012-048A and 2012-048P) which was launched in 2012, as can be seen in the figure below. That also lines up with a new NOSS-launch: NOSS-pairs are typically replaced after 10 years on-orbit.

The shift in launch time with date due to the two launch postponements agree with the estimated orbital altitude and orbital plane and matches the nodal precession of a typical NOSS orbital plane.

click image to enlarge

 

The Navigational Warnings for this launch (NAVAREA IV 336/22 NAVAREA XII 228/22 and HYDROPAC 987/22) define a launch direction towards the south-southeast, and agree with the 63.5 degree orbital inclination of the launch contract tender. 

[EDIT: The first NavWarning has been corrected: I initially copied the wrong NavWarning for this post.....]

100706Z APR 22
NAVAREA XII 228/22(18,21).
EASTERN NORTH PACIFIC.
CALIFORNIA.
1. HAZARDOUS OPERATIONS 1150Z TO 1514Z DAILY
   15 AND 16 APR IN AREAS BOUND BY:
   A. 34-41N 120-38W, 34-39N 120-40W,
      34-28N 120-38W, 34-04N 120-17W,
      34-04N 120-05W, 34-19N 120-14W,
      34-39N 120-19W.
   B. 32-03N 118-53W, 32-01N 118-49W,
      30-51N 117-56W, 30-21N 117-39W,
      30-08N 117-47W, 30-11N 118-01W,
      30-32N 118-18W, 31-54N 118-53W.
2. CANCEL THIS MSG 161614Z APR 22.

100644Z APR 22
HYDROPAC 987/22(22,83).
EASTERN SOUTH PACIFIC.
DNC 06.
1. HAZARDOUS OPERATIONS, SPACE DEBRIS
   1425Z TO 1649Z DAILY 15 AND 16 APR
   IN AREA BOUND BY
   20-12S 123-30W, 19-00S 119-00W,
   33-48S 109-30W, 36-00S 114-12W.
2. CANCEL THIS MSG 161749Z APR 22.

 

I have mapped the hazard areas from the Navigational Warnings and the resulting launch trajectory in the map below (the times listed along the trajectory are in UT and for the updated launch date with launch at 13:13 UT (17 April):
 

click map to enlarge

Based on the parameters from the launch contract tender, this is my orbital estimate, valid for launch at 13:41 UT on April 15 updated for launch at 17 April 13:13 UT:

NROL-85                         for launch on 17 Apr 2022 13:13:00 UT
1 70002U 22999A   22107.55069445 0.00000000  00000-0  00000+0 0    02
2 70002  63.5350 124.8521 0131000 190.0000 291.3542 13.36458926    04

 

There is an uncertainty of several minutes in pass time in this elset, progressively so after more than one revolution, and some cross-track error is possible. But the elset should be good enough for a plane scan, taking a wide time window around a predicted pass. Be carefull not to misidentify the NOSS 3-6 duo as NROL-85. An elset for NOSS 3-6 can be found here.

If the eventual launch time turns out to be later than 13:13 UT, the elset above can easily be adjusted to match the new launch time using my "TLE from Proxy" software downloadable here.

The Northern hemisphere will see good, fully illuminated evening passes on the day of launch and the days after it, so prospects are good for a quick on-orbit detection after launch.

The Falcon 9 upper stage deorbit is over the southern Pacific, just after the end of the first revolution. The deorbit-burn might be visible from south and/or central Asia.

The launch patch (see top of this post) features a cat, with a tiger as its reflection. The NRO itself explains some of the symbolism in the patch in this way:

"In the NROL-85 patch, the 3 stars represent guidance, protection, and allegiance. The cat represents loyalty and devotion shared among our nation and partners. The tiger in the cat’s reflection demonstrates that while space can be challenging, a determined attitude helps NRO succeed in going"

Given that this is going to be NOSS 3-9, the 9th instance of the Block III NOSS generation, I wonder if the cat was inspired by the proverbial 'nine lives' of cats.

It is possible that a number of other small satellites will be included in this launch as a rideshare.

The NRO press kit for NROL-85 is downloadable here.

FOLLOW-UP POST HERE reporting the first observations of NROL-85 from the evening of April 17. NROL-85 might not be an INTRUDER/NOSS after all!

A SECOND FOLLOW-UP POST HERE, going a bit deeper into various speculations about what the NROL-85 payload might be.

[a small update to this post was made 13 April 2022 09:00 UT, adding a bit more background information]

[an error where I had initially copied the wrong text of a NavWarning into this post was corrected at 13 Apr 20:30 UT - many thanks to the anonymous sharp-eyed reader who noted it!] 

[updated April 15 & 16 to reflect launch postponements] 

[updated 17 Apr 8:45 UT with updated launch trajectory map and orbital plane diagram]

[UPDATED] Reentry predictions for the Falcon 9 RB 2021-017BN

click diagram to enlarge

In my previous post, I discussed 2021-017BN, the Falcon 9 upper stage from the March 4 Starlink launch that should have been deorbitted after 1.5 revolutions on March 4th, but didn't.

