Sunday, 24 August 2025

X-37B OTV 8 and Limasat (the USSF-36 payloads) imaged

 

This morning (early 24 August 2025) weather finally cooperated and I managed to observe both of the USSF-36 payloads, two days after launch: the X-37B Spaceplane OTV 8 (2025-183A) and  LIMASAT (2025-183B). Limasat was about half a minute in front of OTV 8.

Above is footage from this pass, showing both objects. The footage was obtained from my home in Leiden, the Netherlands, using a WATEC 902H2 Supreme camera with a Samyang 1.4/85 mm lens filming at 25 frames/second. This was an early twilight pass low in the south-southwest (27 degrees maximum elevation).

Below are framestacks from parts of the footage (both framestacks are 51-frame stacks):

Limasat (stack of 51 frames)

 
X-37B OTV 8 (stack of 51 frames)


 

Current observations show OTV 8 in a 331 x 342 km, 49.5 degree inclined orbit. Limasat is in a 330 x 341 km, 49.5 degree inclined orbit. Limasat was probably carried piggyback on the X-37B Service Module before being released.

Saturday, 23 August 2025

X-37B Spaceplane mission OTV 8 located on orbit

OTV 8 imaged by Kevin Fetter 5 hours after launch. Image (c) Kevin Fetter, used with permission

OTV 8, the 8th mission of the US Space Force's X-37B Spaceplane, launched on 22 August 2025 at 03:50 UTC. It has been catalogued as 2025-183A (cat. nr. 65271) under the name of  'USA 555', along with a second payload, called LIMASAT (2025-183B, 65272). The latter has probably been dispensed from the OTV 8 service module.

Five hours after launch, Kevin Fetter managed to observe OTV 8. Above is one of his images, showing OTV 8 as a short bright trail in a partly cloudy sky. 

A preliminary orbit fit suggests that OTV 8 is in a 327 x 334 km, 49.5 degree inclined orbit [update 25 Aug 2025: the latest improved orbit update shows it in a 331 x 342 km, 49.5 degree inclined orbit]: a slightly (~20 km) lower orbital altitude than my initial pre-launch guess but otherwise a quite comparable orbit.

Click image to enlarge

 


An overview of the OTV missions so far: 

MISSION  ORBITER  LAUNCH   INCL   ORBIT   DURATION
--------------------------------------------------
OTV 1    I        2010     40.0   LEO     224 days
OTV 2    II       2011     42.8   LEO     468 days
OTV 3    I        2012     43.5   LEO     674 days
OTV 4    II       2015     38.0   LEO     717 days
OTV 5    II       2017     54.5   LEO     780 days
OTV 6    I        2020     45.0   LEO     909 days
OTV 7    II       2023     59.1   HEO     435 days
OTV 8    I        2025     49.5   LEO         tbd
--------------------------------------------------

Bad weather in the Netherlands has so far precluded me from trying to observe the latest launch.
 

EDIT (24 August 2025): 

I imaged both the USSF-36 payloads (OTV 8 and Limasat) in the early morning of 24 August, see this follow-up blogpost with footage. 

Monday, 18 August 2025

An upcoming Hypersonic Missile Test (repeat of FT-3) from Kodiak to Kwajalein [UPDATED]

Click map to enlarge


Navigational Warnings have been published that point to a Hypersonic Missile Test (a repeat of the failed FT-3 from 2021) from the Pacific Space Port at Kodiak Island, Alaska, to the Ronald Reagan Test Site at Kwajalein, Marshall Islands, between August 22-26, 2025. The range is about 6350 km.

Navigational Warning NAVAREA XII 520/25 defines three hazard zones (A, B and C in the map above), one near Kodiak Island and two in the mid Pacific, for the splashdowns of the three rocket booster stages. Navigational Warning HYDROPAC 2097/25 defines a hazard area at Kwajalein Atoll for the Hypersonic payload impact area. I have plotted the areas in the map above.

