Questions tagged [entry-descent-landing]

Questions about the end-to-end process of landing a spacecraft on a target

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Why does the SpaceX Falcon 9 perform a entry burn? [duplicate]

Why should SpaceX perform 2 burns which increases the probability of failure? I understand the landing burn, but what is the purpose of the entry burn? On SpaceX webcasts it says "To slows our ...
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5 votes
1 answer
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How did "STOP" button work on Lunar Module?

The button to stop the descent engine of Lunar Module was not "just a button": it evolved and changed multiple times during development, and this is one of the many existing designs: What ...
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With and without refilling at LEO, how much more than the landers weight of the Venera 9 mission could a Starship deliver near a pole of Venus?

Venera 9 was a Soviet space mission to Venus that consisted of an orbiter and lander with a launch mass of 4936 kg and with an entry mass of 1560 kg. It was the first spacecraft to return an image ...
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Apparent close encounter of Inspiration4: Is the airspace cleared for returning spacecraft?

In the recording of the SpaceX live-stream covering the return of the Inspiration4 crew one can see an aircraft cross path with the capsule at 22:59:58. This image is a frame grab of the scene seen ...
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2 votes
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From what altitude will they cut Dragonfly helicopter loose on Titan and make it land itself, and what are the main factors determining this altitude?

Titan's surface pressure is about 1.5 bar and because the surface gravity is low pressure falls off much more slowly with altitude than it does on Earth. From Wikipedia's Atmosphere of Titan; vertical ...
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Why does the landing trajectory of a blunt body take an S shape in the lower atmosphere?

I coded some Matlab plots of altitude vs time for the re-entry of a point mass (so no aerothermo analysis included). In all the trajectories, there is an S shape closer to the ground. Why? Please ...
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28 votes
7 answers
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Curiosity and Perseverance landing - with so much dust blown everywhere, what's the point of the skycrane?

Curiosity and Perseverance were landed using the rather complex skycrane system because it would prevent the rockets from contaminating the landing site. But the video shows a great deal of dust being ...
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How many spacecraft bounced like a ball on Mars? How many tried to?

The answer to Why a rover bounces after landing on Mars? is "the Mars Exploration Rovers" of which there were two. However, they might not be the only spacecraft to use bouncing like a ball ...
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3 votes
1 answer
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How to get MARS2020/Perseverance EDL trajectory data from spice kernels?

For MSL EDL it is available this answer: How to retrieve MSL EDL trajectory using Javascript and webgeocalc API? How can I adapt it to MARS2020/Perseverance?
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How is parachute cover during Mars EDL prevented from crashing onto parachute or lander upon parachute opening?

MARS2020/Perseverance footage of parachute opening shows that parachute cover ejected by the lander (together with other "things") followed same trajectory of parachute box, until parachute ...
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2 votes
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What were Mars 2's conical aerodynamic braking shield and "gunpowder" engines?

The Soviet Mars 2 and Mars 3 lander missions were the first (human-made) spacecraft to reach the surface of Mars with Mars 3 the first successful landing. They both carried Prop-M's; the first wheel-...
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What are the rules for callouts during mission landings?

I remember hearing at one point that in the control room at JPL, only the GN&C Lead is allowed to make the announcement for touchdown. It's because they don't want someone prematurely (and ...
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27 votes
3 answers
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Why won't NASA show any computer screens?

This question was inspired by yesterday's NASA video stream of Perseverance landing on Mars (congratulations). I like watching rocket launches, they are really awe-inspiring, even if it's just a SN9 ...
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2 votes
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When NASA spacecraft arrive at Mars, is Mars always always above the horizon in the US?

Writing How long did the plasma blackouts of Perseverance's signals to MRO and direct-to-Earth last during its seven minutes of terror? I noticed that Mars was high in the sky over the Green Bank ...
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Has there ever been an attempt or serious consideration for spacecraft to land on Mars without an ablative-type heat shield?

My answer to Do exploration spacecraft enter Mars atmosphere against Mars rotation, or on the same direction? lauds the use of ablative heat shields for minimizing radiative heating of a spacecraft by ...
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7 votes
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Is Perseverance's heat shield's thickness radially symmetric?

