Thursday, 29 July 2021

Nauka and it's Proton-M rocketbooster

 

click image to enlarge

On 21 July 2021 at 14:58 UT, Roscosmos launched the new MLM-NAUKA module for the ISS from Baikonur, using a 3-stage Proton-M rocket. After its arrival at the International Space Station (ISS) on July 29, it will replace the PIRS module. Docking is set for 13:24 UT on the 29th.

The NAUKA launch came much belated: originally slated for launch in 2007 (!) it was postponed several times, amongst others after a problem with iron fillings in the engine plumbing was discovered.

With NAUKA, also ERA, the European Robotic Arm, was launched.

In order to make room for NAUKA, the PIRS module was undocked on 2021 July 26 near 10:56 UT, and deorbitted (using Progress MS-16 as a 'tug') into the southern Pacific Ocean on July 26 near 14:42-14:52 UT:

click map to enlarge

Soon after launch, it became apparent that NAUKA was in trouble. There was an initial telemetry problem, and (very worryingly) the main engines didn't work. Russian flightcontrol eventually used the auxilliary engines to raise the module's orbit.

click diagram to enlarge

For European observers, the first few nights after launch offered good sighting opportunities for the free-flying NAUKA (2021-066A), it's Proton-M 3rd stage (2021-066B), and the ISS, the three on the first evening passing within a few minutes of each other in evening twilight.

The images below show NAUKA and the Proton-M 3rd stage in evening twilight of 22 July, imaged with a Canon EOS 80D + EF 2.0/35 mm lens (first Nauka, then the Proton rb):

click image to enlarge

click image to enlarge

The Proton rb, and initially NAUKA as well, were  passing through a very low perigee (initially 187 km for the RB, 195 km for NAUKA) over Europe on the first nights. As a result, they passed at a very high, zipping speed through the sky, which was quite spectacular to see. They were bright too.

The video below shows the Proton RB zipping through a partially clouded Leiden sky at 21 July. In the video, it can be seen that three debris pieces accompanied it (these debris pieces were not catalogued by Space-track). Because of the very fast movement (the rocket stage was at only 187 km altitude at the time!) the video is a bit chaotic: I had to continually adjust the camera pointing:

 

 

This framestack from a part of the video shows the three debris pieces:


I initially had bad luck filming NAUKA: on two evenings I though I had restarted the video camera recording, but didn't. I succeeded on 23 July however:


The videos were made with a WATEC 902H2 Supreme + Zeiss 1.4/35 mm lens.

My current estimate for the reentry date of the Proton-M 3rd stage is within 2 days of August 6, 2021. I will issue regular updates in a new post once we come closer to this date.

 

UPDATE 29 July 13:45 UT:

Nauka successfully docked to the International Space Station at 13:29 UT (July 29) near 45.5 N, 110.2 E at an altitude of 425 km above earth surface.

Thursday, 8 July 2021

A possible missile test (AGM-183 ARRW, or not?) in the Pacific on July 10


 

Three related Navigational Warnings have appeared (NAVAREA XII  nr 304, 305 and 306) that together seem to define the trajectory of a missile test in the Pacific on July 10 between 9:00 and 18:00 UT, with a backup date on July 13:

 060344Z JUL 21
 NAVAREA XII 304/21(18).
 EASTERN NORTH PACIFIC.
 CALIFORNIA.
 1. HAZARDOUS OPERATIONS 100900Z TO 101800Z JUL,
    ALTERNATE 130900Z TO 131800Z JUL
    IN AREA BOUND BY
    33-08-45N 121-27-34W, 33-27-41N 121-29-48W,
    33-33-57N 120-11-14W, 33-14-46N 120-09-15W.
 2. THIS MSG 131900Z JUL 21.


 060353Z JUL 21
 NAVAREA XII 305/21(18).
 EASTERN NORTH PACIFIC.
 1. HAZARDOUS OPERATIONS 100900Z TO 101800Z JUL,
    ALTERNATE 130900Z TO 131800Z JUL
    IN AREA BOUND BY
    32-32-16N 129-10-43W, 32-08-05N 131-47-11W,
    31-53-04N 131-45-39W, 32-17-48N 129-09-11W.
 2. CANCEL THIS MSG 131900Z JUL 21.


 060445Z JUL 21
 NAVAREA XII 306/21(19).
 EASTERN NORTH PACIFIC.
 1. HAZARDOUS OPERATIONS 100900Z TOP 101800Z JUL,
    ALTERNATE 130900Z TO 131800Z JUL
    IN AREA BOUND BY
    31-13-21N 136-21-34W, 31-04-36N 137-16-57W,
    30-49-37N 137-15-27W, 31-01-22N 136-20-03W.
 2. CANCEL THIS MSG 131900Z JUL 21.

Below I have plotted the areas from these three Navigational Warnings on a map:

click map to enlarge

The three areas seem to define a ballistic trajectory for a missile fired, either from a ship, submarine or aircraft, in the Point Mugu Sea Range near the Channel Islands of California, in the general direction of (but maybe not as far as) Hawaii. The distance between the easternmost and westernmost area from the Navigational Warnings is about 1600 km. The distance to Hawaii is about 3950 km.

The question is whether the apparent line-up with the Pacific Missile Range Facility at Hawaii (for which there is a perpetual Navigational Warning) is coincidence or not (the map below shows a simple ballistic trajectory from the esternmost area in the Point Mugu Sea Range to Hawaii PMRF: the three areas and PMRF line up well):

click map to enlarge

If the line-up with Hawaii is coincidence, i.e. if we ignore a possible target area near Hawaii, then one option is that this is a flight test of the AGM-183A ARRW (Air-launched Rapid Response Weapon), a hypersonic missile launched from a B-52 aircraft. Little is known about the range of this new missile, and estimates differ: from 925 km to a quoted "almost 1000 miles". 

The latter is somewhat similar to the ~1600 km range between the easternmost area (NAVAREA XII 304) and westernmost area (NAVAREA XII 306) from the current Navigational Warnings. However, the similarity between "925 km" and "almost 1000" also makes me wonder whether kilometer and miles were mixed up in the latter statement. 1600 km equals 994 statute miles, or 863 nautical miles. 

Early June 2021, a test firing of AGM-183A was announced to probably take place this month (July 2021), which is one reason to suspect a connection of these Navigational Warnings to AGM-183.

If these Navigational Warnings indeed do refer the announced July AGM-183 test, then area 304 is where the missile is fired (from an airborne B-52), area 305 where the booster stage splashes down, and area 306 likely the missile target area.

The last (failed) test attempt of AGM-183A was in April, according to sources. It failed because the missile refused to separate from the aircraft.

The areas from the three July 10 Navigational Warnings are 100% identical those those of three earlier Navigational Warnings issued for May 17 (which I at that time, mistakenly probably, thought might be an SLBM test): Navigational Warnings NAVAREA XII nr 210, 211 and 212:

 


So either there was an aborted/failed test attempt in May as well, or these warnings (both the current and those for May 17) do not refer to AGM-183A.

The AGM-183A ARRW is a hypersonic missile fired from a B-52 aircraft. A rocket stage initially propels it and brings it to high altitude at the edge of space (i.e. not as high as an ICBM which truly enters space), after which it glides down and attains hypersonic speeds up to 6.86 km/s. It is still in its experimental phase with, as far as known, no successful test flight yet.


