Questions tagged [entry-descent-landing]

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

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3
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2answers
336 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 ...
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1answer
106 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 ...
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1answer
136 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 ...
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4answers
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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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3answers
197 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
171 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 ...
7
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1answer
133 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
187 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 ...
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0answers
76 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, ...
6
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1answer
149 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 ...
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1answer
763 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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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
305 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
71 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
196 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 ...
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74 views

What can a Long March 4 do with grid fins?

NASA Spaceflight's Long March 4B launches Gaofen-7 – tests grid fin system mentions that images and video of the recent launch show that the first stage was equipped with grid fins. Question(s): In ...
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1answer
340 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/...
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1answer
231 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 ...
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1answer
84 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 ...
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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 ...
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0answers
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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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1answer
190 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?
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3answers
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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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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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1answer
862 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 ...
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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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1answer
271 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....
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2answers
292 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. ...
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2answers
440 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 ...
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1answer
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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 ...
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182 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- ...
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0answers
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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 ...
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2answers
219 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 ...
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2answers
142 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 ...
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3answers
291 views

Where can I find high quality “descent” photos at as many different altitudes as possible?

I'm working on a graphical simulation and I'd like to get the "look and feel" to seem as realistic as possible. Other than Apollo landing videos (which seem pretty limited and low quality obviously) ...
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1answer
315 views

Archimedean braking for low density Venus lander + subsidiary question

Subsidiary question: Imagine a sphere 10cm in diameter in low venusian orbit. Slow it down a little in order to deorbit it. What's the density of the sphere, in order to touch the ground at 0 vertical ...
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0answers
222 views

Lunar Descent and Landing Simulation

I am trying to simulate lunar descent and landing as a part of my undergraduate project. For time being, I have included gravity turn guidance scheme and used these equations Now, I can solve ...
7
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1answer
98 views

Meteor color hints at chemistry

This recent meteor over the midwest. Reports described it at blue / green. I have seen blue / white, red and yellow meteors. I presume red means iron, green means copper. Can meteoritics or meteor ...
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2answers
821 views

Can we significantly reduce entry velocity with this method by airbraking alone for interplanetary travel?

For example, can a space ship overshoot Mars in a reverse gravitational slingshot mixed with a little air breaking, steering to keep the spacecraft from orbit and then land on Mars with a near 0 ...
3
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1answer
820 views

Blimp on Earth, but a glider on Mars?

Could enough surface area be created with a blimp to shed speed using Mars' atmosphere to have a controlled soft landing to minimize the need for retrorockets? Runway would need to be in place. While ...
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2answers
232 views

Is there a way to recover any of the energy of reentry of a Mars lander?

Is there a way to recover any of the energy of reentry of a Mars lander? Tremendous energy is generated as a craft enters the atmosphere – admittedly over a fairly short time - and only one time. We ...
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2answers
590 views

Can a reusable electric powered blimp stage for launch possible?

Originally this question asked about using blimps and electricity in replacement of boosters. As written then it was no good and got down votes. I had a few question marks and each question really ...
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5answers
888 views

Can a blimp dead drop on Mars or Earth this way?

I saw a space jump where someone had exceeded the speed of sound before the air slowed him down enough to deploy a parachute, because the air was not dense enough to tear him apart in the upper ...
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1answer
254 views

What are transonic oscillations (wrist mode) and would Schiaparelli have been transonic at 2 to 4 km altitude?

edit: Considering that the recent (23-Nov-2016) ESA update suggests that a saturation of the rotational sensors in the IMU may have set off a series of miscalculations leading to mission loss, the ...
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1answer
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What is a “suicide burn”?

The term suicide burn occasionally comes up in answers and comments, usually without any real explanation or definition. What is meant by the term "suicide burn"?