Friday, 27 November 2020

USA 310 (NROL-31) and it's Centaur on 25 November

click image to enlarge

The image above was taken between 1:28:22 - 1:28:27 UT on November 25, and shows both USA 310 (the NROL-101 payload) and its Centaur upper stage in one image. 

At the moment of imaging they were only some 48 arcminutes apart in the sky. Their real distance to each other was ~541 km. The image was made with a Canon EOS 80D and Samyang 2.0/135 mm lens.

Since launch the Centaur, which is is a somewhate lower, more eccentric orbit than the payload, has gained one complete lap on the payload, and it was overtaking it while I was imaging them in the early hours of  November 25. Their closest approach (at a very safe distance of 533 km) was  a few minutes after the image above, at 1:33:29 UT (25 November 2020).

Note the brightness difference between the two, the Centaur upper stage being clearly brighter than the payload. In this image, the Centaur is near the peak of its periodic brightness variation. In a previous post I have detailed the character of the brightness variation of the Centaur.

Tuesday, 24 November 2020

Brightness variation of the NROL-101 Centaur upper stage from video observations

 In my previous post I discussed our tracking of the recently launched NROL-101 objects: the payload (USA 310, 2020-083A) and the Centaur upper stage (2020-083B). The latter is variable in brightness (which is one reason why we think it is the Centaur), and I included a preliminary flash period determination of ~140 seconds in that post, based on analysis of my photographs.

click diagram to enlarge


I can now revise this to 138.02 seconds peak-to-peak, as the result of video observations on 22 November. The Centaur was semi-continously imaged over a 23-minute period, covering 10 brightness peaks, with a WATEC 902H2 Supreme and Samyang 1.4/85 mm lens. Photometric analysis with TANGRA yielded the curve above. 

The brightness diagram starts around the time of zenith passage, at an elevation of 87.6 degrees and ends at an elevation of 56.3 degrees. The phase angle changes from 30.6 degrees at the start to 32.3 degrees at the end, the range from 10525 to 11254 km.

The fitted sinusoid gives a peak-to-peak periodicity of 138.02 seconds. The rocket stage varied between roughly magnitude +6 and +8.5 in brightness. The corresponding absolute magnitude, given the range and phase angle, is +2.0 (peaks) to +4.5 (valleys). 

In the first 'valley' in the curve, there is a brief specular flare. Likewise, there seems to be a narrow steep feature on the top of the brightness peaks.

Filming was done at 25 frames/second. A brightness determination was done at every 4th frame. The curve shows 3-point running averages of these determinations.

The calibration from Red magnitude to Visual magnitude is provisional. Gaps in the curve are periods without data, due to e.g. repositioning of the camera field.

Sunday, 22 November 2020

Tracking objects in MEO from the NROL-101 (USA 310) launch [updated]


NROL-101 payload USA 310. Click image to enlarge

On 13 November 2020 at 22:32 UT, the United Launch Alliance (ULA) launched NROL-101 for the National Recconnaissance Office (NRO) from SLC-41 at Cape Canaveral. CSpOC catalogued the payload as USA 310 under #46918 (2020-083A) and also catalogued the Centaur r/b as #46919 (2020-083B). The payload is classified and orbital elements for both the payload and Centaur were withheld, as is usual for NRO launches.

I wrote about this mission in an earlier post. Initially, we thought that this satellite was perhaps a new SDS and would be launched into HEO (a 63-degree inclined 'Molniya orbit'). Subsequent observations of a fuel vent by the Centaur upper stage seen from the western USA four hours after launch did not seem to fit this, and made us speculate whether the payload perhaps was something new and went into a 58 degree inclined MEO (see the discussion at the bottom of this previous post).

The latter speculation turns out to be correct. On November 18, I imaged an object in a 58.5 degree inclined, 11034 x 11067 km Medium Earth Orbit (MEO). It was steady in brightness. The image in top of this post shows the object in a 6-second exposure with a Canon EOS 80D with Samyang 2.0/135 mm lens. 

Observing conditions on this night were very dynamic: at one moment it could be completely clear, then two minutes later completely overcast, and five minutes later completely clear again.