AGM-183 under the wing of a B-52 during a Captive Carry test. Image: US DoD (Giancarlo Casem)

 

EDIT: just after I hit the "publish" button Hans Kristensen alerted me to the arrival of an Ohio-class Nuclear Missile submarine in San Diego at July 7th. So, maybe an SLBM test after all (but not a standard Trident-II D5 test then, as the positions of the drop zones do not match with earlier Trident tests).


UPDATE 11 July 2021:

This Navigational Warning cancelling warnings NAVAREA XII 304, 305 and 306 just appeared, the wording of which ("operations completed") suggests that something did take place:

101832Z JUL 21
NAVAREA XII 314/21(18).
EASTERN NORTH PACIFIC.
CALIFORNIA.
CANCEL NAVAREA XII 304/21, 305/21, 306/21
AND THIS MSG, OPERATIONS COMPLETED.

Wednesday, 7 July 2021

Imaging objects from the 'Tubular Bells' launch

image: Virgin Orbit

During the first days of July, I have tried to image objects from the June 30 Virgin Orbit 'Tubular Bells' launch, that launched a number of smallsats including Brik-II, the first Dutch military satellite (see earlier posts here and here).

I so far managed to unambiguously image three objects from the launch. One of these is probably the LauncherOne upper stage, the other two must be payloads.

On July 2nd, I imaged objects A and B, A using a 2.0/135 mm and B using a 1.4/85 mm lens on the WATEC 902H2 Supreme low light level video camera. B was very faint and barely visible.

On July 4th, I unambiguously imaged objects B and H using a 2.0/135 mm lens.

Object A is relatively bright and well ahead of the other objects. It is in a somewhat lower orbit: a 418 x 504 km orbit, whereas the other objects are in a 496 x 522 km orbit. So object 2021-058A almost certainly is the LauncherOne upper stage.

Below is video of the A-object, shot on July 2nd with the 2.0/135 mm lens. The bright star top left is Polaris. I could not see the other objects (passing about 30 minutes later): for passes to the north of me, the illumination angle is less favourable than for passes to the south of me.





 

The B and H objects are fainter, and only visible during passes to the south of me. The video below shows them, faint but unmistakenly, during a pass in evening twilight on July 4th (sun at only 7 degrees below the horizon, so the sky background was still quite bright).

 


A fourth object, Object C, was possibly seen on July 2nd when I watched the pass live on screen, but I could not see it anymore when inspecting the footage afterwards. 

Objects D, E, F and G were not seen, but on all imaged passes observing conditions were not perfect (on July 2, cirrus clouds were invading the FOV around the time of the objects D, E, F and G passing; while on July 4th the sky background was still very bright).

It is not clear which object is which at the moment, although I have reasons to believe that Brik-II must be either object D, E or F. I have some suspicion that objects B and H are part of STP27-VPA. [edit: see updates below: Object H was, but B is not)

 

UPDATE 14 Jul 2021:


Object B actually appears to be one of the STORK satellites, based on Dopplerfitting of  radiosignals received at 401.1 MHz (and first detected by Alicja Musial in Poland). Object C also appears to be a STORK, based on Doppler fitting of the radio signal.. 

Objects D and E are now listed by CSpOC as CNCE3 and CNCE1, which are part of STP27-VPA.

Objects F, G and H then are Brik-II, Gunsmoke-J and Halo-NET (the latter two are part of STP27-VPA), with not certain which is which.





UPDATE 16 Jul 2021

Object F is now identified as Brik-II. Object H (One of the two objects I imaged on July 4) is now identified as Gunsmoke-J 2

As, from radio Doppler fitting, we know objects B and C are the STORKS (not yet identified as such by CSpOC), this means object G must be Halo-NET:

Object A    LauncherOne rb

Object B    Stork

Object C    Stork

Object D    CNCE3*

Object E    CNCE1*

Object F    Brik-II

Object G   Halo-NET*

Object H    Gunsmone-J 2*

* part of STP27-VPA

Bob Christy has pointed out that there might be a swap of the A and G designation in the future, to make the A designation a payload rather than the RB.

Saturday, 3 July 2021

OT (but missile related): on Ian Fleming, Bond, and the fictional Moonraker ICBM



 Note:  an update was added at the end of the post, a day after initial publication

Recently, I was re-reading Ian Fleming's 1955 James Bond novel 'Moonraker'. The plot of this novel revolves around an ICBM test launch from a site on the coast of Kent. Re-reading the novel, I exclaimed at some point: "Ha, obviously a lofted trajectory!'.

 

 

That started me down a rabbit hole, for my next thoughts were: does the Moonraker test-flight and distances mentioned in the novel make sense? What if I modelled it in STK? 

So I tried, and discovered amongst others that Fleming apparently mixed up nautical miles and kilometers at some point. And used his car to measure distances.

 

Moonraker: the novel, not the movie

First, since most people will be familiar with the movie rather than the novel: the plot of the 1979 movie 'Moonraker' is quite different from the plot of the 1955 novel

Basically, the only things they have in common are the title and the name of the villain. In addition, both plots involve rocketry (but of a very different kind).

The 1979 plot of the movie starring Roger Moore involves Space Shuttles (one of which is named 'Moonraker') launched from the Jungle of Brazil; a stealth Space Station, (that has a radar cloaking device, totally ignoring that optically it would still be very visible and a naked eye object in the sky); and a plan by a megalomaniac Space Entrepreneur, Hugo Drax, to bombard Earth from that Space Station with a gas meant to exterminate the whole Earth population, except for a suspiciously Arian elite aboard his Space Station.

The 1955  novel plot on the other hand has no Space Shuttles and no Space Stations and, unusual for a Bond novel, all action takes place in the UK. The plot entirely revolves around the test launch of an experimental ICBM called 'Moonraker', developed by a megalomaniac entrepreneur called Hugo Drax, from an RAF test site on the coast of Kent in the UK. 

 

my 1965 Signet Book copy of the novel

 

The 1955 Moonraker plot

Let us first go into the plot of the novel a bit more in detail, for those not familiar with it, in order that you will better understand the analysis that will follow. Those of you who know the book, can move on to the next part of this post.

Somewhere in the first half of the 1950-ies, the development of a British ICBM and ICBM test site on the coast of Kent is being funded by a wealthy mineral merchant called Sir Hugo Drax, who ostensibly offers this service as a patriotic coronation present to the newly crowned Queen Elizabeth II. The ICBM, called 'Moonraker', is meant to end the danger of a new war (note that the book was written less than 10 years after the end of World War II) because it will be able to strike any European country trying to atom-bomb London. There is nuclear deterence for you, in a 1950-ies novel!

Sir Hugo Drax, the villain, has a shady history. He purports to be a former British soldier who is a survivor of a Nazi Werwolf attack at the end of WW-II, the bombing of an Allied Headquarters. In reality, he perpetrated that bombing but was caught up in the resulting explosion, after which he took on the identity of one of the British casualties. His real name is Graf Hugo von der Drache, and he is a German Nazi and former SS officer c.q. Werwolf operative, who is longing for revenge on Britain for the German defeat in WW II. 

