MUOS 5 stuck in GTO

The website Spaceflight.com has broken the news that something has gone wrong with the orbit raising manoeuvres of MUOS 5. They have therefore been halted for the moment. A formal statement by the US Navy on this all is here.

So MUOS 5 at this moment appears to be stuck in the aproximately 15240 x 35700 km Geostationary Transfer Orbit (GTO) in which Paul Camilleri and me observed it between July 3 and 5 (see my previous post).

It is the white orbit in the plots below (replaced with new versions July 9):

Orbit in TLE form:

MUOS 5                                               15242 x 35703 km
1 41622U 16041A   16186.93646397 0.00000000  00000-0  00000+0 0    08
2 41622   9.8319 324.4682 3211964 178.4686 182.8307  1.52727671    09

rms   0.003   from 14 observations Jul 3.46 - Jul 5.57 (arc 2.1 days)

Tracking MUOS 5 in GTO [UPDATED]

click to enlarge

Over the past days, Paul Camilleri in Australia and me in the Netherlands have been tracking an object in GTO with a Mean Motion of 1.5 revolutions per day. It produces brief bright (mag +8) flashes each ~5 minutes. We are certain this is MUOS 5 (2016-041A) launched June 24 (see my earlier post here, about Paul's orbit insertion and Centaur fuel vent imagery).

The image below was shot by me from Leiden, the Netherlands, during the night of 4-5 July 2016. The object was at an elevation of only 16 degrees above the horizon:

click image to enlarge

Paul first imaged it from Australia on June July 3, when it passed a few degrees from the position where we expect MUOS 5 to be placed in GEO. I next imaged it from the Netherlands during the night of June July 4-5, low at my southeast horizon not far from Mentor 6. A few hours later, Paul observed it again from Australia. All these observations can be fitted to yield this GTO orbit:

MUOS 5                                               15242 x 35703 km
1 41622U 16041A   16186.93646397 0.00000000  00000-0  00000+0 0    08
2 41622   9.8319 324.4682 3211964 178.4686 182.8307  1.52727671    09

rms   0.003   from 14 observations Jul 3.46 - Jul 5.57 (arc 2.1 days)

Comparing this orbit to the initial GTO insertion orbit from June 24-25 provides a clear link. The RAAN values of both orbits agree to within a few degrees, and the apogee direction is also very similar, as can be see in the plot below:

click to enlarge

In the plot above, the red orbit is the June 24 initial GTO insertion orbit. Somewhere after June 25, the satellite manoeuvered (multiple times probably) to increase its perigee from 3900 km to 15240 km. The white orbit is the resulting "current" GTO orbit from the July 3-5 observations.

[ UPDATE 7 Jul 2016 17:25 UT: I have since done an analysis that suggests that a perigee-raising manoevre from the initial 3903 km to 15242 km could have happened on July 3, near 14:33 UT, in apogee. I suspect however that it was in reality a series of smaller manoeuvres [update July 8: series of manoeuvres confirmed here]]

The grey orbit is the eventual geosynchronous orbit in which MUOS 5 will be inserted a few days from now (probably with a position near longitude 172 W). It will probably make more manoeuvres for that purpose the coming days. [update: there is a possibility it actually did so only a few hours after our last observation on July 5] 


UPDATE July 8 17:00 UT: News has come in that something went wrong and MUOS 5 is snagged in GTO for now. More on the Spaceflight.com website and a brief follow-up post here].

The plot below shows how during this manoeuvering, the orbital inclination has been lowered, from 19.0 degrees initially, to 9.8 degrees currently. It will be further lowered to ~5.0 degrees upon GEO insertion:

click to enlarge

The object shows a clear brightness variation, from mag +8 to invisible, with a peak-to-peak period of ~5.0 minutes, indicating the satellite is spin-stabilized. [update:  Ted Molczan has noted that this 5-minute periodicity seems to be typical for the Lockheed A-2100 bus in GTO].The bright peaks are of short, specular and somewhat variable duration: lasting ~0.5 to 1 minute. During the lows, the object was not visible for my equipment.