Two night later, on November 20, I imaged a second related object, in a slightly lower 58.8 degree inclined 10510 x 11043 km Medium Earth Orbit.  Below is one of my images:

NROL-101 Centaur RB. Click image to enlarge

This object is slightly variable in brightness, indicating a slow tumble and during it's peaks it is brighter than the first object. The brightness variation has a peak-to-peak period of 140 seconds. Below, the brightness variation can be seen in a 19-image stack:

click to enlarge

A diagram of the measured pixel brightness of the trails in a series of images, shows the mentioned periodicity, and also shows thge presence of a more specular peak at the tops of the curve:

(click diagrams to enlarge)

(note added 24Nov: an update to this curve from video observations, yielding a 138.02 second peak-to-peak period, is here).

For the moment, we interpret the first, steady object in the 58.5 degree inclined orbit as the payload (USA 310), and the second variable object in the 58.8 degree inclined orbit as the Centaur upper stage.

Here is a TLE for the payload, based on a 3.2-day observing arc:

1 46918U 20083A   20326.25970612 0.00000000  00000-0  00000+0 0    08
2 46918  58.5335 293.1790 0007646 263.2891  96.6658  3.77323127    09

RMS 0.01     arc Nov 18.17 UT - Nov 21.37 UT

The orbit repeats in a 3-4-3 days pattern.


Here is a very preliminary TLE for the Centaur RB, based on a short 43-minute observing arc, hence the values for the eccentricity and Mean Motion still are privisional values:

1 46919U 20083B   20325.05807551 0.00000000  00000-0  00000+0 0    07
2 46919  58.8264 292.5498 0070000 327.1858  32.4248  4.01148244    05


[update] Here is an updated elset for the Centaur RB based on a 3-day observational arc:

NROL-101 Centaur
1 46919U 20083B   20327.90329491 0.00000000  00000-0  00000+0 0    05
2 46919  58.8253 291.9447 0155268 103.5440 258.2387  3.86388179    00

RMS 0.02            arc Nov 0.14 UT - Nov 23.00  UT


The preliminary orbits match well with the fuel vent in Northern Saggitarius observed from Joshua Tree, California and Taos, New Mexico, on 14 Nov ~2:30 UT (18:30 local time in Joshus Tree). The positions match to within a few degrees:

click to enlarge [updated figure]

The orbit of USA 310 is decidedly odd. There have never been classified launches in such an orbit before. One commercial object was launched in a somewhat similar orbit (the orbital inclination is lower), the first (and only) of an ill-fated commercial communications network in MEO: ICO F2 (2001-026A) launched in 2001.

Click to enlarge [updated image]


Because this type of orbit is new for an NRO payload, it is probably something experimental, i.e. a technology demonstrator. We can only guess as to the function, although future orbital behaviour might shed some light. Options include: 


- Communications


- SAR imaging

- Low resolution, wide area optical IMINT

- Space-Based tracking.


In seems that the last few years the NRO and associated organisations are experimenting a lot with new, experimental spacecraft and new types of orbit. We have seen a number of launches into ~50-degree LEO orbits for example (e.g. USA 276, and the failed ZUMA launch). Now unusual MEO orbits are added, it seems. It will be interesting to see how this object will behave, and if other payloads will be launched into a similar orbit in the future.

I, for one, welcome these new oddities: when things become too predictable, it gets boring. So yay for the new and unusual! 

ADDED NOTE (24 Nov):
Now that  both the payload and the Centaur r/b have been observed over a reasonable arc and the orbits have improved, I can provide an estimate for the separation of the Centaur and payload: 14 Nov ~1:00 UT, near the southern apex of the orbits. This was followed by an avoidance burn and fuel dump by the Centaur, so there is some leeway in this.

click to enlarge

Sunday, 15 November 2020

SM-3 Block IIA Missile Defense test FTM-44 against an ICBM-class target imminent, 17-19 November 2020 [UPDATED]

Click to enlarge. Image: MDA

Three days ago, on 12 November 2020, a Navigational Warning appeared that denoted three hazard zones in the northern Pacific for the period 17 to 19 November, connected to what clearly is some kind of missile test:


121041Z NOV 20
   ALTERNATE 0400Z TO 1000Z DAILY 18 AND 19 NOV 
   A. 09-12N 167-43E, 09-01N 167-40E, 
      08-58N 167-43E, 08-58N 167-48W, 
      09-00N 167-59W, 09-30N 168-18E, 
      09-43N 168-04E. 
   B. 11-22N 170-00E, 11-08N 170-10E, 
      11-44N 173-34E, 13-13N 176-53E, 
      15-39N 178-17E, 18-07N 179-23E, 
      18-48N 177-48E, 17-13N 174-19E,
      16-18N 173-08E, 13-08N 171-00E. 
   C. 44-06N 133-00W, 35-00N 131-00W, 
      28-30N 143-30W, 44-06N 140-30W. 
2. CANCEL THIS MSG 191100Z NOV 20.