It is still on orbit. At the moment of writing, 23 March 2021 at 11:00 UT, it is in a 217 x 200 km orbit according to the latest available elements from CSpOC, and it will stay on orbit for a couple of days to come. But the end is near: the orbital altitude of the rocket stage is quickly decaying, as can be seen in the diagram below:

click diagram to enlarge

My current reentry prediction (see diagram in top of post and table below) is that it will come down in the early hours of March 26 (2021). My prediction, based on modelling in GMAT R2020a using the MSISE90 model atmosphere, appears to be well in line with the TIP from CSpOC so far.

[UPDATE: my final post-cast predicted reentry at 26 Mar 04:34 UT, which is some 35 minutes too late. It is based on a 2/3rd maximum drag surface value. Interstingly, using the maximum drag surface leads to a reenrty at 3:56 Ut, within minutes f the actual time]

Revisit this post for prediction updates in the coming days.

orbit epoch     pred. date     reentry time (UT)
21081.600725    26 Mar 2021    02:33 +- 16.8 hr
21081.922054    26 mar 2021    03:36 +- 15.5 hr
21082.113317    26 Mar 2021    03:59 +- 14.7 hr
21082.216601    26 Mar 2021    03:40 +- 14.1 hr
21082.278149    26 Mar 2021    03:43 +- 13.8 hr
21082.462749    26 Mar 2021    05:29 +- 13.3 hr
21082.585776    26 Mar 2021    05:29 +- 12.7 hr
21082.708770    26 Mar 2021    05:37 +- 12.1 hr
21082.954651    26 Mar 2021    06:13 +- 11.1 hr
21083.138960    26 Mar 2021    05:03 +-  9.9 hr
21083.261785    26 Mar 2021    05:15 +-  9.4 hr
21083.296296    26 Mar 2021    05:20 +-  9.2 hr
21083.507296    26 Mar 2021    05:28 +-  8.3 hr
21083.875164    26 Mar 2021    05:26 +-  6.5 hr
21084.120127    26 Mar 2021    05:59 +-  5.4 hr
21084.181325    26 Mar 2021    05:20 +-  5.0 hr
21084.486963    26 Mar 2021    05:00 +-  3.5 hr
21084.548018    26 Mar 2021    03:19 +-  2.8 hr
21084.974688    26 Mar 2021    04:46 +-  1.1 hr * post-cast
21085.095602    26 Mar 2021    04:34 +-  0.5 hr * final post-cast

UPDATE  26 March 2021  12:30 UT:

The reentry happened last night, over North America, and was widely seen from the US States Washington and Oregon, near 4:00 UT (March 26 UT: that is 9 pm on March 25 local time for that area).

CSpOC's final TIP places the reentry at 03:58 +- 1 min UT. This time matches the reports from Washington and Oregon well, and based on the last orbit it would indeed place the rocket stage near the NW United States coast.

The listed geographic position in the TIP, 24.5 N, 151 W, does however not match well (it is further down the track, near Hawaii, corresponding to the Falcon 9 position about 6 minutes prior to the observed reentry). We have  noted such discrepancies more often in recent TIP messages. In this case, I half suspect the position was that given by their reentry model, and they forgot to update it when the SBIRS detection of the actual reentry fireball came in.

click map to enlarge

My own final "post-cast" places reentry some 35 minutes after the actual reentry.

Here are some of the reentry sightings as reported on Twitter:

DID YOU SEE THIS? I have never in my life seen something so incredible. I am in awe. Just happened over Portland about 10 minutes ago. #LiveOnK2 pic.twitter.com/L9wLEXBrcW

— Genevieve Reaume (@GenevieveReaume) March 26, 2021

uuuuuhhhh holy shit we just saw this meteor shower across the sky?!?! #pdx pic.twitter.com/umaE0joW7J

— lynseylou (@lynseylou) March 26, 2021

 

UPDATE 2 April 2021 23:00 UT:

Debris has been recovered from this reentry. In Grant Country, Washington, a Composite Overwrapped Pressure Vessel (COPV) was found on farmland.

 

 

SpaceX recovered a Composite-Overwrapped Pressure Vessel from last week’s Falcon 9 re-entry. It was found on private property in southwest Grant County this week. Media and treasure hunters: we are not disclosing specifics. The property owner simply wants to be left alone. pic.twitter.com/dEIQAotItY

— Grant County Sheriff (@GrantCoSheriff) April 2, 2021

Apparent failed deorbit of the Starlink-18 Falcon 9 upper stage [UPDATED]

On 4 March 2021, after several delays, SpaceX launched the 18th Starlink batch (Starlink-18 or V1.0-17). While the launch and deployment profile appears to have been similar to other recent Starlink launches, it appears that something went wrong with the Falcon 9 upper stage near the end of its mission.

