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Time Magazine's UAE's Mission to Mars Launches Successfully—a First for the Arab World says that the Mars orbiter named Al-Amal (Hope) or Emirates Mars Mission:

...blasted off from the Tanegashima Space Center on a small southern Japanese island aboard a Mitsubishi Heavy Industries’ H-IIA rocket, on time at 6:58 a.m. (2158 GMT Sunday) into the blue sky. Mitsubishi said the probe has been successfully separated from the rocket and is now on its solo journey. The launch had been delayed for five days because of stormy weather.

Question: What was the duration of the launch window this day? Did it first enter a short period of LEO for phasing and/or staging, or did it launch directly into its interplanetary trajectory? How many stages were involved?

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What was the duration of the launch window this day?

According to Spacelaunchnow, the daily launch window was instantaneous, but there were daily opportunities from July 15 to August 12.

Did it first enter a short period of LEO for phasing and/or staging, or did it launch directly into its interplanetary trajectory?

From the timeline, it appears that it did about a half-orbit between second-stage first cutoff (SECO-1) (orbital insertion) at T+0:11:21 and second-stage second burn (trans-Martian injection) forty-five minutes later at T+0:56:39. (As a rule of thumb, the period of circular low Earth orbit is a little over 90 minutes, so 45 minutes between the two events means about half an orbit).

T-0:00:00:   Liftoff
T+0:01:31:   SRB-A Burnout
T+0:01:46:   SRB-A Jettison
T+0:04:06:   Payload Fairing Jettison
T+0:06:34:   MECO
T+0:06:42:   Stage Separation
T+0:06:52:   Second Stage Ignition 1
T+0:11:21:   SECO 1
T+0:56:39:   Second Stage Ignition 2
T+1:00:33:   SECO 2
T+1:01:34:   Hope Separation

How many stages were involved?

The H-IIA uses two hydrogen-oxygen core stages, plus solid rocket boosters. The first core stage is ignited at liftoff.

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    $\begingroup$ I am a little puzzled by the speed and altitude figures shown at those two points; if the initial orbit was 272km x 258km I'd expect much higher speed at SECO-1. $\endgroup$
    – Russell Borogove
    Commented Jul 20, 2020 at 22:34

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