Questions tagged [entry-descent-landing]

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

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27
votes
7answers
6k views

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 ...
3
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1answer
123 views

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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2answers
99 views

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-...
6
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0answers
55 views

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 ...
27
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3answers
6k views

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 ...
2
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0answers
62 views

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 ...
1
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0answers
128 views

Has any spacecraft attempted 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 ...
4
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0answers
137 views

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 ...
8
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1answer
448 views

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 ...
4
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2answers
164 views

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 ...
2
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1answer
74 views

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 ...
0
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0answers
43 views

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 ...
0
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1answer
104 views

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 ...
3
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0answers
48 views

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 ...
2
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1answer
83 views

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 ...
3
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0answers
68 views

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?
6
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0answers
175 views

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 ...
3
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2answers
735 views

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 ...
4
votes
1answer
110 views

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 ...
7
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1answer
162 views

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 ...
18
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4answers
3k views

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 ...
4
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3answers
203 views

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 ...
4
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1answer
180 views

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 ...
8
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1answer
148 views

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) ...
6
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1answer
608 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 ...
3
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0answers
80 views

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, ...
5
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1answer
164 views

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 ...
9
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1answer
851 views

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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0answers
93 views

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 ...
4
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1answer
328 views

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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0answers
94 views

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 ...
9
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1answer
207 views

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 ...
6
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1answer
357 views

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/...
0
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1answer
256 views

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 ...
1
vote
1answer
95 views

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 ...
7
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1answer
2k views

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 ...
2
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0answers
78 views

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 ...
2
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1answer
196 views

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?
36
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3answers
6k views

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 ...
15
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3answers
2k views

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 ...
9
votes
1answer
866 views

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 ...
5
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2answers
133 views

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 ...
8
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1answer
324 views

How different was the Apollo LM descent trajectory from the most fuel-efficient?

In most diagrams of the Apollo Lunar Module descent profile (example at the start of this video), it looks like the LM turns over and points some of its thrust downward relatively early in the process....
6
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2answers
316 views

Drawbacks and advantages of two slidable & rotatable control surfaces for BFS sized spaceships

BFS (SpaceX's Big Falcon Spaceship) is in development and has seen between 2016 and 2018 three major design modifications. January 2018 I asked here how BFS planned to manoever during aerobraking. ...
10
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2answers
450 views

Why does in-flight mission abort often ends in ballistic high-g reentry?

I am seeing a lot of references to the “ballistic reentry” mode of the crew return vehicle in relation to the abort during the powered ascent stage. In partiulat, the recent crewed Soyuz MS-10 abort ...
11
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1answer
2k views

How does a gamma ray altimeter work? What kind of sensor is used?

The answers to the Space SE question Soyuz landing ground detection really surprised me. A gamma ray altimeter is used by the returning Soyuz capsule to detect the presence of solid ground immediately ...
3
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0answers
184 views

Atmospheric Entry Simulation: Numerical Inaccuracy

I am trying to make an atmospheric entry/aero-assist simulation. For the propagator, I have used conventional equations of motions in planet fixed reference frame: where the scalar states are- ...
3
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0answers
56 views

Atmospheric Entry Vehicle: Wind frame representation and Visualization

I am looking at entry dynamics for a convex blunt aeroshell. We use Heading angle, bank angle and flight path angle for description of attitude from local horizon axes system. While it is sufficiently ...
2
votes
2answers
233 views

Maximum dynamic pressure upon Mars entry

I have a Mars landing simulation, and one of the things it calculates is the dynamic pressure as the spacecraft descends through Mars' thin atmosphere (given by $q=\frac{1}{2}\rho v^{2}$). I know it ...
0
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2answers
143 views

How would a landing escape system be designed? [duplicate]

Launch escape systems have been used for half a century and have worked great when tried. But entering Earth's atmosphere from orbit and landing is at least as dangerous to astronauts, and have cause ...