I have plotted the three area's  in the map below. Note that there appears to be a clerical error in the Navigational Warning for two of the positions defining area A: those reading "W" should probably read "E", which results in a hazard area which makes much more sense (in the map below, the original, probably erroneous, shape for area A is depicted in red: what was likely meant in white).

(note added 17 Nov: an update to this Navigational Warning issued as HYDROPAC 3337/20 confirms the clerical error)

click map to enlarge

The location of the areas lead me to believe it points to a Missile Defense test: an attempt to intercept a dummy Ballistic Missile launched from Kwajalein towards the US main land. Area A denotes the immediate launch hazard zone for the dummy ICBM at Kwajalein; area B where the first second stage of the dummy ICBM will come down; area C the intercept area where the SM-3 interceptor will be fired and the intercept occurs.

Based on the location and shape direction of area C, I initially (and erroneously) thought it might be a Ground-Based Midcourse Defense test from one of the GBMD sites in Alaska. However, after some discussion with the Twitter missile community and some digging around, I am now quite confident that this is not a GMBD test, but an AEGIS SM-3 test, with the SM-3 intercept missile fired from a US Navy Destroyer located in the Pacific in the north of area C. Basically, the situation below:

Click to enlarge

(those of you who remember the infamous Operation Burnt Frost will know the Standard Missile 3 (SM-3): it was used to destroy the malfunctioned USA 193 satellite on 20 February 2008)

Indeed, a Missile Defense test with an SM-3 Block IIA missile, designated as test FTM-44, is known to have been originally scheduled in the Pacific for the third quarter of 2020.  It next was postponed due to the impact of the Corona pandemic, to late 2020

The Navigational Warning NAVAREA XII 509/20 that appeared three days ago now suggests that the FTM-44 test is imminent, and will take place between 17 and 19 November with the daily window running from 04:00 to 10:00 UT. The locations and shapes of the hazard zones designated in the Navigational Warning NAVAREA XII 590/20 fit well with what we know about the FTM-44 test (see below).

A US Naval Institute news release from August 2020 includes the following schematic graphic for FTM-44: compare this to the graphics above and note the clear similarity (note that my figure above is a view from the north,while the MDA figure below is a view from the south):

Click to enlarge. Image: MDA

Test FTM-44 will be the first attempt at intercepting an ICBM-class  missile rather than a MRBM, extending the system to include ICBM targets. AEGIS previously only included short- and medium range ballistic targets. From the position of area C, the intercept will take place at a range of about 6500 km from the Kwajalein launch site.

As can be seen from the MDA diagram above,  the test includes the use of Space-Based assets (satellites): the Space-Based Infra-Red System (SBIRS) for the initial detection of the launch of the dummy ICBM from GEO and HEO, and the Space Tracking and Surveillance System (STSS) for additional tracking of the ICBM missile through midcourse.

Satellites from the STSS system make passes with view of the test area around the following times during the 3-day test window:

Nov 17  ~04:15 UT
Nov 17  ~05:15 UT
Nov 17  ~06:15 UT
Nov 17  ~07:15 UT
Nov 17  ~08:15 UT
Nov 17  ~09:15 UT
Nov 17  ~10:00 UT

Nov 18  ~04:40 UT
Nov 18  ~05:40 UT
Nov 18  ~06:40 UT
Nov 18  ~07:40 UT
Nov 18  ~08:40 UT
Nov 18  ~09:40 UT
Nov 18  ~10:00 UT

Nov 19  ~04:05 UT
Nov 19  ~05:05 UT
Nov 19  ~06:05 UT
Nov 19  ~07:05 UT
Nov 19  ~08:05 UT
Nov 19  ~09:05 UT
Nov 19  ~10:00 UT

The US Naval Institute news release from August 2020 suggests that the FTM-44 SM-3 interceptor will be fired from the USS John Finn. This Arleigh-Burke class Destroyer will probably be located in the northern part of area C from the Navigational Warning.

