The model number indicates that there are two SRB-A3 solid boosters attached to the first stage; the 4/4D-LC fairing is a 4-metre diameter nose fairing with two main sections, an upper section which splits into two parts and contains XRISM, and a lower part which splits into three parts and contains SLIM.
The illustration above shows the upper fairing halves being jettisoned during first stage burn. They fall back to the ocean. XRISM is the small box at the tip; the white cylinder below it is the lower fairing.
XRISM sits on the lower fairing cap. Once it separates into orbit (left) the lower fairing cap is ejected, and then the two halves of the lower fairing cylinder (right), revealing SLIM. The three bits of the lower fairing remain in orbit as space debris.
Here is the launch timeline: (note for CfA folks: 2342 UTC Sep 6 is 7.42pm EDT Wed Sep 6)
| Time UTC (Sep 6/7) | MET hh:mm:ss | Event |
|---|---|---|
| Sep 6 2342:11 | 00:00:00 | Launch from Pad 1, Yoshinobu Site, Tanegashima |
| Sep 6 2343:41 | 00:01:30 | Left and right SRB-A3 motor cutoff |
| Sep 6 2343:56 | 00:01:45 | Left and right SRB-A3 motor jettison |
| Sep 6 2346:21 | 00:04:10 | Left and right upper fairing halves jettison |
| Sep 6 2348:49 | 00:06:38 | H2A core stage LE-7A engine cutoff |
| Sep 6 2348:57 | 00:06:46 | H2A core stage separates and falls to ocean |
| Sep 6 2349:07 | 00:06:56 | H2A second stage LE-5B engine first ignition (SEL1) |
| Sep 6 2355:41 | 00:13:30 | H2A second stage LE-5B engine cutoff (SECO1), in 550 x 550 km x 31 deg orbit |
| Sep 6 2356:32 | 00:14:21 | XRISM separates from lower fairing cap |
| Sep 7 0000:02 | 00:17:51 | Lower fairing cap ejected |
| Sep 7 0000:07 | 00:17:56 | Lower fairing left/right sides ejected |
| Sep 7 0027:02 | 00:44:51 | H2A second stage LE-5B engine second ignition (SEL2) |
| Sep 7 0029:00 | 00:46:49 | H2A second stage LE-5B engine cutoff (SECO2), orbit 575 x 98000 km x 31 deg |
| Sep 7 0029:50 | 00:47:39 | SLIM separates from second stage |
| Sep 7 2100? | Space Force orbital data probably available by this time | |
| Sep 11 1300 | 4.5 d | SLIM apogee raise to 112000 km |
| Sep 26 0100 | 19 d | SLIM apogee raise to 225000 km |
| Sep 30 1700 | 23 d | SLIM apogee raise to 394000 km, translunar injection |
| Oct 4 0648 | 27 d | SLIM first lunar flyby, 5000 km |
| Dec 13 | SLIM weak lunar capture | |
| Dec? | XRISM commissioning phase complete, begin cal/PV | |
| Dec 25 | SLIM lunar orbit adjust to 685 x 3924 km x 89.8 deg | |
| Jan 17 | SLIM lunar orbit adjust to 148 x 611 km x 89.8 deg | |
| Jan-Feb? | SLIM landing attempt | |
| Jun? | XRISM GO phase begins |
The launch site is on an island called Tanegashima. The rocket flies east from Tanegashima over the Pacific, as shown below. The "XRISM" label shows the point at which XRISM separates from the second stage.
Press kit docs in Japanese here
XRISM is 8m long and 3m diameter with 9m solar panel span, and has a mass of around 2300 kg. Target orbit is 550 x 550 km x 31 deg. The attitude control system has a limited capability for small debris avoidance burns, necessary in this age of space junk.
XRISM being prepared for launch
XRISM artist's impression
XRISM internal layout.
XRISM XMA (X-ray mirror assembly). The XMA has 203 coaxial thin shells with 5.6m focal length and 0.45m outer diameter.
The SXI XTend imager has a 2 x 2 array of 640 x 640 pixel CCDs covering 0.4-12 keV and a 38 arcmin FOV with arcminute resolution. Effective area is 360 sq cm at 6 keV.
The SXS Resolve microcalorimeter has a 6 x 6 pixel array held at 50 mK by a three-level refrigerator. FOV is 3 arcmin, effective area is 210 sq cm at 6 keV, and energy resolution is 7 eV at 6 keV.
After separation from the H2A the probe will make a lunar flyby a few days later, then head out towards the Sun-Earth Hill sphere and slowly fall back to the orbit of the Moon in early 2024, when it will enter lunar orbit. This long trip allows a smaller lunar orbit insertion burn, saving mass.
SLIM will enter a 15 x 600 km lunar orbit. On landing day it carries out powered descent to just above the surface, leans forward, and touches down on two legs. It then gently (hopefully) topples over to a horizontal position. This approach lets them land on hillier terrain.
Target location is crater Shioli at 25.2E 13.3S.
SLIM probe
SLIM in vertical descent
SLIM on lunar surface