He hatches a plan where, using his post-war accumulated wealth from the trade in Columbite (a metal vital for rocket engines) and his Columbite stash, he develops and builds the Moonraker, a single stage ICBM with a range of 4000 miles, ostensibly for the British Government. 

The rocket is to be launched from a RAF facility on the chalk cliffs of Kent, on the Channel coast between Kingsdown and St Margaret's Bay. The target for the test launch is an empty part of the North Sea some 80 miles from the launch site  (i.e. it is launched on a highly lofted trajectory). Drax, however, plans - and nearly succeeds were it not for the interference by Bond - to illicitly swap the instrument payload for a nuclear warhead, and target Buckingham Palace instead. He has hidden a homing device for that purpose in a house on Ebury Street, London, close to the Palace. He is in cahoots with the Soviets, who supply him with the nuclear warhead as well as a 50-man crew of German ex-Werwolf and rocket experts from Peenemünde. They also attempt to provide him an escape by submarine.

James "007" Bond has his first encounter with Drax when his MI6 superior M wants him to investigate whether Drax cheats at cards (!) at the private Club 'Blades' of which M is a member. Drax does indeed cheat, and Bond then tricks him in overplaying his hand, causing Drax to lose 15000 British Pound to Bond.

Shortly after that, Bond meets Drax again as Bond is send on loan to Scotland Yard Special Branch, after one of the Ministry of Supplies' security agents on the Moonraker site, Tallon (who had discovered something was afoot, having spotted the Soviet submarine delivering the nuclear warhead to Drax), is murdered. With the help of a Special Branch agent already embedded in the facility, a female agent called Gala Brand (interestingly, one that proves immune to Bond's charms), he tries to find out what secret the facility is hiding. Following an assasination attempt on Bond and Brand and some further shenanigans, Brand is found out and kidnapped after she steals Drax notebook, and realises that the gyroscope settings for the test flight have been changed such that it will come down at another target than the empty piece of North Sea intended (this target turns out to be Buckingham Palace: Drax has hidden a radio homing devive in a house on Ebury Street close to Buckingham Palace). 

After Bond, in pursuit of the car with the kidnapped Brand, is captured too, Drax unveils his personal history and evil revenge plan to them, and places them, bound, in the Moonraker launch silo, with the intention that the exhaust flame from the launch will burn them to ashes. Bond and Brand manage to get rid of their constraints, change the gyroscope settings back to the original values, close the explosion-resistant metal doors between the silo and Drax office, and lock themselves in the shower of Drax' office, letting the water run, to survive the blast (and there you though Indy locking himself in a fridge in "Indiana Jones and the Kingdom of the Crystal Skull" was jumping the shark!). The Moonraker is launched, and Drax and his men are picked up by the Soviet submarine that speeds off towards the north, into the original target area. Upon impact of the Moonraker in the target area in the North Sea, the nuclear warhead explodes, causing a tsunami that sinks the Soviet submarine (all hands on board including Drax perish) and incidentally also creates havoc on the Dutch coast. 


Leads and information from the novel

Fleming provides several pieces of information on the Moonraker ICBM and the locations involved in the plot that are hepfull for this analysis.

1. the Moonraker facility in Kent

The location of the RAF facility from where Moonraker is launched is at the edge of a chalk cliff near Kingsdown and St. Margaret's Bay on the coast of Kent, overlooking the English Channel. The flame trench (rather a tunnel) of the launch silo ends on the beach. The location can be positively geolocated to the grounds of the Walmer and Kingsdown Golf Club, at about 51.17 N, 1.40 E (see image below). The Golf Course, established in 1909, was requisitioned by the British Government during World War II and turned into a facility for the Army, RAF and Royal Navy. After the war, in 1948, it was handed back and turned back into a golf course. 

For the purpose of the novel, Fleming let the Ministry of War hold on to the site for a few more years than they in reality did.

 

location of the fictional Moonraker site, between Kingsdown and St. Margaret's Bay

 

Ian Fleming in fact was very familiar with this area of Kent. He had a lease on a cottage on the beach of St. Margaret's, called "Summer's Lease", just 2.5 km south of the site, where he spent long weekends and hollidays with his wife and friends. Given his wartime background in Navy Intelligence, the existence of the former military facility close to his weekend hideout will certainly have been known to him, even though it was no longer used by the Government by the time he wrote his novel.

2. The location of the homing device at Ebury Street, London

Drax' house near Buckingham Palace in London, where he places the radio homing device for the Moonraker, is described as 'a small house at the Buckingham Palace end of Ebury street' and 'just behind Buckingham Palace'. From the description given when Bond is in pursuit of Drax' car with the kidnapped Gala Brand (who is initially brought to the Ebury Street house), it must be only a few meters from the corner of Lower Grosvenor Place and Ebury Street (this is called Beeston Place now but formerly was part of Ebury Street), near the corner with Victoria Square, at approximately 51.4979 N, 0.1455 W.

 

location of Drax' fictional house on Ebury Street (image: Google Streetview)

 

This is indeed very close to Buckingham Palace: some 350 meters from the Palace building itself, and only a hundred yards (as stated in the novel) from the surrounding Palace grounds.

Again, this was a familiar spot for Fleming: between 1936 and late 1939 he himself lived in Ebury Street, at number 22B, some 250 yards further along the road (a little bit too far to entertain the idea, as I initially did, that the house in question actually is meant to be number 22B: this would however not fit the location descriptions well). Interestingly, the previous tenant of the same appartement had been the infamous British Fascist leader Oswald Mosley.

 

Ebury Street 22B, London, Fleming's former home (image: Google Streetview)


Moreover, around the time he was writing 'Moonraker', Fleming and his wife Ann lived (when in London and not at their Goldeneye estate in Jamaica, where Fleming did most of his actual writing) very close to the actual location indicated: at 16 Victoria Square. This is only some tens of meters (!) from the indicated location in Ebury Street, in what is basically a side street of it (see Google Earth image below). This would place Drax' house and the hidden radio homing device almost in Fleming's proverbial backyard!

[added note: pretty much the same conclusions are reached in this blogpost on the "Mapping the World of James Bond" blog, which I only found after I wrote mine].

Fleming's Victoria Square residence. Ebury street at left.


3. The effects of a nuclear bomb detonation in this location

So what would the effects be, on Buckingham Palace and London, of a nuclear detonation at the indicated spot on Ebury Street?

This of course depends on the yield of the nuclear warhead. The warhead in question is provided by the Soviets in the novel. It stands to reason that it could have been an RDS-4,  a 28 kiloton device that was first tested by the Soviets on August 23, 1953. It was their first mass-produced atomic bomb, compact, weighing 1200 kg, and went on to become one of the warheads used on the first Soviet strategic nuclear missile, the medium range R-5M (or SS-3).

So what would a 28 kiloton RDS-4 detonation in Ebury street do? I turned to Alex Wellerstein's fabulous NUKEMAP website to answer that question. Below are three maps, the first two for a ground detonation (second map is a detail of the first), the third for a detonation at 600 meter altitude:


28 kiloton ground detonation. Click to enlarge

28 kiloton ground detonation: detail of ground zero. Click to enlarge

 

28 kiloton airburst at 600 meter. Click to enlarge
 

The results would be dramatic for both central London and Buckingham Palace (and a much wider area of southeast Britain when we consider the nuclear fall-out). Buckingham Palace would indeed be in the major devastation zone, with almost certain 100% casualties.