USS John Finn. Image: US Navy (through Wikimedia)

UPDATE  (17 Nov 11:25 UT):

A news release from the Missile Defense Agency (MDA) has confirmed that FTM-44 has taken place this morning, and was successful. It states that the target was launched from the Ronald Reagan Ballistic Missile Defense Test Site at Kwajalein at 7:50 pm Hawaii Standard Time (=17 Nov 5:50 UT). With an approximately 21 minutes flight time, this should place the intercept near 6:11 UT (17 Nov 2020). [edit: but this assumes a typical ICBM speed, zo there is leeway in this time of intercept]

Between the time of launch and intercept, the STSS DEMO 2 satellite (2009-052B) was well positioned to track the target-ICBM mid-course (note: the position of the Destroyer that fired the SM-3 interceptor missile in the image below, has been assumed):

click image to enlarge


Footage from the test has been released and can be seen here on the MDA website.

Graphic simulation of the test on the MDA website.

The MDA footage of the target launch and the MDA simulation linked above, confirm that the target ICBM was launched from 9.0065 N, 167.7270 E.

click to enlarge. Image: Google Earth

Acknowledgement: this blog post benefitted from discussions with Simon Petersen, Scott Lafoy and Ankit Panda.

Friday, 13 November 2020

Crew Dragon-1

click map to enlarge

[Edit 13 Nov 23:25 UT:  due to the weather the launch has been postponed one day to 16 Nov 00:27 UT]

If weather cooperates, SpaceX will launch Crew Dragon-1 for NASA from Cape Canaveral platform 39A on 15 November 00:49 UT 16 November 00:27 UT. Onboard will be be JAXA astronaut Soichi Noguchi and NASA astronauts Mike Hopkins, Shannon Walker, and Victor Glove. Docking to the ISS will be on 16 Nov 8:57 UT, 8.5 hours after launch. Docking to the ISS will be on 17 November around 4:00 UT

Unfortunately, the time of the launch means that it will not be visible during its pass over Europe some 23 minutes after launch: the pass is completely in earth shadow. In the map above  the dashed line is where the Crew Dragon is in earth shadow, the solid line where it is sun-illuminated. It will not be visible on the second and (for southern Europe) third pass either.

For radio observers: a TLE estimate for the first revolution is on the launchtower.

Sunday, 1 November 2020

NROL-101: probably a HEO mission [or maybe not! See update at bottom]

click map to enlarge

EDIT 4 Nov 2020 22:30 UT: 

post UPDATED with new maps and new value for inclination parking orbit

EDIT 2, 22:50 UT (Nov 4): the launch has been SCRUBBED for at least 48 hours...

EDIT 3, 7 Nov 22: launch is now currently scheduled for 11 Nov, 22:22 UT 

EDIT 4, Nov 13:  NROL-101 cleared the tower at 22:32 UT (Nov 13)

If weather cooperates,ULA will launch NROL-101, a classified payload for the NRO, on November 11 (postponed from November 3 and 4). Based on Navigational Warnings, the launch window is from 22:00 UT (Nov 11) to 02:45UT (Nov 12), with ULA indicating a launch window start at 22:22 UT. 

[ EDIT: eventually, NROL-101 launched on 13 Nov 2020 at 22:32 UT

The launch is from platform 41 on Cape Canaveral, using an Atlas V rocket in 531 configuration (5-m fairing, 3 strap-on boosters, 1 single engine Centaur upper stage). It would have originally flown in 551 configuration but this was changed. It is the first Atlas V flight to feature the new GEM 63 solid fuel strap-on boosters.

This Navigational Warning has appeared in connection to this launch (updated):

062038Z NOV 20
NAVAREA IV 1074/20(GEN).
   112200Z TO 120245Z NOV, ALTERNATE
   122200Z TO 130245Z AND 132200Z TO 140245Z
   A. 28-38-50N 080-37-34W, 29-58-00N 079-28-00W,
      29-54-00N 079-21-00W, 29-34-00N 079-36-00W,
      29-15-00N 079-45-00W, 28-36-00N 080-23-00W,
      28-30-57N 080-33-15W.
   B. 30-01-00N 079-33-00W, 31-08-00N 078-36-00W,
      30-54-00N 078-14-00W, 29-47-00N 079-11-00W.
   C. 36-38-00N 073-35-00W, 39-03-00N 071-00-00W,
      38-30-00N 070-13-00W, 36-05-00N 072-46-00W.
   D. 51-37-00N 049-45-00W, 53-32-00N 044-58-00W,
      52-54-00N 044-15-00W, 51-03-00N 049-07-00W.
2. CANCEL THIS MSG 140345Z NOV 20.

