Background

TacRL is probably an abbreviation of 'Tactical Rapid Launch', a US Space Force programme designed to put together the components of a launch (small satellite and launch vehicle) within a short space of time - a small number of weeks.

It is not clear whether TacRL-1 was ever flown or if it is still awaiting launch. Navigation warnings for TacRL-2 indicate planned launch June 13 with June 14 as a backup.

The TacRL-2 launch will use a Pegasus-XL rocket released from a Lockheed L-1011 Tristar carrier aircraft flying out of Vandenberg.


Announced Launch Time

The analysis below predates news stories from June 11 that revealed the planned launched time to be 08:11 UTC. Analysis (below) of the navigation warnings pointed to it being between 08:00 and 08:30 UTC which has now been confirmed.


Payload & Orbit

Details of the actual satellite are currently unknown so it may be classified. t has been described as being a 'space situational awareness' mission, implying that it carries sensors covering some aspect of monitoring satellites and debris in orbit. It will probably receive the name USA 316 on successfuly reaching orbit, in parallel with the name 'Odyssey'.

Navigation warnings issued for the drop zones of various elements of the Pegasus point to an orbital inclination near 96° so, although the orbit is polar and at a retrograde inclination, it is not set to be truly sun-synchronous. A launch during the time window covered in the navigation warnings would have a Descending Node near 23:40, indicating that the satellite is unlikely to be carrying an optical Earth imaging payload.

Orbit height is likely to be at least 500 km to avoid the worst effects of air drag and to maximise payload mass.


Implied Launch Time

The 1.25 hour window for the NAVAREA XII warning (below) allows for manoeuvres of the carrier aircraft prior to releasing the Pegasus and immediately after. The window opening is consequently somewhat in advance of the actual release time and there is probably a post-release time allowance to protect any necessary wind-down activities.

The times are identical for June 13 and June 14.

The HYDROPAC warning (also below) is for a much narrower time period and implies that Pegasus release is aimed between about 08:00 and about 08:30 UTC.


Navigation Warning - NAVAREA XII

The warning covers four areas, each of which has its own specific set of times. The full time span of the warning therefore covers the whole sequence with a single time slot.

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.


Navigation Warning - HYDROPAC

A separate warning was issued for Zone D that gives a better indication of the time span of the actual launch window than does the one implied by the NAVAREA XII warning.

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.