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[Image]image: ULA
(updated 27 Apr 2021 with first observational orbit, see end of post)

If the weather and the launch Gods cooperate, ULA will launch a Delta IV Heavy with a classified payload for the NRO on 26 April 2021. The launch is designated NROL-82 and the payload will likely receive the designation USA 314. In a tweet from April 19, ULA mentions a prospective launch time of 20:46 UT.
Several lines of evidence lead us to believe that the payload is a KH-11 EVOLVED ENHANCED CRYSTAL optical reconnaissance satellite, colloquially also known as a 'Keyhole'. It is the kind of satellite that makes these kind of detailed pictures of areas of interest for the NRO.A map in the ULA Mission Overview for this launch, and the Navigational Warnings issued for this launch (NAVAREA XII 173/21 and HYDROPAC 1221/21) provide information on the launch azimuth and from that the orbital inclination targetted. Likewise the position and time window of the upper stage deorbit area provides - in a very broad sense- information on the orbital altitude aimed for. Together they indicate a launch into a sun-synchronous Low Earth Orbit with an orbital inclination near 98 degrees. This is a very familiar orbit, as we will discuss later in this post.Below is a map I prepared depicting the hazard areas from these Navigational Warnings as well as the launch trajectory I calculate based on this information:
[Image]click map to enlarge
The listed times along the track are for launch at 20:46 UT into the 250 x 1020 km, 97.9 degrees inclined estimated orbit below: NROL-82 (USA 314)          for launch on 26 April 2021 at 20:46:00 UT
1 70002U 21999A   21116.86527778  .00000000  00000-0  00000-0 0    03
2 70002 097.8600 222.0898 0548970 157.1680 337.2110 14.78203944    02 The text of the Navigational Warnings:

220434Z APR 21
NAVAREA XII 173/21 (also: HYDROPAC 1221/21)
EASTERN NORTH PACIFIC.
EASTERN SOUTH PACIFIC.
CALIFORNIA.
1. HAZARDOUS OPERATIONS:
   A. 2016Z TO 2257Z DAILY 26 THRU 28 APR
      IN AREA BOUND BY
      34-38N 120-40W, 34-36N 120-30W,
      34-07N 120-39W, 34-08N 120-44W.
   B. 2016Z TO 2257Z DAILY 26 THRU 28 APR
      IN AREA BOUND BY
      22-57N 120-46W, 23-47N 125-18W,
      26-27N 124-45W, 25-36N 120-08W.
   C. 2016Z TO 2257Z DAILY 26 THRU 28 APR
      IN AREA BOUND BY
      13-28S 121-20W, 10-47S 138-34W,
      00-47S 136-41W, 03-52S 119-54W.
   D. 2253Z TO 0029Z COMMENCING DAILY
      26 THRU 29 APR IN AREA BOUND BY
      63-14S 174-16W, 32-49S 159-58W,
      33-23S 156-28W, 64-16S 168-07W.
2. CANCEL THIS MSG 300129Z APR 21. Area D from the Navigational Warnings, located in the southern Pacific Ocean, appears to be the deorbit area for the Delta Cryogenic Second Stage (DCSS). The DCSS deorbit takes place some two hours after launch, just after the start of the second revolution (with the deorbit burn happening over the Arctic, near the end of the first revolution).
As mentioned above, the orbit that seems to be targetted is one that is very familiar in terms of orbital inclination and sun-synchronous character. It is the typical orbit of a KH-11 EVOLVED ENHANCED CRYSTAL electro-optical reconnaissance satellite. Several years ago I discussed the KH-11 orbital constellation in depth on this blog ("Past and future of the KH-11 Keyhole/Evolved Enhanced CRYSTAL constellation" - 2013). As a side note, the type of rocket used to launch NROL-82 is consistent with a KH-11 launch too: the Delta IV Heavy has a long history of launching KH-11's.Currently there are at least three, and possibly four active KH-11 satellites on orbit: USA 186 (2005-042A), USA 224 (2011-002A), USA 245 (2013-043A), and possibly USA 290 (2019-004A).  The latter, USA 290, is in an odd orbit for a KH-11 and its identification as a KH-11 is open to questioning (I will discuss this later in this blog post).Historically (see "Past and future of the KH-11 Keyhole/Evolved Enhanced CRYSTAL constellation"), new KH-11 satellites are launched into one of two primary orbital planes some 48 degrees apart in RAAN: a "primary East" plane and a "primary West" plane. The time window and the 20:46 UT launch time given by ULA for the upcoming April 26 launch corresponds well with targetting the "primary East" plane. This orbital plane results in passes around local noon and midnight. The KH-11 satellite currently occupying this orbital plane is USA 224 launched 10 years ago in 2011. [Image]USA 224 imaged in June 2014. click image to enlarge

[Image]KH-11 constellation (minus USA 290), situation mid-April 2021 (polar view). Click to enlarge
 The orbital plane of USA 224 passes over the launch site of NROL-82, Space Launch Complex 6 (SLC-6) at Vandenberg Air Force Base, around 21:20 UT on April 26. This is a difference of some 35 minutes with the launch time (20:46 UT) from the ULA tweet.

