Questions tagged [landing]

Questions regarding the specific part of flights, during which a spacecraft touches down on the solid ground of a celestial body.

Filter by
Sorted by
Tagged with
31
votes
7answers
12k views

How could a 90 m/s delta-v be enough to commit the space shuttle to landing?

Wikipedia claims (although with no citation) that in order to make the space shuttle land, an initial powered delta-v of 322 km/h was applied in orbit, retrograde to the shuttle's orbit. 322 km/h is ...
24
votes
4answers
5k views

How does the Falcon 9 know where the landing barge/pad is?

The descending Falcon 9 has got to hit (preferably gently) the tiny target of the Autonomous Spaceport Drone Ship (ASDS) in the middle of the ocean. How does the Falcon 9 know where the ASDS is? ...
-7
votes
3answers
2k views

Why does the Mars InSight Lander look wet like a cardboard box that came in contact with water? [closed]

NASA has just released a photo showing a part of the InSight Mars lander wet, like a cardboard box that came in contact with water (see the picture). What is that liquid? The Instrument Deployment ...
43
votes
4answers
10k views

Why was Venus rather than Mars targeted for the first interplanetary landings?

This is a question about early planetary missions. It looks like there was only one early (unsuccessful) landing mission to Mars and that subsequently Venus became the target for interplanetary ...
56
votes
2answers
25k views

How does the Falcon 9 first stage avoid burning up on re-entry?

Now that a Falcon 9 first stage has successfully landed after a launch mission, I want to know how the first stage can avoid burning up when coming back down to earth. There doesn't appear to be any ...
6
votes
2answers
2k views

Why were three engines used for the F9 1st stage landing burn (BulgariaSat-1)?

As pointed out in the question What is the “emergency crush core”?, an Elon Musk tweet about the Falcon 9 1st stage landing following the BulgariaSat-1 launch says: Rocket is extra toasty and hit ...
18
votes
4answers
5k views

What is the largest hurdle of the mission to Mars?

I was shocked when I recently found out just how long it takes to get to Mars. I've been conducting a very informal survey amongst peers of how just how long people think it takes us to travel to Mars....
4
votes
2answers
2k views

Can Falcon 9 first stage landing final burn using one, two, and three engines? Tradeoffs?

This question is about the final burn in the landing sequence of the Falcon 9 first stage return to Earth tests. If I understand correctly, there is usually far more thrust than there is weight at ...
24
votes
2answers
15k views

How are the SpaceX Falcon 9 Mod 3 and Mod 4 grid fins different?

Elon Musk tweeted "Flying with larger & significantly upgraded hypersonic grid fins. Single piece cast & cut titanium. Can take reentry heat with no shielding." These have been commonly known ...
21
votes
3answers
7k views

Why did the Apollo Lunar Module have four landing legs?

Why did the Apollo Lunar Module have four landing legs? Is not just three legs enough? Also, three legs guaranties they always form a plane, four does not, as the fourth leg may dangle. To have the ...
19
votes
2answers
3k views

On the Falcon Heavy, why are the side boosters using Ti Grid fins, but not the center core?

Elon Musk showed a picture of the almost ready to fly Falcon Heavy in the HIF (Horizontal Integration Facility, aka rocket barn). You can see the darker, larger grid fins on the side cores, and the ...
11
votes
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 ...
15
votes
1answer
5k views

How effective are Falcon 9 1st stage grid fins in the last few seconds before landing?

This answer discusses the three methods that the Falcon 9 1st stage uses for attitude control during re-entry and landing. They are: cold nitrogen jets, "hypersonic" grid fins, and thrust vectoring of ...
21
votes
5answers
9k views

Olympus Mons - viable Mars landing site?

I'm becoming interested in how Mars missions are planning their landings. One aspect I see brought up time and again is Mars' awkward atmosphere - 'just enough there that you have to care about it'. ...
11
votes
1answer
1k views

Which crewed spacecraft provides the gentlest decent and/or landing?

Landing with a Soyuz capsule is often compared to being in a car accident1, it's pretty violent on touch-down. On the other hand, I imagine the Space Shuttle's touch-down to be a little like a rough ...
3
votes
3answers
625 views

Ways to mitigate the forever violent re-entry? (Moon landings vs Earth landings)

The frequently used reasoning for why the re-entry should always be performed at neck-breaking speeds is that it would take almost as much fuel to slow the craft down as it takes to launch it into ...
25
votes
11answers
9k views

Could the Space Shuttle have landed on any long runway other than those specially reinforced at Kennedy (TTS), and Edwards (EDW)?

