James Webb Space Telescope - Launch Timeline



Time since launch Planned time Time Event Altitude
L+(dd:hh:mm[:ss]) UTC (km)
Actual[Prelaunch] Actual
-0:00:00:072021 Dec 25 1220:00 Vulcain 2 engine ignition 0
+0:00:00:002021 Dec 25 1220:07 Launch 0
0:00:02:21 2021 Dec 25 1222:28 EAP solid boosters shutdown and separation 72
0:00:03:26 2021 Dec 25 1223:33 Ariane fairing halves separation 126
0:00:08:41? 2021 Dec 25 1228:48 Ariane EPC core stage shutdown
0:00:08:47 2021 Dec 25 1228:54 Ariane EPC core stage separation 229
0:00:08:51 2021 Dec 25 1228:58 Ariane ESC-D engine start 229
0:00:24:51 2021 Dec 25 1244:58 Ariane ESC-D engine cutoff 928
0:00:27:07 2021 Dec 25 1247:14 Ariane ESC-D stage separates from JWST 1391
0:00:28:16? [L+ 33 min] 2021 Dec 25 1248:23? JWST deploy solar array 2600
0:00:29? 2021 Dec 25 1249? Ariane ESC-D stage performs EOLM (End of Life Manuever)
0:12:30:00 [L+12.5h] 2021 Dec 26 0050 JWST MCC-1a burn, SCAT-1/2, 16 to 17 m/s? 133700
0:13:35:00 2021 Dec 26 0155 JWST MCC-1a burn complete. Actual dV UNKNOWN
1:02:40 [L+ 1d] 2021 Dec 26 1500? JWST deploy GAA (Gimballed Antenna Assy) high gain comms antenna (and MGA?)228000
2:07:38 2021 Dec 27 1958 JWST pass lunar orbit 377000
2:12:00 [L+ 2d] 2021 Dec 28 0020 JWST MCC-1b burn, SCAT-1/2, 9m27s, 2 m/s? Actual dV UNKNOWN 388500
3:02: L+ 3.0 days 2021 Dec 28 1430? Begin Forward UPS (unitized pallet structures)444000
3:06:01L+ 3.0 days 2021 Dec 28 1821 Complete Deploy Forward UPS (unitized pallet structures)458000
3:12:07L+ 3.16 days 2021 Dec 29 0027 Complete Deploy Aft UPS (unitized pallet structures) 480000
L+4.07d 2021 Dec 29Spacecraft-to-Optical Telescope Element launch release mechanism
L+4.1d 2021 Dec 29 Spacecraft-to-ISIM Electronics Compartment launch release mechanism
4:02:25L+ 4.2 days 2021 Dec 29 1445 Begin to raise DTA (deployable telescope tower assembly)528000
4:09:04L+ 4.2 days 2021 Dec 29 2124 Complete raising DTA (deployable telescope tower assembly)549000
L+ 4.48 days Release CJAA (Cryocooler Jitter Attenuation Assy)
L+ 5.0 days Release CCA (Cooler Compressor Assy)
5:02? L+ 5.05 days 2021 Dec 30 1400? Deploy solar trim tab (Aft Momentum Flap) on right(?) panel 600000
L+ 5.1 days Release sunshade restraints 600000
5:05:07L+5.17 days 2021 Dec 30 1727 Sunshade central covers retracted600000
6:06:10L+6.02 days 2021 Dec 31 1830Start Deploy +J2 mid-boom (port sunshade boom) and DRSA-H Deployable Radiator Shade Assy/Horiz676000
6:09:29L+6.02 days 2021 Dec 31 2149 Complete Deploy +J2 mid-boom (port sunshade boom) and DRSA-H Deployable Radiator Shade Assy/Horiz684000
6:11:11L+6.25 days 2021 Dec 31 2331 Begin deploy -J2 mid-boom (stbd sunshade boom) and DRSA-H Deployable Radiator Shade Assy/Horiz688000
6:14:53L+6.25 days 2022 Jan 1 0313 Complete deploy -J2 mid-boom (stbd sunshade boom) and DRSA-H Deployable Radiator Shade Assy/Horiz698000
9:02:40L+7.0 days 2022 Jan 3 1500Start of Sunshade tensioning and layer separation831000
9:08:28 2022 Jan 3 2048 Layer 1 tensioned843000
9:08:49 2022 Jan 3 2109 Layer 2 tensioning begins843500
9:10:03 2022 Jan 3 2223 Layer 2 tensioned846000
9:10:28 2022 Jan 3 2248 Layer 3 tensioning begins847000
9:11:39 2022 Jan 3 2359 Layer 3 tensioned849000
2022 Jan 4 Layer 4 aft tensioning begins
10:03:03 2022 Jan 4 1523 Layer 4 tensioned879000
10:03:50 2022 Jan 4 1610 Layer 5 tensioning begins
10:04:39 2022 Jan 4 1659 Layer 5 tensioned882000
L+8.0 days 2022 Jan 4 1700 Complete Sunshade tensioning and layer separation882000
L+9.0 days Deploy DRSA-V Deployable Radiator Shade Assy/Vert.
