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Questions tagged [launch-window]

Questions regarding the limited period of time where a specific mission plan can be used.

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What's the reason behind SpaceX's timing of launching Starlink satellites?

I noticed a pattern in the timing of Starlink launches: In the first half of each year, Starlink launches occur rather during the day, and in the second half, they occur rather during the night (...
Hannes's user avatar
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0 answers
109 views

Why was the Moon's antipode at 10 degrees south on July 1969?

From what I understand, the TLI burn should be around the Moon's antipode projection on Earth. I get that. What I don't understand is why, according to this picture https://history.nasa.gov/afj/...
lester289's user avatar
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5 votes
1 answer
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What is the reason for the short-duration cutouts in the Artemis I launch window?

Near the end of the hold at T-10 the announcer noted that, in determining a new T0, the launch team had to consider "various cutouts in the launch window, varying from 1 seconds up to a minute&...
Ludo's user avatar
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29 votes
4 answers
5k views

Why does Artemis I need a launch window?

I know that a rocket needs to launch at the right time in order to be able to reach a specific point in orbit (e.g. the ISS). This launch window is quite small (correct?). But why does Artemis I ...
Andrei Herford's user avatar
4 votes
0 answers
173 views

Why was the "lunar launch window" different between the Cape Canaveral and Baikonur launch sites?

I'm reading A Man on the Moon: The Voyages of the Apollo Astronauts (page 78), and I was confused about this passage: As the fall of 1968 wore on, apprehension surfaced once more within NASA. Would ...
carleton's user avatar
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3 votes
0 answers
134 views

Porkchop plots/launch windows for Sun-Earth L2 to Mars transfers?

I've been using Earth-Mars launch windows, found with NASA's Trajectory Browser and EasyPorkchop, as launch windows from the Sun-Earth L2 Lagrange point to Mars, with the logic that since the L2 point ...
kardalos's user avatar
  • 359
4 votes
0 answers
94 views

Why are the four launch opportunities within each Inspiration4 launch window "about an hour apart"?

In the SpaceX Inspiration4 Launch broadcast at about T-01:31:05 (91 minutes before launch) the process for selection of launch windows for the mission is roughly ...
uhoh's user avatar
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3 votes
1 answer
176 views

When the lunar module ascent stage launched to take astronauts back to the command module, how long was the launch window? [duplicate]

This excellent animation says the launch must happen at "just the right time", but how long was the actual launch window, how precisely (how many seconds or minutes) did the launch need to ...
mherzl's user avatar
  • 133
2 votes
0 answers
64 views

Propulsion thrust vs high winds?

While I do understand that high wind speed is a risk for space launches (and all air flights), still, is it a physical constraint or a computational problem given we are not dealing with a hurricane/...
J. Doe's user avatar
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1 vote
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73 views

Calculating the length of a launch window?

May somebody guide me what exactly determines the length of a launch window? When doing the (basic) celestrial mechanics caclulations for e.g. a transit from Earth to Venus, one usually assumes point-...
B--rian's user avatar
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7 votes
1 answer
725 views

How could the landing date of Perseverance Rover be fixed irrespective of 26 days launch window?

I am very much aware of this question from 2018 by @uhoh - Why would InSight's arrival date at Mars be fixed, and independent of the launch date?. I was led here by a similar question which arose in ...
OrangeDurito's user avatar
7 votes
3 answers
345 views

Can Falcon 9 be fueled slowed to delay the instantaneous launch window?

DM-2's first launch attempt was scrubbed at about T−17 minutes due to bad weather at the instantaneous launch window, even though the weather was predicted to clear up as early as T+10. It was ...
Adám's user avatar
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1 vote
0 answers
194 views

Were there any identified launch windows and gravity-assist trajectories that could put a probe on a "Grand Tour" trajectory around 1981?

For context, I am developing an alternate history that features a far more ambitious Voyager program than the one undertaken in real life. However, despite the increase in NASA funding provided in the ...
Grant Hartlage's user avatar
12 votes
1 answer
160 views

Why did GRACE mission have launch window?

GRACE mission which was launched on March 17th, 2002 had a 10 minutes launch window. The mission was to launch a couple of earth observation satellites. And interestingly, NASA's GRACE Launch Press ...
karthikeyan's user avatar
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2 votes
1 answer
136 views

Impact of Constellations on Space Debris and Launch Windows

With the decline of massive GEO satellites and a big increase in smallsat and cubesat, especially those in constellations, I wonder what their impact is on space debris. Those smaller satellites do ...
GittingGud's user avatar
7 votes
0 answers
101 views

Are "launch-on-minute" or other discrete launch times protocols currently the norm for wide launch windows?

This excellent answer to a question about collision avoidance practices for launches begins with: While the length of a launch window varies, launches within the window typically occur at discrete ...
uhoh's user avatar
  • 149k
6 votes
3 answers
595 views

How does the Parker Solar Probe have such a wide launch window?

The Parker Solar Probe is set to launch on August 11th 2018. It will perform 7 orbit-lowering gravity assists around Venus for ~6 years before reaching its final operational orbit. It has been well ...
Jack's user avatar
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20 votes
6 answers
8k views

What is the rarest launch window?

What situation would make a launch window rare? What is the rarest known launch window?
Muze's user avatar
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19 votes
1 answer
1k views

Why was TESS' launch window open for only 40 seconds per day?

The BBC news podcast Science in Action episode New Planet Hunting Mission covers the upcoming TESS mission between 01:00 and 07:15 with Sara Seager, TESS deputy ...
uhoh's user avatar
  • 149k
15 votes
2 answers
3k views

What's the reasonable "window" in days for a Mars-Earth Hohmann transfer?

As any popular science reader knows, when traveling between Earth and Mars, there's a Hohmann transfer opportunity about every two years (I believe it's every 26 months, specifically). What I've ...
Fattie's user avatar
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7 votes
1 answer
389 views

What factors determine how long a window of opportunity opens for an interplanetary hohmann transfer?

I know that one can determine the approximate wait time for a window of opportunity to open up for an interplanetary transfer based on the relative positions and velocities of the two planets in ...
Paul's user avatar
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16 votes
1 answer
2k views

When are there launch windows to Neptune via Jupiter?

I suppose there's a launch window to Neptune by using Jupiter as often as there are Jupiter/Neptune conjunctions, every 13½ years. But which years are Jupiter and Neptune best aligned for gravity ...
LocalFluff's user avatar
3 votes
1 answer
320 views

Why would there be a launch window for a Geosynchronous orbit? [duplicate]

The question is pretty much stated in the title. Is there anything other than "human caused" reasons for this (such as clearing airspaces, etc.)? I'm only looking for possible natural reasons (other ...
Steve's user avatar
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10 votes
1 answer
702 views

Do geosynchronous satellite launches require a tight launch window?

I thought only launches to rendezvous (resupply, repair, space station expansion etc) and direct launches into interplanetary trajectory require precisely timed launch window. Then I read: Geosync ...
SF.'s user avatar
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