Drax' attempt to bomb London was eventually foiled by Bond and Brand. But how about the original test target in the North Sea: where would that be located?

 

4. The location of the Moonraker test target area in the North Sea

Here, we run into a bit of a problem: Fleming's descriptions of where the North Sea test target area is located, are ambiguous, as distances and descriptions given by him do not fit each other

He mentions a distance of '80 miles' from the launch site, but also describes it as being on a line 'between the Frisian Islands and Hull'. These two indications cannot be well reconciled as the mentioned line Hull-Frisian Islands is much further away than 80 miles, in fact over twice as far, close to 280-290 km or 175-180 miles (depending a bit on which of the Dutch Frisian islands you take). I will return to this later in this post.

What is also implicated in the novel, is that the bearing of this location as seen from the launch site is at an approximate 90 degree angle to the bearing of the secret target in London. This would place the bearing to the North Sea target site as seen from the Moonraker facility in Kent at about 19.5 degrees from north. This bearing would intersect a line between Hull and the Frisian Islands at about the middle of the latter line, near 53.2 N, 2.6 E, some 80 km from the nearest British and 145 km from the nearest Dutch coast: which seems very reasonable if you want it to be as far as possible from any land, at that range. By contrast, a distance of 80 miles along this bearing would place the spot much closer to the British coast, at around 52.26 N, 2.03 E, about 25 km out of the coast near Lowestoft.

Fleming seems to have choosen the "80 miles" value in order to get a similar distance between the Kent launch site and the North Sea target area, as the distance between the Kent launch site and Ebury street in London. This reveals something interesting: the real distance to Ebury street as seen from the Walmer and Kingsdown site is actually a bit shorter than 80 miles: 114 km or about 71 miles, 10 miles short. So why the '80 miles' then?

The likely answer is that Fleming did not take this distance from a map, but measured it by driving the distance in his car (or rather, have his stepson do that). Google Maps tells me that the road distance (as opposed to the distance as-the-crow-flies) between Fleming's house in St. Margaret's Bay and Ebury street in London is 81 miles. It is known that Fleming actually had his stepson drive the distance in order to check the fastest possible driving time between the two locations (which he needed for the car chase scene when Gala Brand is kidnapped and brought to Ebury Street).

Incidentally, the value helps establish that the miles mentioned in the novel are statute miles, not nautical miles. This is relevant, as in rocketry either kilometers or nautical miles are generally used, while Fleming, as a former Navy Intelligence officer, would have been familiar with nautical miles too. The average British novel reader on the other hand, would interpret 'miles' as statute miles, and that is what they appear to be here.

There is a potential for confusion here, and perhaps that is what happened and created the mismatch between '80 miles' and 'on a line between Hull and the Frisian Islands'.

Let us plot some of these distances (and the highly lofted trajectories involved) in a map. This is an oblique view of the situation, created with STK: note that the indicated 80 mile radius is in statute miles, while the outer circle, touching the line between Hull and the Frisian Islands, is 129 nautical miles instead (I did this for a reason, see below). For reference, 1 statute mile = ~1.6 km, and 1 nautical mile = ~1.8 km.


click to enlarge

One way Fleming could have introduced the erroneous description of the target area being "on a line between Hull and the Frisian islands" is by plotting the distance on a nautical map, e.g. an Admiralty chart, and making a mistake with the map units (perhaps after a drink too many). 

The 1950-ies era Admiralty charts had drawn scale bars in feet, nautical miles and meters, but not in statute miles, so Fleming might have converted statute miles to (kilo-) meters. Since 80 statute mile equals ~129 km, did Fleming perhaps by mistake plot 129 nautical miles instead of 129 kilometer? This would bring you close to a line between Hull and the southernmost of the Frisian Island. 

Alternatively, he could have mistakenly converted 180 miles instead of 80 miles, to kilometers (180 statute miles is ~290 km), which would bring you slightly further out, on the line between Hull and the northernmost Frisian Islands, at about 155 nautical miles.

5. The Moonraker maximum range and delta V

Before going to Drax' Kent facility, Bond is briefed on the Moonraker missile. From this briefing, we learn that the missile has a range of about 4000 miles (6437 km), apogee (the highest point it reaches above earth surface) at 1000 miles (1609 km), and can reach a speed of 15000 miles an hour. The latter translates to about 6.7 km/s.

Using STK, I modelled a missile trajectory with a range of 6437 km and apogee at 1609 km. For such a trajectory, I get a delta V of 6.44 km/s, or about 14417 miles/hour, so Fleming's ~6.7 km/s is not far off, certainly if we allow the "15000 miles per hour" to be a rounded-off value (during te briefing, this is said to be a value "in te neighborhood off"). In that sense, the specifications of the Moonraker appear realistic and correct.

The Moonraker itself is a single stage rocket: from the descriptions basically a V2 on steroids. That raises some eyebrows given the quoted 6400 km range. While both the USA and Soviet Union worked on single stage ICBM designs during the 1950-ies, none of this ever went beyond the design stage, and that was probably for a reason. The closest to it that did fly (and here I am obliged to the combined Hive Mind of Missile Twitter for their help) and had a range similar to the Moonraker was the US SM-65 Atlas, which first flew in 1957. This was however a "1.5 stage" rocket as it had two auxiliary jettisonable side boosters.

But let that be, and let us accept the premise of a single stage Moonraker. With a 4000 mile (6437 km) range, the whole of Europe and a considerable part of the Soviet Union would be in range: only eastern Siberia would not be. In that sense, the Moonraker missile would fulfill its quoted deterence role.

 

click to enlarge

So what would be the apogee of the highly lofted Moonraker test shot into the North Sea?

I used the 6.4 km/s delta V value I calculated, to determine the apogee altitude for the lofted trajectory
(a 'lofted trajectory' is where you fire your missile at full engine capacity, so you can test its maximum performance, but limit your horizontal range, by firing it under a very high angle, almost straight upwards. This way you can monitor the missile over almost its full trajectory from the launch site, and avoid overflying neighbouring countries. North Korea for example did this on several of their ICBM test launches).

The 80 statute mile and 129 nautical mile ranges respectively give quite similar results: an apogee at 3169 resp. 3168 km altitude. Quite a lofted trajectory indeed! It is only slightly less than the 28 July 2017 North Korean lofted test of a (two stage) Hwasong-14 missile.

The image below shows a maximum range operational trajectory (red) for the Moonraker, as well as the lofted trajectories for target sites at 80 statute miles (solid white), 129 nautical miles (dashed white), and the secret London target (dashed yellow)

click to enlarge


Conclusions

Fleming appears to have done his homework well with regard to ballistic missiles: his speeds, apogees and maximum ranges match. He did make a curious mixup in defining the North Sea target area for the lofted trajectory test around which the novel revolves: his stated distance in miles does not match with the description of "on a line between Hull and the Frisian Islands". Perhaps, he mixed up kilometers and nautical miles when measuring distances on a map. 