I came across this video1 about the Mars 2020 Perseverance rover mission, especially the atmospheric entry phase. It says between about 03:50 and ...
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9 votes
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Can the space shuttle use OMS engines during landing?

Can the space shuttle use its OMS engines if the shuttle is short during the runway approach? Is fuel available for use in such a situation and will the engines provide reasonable thrust to get to the ...
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4 votes
2 answers
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How was an emergency landing site at Diego Garcia used during the Apollo program?

On the current Starlink mission as the 2nd stage passed over the Indian Ocean I heard mention of contact with a ground station at Diego Garcia. Checking that article I found the subsection Space ...
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2 votes
1 answer
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How to retrieve MSL EDL trajectory using Javascript and webgeocalc API?

I found a "javascript gateway" to NASA SPICE data, the "webgeocalc" web api: https://wgc2.jpl.nasa.gov:8443/webgeocalc/example/perform-calculation.html It works both online and ...
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How long to flip over stage 1 of Falcon 9?

Curious how fast stage 1 flips over. 180 degrees is a lot of turning. At a rate of 5 deg/s, it would take 36 seconds to flip. This seems very long for the maneuver. A more modest duration of 10 s ...
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Falcon 9 altitude and speed during reentry burn?

After MECO, stage 1 of Falcon 9 does up to three engine burns: a boostback burn followed by a reentry burn followed by a final landing burn. I'm interested here in the reentry burn. How high and how ...
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3 votes
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How to get MSL coordinates during EDL from SPICE kernel?

Upon trying to extract MSL position above surface by decoding a SPICE kernel, I am gettin this error: At epoch 3.9750216818313E+08 TDB (2012 AUG 06 05:16:08.183 TDB), there is insufficient ...
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2 votes
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How long do the ascent and the descent of Virgin Galactic's spacecraft take?

The VMS Eve mothership releases the VSS Unity spacecraft after ca. 48 minutes. The total duration is approximately 2 hours. As a result, the ascent time + the descent time that the Virgin Galactic's ...
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6 votes
1 answer
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Starship surface heating on Mars landing

Mars atmosphere is much thiner than Earth's And then how much will Starship heat on a Mars landing comparing to a landing on Earth?
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7 votes
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Would this Starship design alternative be viable?

Considering Starship atmospheric entry, belly dive and "bellyflop", latest iteration displays four aerodynamic surfaces, two aft fins and two carard fins. Soon will this configuration be put ...
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3 votes
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What is the return speed of the Falcon 9 booster?

The Falcon 9 first stage detaches at about 70 km high and it descends in about 6 minutes. That means an average descending speed of 200 m/s But what is the maximum speed it reaches on descent? And ...
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4 votes
1 answer
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Why Crew Dragon needs 18 hours between ISS separation and descent?

The Crew Dragon undocks from ISS but then it spend 18 hours in orbit before deorbit burn. From there, it takes less than one hour to come back to Earth. Why it needs 18 hours? Evven if they check all ...
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7 votes
1 answer
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Can the SuperDraco engines aboard Crew Dragon be used to save the crew on splashdown if the chutes failed?

I've heard it several ways, so I should ask here. In the case of a main chute failure, are the SuperDracos able to attempt a contingency propulsive splashdown to save Dragon's crew? If this is in the ...
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18 votes
4 answers
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Is there a risk that re-entering capsules or other components will hit ships or islands?

How precisely can the splash-down point of re-entering capsules (from Mercury onwards) be known in advance? Wasn't there a risk that capsules would hit a ship or an island? Likewise, Russian and ...
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4 votes
3 answers
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How much time it takes for the capsules to descend from ISS back down to Earth?

How much time it takes for the space capsules to descend from ISS back down to Earth? Soyuz, Dragon, Crew Dragon, Cygnus, European ATV and Japanese HTV and any other such craft. From the moment they ...
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4 votes
1 answer
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How long does the descent of the Falcon 9 first stage take?

After separating from the second stage, how long does it take for the Falcon 9 to come back to Earth? From LEO and from GEO. Note: this question is similar: How long does it take to recover the first ...
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8 votes
2 answers
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Falcon 9: Why does F9 first stage always lose Video Link during Entry Burn?