The launch azimuth from the location of the hazard zones in this Navigational Warning and the initial launch azimuth depicted in a map tweeted by ULA point to an initial lauch into a [value updated] ~56-degree ~57.75 degree inclined orbit:


click map to enlarge

However: this is likely only a temporary parking orbit. The 531 rocket configuration has never been used for a launch into LEO so far, but always for launch into GEO. Given the launch azimuth, NROL-101 will certainly not be launched into GEO. 

So either the payload is destined for LEO but unusually heavy or (more likely) the final orbit aimed for is a HEO orbit (also known as a  Molniya orbit) with inclination ~63 degrees, perigee at ~2000 km over the southern hemisphere and apogee near 37 8000 km over the Arctic. [But: see major update at bottom! It might have been MEO rather than HEO, but this remains uncertain!]

A 63-degree inclined Molniya orbit cannot be reached directly from the Cape, because of overflight restrictions. Hence the initial launch azimuth corresponding to a ~58-degree inclined orbit. If NROL-101 goes into a Molniya orbit, it will do a dog-leg some time after launch, or (more likely) coast in a ~58-degree inclined parking orbit for perhaps several hours before being boosted into a Molniya orbit by the Centaur.

This appears to be underlined by the fact that to date (Sunday Nov 1) no Navigational Warnings have been issued for the reentry area of the Centaur upper stage. This could indicate that the upper stage will be left orbiting in a ~2000 x 37 8000 km transfer orbit, or is disposed into a Heliocentric orbit.

The NRO so far launched three kinds of  satellites into HEO orbits:

1) Data communication satellites (SDS);

2) SIGINT satellites (Trumpet FO);

3) combined SIGINT (Trumpet FO) and SBIRS Early warning satellites.

The last SIGINT/SBIRS combination launched into HEO was USA 278, launched in 2017. The last SDS launch into HEO was USA 198 in 2007 (there was also a launch in 2017 but this was into GEO, not HEO). As Ted Molczan pointed out in  a private com, SIGINT launches into HEO usually were done from Vandenberg, SDS launches from Cape Canaveral. So perhaps NROL-101 will carry a new SDS satellite, but this is far from certain. Radio observations after launch might shed some light on both orbit and payload character.

The initial trajectory will take it over NW Europe some 23 minutes after launch, but in Earth shadow, so the pass will not be visible:

click map to enlarge


UPDATE 15 Nov 2020 15:20 UT

Around 2:30 UT on Nov 14, four hours after launch, sightings of a fuel venting event were observed from the western USA.

This image tweeted by  Marc Leatham shows the V-shaped cloud in Saggitarius, imaged from Joshua Tree National Park:

There is also allsky imagery of the fuel cloud from Taos, New Mexico (look low at the horizon where the milky way touches the horizon(right side), for a 'moving' piece of Milky Way. This is the fuel cloud):

These sightings lead us to believe that the payload perhaps went into the lower part of MEO, not HEO. This is however (emphasis) not certain at this moment.

The launch sequence then could have been insertion into a LEO parking orbit; an apogee raising burn; a perigee raising/circularization burn bringing it into HEO; and fuel vent/orbit separation burn by the Centaur rocket. That latter event caused the observed fuel cloud, at about 8500 km altitude.

ULA reported 'mission successful' around 1:48 UT. For the launch provider, their mission is completed upon payload separation. 1.48 UT corresponds to a pass through the southern apex of the orbit, suggesting payload separation was at that point. This, in combinbation with the observed Centaur vent, would argue against insertion into HEO but does fit insertion into MEO.

If my guess is correct, then this should be the approximate orbit (orbital position is the approximate position for the time of the Joshus Tree fuel cloud sighting):

click to enlarge


Both the Centaur and payload have been catalogued (but without orbital elements) by CSpOC, as #46918 (2020-083A) USA 310 and #46919 (2020-083B) Atlas V Centaur R/B.

If USA 310 indeed went into HEO, then the identity/character of the payload remains a big guess.

Added note, 4 Nov 2020, 21:30 UT: the maps and inclination of the initial parking orbit have been updated based on a map showing the initial trajectory up to fairing jettison tweeted by ULA boss Tory Bruno.

This post benefitted from discussions with Cees Bassa, Scott Tilley, Ted Molczan and Bob Christy.