As an aside, we can deduce that he measured the distance between the launch site on the Kent coast and the secret target near Buckingham Palace in London by driving the distance in a car, rather than measuring it on a map. 

All locations mentioned in the novel were familiar to Fleming, as he lived or had lived in houses quite near them. 

Conspicuously absent in the novel: grid fins!


ADDENDUM 4 July 2021

Following publication of this post, some great questions were raised on Twitter about the fate of the Soviet submarine. How could it get to the impact area so soon?


In fact, with such a highly lofted trajectory, it would take the Moonraker some 38 minutes to complete its flight, from launch to target impact, giving the Soviet submarine some time to travel northwards. And the Soviet submarine is not sunk by the immediate blast effect of the nuclear detonation, but by the resulting tsunami wave, which travels further than the blast wave.

BBC Radio reporter Peter Trimble, who due to the tsunami perishes aboard the HMS Erganzer while live-reporting the test flight, tells his audience that he and the Navy ship are just north of the Goodwin Sands, with the target area some "70  miles north" of him. He could see the Moonraker launch, "must have been ten miles away". So this all places him some 10 miles (16 km) from the launch site.

He sees the Soviet sub at a distance of about 1 mile, heading north towards the impact area. After it submerges, he tells the audience that the ASDIC operator says it is travelling at 25 knots, or about 46 km/h (this is a bit faster than the Soviet submarines of this era were actually capable off: their peak speed when submerged was near 16 knots). This means that from the moment of launch of the missile (when the submarine left with Drax cum sui) to the moment of impact of the missile, it could have travelled some 29 kilometers towards the target area. This would place it some 100 km south of the impact area (going from the "80 mile" figure for the impact area distance to the launch site) at the moment of impact and nuclear detonation. Not quite in the impact area, as Trimble suggests.

I used an online tsunami speed calculator to get an idea of how long it would take the tsunami wave generated by the nuclear explosion to reach the HMS Erganzer and the submarine. A look at a bathymetry-map shows that the relevant part of the North Sea is between 25 and 50 meters deep. Bond's superior M, at the end of the novel, mentions that the wreckage of the submarine is located at a depth of 30 fathoms, or 55 meter. If we go with that value, a tsunami wave would travel at a speed of about 23 meter/s (or 83 km/h). It would take it some 80 minutes to reach HMS Erganzer. It would reach the Soviet submarine, travelling towards the wave at 46 km/h, a bit earlier, roughly 50 minutes after the detonation. The submarine by then, assuming a course straight towards the impact point, would be some 70 km from the impact point when it meets the tsunami wave.

This clearly does not tally with the live radio report, which suggests the submarine is in visible range of the HMS Erganzer when the tsunami hits (with both vessels hit at about the same moment). It is also clear that the sequence of events would take much longer than the novel implies: in the novel, which quotes a verbatim live radio report, it looks like the events unfold in matters of seconds.

Of course it is all fiction, and Fleming never meant Bond's adventures to be a poster-child for realism, so we should not be surprised by these lapses in the plot. Although it surprises me that Fleming, as an ex Navy Intelligence Officer, get's the missile part quite right, but not the nautical part!

I have been looking for information on whether a 28 kiloton nuclear explosion would be able at all to generate a tsunami strong enough to create havoc at 100+ km from the detonation site. I found this but the math involved is a bit too complex for me. Some of the approximate scaling equations at the end of the book, which are however for deep water, would suggest it to be not a big deal at this distance, in fact.

As a last note: Trimble, in his radio broadcast, mentions at a certain moment: "Twelve minutes past noon. The Moonraker must have turned and be on her way down". If we take this to mean that apogee was reached at 12:12 GMT, then, given the trajectory I modelled in STK, we can determine that launch of the Moonraker was around 11:53 GMT. Bond manages to reset the gyroscopes four minutes before the launch moment, Fleming tells us, which would be 11:49 GMT then, which could fit as Fleming also tells us that Bond, looking at his watch when he does so,  is leaving his hiding place for the missile at 11:47. This gives him 2 minutes to get to the missile and do his thing, and then two more to get back from the missile to Brand at Drax' office. In fact he must have done it in a minute, as he spends at least one minute (as at some point he says "only one minute more [to launch]" in the office before the launch moment.


Sunday, 27 June 2021

Navigational Warnings have appeared for the launch of the first Dutch military satellite, Brik-II [UPDATED]

 

artist impression of Brik-II in space (The Netherlands Ministry of Defense)

It was originally scheduled for launch in 2019, and postponed several times. But it now seems it will finally happen, on or near June 30: the launch of the Netherlands' first own military satellite, a 6U cubesat named 'Brik-II'.

The ministry of Defense of the Netherlands is partner in several already launched military satellites, but this will be the first satellite that is truely it's own. 

Brik-II was built by the Dutch aerospace company ISISPACE in cooperation with Delft Technical University, Oslo University and NLR and will be operated by the Royal Netherlands Air Force (RNLAF).

It is a small 6U cubesat (10 x 20 x 30 cm, weighing 10 kg) that contains equipment for communications relay, for Space Weather monitoring, and for ELINT (see my earlier post on Brik-II here).

 


image: The Netherlands Ministry. of Defense

 

Brik-II will be launched by Virgin Orbit as part of their  'Tubular Bells, part 1' mission that launches a number of small payloads: apart from Brik-II for the RNLAF, it will launch three or four (sources differ on the number [edit July 1: it were four payloads]) payloads for the US Dept. of Defense, and two payloads for the SatRevolution company.

The launch is an airborne launch, using a two-stage LauncherOne rocket launched from the Virgin Orbit Boeing 737 747-400 'Cosmic Girl' in front of the California coast.


images: Virgin Orbit

The launch was postponed several times, including this month, but Navigational Warnings have now appeared indicating an aimed launch date of 30 June (with backup dates July 1-5). 

The 3-hour launch window runs from 13:00-16:00 UT [edit: launch eventually was at 14:47 UT]. According to Virgin Orbit, the orbit aimed for is a 60-degree inclined circular orbit at ~500 km altitude. [edit] An infographic by the Royal Dutch Air Force mentions an orbital inclination of 60.7 degrees.

This is the navigational warning, NAVAREA XII 292/21:

 262041Z JUN 21
 NAVAREA XII 292/21(18,21).
 EASTERN NORTH PACIFIC.
 CALIFORNIA.
 1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
    301300Z TO 301600 JUN, ALTERNATE
    1300Z TO 1600Z DAILY 01 THRU 05 JUL
    IN AREAS BOUND BY:
    A. 33-36-44N 120-23-05W, 33-24-22N 120-17-14W,
       32-55-44N 119-55-39W, 30-38-19N 118-13-14W,
       28-24-39N 116-37-52W, 28-03-32N 116-17-09W,
       28-10-00N 116-05-44W, 28-24-41N 116-11-12W,
       29-07-31N 116-36-05W, 30-50-51N 117-46-19W,
       33-08-50N 119-32-16W, 33-33-26N 119-54-35W,
       33-45-27N 120-06-00W, 33-43-27N 120-16-02W,
       33-36-44N 120-23-05W.
    B. 23-13-25N 112-20-09W, 23-51-12N 113-00-01W,
       24-04-05N 113-17-34W, 24-00-35N 113-35-42W,
       23-49-04N 113-49-26W, 23-23-22N 113-46-59W,
       22-46-17N 113-39-25W, 22-01-49N 113-03-13W,
       21-54-11N 112-57-20W, 21-46-52N 112-49-48W,
       21-41-03N 112-38-21W, 21-40-45N 112-26-55W,
       21-44-25N 112-12-12W, 21-52-03N 112-03-22W,
       22-03-39N 111-58-08W, 22-13-42N 111-57-29W,
       22-26-28N 112-02-59W.
 2. CANCEL THIS MSG 051700Z JUL 21.