The test appears to be a repeat of the failed FT-3 test from 2021. This test was scrubbed in June 2021 and next failed on a second attempt on 21 October 2021, reportedly when one of the booster stages failed in flight.

Details on FT-3 can be found in this US DoD document. A three-stage STARS (Strategic Target System) launch vehicle consisting of two Orion stages and a C4 stage would launch the hypersonic payload from the Kodiak Pacific Space Port Complex and (based on Navigational Warning HYDROPAC 2097/25) target the Northeast Deep Water Impact Zone near Gagan island on Kwajalein.

Here is the text of the Navigational Warnings:

080912Z AUG 25
NAVAREA XII 520/25(16,19).
GULF OF ALASKA.
NORTH PACIFIC.
ALASKA.
1. HAZARDOUS OPERATIONS 220400Z TO 221000Z AUG, 
   ALTERNATE 0400Z TO 1000Z DAILY 23 THRU 26 AUG
   IN AREAS BOUND BY:
   A. 54-12.00N 156-36.00W, 54-03.00N 156-14.00W,
      55-16.00N 153-14.00W, 56-32.00N 152-01.00W,
      57-29.00N 152-06.00W, 57-32.00N 152-20.00W,
      56-59.00N 153-06.00W, 57-00.00N 153-30.00W.
   B. 46-32.00N 167-23.00W, 46-24.00N 167-05.00W,
      45-43.00N 167-45.00W, 45-51.00N 168-03.00W.
   C. 37-36.00N 175-36.00W, 37-19.00N 175-00.00W,
      32-19.00N 178-40.00W, 32-41.00N 179-12.00W.
2. CANCEL THIS MSG 261100Z AUG 25.


080852Z AUG 25
HYDROPAC 2097/25(81).
NORTH PACIFIC.
MARSHALL ISLANDS.
DNC 12.
1. HAZARDOUS OPERATIONS 220400Z TO 221000Z AUG, 
   ALTERNATE 0400Z TO 1000Z DAILY 23 THRU 26 AUG
   IN AREA BOUND BY
   09-43.00N 167-47.00E, 09-36.00N 167-59.00E,
   09-11.00N 167-44.00E, 09-17.00N 167-33.00E.
2. CANCEL THIS MSG 261100Z AUG 25. 

 

UPDATE 23 Aug 2025:

The launch happened on 22 August 2025 at 06:10 UTC. Footage of the launch shot from Seward, Alaska, by Seth Andrzejewski is here on twitter 

Sunday, 17 August 2025

The upcoming launch of the X-37B Spaceplane mission OTV 8

X-37B mission OTV 6 after landing (Image: US Air Force)

Navigational Warnings have appeared for OTV 8, the 8th launch of the secretive X-37B spaceplane by the US Space Force (launch USSF-36). The launch, on a SpaceX Falcon 9, will be from Cape Canaveral launch pad 39A. The window of the Navigational Warning runs from 22 to 28 August 2025, with a time window of 08:30 - 10:30 UTC 03:40 - 08:03 UTC for August 22 (August 21 local date in Florida). There is something odd with these times by the way, on which more later.

Navigational Warnings NAVAREA IV 877/25 and HYDROPAC 2096/25 define two hazard zones. One is the immediate launch hazard zone on the Florida coast. The other is the deorbit area for the Falcon 9 upper stage, in the Eastern Pacific, near the end of the first revolution. 

While the direction of the first hazard zone on the Florida coast suggests a 42 degree inclined orbit, the location and direction of the Falcon 9 upper stage deorbit area is incompatible with this. Rather, it fits a 49.5 degree inclined orbit. The location and the time difference of the deorbit window start compared to that for the launch area, strongly point to launch into a Low Earth Orbit, with an orbital altitude likely near 350-400 km, just like the first six missions (remember that mission OTV 7 surprisingly was sent into a Highly Elliptical Orbit, see several previous posts, e.g. here).

