Questions tagged [reentry]

Questions related to the movement of human-made objects as they enter atmosphere of Earth or other planetary bodies with atmospheres from space after being successfully launched.

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30
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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 ...
16
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2answers
949 views

Have spacecraft ever dipped below the Karman line and then safely continued spaceflight?

The item in Science Alert's A Harvard Astrophysicist Says Outer Space Is Actually Closer Than We Think (see also Science; Outer space may have just gotten a bit closer) talks about the recent Acta ...
15
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4answers
2k views

What are the conditions for re-entry of an object in a (highly) elliptical orbit?

There's something I don't understand: When it comes to de-commissioned satellites, rocket bodies etc. I thought one way of re-entry was via a highly elliptical orbit: The perigee gets low enough (app....
11
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2answers
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What aspects of reentry heating 'scale as the 8th power'?

Elon Musk just commented in the post Falcon Heavy Test Flight press conference that reentering at interplanetary velocities means dealing with 'some of the heating things that scale to the 8th power'. ...
7
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2answers
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If there was a non-rotating skyhook in Earth orbit, what would re-entry be like after dropping from its foot?

I have been looking at a space station that orbits Earth at an altitude of 3500 km above the equator, and has tethers that extend from it downwards to 250 km above the surface, and outwards to 6500 km ...
5
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1answer
708 views

Why does Earth's atmospheric density have a big “knee” around 100 km? Is there a good analytical approximation?

I've used a quick very rough approximation of the drop of atmospheric density with altitude in this answer and in this answer by using a single exponential and scale height parameter, but that's not ...
13
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3answers
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Could you take a Cessna from the ISS to Earth?

The shuttle had a empty gross weight of 172,000 lb (78,000 kg), and the only feasible way shedding the 27,724 kilometres (17,227 mi) per hour, of the relative speed of the ISS is Aerobraking. A four ...
22
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4answers
1k views

Gliding into the atmosphere

The recent question about Cessna reentering from ISS got the answers that all imply a rapid drop. But from what I know, air drag is proportional: to square of airspeed to air density to attack ...
10
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2answers
700 views

Challenging the Kármán line from above

The initial conditions of the thought experiment is (very) LEO / reentry. capsules, space shuttle and other spacecraft can generate lift in upper atmosphere during reentry, in order to reduce ...
55
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2answers
23k 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 ...
21
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3answers
13k views

How does skipping off the atmosphere work?

I searched the web and found a couple entries on Wikipedia (Skip reentry & Atmospheric entry) that kind brush at the topic. The article on Stone skipping has some science and physics involved (...
14
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1answer
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Why did early satellites (e.g. China's Fanhui Shi Weixing) re-enter the atmosphere narrow end (nose)-first?

I was surprised to find out from @JohnnyRobinson's new answer that China's series of Fanhui Shi Weixing spacecraft (FSW) used impregnated oak heat shields. I found this in astronautix: The capsule ...
3
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3answers
851 views

Would a balloon pop if dropped from space?

Could a "simple" inflated party balloon be dropped from space entering an atmosphere? The first case at orbital speed, the second case just outside the atmosphere and the third interplanetary? The ...
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3answers
607 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 ...
29
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1answer
5k views

Why are spaceship capsules frustum shaped?

Why do spaceships have a frustum (portion of a cone) shape like e.g. the pressure capsule of the SpaceX Dragon on the image below?     I think there is some engineering stuff behind ...
12
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3answers
3k views

Can a reentry be done slowly?

The usual approach to reentry is fast and hot. There's a lot of energy to be lost, and doing it quickly has some advantages: You can dump energy into hypersonic air, and then leave that heat behind ...
14
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2answers
2k views

Artificial Shooting Stars - how could this possibly work (economically/technologically)?

update March 2018: I just saw this in Buzzfeed (Google sent me there, I don't normally read it): Rich People Will Soon Be Able To Buy Fake Meteor Showers On Demand @Antzi mentioned below the question ...
13
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5answers
32k views

What are the top temperatures occurring during reentry?

We all know spacecraft reentry causes extreme heat - plasma, ablator, flaming trail, all that jazz. I'd like to know just what level of heat are we dealing with - could someone throw some numbers, ...
13
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2answers
2k views

What is feathering?