I have plotted the two areas on the map below, along with the trajectory for a 60-degree inclined ~500 km orbit, with times along the trajectory valid for launch at 13:00 UT, the start of the window (it will, however, probably launch a little after that: the second map is for a 60.7 degree inclined orbit and denotes times in minutes after launch):

click map to enlarge
click map to enlarge

While Virgin Orbit mentions a 500 km target orbit for 'Tubular Bells', earlier news reports on Brik-II mentioned a 600-700 km orbital altitude.

Brik-II is named for an earlier 'Brik', the name of the very first aircraft of the RNLAF progenitor, the 'Luchtvaartafdeeling', 108 years ago, in 1913:


The first Brik, photographed in 1916. Photo: Netherlands Institute for Military History

 

"Brik" has several meanings in Dutch. Originally it was a name for a type of ship (equivalent to the English 'Brig'), and it was also used for carts. Later, it became a name for old bicycles and old, decrepit  cars. "Brik" in addition is one of several Dutch names for a brick, hence the mission patch for Brik-II:

Brik-II mission patch (collection author)

Update 1 July 2021:

CSpOC TLE's have appeared on Space-Track for 8 objects from the launch: the seven payloads and the LauncherOne upper stage. They have catalogue numbers 48871 to 48878. The first object, 48871, is in a lower orbit  of 418 x 504 km and almost certainly the LauncherOne upper stage. The seven others are close together in higher, approximately 495 x 522 km orbits, inclined between 60.66 to 60.70 degrees.

Of these objects, either object D, E, or F (catalogue nrs. 48874, 48875, 48876) appears to be Brik-II.

My pre-launch estimate for the orbit appears to have a quite reasonable agreement with the eventual orbits for these objects (the green arrow and object in the images below indicates my pre-launch estimate. the plot is for 1 July 6:35 UT,  about 16 hours after launch):



click images to enlarge

Thursday, 17 June 2021

An intriguing apparent Missile Defense (?) test from Kodiak and Kwajalein

 

click map to enlarge

A Navigational Warning issued on June 16 seems to point to a possible Missile Defense test on June 21, with missile launches from Kodiak Island in Alaska (the Pacific Space Port Complex) and the Kwajalein Test Range in the Marshall islands.

Below is the text of the Navigational Warning in question, NAVAREA XII 271/21, defining four areas A to D. I have mapped the areas in the map in top of this post, with one of several possible interpretations (in this interpretation, an interceptor is launched from Kwajalein to intercept an ICBM launched from Kodiak. The flight distance involved for the interceptor in this scenario does not sit well with me though).

160922Z JUN 21
NAVAREA XII 271/21(16,19,81).
GULF OF ALASKA. 
NORTH PACIFIC.
ALASKA. 
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING 
   210830Z TO 211430Z JUN, ALTERNATE 
   0830Z TO 1430Z DAILY 22 THRU 25 JUN 
   IN AREAS BOUND BY:
   A. 57-29N 152-20W, 57-20N 152-11W, 
      56-39N 153-28W, 56-41N 153-33W,
      57-11N 152-47W, 57-16N 152-43W,
      57-19N 152-38W, 57-21N 152-38W,
   B. 51-08N 160-22W, 50-58N 159-50W,
      51-01N 159-26W, 51-17N 158-58W,
      51-42N 158-35W, 52-29N 158-16W,
      52-32N 158-24W, 51-51N 159-35W,
      51-23N 160-14W.
   C. 33-50N 171-41W, 33-44N 171-27W,
      36-52N 169-25W, 38-40N 168-15W,
      39-58N 167-47W, 40-02N 167-59W,
      39-15N 168-39W, 38-27N 169-18W,
      37-05N 170-02W.
   D. 12-45N 172-48E, 08-11N 166-38E, 
      08-56N 166-01E, 13-34N 172-11E.
2. CANCEL THIS MSG 251530Z JUN 21.

There is an additional Navigational Warning, NAVAREA XII 270/21, defining several areas west of Hawaii for several dates around the possible test, in the general area where the launch trajectories from Kodiak and Kwajalein seem to meet. One of the dates issued (nr 2, highlighted in red) has a time window that, while not similar, does overlap with the time window of warning NAVAREA XII 271/21:

150910Z JUN 21
NAVAREA XII 270/21(19).
NORTH PACIFIC. 
1. HAZARDOUS OPERATIONS 192100Z TO 201000Z JUN 
   IN AREA BOUND BY 
   22-42.0N 172-13.0W, 22-28.2N 171-01.3W, 
   21-08.4N 171-20.8W, 21-22.0N 172-35.0W.
2. HAZARDOUS OPERATIONS 202100Z TO 211000Z JUN 
   IN AREAS BOUND BY:
   A. 30-37.0N 169-02.0W, 30-13.0N 167-20.0W, 
      29-07.0N 167-41.0W, 29-24.0N 169-04.0W.
   B. 24-05.0N 171-50.0W, 23-50.7N 170-36.7W, 
      22-28.2N 171-01.3W, 22-42.1N 172-13.0W.
   C. 23-06.0N 178-55.0W, 23-06.0N 175-15.0W, 
      21-40.0N 175-15.0W, 21-40.0N 178-55.0W.
   D. 22-00.0N 167-58.0W, 22-00.0N 166-36.0W, 
      20-19.0N 166-36.0W, 20-19.0N 167-58.0W.
3. HAZARDOUS OPERATIONS 212100Z TO 221000Z JUN 
   IN AREAS BOUND BY: 
   A. 29-10.0N 169-54.0W, 28-25.0N 167-54.0W, 
      27-28.0N 168-11.0W, 28-06.0N 170-23.0W.
   B. 23-50.7N 170-36.7W, 23-37.0N 169-28.0W, 
      22-14.8N 169-48.4W, 22-28.2N 171-01.3W.
   C. 23-06.0N 178-55.0W, 23-06.0N 175-15.0W, 
      21-40.0N 175-15.0W, 21-40.0N 178-55.0W.
   D. 22-00.0N 167-58.0W, 22-00.0N 166-36.0W, 
      20-19.0N 166-36.0W, 20-19.0N 167-58.0W.
4. HAZARDOUS OPERATIONS 222100Z TO 231000Z JUN 
   IN AREAS BOUND BY: 
   A. 28-06.0N 170-12.0W, 27-28.0N 168-11.0W, 
      26-30.0N 168-27.0W, 27-00.0N 170-30.0W.
   B. 22-28.2N 171-01.3W, 22-14.8N 169-48.4W, 
      20-55.0N 170-08.0W, 21-08.4N 171-20.8W.
   C. 20-19.0N 170-20.0W, 20-29.0N 168-01.0W, 
      18-01.0N 168-01.0W, 18-01.0N 170-20.0W.
5. HAZARDOUS OPERATIONS 232100Z TO 241000Z JUN 
   IN AREA BOUND BY 
   20-19.0N 170-20.0W, 20-29.0N 168-01.0W, 
   18-01.0N 168-01.0W, 18-01.0N 170-20.0W.
6. CANCEL THIS MSG 241100Z JUN 21.