I have plotted the two hazard zones and a launch trajectory for a 49.5 degree inclined, ~350 km altitude orbit in the map below. Numbers next to the trajectory refer to the flight time in minutes after launch:

 

Click map to enlarge

 

Below are the two Navigational Warnings:

142327Z AUG 25
NAVAREA IV 877/25(11).
NORTH ATLANTIC.
FLORIDA.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING 
   220340Z TO 220803Z AUG, ALTERNATE
   230400Z TO 230823Z, 240420Z TO 240843Z,
   250440Z TO 250728Z, 260500Z TO 260748Z,
   270345Z TO 270808Z AND 280540Z TO 280833Z AUG
   IN AREA BOUND BY
   28-40.25N 080-38.57W, 28-50.00N 080-22.00W,
   28-39.00N 080-11.00W, 28-27.24N 080-31.58W.
2. CANCEL THIS MSG 280933Z AUG 25.


141931Z AUG 25
HYDROPAC 2096/25(83).
PACIFIC OCEAN.
DNC 06, DNC 13.
1. HAZARDOUS OPERATIONS, SPACE DEBRIS
   220500Z TO 220911Z, 230520Z TO 230931Z,
   240540Z TO 240951Z, 250600Z TO 250836Z,
   260620Z TO 260856Z, 270505Z TO 270916Z
   AND 280700Z TO 280941Z AUG 
   IN AREA BOUND BY
   09-55.00N 120-25.00W, 10-41.00N 121-25.00W,
   07-44.00S 135-45.00W, 08-30.00S 134-45.00W.
2. CANCEL THIS MSG 281041Z AUG 25.


Note the shift in launch time with date: 03:40 - 08:03 UTC for the 22nd, 04:00 - 08:23 UTC for the 23rd, etcetera: a shift forward in time of 20 minutes per day. [edit: as noted by Ted Molczan, the times next suddenly shift to - nearly - the initial times again by August 27. I still cannot make sense of it]

The direction of this shift is odd. It is forward, to a later time each day: if a particular orbital plane is aimed for, it should however shift backwards, to an earlier time, each day. I wonder if this is a mistake and someone added corrections into the wrong direction...

The X-37B spaceplane (there are actually two of them) is the subject of a lot of conjecture and wild tales. My interpretation is that it is a technology testbed, not some space weapon such as the Russians and Chinese would have it. 

The rumoured "high manoeuverability" is often misunderstood: in flight, the X-37B does not change its orbital plane (see this earlier post from 2019). It does change orbital altitude frequently, and during the last mission (OTV 7) into HEO, it used Aerobraking (briefly dipping into the upper atmosphere during perigee) near the end of its mission to reduce orbital speed and altitude in preparation for landing. It manoeuvered almost daily during that mission. However, and I want to re-emphasize this as it is a common misunderstanding, it does not swirl and manoeuver like an X-wing Starfighter or Tie-fighter, changing orbital plane at will. In many ways, on-orbit it is just another satellite, moving in a fixed orbital plane (this is how we trackers find it back after an orbit raising or lowering manoeuver: we do a plane scan). The wings only function in the atmosphere, not in space.

According to this Space Force bulletin, mission OTV 8 will experiment with laser communications with "proliferated commercial satellite networks in Low Earth Orbit" (read: Starlink). It will also test a new navigation device, a "quantum inertial sensor" which works by "detecting rotation and acceleration of atoms without reliance on satellite networks like traditional GPS". This experimental technique is important to be able to continue navigating in space when GPS is being jammed/spoofed, and will become an important means of navigation in XGEO (CisLunar Space) in the future.

Wednesday, 6 August 2025

The SatTrackCam (B)log is 20 years old!

 

On 6 August 2005, this blog saw its very first post. This means that the SatTrackCam blog is now

20 Years Old! 

 

Since that first post, we are now 20 years and over one-thousand blogposts further. 