The image sequence below, from my June July 4-5 imagery, shows a part of the described brightness behaviour:

click image to enlarge

As I have written earlier, MUOS 5 will likely be placed in a geosynchronous, 5-degree inclined orbit near longitude 172 W, probably within a few days from now or perhaps even on July 5th already [see the update already mentioned above: MUOS 5 has got stuck in GTO! See also the brief follow-up post here]. This is an initial check-out position. It will stay there for 4 to 6 months, and then be moved to longitude 72 E where it will be placed as an on-orbit spare. In 2015, we observed this with MUOS 4 (see previous posts here and here).

(this post was thriple updated, on 7 Jul 17:25 UT and 8 Jul 8:30 UT and 17:00 UT)

MUOS 5 GTO insertion and Centaur fuel dump imaged from Australia

click to enlarge
image (c) Paul Camilleri - used with permission

The spectacular image above was kindly made available to me by Paul Camilleri from Warners Bay in Australia. Taken around 18:03 UT using a 180 mm lens, it shows the just launched MUOS 5 satellite and the associated Centaur upper stage: the latter is venting fuel creating a "comet-like" cloud.

The image was made some 40 minutes after MUOS 5 separated from the Centaur stage (separation happened at ~17:23 UT). The two objects were at an altitude of ~30 000 km at that time, in a Geosynchronous Transfer Orbit (GTO).

Following separation, the Centaur upper stage had made a Collision and Contamination Avoidance Manoeuvre (CCAM) and next started to dump exces fuel in order to reduce the risk of later on-orbit explosions. This fuel-venting causes the comet-like cloud. MUOS 5 itself is visible as a small trail just under the Centaur and its fuel cloud.

Two other classified objects are, by chance, visible in the image as well: Milstar 4 and USA 155. Like MUOS 5, Milstar 4 is a military communications satellite: USA 155 is an SDS data relay satellite.

MUOS 5 was launched today at 14:30 UT (24 June 2016) from Cape Canaveral, using an Atlas V rocket with a Centaur upper stage. For a timeline and details, see here.

Over the next couple of days, MUOS 5 will use its own engines to make a series of orbit raising manoeuvres, followed by an orbit circularization to bring it in a ~5-degree inclined Geosynchronous orbit. Most likely it will initially be placed in a check-out position near longitude 172 W: I observed MUOS 4 in this position last year.

After 5 months or so, when check-out is completed, it will next be moved to longitude 72 E, where it will be parked as an on-orbit spare in the MUOS constellation (see also my earlier post on MUOS 4 here).

MUOS 5 is the fifth satellite in the Mobile User Objective System (MUOS) system of Geosynchronous narrowband communication satellites. The first MUOS satellite was launched in 2012. This system of military COMSAT is to provide communication facilities to 'mobile users': i.e. military personel in non-fixed positions such as ships, aircraft, tanks and vehicles or on foot. It is a replacement for the aging UFO constellation of COMSAT and will be able to be used by legacy UFO equipment.

The MUOS system now consists of four operational satellites (MUOS 1 to 4) and MUOS 5 as said is to function as an on-orbit spare. According to a publication by Oeting et al. in the Johns Hopkins APL Technical Digest 30:2 of 2011, it will be parked at 72 E for this purpose.


I thank Paul Camilleri for permission to feature his splendid image!

MUOS 4 recovered at 75 E

MUOS 4 at 74.8 E on 8 March 2016
image (c) by Greg Roberts, South Africa
(click to enlarge)

In a recent post I wrote that MUOS 4 (2015-044A) had left it's check-out position at 172 W near Hawaii late January, drifting westwards. I presumed that it was being moved to its assigned operational spot at 75 E, over the Indian Ocean just south of India.

This is now confirmed. On 8 March 2016, Greg Roberts from Cape Town, South Africa, recovered MUOS 4 at 74.8 E. Greg's recovery image (used with his permission) is above. As I wrote before, it probably arrived there on 29 February 2016, after a 37-day drift westwards at a rate of ~3 degrees/day.

With four satellites at their operational positions, the MUOS constellation is now complete.

MUOS 1   2012-09A       177 W  Pacific
MUOS 2   2013-036A      100 W  CONUS
MUOS 3   2015-002A     15.8 W  Atlantic
MUOS 4   2015-044A       75 E  Indian

However, one more MUOS satellite will be launched. This fifth satellite will be parked at 72 E and will function as an on-orbit spare, in case one of the other four MUOS satellites malfunctions on-orbit.