L+9.06 days Deploy Star Tracker Support Assy
11:03:56L + 9.9 days 2022 Jan 5 1616Begin deploy SMSS (Secondary Mirror Support Structure) 924000
11:04:32L + 9.9 days 2022 Jan 5 1652 Deploy SMSS (Secondary Mirror Support Structure) complete 925000
12:01:28L+11.0 days 2022 Jan 6 1348 Raise ADIR (Aft Deployed Instrument Radiator) on back of ISIM960000
13:01:26L + 12.0 days 2022 Jan 7 1336 Begin unfold lateral PMBA (Primary Mirror Backplane Assembly) Wing 1 (port, +V2)998500
13:06:51L + 12.0 days 2022 Jan 7 1911 Complete unfold lateral PMBA (Primary Mirror Backplane Assembly) Wing 1 (port, +V2)1007100
14:03:00L+13.0d 2022 Jan 8 1520? Begin unfold lateral PMBA (Primary Mirror Backplane Assembly) Wing 2 (stbd, -V2)
14:05:57L + 13.0 days 2022 Jan 8 1817 Complete unfold lateral PMBA (Primary Mirror Backplane Assembly) Wing 2 (stbd, -V2)1041300
14:05:57L + 13 days 2022 Jan 8 1817 PMSA (Primary Mirror Segment Assembly) deployment complete1041300
L + 13.8 days Begin ACS activation
18:L+15.5 days 2022 Jan 12 Begin PMSA (Primary Mirror Segment Assy) and SMA actuation/deployment
18:03 2022 Jan 12 1500? Ariane 5 upper stage leaves Earth Hill Sphere
25:L+25.3 days 2022 Jan 19 Complete mirror segment actuation/deployment
25:L+25.3 days 2022 Jan 19 Activate K-band comms
30:06:40L + 29 days 2022 Jan 24 1900 MCC-2 with SCAT-3/4 thrusters, 1.5 m/s, 298 s burn - Arrive Sun Earth L2 halo orbit1379000
30:06:45L + 29 days 2022 Jan 24 1905 MCC-2 complete 1379000
L + 29 days Begin cooldown
34: 2022 Jan 28 FGS powered on
36:L+36 days Begin telescope commissioning
37:L+36 days 2022 Jan 31 Begin mirror alignment
39: 2022 Feb 2 NIRCam first photons
45:? L+77d 2022 Feb 8? MIRI cooler activated
50:L+O(1 mo) 2022 Feb 13 FGS guiding
L+O(50d) SKM-1 stationkeeping burn with SCAT-3/4
55:L+45d 2022 Feb 18 Segment Image Identification, OTE segments in formation
L+60d? Phasing of OTE
76: 2022 Mar 11 Fine phasing completed, NIRCAM
82: 2022 Mar 17 Begin MIMF (Multi Instrument Multi Field) alignment
L + 120d Instruments complete cooling to 50K
117:L + 120d 2022 Apr 21 MIRI cooled to 7K
124:L+124 days 2022 Apr 28 Complete mirror alignment, PSF checks
124:L+124 days 2022 Apr 28 Complete telescope commissioning
124:L+124 days 2022 Apr 28 Begin science instrument commissioning
L + 120d Instrument calibration
L + 180d Science instrument commissioning complete
L + 180d Begin Cycle 1 GO observations
L + 180-210d RELEASE FIRST IMAGES (ERO, Early Release Observations)

Note: "Altitude" is relative to Earth surface, add 6378 km to get geocentric distance.