ALOS-3

Advanced Land Observing Satellite 3 (ALOS-3), also called Daichi 3, was a 3-ton Japanese satellite launched on March 7 2023 which failed to reach orbit. It was to succeed the optical sensor PRISM (Panchromatic Remote-sensing Instruments for Stereo Mapping) carried on the ALOS satellite, which operated from 2006 to 2011. The ALOS-2 satellite and the ALOS-4 satellite carry synthetic-aperture radar.

Advanced Land Observing Satellite 3

Names	Daichi 3
Mission type	Remote sensing
Operator	JAXA
Website	www.jaxa.jp/projects/sat/alos3/index_j.html
Mission duration	13 minutes and 55 seconds
Spacecraft properties
Manufacturer	Mitsubishi Electric
Start of mission
Launch date	7 March 2023 1:38:15 UTC [1]
Rocket	H3-22S
Launch site	Tanegashima LP2
Contractor	Mitsubishi Heavy Industries
End of mission
Disposal	Destroyed via FTS
Last contact	March 7 2023 1:55 approximately
Decay date	March 7 2023
Orbital parameters
Reference system	Geocentric
Regime	Sun-synchronous
Instruments
OPS: OPtical Sensor IRS: InfraRed Sensor[2]
← ALOS-2 ALOS-4 →

The satellite was launched as the payload on the first launch of the H3 rocket in March 2023. A failure of the second stage engine to ignite led to the rocket along with its payload ALOS-3 being destroyed by use of Flight Termination System (FTS) to prevent risk of falling debris.

Spacecraft details

ALOS-3 had a mass of 3 tonnes, and 7 reaction wheels.^[3]

Launch

ALOS-3 launched from Tanegashima, Japan by a H3 rocket on 7 March 2023.^[1] Initially the launch was scheduled for 17 February but was aborted seconds before liftoff.^[4]

Timeline

MET	Time		Date(UTC)	Event
	JST	UTC
X-22:00:00	12:37:55	03:37:55	6 March 2023	1st Go/No-Go Decision
X-18:00:00	16:37:55	07:37:55		Airframe movement (VAB > LP2)
X-12:00:00	22:37:55	14:37:55		2nd Go/No-Go Decision
X-00:57:00	09:40:55	00:40:55	7 March 2023	3rd Go/No-Go Decision
X-00:10:00	10:27:55	01:27:55		Final Go/No-Go Decision
X-00:08:00	10:29:55	01:29:55		Start of Countdown
X-00:07:00	10:30:55	01:30:55		Safety System ready
X-00:07:00	10:30:55	01:30:55		Completion of Firing System Preparation
X-00:05:00	10:32:55	01:32:55		Satellite System ready
X-00:04:00	10:33:55	01:33:55		Automatic Countdown Sequence Start
X-00:04:00	10:33:55	01:33:55		Start of Pressurization of each tank
X-00:02:50	10:35:05	01:35:05		Power Switching (External to Internal)
X-00:00:55	10:37:00	01:37:00		Completion of each tank Pressurization
X-00:00:53	10:37:02	01:37:02		Frame deflector operation
X-00:00:35	10:37:20	01:37:20		Water Curtain operation
X-00:00:18	10:37:37	01:37:37		Flight mode on
X-00:00:15	10:37:40	01:37:40		Single-Stage Thermal battery activation
X-00:00:15	10:37:40	01:37:40		All System are ready
X-00:00:12.	10:37:43.	01:37:43		Pyrotechnic Torch Ignition
X-00:00:06	10:37:49	01:37:49		LE-9 Engine Start
X+00:00:00	10:37:55	01:37:55		SRB-3 Engine Start & Liftoff
X+00:01:06	10:39:01	01:39:01		Max Q
X+00:01:56	10:39:51	01:39:51		SRB-3 Jettision
X+00:03:32	10:41:27	01:41:27		Satellite Fairing Separation
X+00:04:56	10:42:51	01:42:51		Main Engine Cutoff (MECO)
X+00:05:04	10:42:59	01:42:59		1st and 2nd Stage Separation
X+00:13:55	10:51:50	01:51:50		Flight Interruption

Mission and sensors

If it had been successfully launched, ALOS-3 would have been an Earth observation satellite and was to be used to monitor natural disasters as well as for cartography.^[3] ALOS-3 carried OPS (OPtical Sensor), a multi-band optical camera which is an upgrade from the PRISM sensor.^[2] OPS was capable of observing a 70-kilometer (43 mi) wide strip of land on Earth.^[5] In addition to the RGB and infrared band covered by the predecessor ALOS satellite, ALOS-3 has two additional bandwidths: coastal and red edge. Coastal allows observation underwater up to a depth of 30m, while red edge was to be used to monitor vegetation growth.^[5]

Observation modes of ALOS-3[6]

Strip map observation mode

This was the default observation mode of ALOS-3. It observed in an area which was 70 km in width and 4,000 km in length in the direction of the orbital path(path of the orbit).

Stereoscopic observation mode

This mode acquired stereo-pair image of a certain point from two different directions(it acquired a three dimensional picture of some point on earth).

Pointing observation mode

This mode would have been capable of observing any given point in Japan within 24 hours after receiving the request to use the 'point observation mode' using pointing function of the satellite to point up to 60 degrees in all directions against the satellite nadir.

Wide-area observation mode

This mode was capable of observing a wide-area of over 200km by 100km with the help of multiple scan observations(observations) during an orbital path of the satellite.

Changing direction observation mode

Continuously observe an area, even if it is not along the trajectory, by controlling the attitude(attitude refers to the orientation of the satellite in space, or how it's pointing, relative to a reference frame like the Earth or the Sun. It's essentially describing the satellite's "direction" or "pointing angle") of the satellite and changing the direction of observation(the direction where the satellite is observing).

See also

• Spaceflight portal

• 2023 in spaceflight