Wikipedia writes to say Buran was the first space shuttle to perform an unmanned flight, including landing in fully automatic mode. ... The same article writes further The automated landing ...
6
votes
0answers
172 views

How does New Shepard Crew Capsule sense proximity to trigger retropropulsion just before impact?

How does the New Shepard Crew Capsule sense proximity to the ground in order to trigger retropropulsion just before impact? GIFs from Blue Origin NS-10: New Shepard launch & landing, 23 January ...
0
votes
1answer
443 views

From which direction was the Falcon 9 1st stage's landing approach (BulgariaSat-1)?

Looking at this cropped section of the screenshot described below, this is what I think I see: A: Shadow from the leg support on the right, but not the left. B: Scorch marks? C: Scorch marks? D: ...
48
votes
2answers
11k views

How does the SpaceX Falcon 9 first-stage straighten for landing?

I just saw this video of supposed "SpaceX Rocket Camera Landing Footage Fakery" with over a million views. The narrator repeatedly says it's complete garbage because he doesn't understand ...
33
votes
6answers
20k views

Why did SpaceX attempt to land the booster on a barge instead of somewhere on land?

I understand the benefits of reusability for the rocket booster. But I don't understand why they're landing it on a barge. I've read tons of articles about this but not one has even hinted at an ...
32
votes
5answers
6k views

Why were contact sensors put on three of the Lunar Module's four legs? Did they ever bend and stick out sideways?

In the video Brian Eno on Apollo starting at 08:37 there is Apollo-era movie footage of a lunar module taken from the command module as it prepares for descent ...
18
votes
4answers
4k views

SpaceX first stage landing: Why not use an elevated net above the landing platform to catch the rocket?

The rocket would keep same descent system as now (no parachute). But instead of landing on feet, it would have long grid fins on its top that would be catched by an elevated cable net. The previous ...
17
votes
3answers
7k views

Why does the video feed always fail during Falcon 9 landings?

I'm in love with SpaceX and Falcon 9, I watch every live stream and the most special, most amazing, most thrilling part of each launch is the 1st stage landing. Seeing the smoke (or vapor) clear and ...
21
votes
3answers
2k views

Can a single Soyuz return a crew of six back to Earth?

Let's say that the ISS has to be immediately evacuated and that one of the two Soyuz is broken. Could the crew quickly remove "unnecessary weight" (seats maybe?) and fit six person to return back to ...
18
votes
4answers
8k views

If the Space Shuttle missed its landing approach, what could have been done?

As I understand it, the Space Shuttle was essentially a glider when it was coming back to land, and the engines were not there to facilitate powered flight. So what was the procedure, had the Space ...
10
votes
1answer
2k views

Why the strange bands of soot of the landed F9 first stage?

If you look at the daylight photos of the landed first stage of the Orbcomm G2 Falcon 9 mission, there is all sorts of soot covering stuff in interesting patterns. What elements of the soot pattern ...
21
votes
2answers
4k views

How far off did Apollo 11 land?

Armstrong wasn't able to land exactly in the designated landing location, as far as I know it was too rocky. So he had to fly a bit farther to find a suitable spot. But how much farther from the ...
18
votes
2answers
6k views

How will SpaceX achieve landing of the Falcon 9 first stage?

What mechanisms and technologies will be used to control the descent and movement of the falcon 9 rocket's booster stage on its way to the landing pad?
6
votes
1answer
2k views

What is the burn time for the F9 boostback / reentry / landing burns?

I'm trying to figure out the timing of the 3 recovery burns and the total fuel reserve needed to perform them. [Answers Inlined] Boostback: [30] seconds of 3-engines at full-thrust. Reentry: [20] ...
12
votes
3answers
2k views

What were the biggest and heaviest spacecrafts to safely return from orbit?

How big a thing was able to land or splash down? Was there ever anything bigger or heavier than the Space Shuttle? If no then whats next on the list? And secondary question: what is the maximal ...
10
votes
1answer
527 views

How does a Falcon 9 booster know how far away the ground is?

In the latest landing video, it seems the Falcon 9 just hovered for a moment above the ship. That being said, it begs the question, how does the booster know where the ground is? Does it purely work ...
9
votes
2answers
2k views

How precise are our Mars landings?

The idea of surface rendezvous for supply missions to a Mars expedition (either before or after arrival of a manned expedition) seems to come up every now and then. This would allow a manned ...
7
votes
1answer
4k views

What is the velocity profile of a Falcon 9 first stage landing?