(click to enlarge)

As can be seen in the illustrations above, the MUOS satellites are separated by ~90 degrees in longitude, but with a slightly bigger gap (~108 degrees) between MUOS 1 and MUOS 4, a gap representing the Pacific. The latter is probably in order to assure access to/from at least two ground facilities, with Hawaii and California serving MUOS 1. The latter would not have been possible with MUOS 1 at ~90 rather than 108 degrees from MUOS 4. MUOS ground facilities are indicated by yellow squares in the map above.

Imaging a "UFO" (Ultra High Frequency Follow-On)

UFO F2 on 3 March 2016
(click image to enlarge)

The image above is my first image of a UFO...

(* cue X-Files tune *)

No need to call in Mulder, however. The object in the image is a geosynchronous satellite, UFO F2 (1993-056A).

The truth is out there

The acronym 'UFO' in this case does not stand for the classic Unidentified Flying Object. It stands for Ultra High Frequency (UHF) Follow-On, the name of a class of US Navy communication satellites.

The UFO satellite constellation consists of 11 satellites (not all of them operational) in geosynchronous orbit, launched between 1993 and 2003. It serves fleet-wide communication needs for the US Navy (including its submarines, but also Marine units on land). The system is currently being replaced by the newer MUOS constellation (see a previous post) and will gradually be phased out.

UFO satellite constellation on 9 March 2016
(click image to enlarge)

The first launch in the series, the launch of UFO F1 on 25 March 1993 with an Atlas 1 from Cape Canaveral, resulted in a partial failure to reach the intended geosynchronous orbit due to the failure of one of the rocket engines. The second UFO launch, UFO F2, the one imaged above, was the first truely successful launch of this satellite class.

USA 236 on 28 February 2016
(click image to enlarge)

I imaged more geosynchronous objects the past week, taking advantage of clear moonless evenings. The image above shows a star field in Orion in the evening of 28 February 2016, with USA 236 (SDS 3 F7, 2012-033A), an SDS data communications satellite in geosynchronous orbit. These satellites relay data from other US military satellites, optical and radar reconnaissance satellites in Low Earth Orbits such as the KH-11 'Keyhole'/CRYSTAL, Lacrosse (ONYX) and FIA (TOPAZ), to the US.

PAN on 28 February 2016
(click image to enlarge)

I also did my periodic revisit of the enigmatic SIGINT satellite PAN (2009-047A) as well (see image above). PAN is still stable at 47.7 E (see my long-term analysis here), near Yahsat 1B. The image above shows it near that satellite and a number of other commercial communications satellites in an image taken on 28 February 2016.

Mercury 1 r on 3 March 2016
(click image to enlarge)

On Feb 28 and March 3, I recovered Mercury 1 r (1994-054B), the upper stage from the launch of the Mercury 1 SIGINT satellite. We had lost this object for a while, it had not been seen for 153 days when I recovered it. The image above shows it in Hydra on 3 March 2016.

USA 186 on 5 March 2016
(click image to enlarge)

As spring is approaching, the visibility of satellites in Low Earth Orbit is gradually coming back for northern hemisphere observers.  This means we can take over from our lone southern hemisphere observer, Greg. The image above shows the KH-11 'Keyhole'/CRYSTAL optical reconnaissance satellite USA 186 (2005-042A) imaged on 5 March 2016.

[UPDATED] MUOS 4 has been moved to its operational position at 75 E

MUOS 4 imaged while still in its check-out position at 172 W on 27 September 2015

Since September 2015, I have been periodically covering MUOS 4 (2015-044A), a newly launched military communications satellite in geostationary orbit. It was launched on 2 September 2015 and initially placed at 172 W, just west of Hawaii. This position was temporary: it is the "check-out position" where the satellite is initially placed, well situated with regard to key monitoring stations, to check if it is working okay. It stays there for a few months until this check-out is complete: then it is moved to its operational position. In the case of MUOS 4, it is known (see my earlier post and this unclassified publication) that the operational position assigned to MUOS 4 is at 75 E, south of India.

At the start of December 2015, it was announced that check-out had been completed and that the satellite would be moved to its operational position in the spring of 2016.