On March 8th, Polish observer Adam Hurcewicz reported a bright, fast object in the orbital plane of this launch, passing a few minutes before the main Starlink "train". It was seen on subsequent nights and by other observers as well: the video above is from the early morning of March 9. At it's brightest, this fast moving object reportedly reaches mag -3. It does not appear to match a known object from earlier launches. It also didn't match supplementary TLE's for the Starlink-18 payloads from Celestrak (which are based on State Vectors from SpaceX). The Polish observers therefore speculated it was the Falcon 9 upper stage from the launch. 

But that would be against expectations. The Falcon 9 upper stage normally does not stay in orbit: it is de-orbitted soon after payload release, usually about 1.5 revolutions (about 2.5 hours) after launch. So if this object is the Falcon 9 upper stage, this suggests  something went wrong and it failed to deorbit.

The speculation that this object is the Falcon 9 Upper Stage can now be bolstered by additional information. The first orbital element sets for this Starlink launch have appeared on the CSpOC portal  Space-Track late yesterday (11 March), with catalogue numbers ranging from 47722 to 47786. And they show an extra object!

With Starlink launches, 64 objects are usually catalogued: 60 payloads and four 'Falcon 9 debris' pieces. The latter 'debris' pieces are the payload stack retaining rods: four metal rods which keep the satellite stack together on top of the upper stage. They are jettisoned upon payload release.

An elset for the Falcon 9 upper stage is usually not released by CSpOC: as it normally stays on-orbit for barely more than 1 revolution, it is not catalogued.

But this time, not 64 but 65 objects have been catalogued. The extra 65th object must be the Falcon 9 upper stage, and it indicates it stayed on orbit for more than a few revolutions. Which lines up with the observations by the Polish (and later also other) observers.

Although the 65 objects, at the moment of writing, do not have been individually ID-ed by CSpOC yet (all have the temporary designation "TBA - TO BE ASSIGNED"), the 60 payloads, four retaining rods and the upper stage as such can be clearly identified among them. The objects separate in 3 groups in terms of orbital altitude. The 60 payloads all have (for orbits with epoch 12 March) a perigee above 280 km. The four retaining rods have clearly lower orbits: their perigee is near 243-246 km and apogee near 268-278 km.

The 65th object, which by inference must be the Falcon 9 upper stage, is in a still lower orbit . It has the smallest semi-major axis of all of them with perigee near 237 km and apogee near 270 km. The orbit for this object, catalogue nr 47782 (2021-071BN) also closely matches the observations by the Polish observers.

So why is the Falcon 9 upper stage still on-orbit? It suggests of course that the deorbit went not as planned, i.e. it failed for some reason (e.g. the rocket engine refusing to restart).

That the Falcon 9 upper stage should have deorbitted on March 4, after 1.5 revolutions, is clear from the Navigational Warnings that were issued in connection to this launch. Navigational Warning HYDROPAC 695/21 delineates the usual elongated deorbit zone in the Indian Ocean familiar from earlier Starlink launches:

 

021948Z MAR 21
HYDROPAC 695/21(GEN).
SOUTHERN INDIAN OCEAN.
1. HAZARDOUS OPERATIONS, SPACE DEBRIS
   041024Z TO 041326Z MAR,
   ALTERNATE 051004Z TO 051306Z MAR
   IN AREA BOUND BY
   29-43S 060-07E, 24-55S 064-27E,
   38-45S 084-30E, 45-12S 099-45E,
   49-46S 119-13E, 50-42S 138-19E,
   48-50S 156-44E, 51-46S 158-08E,
   54-42S 148-32E, 56-20S 131-03E,
   55-52S 107-50E, 49-11S 085-05E,
   34-32S 064-13E.
2. CANCEL HYDROPAC 685/21.
3. CANCEL THIS MSG 051406Z MAR 21.

I have plotted the zones from the Area Warnings connected to the launch in this map, along with the groundtrack for the first 1.5 orbital revolutions. The large elongated red zone in the southern Indian Ocean is the planned deorbit area from Navigational Warning HYDROPAC 695/21:

click map to enlarge

The position of the reentry hazard zone indicates a reentry was planned around 10:55 UT (March 4), 1.5 revolutions (2h 30m) after launch, following a deorbit burn some 30 minutes earlier.

But the deorbit evidently did not happen as it should have: the upper stage is still orbiting as we speak, a week after launch. The issued Navigational Warning for the deorbit hazard zone strongly suggests this is not intentional.

So how long will the upper stage stay in orbit? The current orbit is low (237 x 271 km), and the object is large (16 x 3.66 meter, with a mass of 4.5 tons) so eventually the rocket stage will have an uncontrolled reentry, somewhere between latitudes 53 deg N and 53 deg S. 

A first assessment using both SatEvo and a GMAT simulation suggests that the reentry will probably happen in the last few days of March or the first few days of April.

UPDATE 14 March 2021:
CSpOC has now added identifications to the objects, and indeed object 47782 is now listed as "Falcon 9 RB"