It is not clear whether these Navigational Warnings really are related to the Navigational Warnings from NAVAREA XII 271/21. They might be, or might not be. If they are, this might be one of several possible interpretations, pointing to a multiple target intercept where both a missile fired from Kodiak and a missile fired from Kwajalein are to be intercepted:

click map to enlarge

When I presented the evidence for a possible 21 June Missile Defense test on twitter, there were some suggestions that this might be the planned test FTT-21

However, what is known of that planned FTT-21 test suggests the target(s) for that test should be SRBM, i.e. a missile with a range of no more than 1000 km. Which is at odds with what seems to be indicated by the Navigational Warnings, with the missile fired from Kodiak  apparently flying at least 6000 km (assuming areas A to C, blue in the map, define the trajectory of one and the same missile) and the Kwajalein missile at least 1800 km if it is to intercept the Kodiak missile or if it is to be intercepted from area B of the second Navigational Warning (the red area A in the map above). That would be ICBM and IRBM targets, not SRBM targets.

In other words: it is not clear what is going on here, which makes this an interesting issue.


Monday, 14 June 2021

USA 224 has manoeuvered

During the night of June 12-13, I was doing a periodic checkup on the KH-11 Advanced Enhanced CRYSTAL satellites  USA 224 (2011-002A) and USA 314 (2021-032A) that occupy the KH-11 primary East plane. This because I expect USA 224 to manoeuvre to the secondary East plane at some point this summer, now USA 314 has recently been launched into its orbital plane as a replacement (see discussion in my earlier blogpost here).

USA 224 did not appear at the nominal time on June 13 but some 2m 20s late, indicating a manoeuvre.

Observations by David Brierley and me on June 12/13 and 13/14 have established this preliminary post-manoeuvre orbit:

USA 224                                                  255 x 998 km
1 37348U 11002A   21165.00715133 0.00014912  00000-0  12302-3 0    05
2 37348  97.8892 276.6083 0530502 157.6427 204.8870 14.81006602    06


It is clear that this is not the big plane-changing manoeuver expected, but a small regular orbit upkeeping manoeuvre: apogee was raised by some 10 km. 

From the pre- and post-manoeuvre orbit,  I calculate that the manoeuvre took place on Thursday June 10 near 14:14 UT, over the Atlantic, during crossing through the descending node and perigee. 

As usual, the manoeuvre happened while perigee was situated over the equator (when the Mean Anomaly is near 180 degrees, this is always a moment to watch out for manoeuvres). This allows to make adjustments in both orbital altitude and inclination in the same burn, with a minimum expense of fuel.

Observing TacRL-2/Odyssey and it's Pegasus upper stage

 

I observed the Space Force's new Odyssey/TacRL-2 satellite last light, some 15.5 hours after it's airborne launch on a Pegasus-XL rocket (see previous blogpost). The Pegasus upper stage of the launch was observed as well, close to the payload.

They can both be seen in the video above, shot with a WATEC 902H2 Supreme and Samyang 1.4/85 mm lens. Which of the two objects is which is unclear at the moment: the identities have switched between successive orbit updates.

The bright object moving at a tangent at 23:43:23 UT is a Starlink satellite. While observing over the past few nights, the by now ubiquitous and still growing number of Starlink satellites was very apparent. There isn't a minute that one doesn't pass through the field of view. They have a large range in brightness.

Saturday, 12 June 2021

NROL-111 and TacRL-2: two upcoming classified launches [UPDATED]

click map to enlarge

 

Two classified launches are slated for the second week of June. One is the launch of TacRL-2, on 13 June at 8:11 UT. The other is NROL-111 on June 15 between 10:00 and 15:30 UT [edit: a potential launch time of 11:00 UT has now been announced]. Both are launched by Northrop Grumman, on behalf of respectively the Space Force and the NRO.

 

TacRL-2

TacRL-2 is described as a "Space Domain Awareness" technology demonstration satellite that is part of the "Tactically Responsive Launch Program" (hence "TacRL") of the US Space Force. The satellite was reportedly developed in less than a year time.

It will be an airborne launch, on one of two remaining Northrop Grumman Pegasus-XL rockets carried by a Lockheed L1011 Tristar aircraft. The launch will be over the Pacific, near California.

The Navigational Warnings issued point to launch into a polar Low Earth Orbit with orbital inclination near 96 to 98 degrees. Below are the Navigational Warnings, which I have also mapped in the map above:

090844Z JUN 21
NAVAREA XII 257/21(18,83).
EASTERN NORTH PACIFIC. 
CALIFORNIA. 
1. HAZARDOUS OPERATIONS 0739Z TO 0855Z DAILY 
   13 AND 14 JUN IN AREAS BOUND BY:
   A. 35-19N 123-44W, 35-13N 122-58W, 
      31-11N 124-05W, 31-16N 124-30W.
   B. 29-34N 125-03W, 29-28N 124-29W, 
      27-32N 124-53W, 27-38N 125-26W.
   C. 20-19N 127-23W, 20-02N 125-41W, 
      15-26N 126-30W, 15-43N 128-11W.
   D. 01-20N 131-46W, 00-35N 127-20W, 
      01-52S 127-44W, 01-06S 132-11W.
2. CANCEL THIS MSG 140955Z JUN 21.
 
080051Z JUN 21
HYDROPAC 1691/21(83).
EASTERN PACIFIC.
DNC 06, DNC 13.
1. HAZARDOUS OPERATIONS, SPACE DEBRIS 130809Z TO
   130840Z JUN AND 140809Z TO 140840Z JUN
   IN AREA BOUND BY
   01-20N 131-46W, 00-35N 127-20W,
   01-52S 127-44W, 01-06S 132-11W,
   01-20N 131-46W.
2. CANCEL THIS MSG 140940Z JUN 21.

In my initial assessment I suggested a 98-degree sun-synchronous orbit as a possibility [EDIT: and it turns out that I was right in that: the payload has been catalogued in a 97.48 degree inclined orbit, catalogue nr 48844]; but I have since revised that assessment based on sensible comments by Bob Christy. His ~96-degree inclined orbital suggestion indeed fits the hazard areas well. Yet, my initial suggestion of a sun-synchronous orbit cannot be totally discounted either [EDIT: see earlier remark: it in fact *is* in a sun-synchronous orbit near ~98 degree inclination, and I am therefore very happy that I included this statement...]. In the map in top of this post, I have plotted the 96-degree inclined option.

UPDATE (13 Jun 11:20 UT): TacRL-2 launched successfully. According to the Space Force, the satellite is named Odyssey.

UPDATE (13 Jun 21:00 UT): Odyssey/TacRL-2 has been catalogued by Space-Track under catalogue nr. 48844, in a 405 x 452 km, 97.48 degree inclined orbit. The orbit is, against expectations, not classified.