To quote the Talking Heads: "And you may ask yourself, "Well, how did I get here?"

Originally it started out as a mere observers activities log, documenting my baby steps into satellite tracking. Most of the early blogposts were very simple, descriptive and brief (and sometimes naive), and contain a lot of complaining about the Dutch weather.

Over the years, as I built up more knowledge, insight and expertise, I started to post more elaborate posts, including increasingly elaborate analysis of observations, events, data, and satellite life histories. It also included occasional Off-Topic posts on asteroids and comets and astrophotography (it still does every now and then). Some 13 years ago, a growing interest in the North Korean Space and Missile program and a chance observation by a German amateur astronomer on La Palma of what eventually turned out to be a Trident-II SLBM launch (see original post here - still containing misinterpretations - and a later revisit post and analysis here), lead to a broadening of the scope of the blog to also include Missile tests.

I can truely say that writing this blog changed my life. With hindsight, this post from July 2014 on a very tragic event (the shootdown of flight MH17, and whether US SBIRS satellites could have seen and geolocated the firing of the missile) was a turning point. It was picked up by Dutch politician Pieter Omtzigt, which one-and-a-half year later, in January 2016, led to me being invited to provide an expert opinion during a Dutch Parliamentary Committee Hearing on the subject. Little did I know at that time, that this was to profoundly alter the course of my professional life, and the beginning of a switch from an essentially amateur hobbyist interest to professional involvement in (military) Space Situational Awareness. It led to warm and ongoing contacts with the Defense Space Security Center (DSSC) of the Royal Netherlands Airforce, and to the initiation of a series of projects around building an optical satellite tracking capacity for the DSSC. In the period 2017-2022 I got a series of small positions at the Astronomy department of Leiden University in the context of these projects. 

Eventually, three years ago in June 2022, it culminated in what is by now a permanent position at the Aerospace Engineering faculty of Delft University of Technology, where I am currently employed as a part-time (0.5 fte) Lecturer in Space Situational Awareness as part of the section Astrodynamics and Space Missions

The second half of the 20 years since I started this Blog truely has been a rollercoaster in this sense, and I am still wildly amazed (and somewhat in disbelief) where it has brought me (apart from landing the academic position,  I found myself at a small invitation-only UNIDIR expert meeting at the United Nations in Geneva just three months ago for example). I never envisioned that to happen, when I decided to make my first blogpost on a rainy August day 20 years ago. It blows my mind.

The blog is no longer the only venue through which I share my thoughts, analysis and observations (but still an important one). There always was the Seesat-L mailing list; and over the past 15 years I grew a large twitter account (sorry, refuse to say 'X") that I still maintain because I do not want to leave the 21.6K followers I still have there (including a lot of journalists). I also have an account with 3.4K followers on BlueSky, and recently have become much more active on LinkedIn as well. I occasionally publish topical analysis in The Space Review, and I am frequently featured in the media (including Dutch, and occasionally foreign, tv and radio, as well as Dutch and international written press and online news media). And then there are of course publications in professional scientific journals as well.

But it all started with this blog (and contributions to the SeeSat-L mailing list), very modestly, now 20 years ago. 

I want to thank all of you who have read my blogposts, who shared insights, and have supported and encouraged me over the past 20 years. A blog is nothing without an audience.

I specifically want to thank Ted Molczan, Jonathan McDowell, Bart Hendrickx, Scott Tilley, Bob Christy, Mike McCants, Cees Bassa, Nico Janssen, Bram Dorreman, Leo Barhorst, Greg Roberts, Paul Camilleri, Jeffrey Lewis, Alice Gorman, Trevor Paglen, Bill Gray, Ankit Panda, the late Pierre Neirinck, and twitter contributor @Dutchspace, plus several members of the Seesat-L list and Twitter's Missile and Space communities, for much appreciated feedback, discussions, suggestions, corrections, and food for thought over all these years.

Now, let's continue towards 25 years!