In 2011, when USA 224 itself was launched to replace USA 161 in the primary East plane, the launch occurred some 20 minutes before the USA 161 orbital plane crossed over the launch site (a similar time difference would hence see launch around 21:00 UT for the upcoming April 26 launch).If history is our guide, the following sequence of event will likely happen. To start with, NROL-82 will be launched into the KH-11 Primary East plane, with an orbital inclination of ~97.9 degrees and orbital altitude of ~250 x 1020 km, almost co-planar with USA 224. The illustration below shows the orbital plane situation around orbit insertion. Note the similarity of the orbital planes of NROL-82 and USA 224:
 [Image]expected situation just after launch of NROL-82. click to enlarge

 After a check-out period of a few weeks, the NROL-82 payload (likely designated USA 314) will take over the primary plane mission from USA 224, the satellite previously occupying this orbital plane. Next, after USA 314 has taken over its role, USA 224 will be moved away from the primary plane, into a new orbital plane with RAAN some 10-20 degrees East of the primary plane: the so called '"secondary East plane". It will also lower its apogee and take up a ~400 km altitude orbit. In this new orbit it will continue to be operational for several years, entering its extended mission phase. From this moment on, for the first time since the deorbit of USA 161 in the winter of 2014-2015, all the two primary planes and all the two secondary planes will be occupied by a KH-11 again. The orbital constellation will become something like that in the image below:
[Image]Approximate KH-11 constellation after expected rearrangement later this year. Click to enlarge

 How about USA 290?
You will have noted that after a brief initial mention, I carefully left USA 290, launched in 2019, out of the discussion so far. So what about that object? Is it a KH-11?
USA 290 (2019-004A) was launched as NROL-71 from Vandenberg on a Delta IV Heavy on 19 January 2019 (see an earlier blogpost) and it was suspected by some noted analysts to be a KH-11. It however went into a weird, 73.6 degree inclined ~400 km altitude orbit that is not sun-synchronous and nothing like previous KH-11 orbits. So, had the NRO broken with the previous 'classic' pattern of the KH-11 orbital constellation and were they trying something new?The identification of  USA 290 as a KH-11 never has been sitting well with me. The odd orbital inclination and non sun-synchronous character of the orbit gives few reasons to think it is an IMINT mission.In light of the apparent return to the known 'classic' KH-11 constellation with the upcoming launch of NROL-82, I have again started to foster these doubts. Maybe USA 290 isn't a KH-11 after all but something else, something experimental (readers of this blog will have noted that the past 4-5 years, a lot of NRO launches appear to be experimental, going into 'new' previously unseen types of orbit. Some of these are, I suspect, radar imaging satellites).
Ted Molczan has recently suggested that USA 290 is a KH-11, and that its odd orbit is inspired by that of the notorious 'Misty' stealth IMINT satellites of the 1990-ies which were launched in ~65 degree orbits. Basically, he argues that USA 290 is a 'Misty' imaging satellite without the stealth!I remain agnostic at best about the identity of USA 290. Perhaps, if new payloads are launched into similar orbits over the coming years, the picture will become more clear. For now, I regard USA 290 as an oddity, and not necessarily a KH-11.UPDATE 27 Apr 2021 11:00 UT

Cees Bassa optically observed the NROL-82 payload on the 2nd and 3rd revolution. Radio observers including Scott Tilley are also tracking it.

Based on a hybrid optical/radio orbit computed by Scott Tilley, the orbital altitude is somewhat different than expected, the orbit less eccentric: but the orbital plane is even closer to that of USA 224.The orbital plane is very close to that of USA 224 indeed: a ~1 degree difference in RAAN and 0.1 degree difference in orbital inclination.

Orbital altitude currently appears to be about 525 x 760 km, i.e. less eccentric than our initila pre-launch estimate. That of USA 224 is 256 x 997 km.The NROL-82 payload might manoeuvre in the coming days and weeks in order to have it's apogee and perigee altitudes match with  that of USA 224.


[Image]click to enlarge