Typically the F9 first stage and the drone ship each lose the video connection once during landing: F9 first stage during entry burn Drone ship during F9 first stage touch down (see here and here) ...
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7 votes
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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 ...
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3 votes
0 answers
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Atmospheric entry of asteroid mining products

This is a more general question than How to get processed asteroid metals back to Earth in a safe manner That question was actually a quick check to see if a particular idea was plausible. Instead, ...
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5 votes
1 answer
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Are there any studies or technology envisioned for Mars entry and landing without a parachute?

Are any space agencies examining the possibility of a Mars landing without a parachute? It wasn't clear to me if the use of the HIAD (Hypersonic Inflatable Aerodynamic Decelerator) would eliminate ...
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10 votes
1 answer
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When things land on Mars what fraction of their velocity do they remove propulsively?

Some recent comments have got me wondering about this What is the distance between one of the mars's satellite revolving near the highest volcano olympus mons and the volcano olympus mons? comments ...
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1 vote
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Why have JPL martian rovers stopped using airbags and started using skycranes? [duplicate]

Pathfinder and the Mars Exploration Rovers used airbags to kill their terminal velocity. The Curiosity and Mars 2020 rovers have or will use skycranes. Why have JPL started using propulsive terminal ...
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4 votes
1 answer
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When during the flights did astronauts use the Valsalva device?

A spongy material is installed to the inside helmets called the Valsalva device (top right in this image) allow astronauts to do the Valsalva maneuver to relieve pressure on their eardrums when there ...
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1 vote
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Defining overshoot and undershoot boundary of entry corridor

I have been reading up on the mathematic of atmospheric entry. I have found different methods to theoretically calculate the corridor width but I don't understand how to define the overshoot and ...
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10 votes
1 answer
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What went wrong in the Chandrayaan-2 mission with the Vikram lander?

On September 7th 2019, ISRO attempted to land a lunar lander ,Vikram, with rover , Pragyan, on the moon. It was very exciting to watch until the lander lost communication with ground station during ...
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6 votes
1 answer
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Did the manned NASA capsules rotate during descent?

Watching the NS-11 launch, I noticed that during descent when the main chutes were deployed, the capsule rotated quite a bit, and would rotate back. Was this an issue as well during the Mercury/...
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0 votes
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Could a Rotary Rocket charge a super capacitor while descending on Mars?

Could a rotary rocket entering the atmosphere collect enough energy in a super capacitor through the rotors (along with auto rotation) while descending to have a controlled landing in the last few ...
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1 vote
1 answer
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Pressure effect during atmospheric entry

Maybe this question has a very obvious answer (I'm no aero engineer though), but I'll appreciate the clarification! So, I was reading an old nasa paper that indicates that the dynamic pressure for ...
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7 votes
1 answer
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What is crossrange and downrange for an entry vehicle?

I have been searching the terms online but still can't get a more intuitive understanding. If you could refer me to some website, book or if you could offer me an explanation I would really appreciate ...
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2 votes
0 answers
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How are Launch Ascent Trajectories and Reentry Constraints Being Implemented these days?

Historically, endoatmospheric guidance for launch ascent has been open loop and suboptimal. Recently, however, it seems as though there has been renewed interest in determining optimal endoatmospheric ...
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2 votes
1 answer
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Manned entry to Mars

Did Insight have a ballistic entry? If so, does NASA plan a ballistic or skip-glide entry for manned missions to Mars?
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36 votes
3 answers
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Why was it necessary to program InSight with an ability to land in dust storms?

If the entire event of EDL (Entry - Descent - Landing) is going to take only 7 minutes and if the command to begin could be signalled based on ground weather conditions, why was it necessary to take ...
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15 votes
3 answers
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What happens to Insight's parachute on Mars?

All of the animations I see show the heat shield detaching and falling to the ground, then Insight detaching and landing. There is no information about what happens with the upper part of the heat ...
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10 votes
1 answer
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Why is InSight's nylon parachute a "soft good"?

NBC News' Mars InSight's landing team leader is all 'nerves and excitement' ahead of risky touchdown includes a conversation with Rob Grover, "who leads the team in charge of InSight's landing at ...
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7 votes
2 answers
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How does a Mars lander reach a chosen landing site?

I see lots of questions how landing sites are chosen, but none so far how these landing sites are reached. It already looks like magic how the target planet can be reached at all, but when are ...
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