When I checked upon MUOS 4 on 4 December 2015 using the 0.51-m telescope of Warrumbungle obs in Australia, it was still at 172 W. For various reasons I did not get to check that position again until a few days ago. When I imaged that location on March 1, 2016, using the same Warrumbungle telescope, MUOS 4 was no longer there. It had been moved somewhere between December 4 and March 1.

This is confirmed by observations of the Russian ISON network. I received two of their MUOS 4 elsets for mid February 2016, which show the satellite drifting westwards at a rate of about 3 degrees/day. From the drift rate I reconstruct from these elsets, I find that the move from 172 W to 75 E started near 23.0 January 2016. At this drift rate, it should have reached its designated operational slot at 75 E 37 days later, on 29.0 February 2016.

[UPDATE 11 March 2016:  On March 8, Greg Roberts in South Africa recovered MUOS 4 at 74.8 E, very close to the expected position]

MUOS 4 at its 172 W check-out location

MiTEx 1 on 16 September 2015
(click image to enlarge)

On September 16, I was using the Warrumbungle 0.51-m telescope in Australia to track MiTEx. Indeed, MiTEx 1 (2006-024A) was imaged as a faint object close to the expected location (image above).

But about 5 degrees Northeast of MiTEx 1, I imaged another, very bright object (see image below) at approximately 172 W. It was too bright to be MiTEx 2 and didn't fit any known object. This UNID turned out to be the newly launched classified military COMSAT, MUOS 4 (2015-044A).

MUOS 4 on 16 September 2015
(click image to enlarge)

MUOS 4 was launched from Cape Canaveral with an Atlas V rocket two weeks earlier, on 2 September 2015. It is the fourth satellite in the Mobile User Objective System (MUOS) system of Geosynchronous narrowband communication satellites, the first of which was launched in 2012. This system of military COMSAT is to provide communication facilities to 'mobile users': i.e. military personel in non-fixed positions such as ships, aircraft, tanks and vehicles or on foot. It is a replacement for the aging UFO constellation of COMSAT.

The MUOS system is to consist of four operational satellites and one spare fifth satellite. According to a publication by Oeting et al. in the Johns Hopkins APL Technical Digest 30:2 of 2011, the operational satellites will be placed in slots at longitudes:

15.5 W
100 W
177 W
75 E

...while the spare satellite (MUOS 5, to be launched) will be placed at longitude 72 E. Compare this to the actual locations of the MUOS satellites according to our tracking:

MUOS constellation, from Oeting et al. 2011
(click image to enlarge)

Current locations of MUOS satellites,
based on amateur tracking:
------------------------------------------
MUOS 1   2012-09A       177 W  Pacific
MUOS 2   2013-036A      100 W  CONUS
MUOS 3   2015-002A     15.8 W  Atlantic
MUOS 4   2015-044A      172 W  (check-out)
------------------------------------------

(click map to enlarge)

The map and table above show the current locations of MUOS 1, 2 and 3 (from Mike McCant's INTTLES file). The positions agree well with the slots depicted in the mentioned publication.

(and yeah: if you think it is a tad silly that these orbits are 'classified' while the intended orbit slots have been published in a publicly available publication, you are of course right).

The yellow dots in the map are ground facilities related to the MUOS system. The MUOS constellation is designed such that each satellite has at least two Radio Acces Facilities (RAF) in range.

MUOS 4 imaged on 24 September 2015

My additional observations on September 24 (see image above) show that MUOS 4 is stationary at 172 W, as depicted in the map below. An approximate orbit for the satellite can be found here.

(click map to enlarge)

As MUOS 4 appears intended for an operational slot at longitude 75 E over the Indian Ocean (red dot in the map above), this means the current location at 172 W is not the intended operational longitude. Rather, it is a temporary initial check-out location. Once check-out is completed (and this might take several weeks), it will probably be moved to longitude 75 E.

(click images to enlarge)

This check-out position at 172 W has been used for the MUOS satellites before, according to Ted Molczan (priv.com). It is in range of three MUOS ground facilities: two Radio Acces Facilities (RAF) at Wahiawa in Hawaii and (although barely) Geraldton in Australia, and the primary Satellite Control Facility (SCF) in Pt. Mugu, California.