How fast is it travelling as it comes into landing, before and after the re-ignition of the engine, and how quickly does it decellerate?? I would expect that it would be falling at about terminal ...
7
votes
3answers
723 views

Why not land booster stages in a cone or net?

Why must you land the boosters on a flat surface? Why not aim for a cone a deep net that can accommodate rough seas, winds, etc? A picture is below - obviously I am not an artist nor an engineer.
3
votes
1answer
415 views

When did soviet capsules begin using retropropulsion immediately before landing?

Wikipedia's Yuri Gagarin says: At about 23,000 feet (7,000 m), Gagarin ejected from the descending capsule as planned and landed using a parachute. and the section Vostok_programme; Vostok 3KA ...
2
votes
3answers
643 views

Could a Falcon 9 booster “abort” a landing, then land shortly thereafter, or somewhere nearby?

This comment below this question has me somewhat convinced that it would be hard for a Falcon 9 booster to abort a landing at the last minute (say within the last 100 meters or something like that) ...
16
votes
2answers
3k views

What are the disadvantages of parachute+airbag for atmospheric landing, versus rocket-based?

After Sojourner success, repeated by Spirit and Opportunity, it seemed like we had developed a fail-proof system for atmospheric landing for our probes: there's very little that can go wrong with the ...
11
votes
2answers
2k views

How to get processed asteroid metals back to Earth in a safe manner

How would you get precious metals (like platinum, lithium, uranium, etc) from an asteroid safely back to Earth? First, assume we don't need the metals in space for in-space manufacturing. Second, ...
44
votes
4answers
10k views

Why can't Falcon 9 fairings touch the water?

SpaceX is spending considerable effort to catch Falcon 9 fairings into a giant net on a ship. I am aware that salt water ruins almost everything in the long run, but the fairings are a composite ...
8
votes
4answers
1k views

Recent Falcon 9 flights - 'topped off' with propellants, or just a margin over what's needed to land?

A simplified version of the landing choices might be - if there's going to be sufficient propellant, the plan is for the F9 first stage to u-turn and go all the way back to the launch area to land. ...
56
votes
4answers
9k views

How were Perseverance's cables “cut” after touching down?

In the NASA conference today regarding Perseverance's successful landing on Mars, they talked about how you can see the cable that held the rover in this picture below (I circled the cable). I'm ...
16
votes
1answer
1k views

What do the Teeth on the SpaceX Falcon Mod4 do?

Can someone explain the purpose of the 'teeth' seen in the last picture of this answer? Do they have a specific name? They look too far up to be used to grab anything since the rockets land ...
16
votes
1answer
1k views

Are launch windows to Mars avoided if they result in landings during dust storm season?

This comment suggests that orbit before descent to Mars' surface allows a mission to delay the landing if the weather conditions are bad. I think that Tianwen-1 will be the first to put a lander rover ...
12
votes
3answers
5k views

Could a Soyuz land in water?

While watching Soyuz exp. 37/1 land, I was struck with a thought: that capsule looks an awful lot like a submarine. This seems to be a problem if the crew ever needed to make an emergency landing ...
11
votes
5answers
943 views

Is it possible to navigate space travel with no computer?

From launch to land could a person travel in space with only mechanical devices like a sextant? With enough experience what would be the minimum devices needed? Which vehicle currently would be easier ...
11
votes
1answer
1k views

Flashing lights on soyuz underside?

Watching the recent landing video of TMA-16M, I noticed a flashing light on the underside of the soyuz (video here). There appears to be an off-centre, bright flash approximately every 10 seconds. ...
10
votes
1answer
587 views

How does the Falcon 9 first stage land on the moving surface of the barge?

From this question we know the barge can be held at a set position with an accuracy of one meter or so. So the barge doesn't really move in the X and Y direction. This takes care of yaw as well. But ...
5
votes
1answer
642 views

Technologies use by SpaceX to enable landing on a drone ship [duplicate]

Even when the Falcon 9 "punched the barge", it did so with extreme precision. SpaceX has now had several successful landings, many of them extremely spot-on. Two questions: There are obvious visual ...
2
votes
1answer
213 views

How did Chang'e-4 hover, rotate, and then descend so gracefully? (Video)

In this incredible video we can see Chang'e-4 in it's final approach and landing on the moon from the point of view of the spacecraft. The view is horizontal as the spacecraft seems to stop and hover ...