NROL-111

Two days after TacRL-2, Northrop Grumman will launch another mission, NROL-111, this time for the NRO. The launch will be on June 15,with a launch window between 10:00 and 15:30 UT. [EDIT: in a tweet, the NRO has now announced 11:00 UT as the launch time)

It concerns the launch of three unspecified small payloads on a Minotaur I rocket. The launch will be from Wallops Pad 0B (Press Kit here). The Navigational Warnings (see below) point to launch into a ~50-degree inclined Low Earth Orbit:

110950Z JUN 21
NAVAREA IV 488/21(GEN).
WESTERN NORTH ATLANTIC. 
VIRGINIA. 
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
   151000Z TO 151530Z JUN, ALTERNATE 
   1000Z TO 1530Z DAILY 16 THRU 21 JUN 
   IN AREAS BOUND BY:
   A. 37-57-27N 075-27-32W, 37-38-42N 074-52-00W,
      37-24-46N 075-06-02W, 37-41-36N 075-37-02W.
   B. 36-46-37N 074-55-59W, 37-18-40N 074-06-36W, 
      37-01-44N 073-19-30W, 36-27-47N 072-14-49W, 
      35-59-28N 072-14-38W, 35-30-18N 073-03-54W, 
      35-39-00N 074-02-06W.
   C. 30-10-19N 069-45-00W, 33-31-19N 067-19-52W, 
      30-57-14N 064-49-52W, 29-31-30N 067-11-42W. 
   D. 07-00-00N 048-09-43W, 10-19-01N 044-06-50W, 
      06-14-02N 038-38-13W, 01-44-13N 043-46-37W.
2. CANCEL THIS MSG 211630Z JUN 21.

 

I have plotted the Navigational Warnings in the map below (click to enlarge):

click map to enlarge

 

We can only speculate about the possible functions of the NROL-111 payloads, and the same is true for TacRL-2 ("Space Domain Awareness" broadly suggests the latter is keeping an eye on other satellites). Both missions appear to be experimental. With regard to NROL-111, I just note that orbital inclinations near 50 degrees lately have become very popular with the NRO for some reason.

Sunday, 23 May 2021

From what altitude does space debris drop vertically?

While gearing up for the CZ-5B reentry in the first week of May, an interesting exchange developed on Twitter between @SpaceTrackOrg, @DutchSpace and me, regarding the way space debris falls down in the last few tens of kilometers before hitting ground surface

It was triggered by the comment by @SpaceTrackOrg that the coordinates in their TIP messages typically refer to the object at 10 km altitude, not ground level:


As I pointed out in the Twitter thread, increasing drag acting on the fragments during reentry will not only make them start to ablate (and fragment), but will also slow them down, to a point where they finally have lost all initial forward momentum. From that point onwards they drop straight down.

During that tweet exchange, I decided to prove my point to initial disbelievers with a General Missions Analysis Tool (GMAT) model. I constructed an orbit for a hypothetical satellite about to reenter. I next ran this object through a GMAT model, modelling descent through the MSISE90 model atmosphere: initially for a 10 kg mass and 1 m2 drag surface, but later I ran the model for 5 kg and 50 kg masses too, capturing a range of area-to-mass ratio's. The initial speed was orbital (7.4 km/s) and the starting orbital altitude was 80 km, just below the tipping point between orbital and suborbital altitude (in this way, rapid reentry in the model was assured).

The movement in latitude and longitude from the model output was next converted to movement in meters at the earth surface (I did this in QGIS), i.e. horizontal displacement, yielding this diagram that maps the horizontal component of movement of each fragment against atmospheric altitude:

click diagram to enlarge

As can be seen, all three objects indeed reach a point where horizontal movement becomes essentially zero - they drop down vertically from a certain point. 

These points where the horizontal movement becomes zero are located at about 45 km altitude for a 5 kg object  (with a 1 m2 drag surface), about 35 km for a 10 kg object (with 1 m2 drag surface), and about 25 km for a 50 kg object  (with 1 m2 drag surface).

So our GMAT model demonstrates what I argued: from a certain point, well above 10 km atmospheric altitude, fragments from a reentry loose their forward momentum and basically start to drop down vertically, essentially a free fall.

But the reality is, of course, a bit different and more complex than this model suggests. Apart from atmospheric drag and gravity, there is another force that starts to act on these fragments once in the (upper) atmosphere, one that GMAT does not account for. The force in question is high altitude winds, which above 50 km altitude can be very strong.

So the reality is, that these high altitude winds at a certain point start to become the main force of horizontal displacement - fragments are litterally being blown away by these winds. As a result, the actual fall from the mentioned altitudes is not straigth down: falling fragments can be blown away laterally from the initial trajectory, or foward along the trajectory, and even be blown backwards along the initial trajectory, depending on the direction of the high altitude winds! The displacement, especially for fragments that are relatively large for their mass (space debris fragments usually are, as they usually are not solid), can be many kilometers.

This effect is well known to meteor astronomers, as it is a complicating factor in calculating where any meteorite fragments from a fireball might have landed. Like space debris, meteorites likewise are slowed down once descending through the atmosphere, and from ~25 to ~15 km altitude (their initial speed is faster than that of space debris and they are more dense, hence they penetrate deeper before losing their cosmic speed) they start the same kind of free fall, moving primarily under the effects of high altitude winds.

As an aside: I would love to see someone add the capability to import and effect high altitude wind profiles into GMAT, so this kind of displacement could be modelled in GMAT!

Note that, in interpreting the diagram above, one should realise that it maps horizontal displacement relative to altitude in the atmosphere. The modelled fragments do not end up in the same geographic location

For a given drag surface, low mass objects will come down earlier along the trajectory than heavier objects. This can be seen in the diagram below, which also shows you that the debris footprint of a reentry can easily be hundreds of kilometers long, something to keep in mind when looking at reentry coordinates in TIP messages:

 

click diagram to enlarge

It takes quite a while for these objects to come down through the lower layers of the atmosphere too, especially if they are large but lightweight:

click diagram to enlarge

The actual fall durations are heavily influenced by the area-to-mass-ratio. Relatively solid fragments (low area-to-mass) will come down faster, sheet-like or hollow objects (high area-to-mass) will come down slower. Surviving fragments will trickle down over tens of minutes. This is one reason why the time windows given for hazard areas during a controlled rocket stage reentry are usually an hour or so in duration.

From meteoric fireball studies, we know that as a rule of thumb, ablation (mass loss, i.e. burning up) of fragments stops once their speed is below ~3 km/s. Note that for low melting point materials like aluminium, the speed might actually be somewhat lower (meteorites are rock or iron with melting points at ~1100-1500 C, while aluminium has a melting point at ~660 C).

For the three modelled fragments (all modelled for a drag surface of 1 m2), the 5 kg fragment reaches this point at 77 km altitude; the 10 kg fragment at 73 km altitude; the 50 kg fragment at 61 km altitude. Note that the results will be different when modelling with the same masses but a different drag surface (for a smaller drag surface, the altitudes for a given mass will get lower, as they don't slow down as rapidly). Also note my earlier remark about materials with low melting point temperatures. But in general: anything that survives to below ~50 km in the atmosphere, will probably reach ground surface.