I heard that Virgin Galactic's SpaceShipTwo just tested something called “feathering”. What is it? How come I didn't hear about the shuttle doing this, it is unique to Virgin Galactic's ship?
7
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2answers
466 views

How does the dynamic pressure evolve during reentry?

During launcher ascent, dynamic pressure evolution is described in this answer for the Saturn V. I suppose this is similar for most launchers. Given the protections designed for reentry, I suppose ...
11
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3answers
960 views

Why are Tiangong-1's Apogee and Perigee Graphs Wobbly?

The apogee and perigee graph of the Tiangong-1 space station, about to re-enter and break up Real Soon Now, is depicted in this graph (source: Wikipedia): Why are the graphs wobbly? Is it because the ...
7
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1answer
709 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 ...
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3answers
4k views

Why don't 3-parachute descent systems collide and collapse?

The Orion reentry vehicle will have a parachute system. Like Apollo, they'll have 3:     Orion Parachute Drop Test on May 1, 2013 A model of NASA's Orion spacecraft glides ...
10
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1answer
511 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 ...
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2answers
2k views

What effect (if any) would leaving the cargo bay doors open have had during a shuttle reentry?

The cargo bay doors of the Space Shuttle were used on-orbit as radiators for thermal control. The cargo bay doors were closed before the reentry burn and descent to the surface, but could there have ...
10
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1answer
18k views

What are reentry speeds of space vehicles?

I found here that the entry speed of meteors reach 48 km/s. I mean just before hitting atmosphere. What are reentry speeds for space vehicles like the lunar command module? What about soyuz ...
29
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1answer
6k views

If I drop a feather from orbit, would it burn up or “hit” the ground?

I know that capsules typically require heat shields to survive reentry from orbit. I'm wondering how an object's size, density and aerodynamic profile affects this. For more specificity: The feather ...
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6answers
5k views

What crewed space flight landed farthest off-target?

Astronauts are usually prepared to land at a random place on Earth; in case the planned reentry burn fails, but by other means they achieve reentry trajectory, the orbital motion will pretty much ...
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4answers
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Why can't you just parachute down right from orbit?

This will surely seem, at least at first sight, a completely stupid idea, seeing the usual “space isn't high away, it's fast away”, and that the heat shields which actually are used need to withstand ...
10
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5answers
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Mathematics used for SpaceX first stage re-entry burn guidance?

I thought it would be fun to make a basic simulation of a first-stage fly-back of SpaceX's Falcon 9, but was wondering what mathematics is used to perform something like this. Looking at this page: ...
18
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3answers
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Do you need a heat shield to enter the atmosphere from non-orbital speeds?

Let's say you launched a rocket straight up, not intending to go into orbit. At its apogee, the rocket is (say) 200 km above the earth: high enough (though certainly not fast enough) for LEO. Would ...
17
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4answers
3k views

Why is it not possible to deorbit in a shallow glidepath?

The fiery re-entry of spacecraft has been a staple of spaceflight since the beginning, making ablative heat shielding a necessary component of any craft wishing to return to Earth intact. This is the ...
16
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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 ...
12
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2answers
2k views

Re-entry Heat Shield Alternative

Why is it that Controlled Re-entry Vehicles (like the most recent Orion & Dragon) do not use a strong magnetic field during re-entry to "shield" the blunt shaped end from plasma ? Reasoning: ...
10
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1answer
980 views

Communication Blackout

All the atmospheric entry missions endure a communication blackout. What parameters except plasma penetration frequency affect the blackout time and how ? Also, Comm Blackout states that space ...
11
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1answer
2k views

Did any Apollo missions have backup parachutes?

NASA's Apollo modules, the ones that went to the moon, had a fairly standard-for-the-time reentry method: Hit the atmosphere at the right angle, deploy a parachute after things are done burning up, ...
9
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3answers
4k views

Requesting an in depth explanation of heat created during atmospheric reentry,

What is(are) the root cause(s) of the heat and friction experienced during atmospheric reentry (or initial entry)? I understand that as items descend to earth they experience a force that can ...
9
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1answer
287 views

How does a Reentry Breakup Recorder survive reentry and then broadcast its data before impact?

Below are two cropped parts of File:ISS-28 Ron Garan prepares the Reentry Breakup Recorder.jpg In the Unity node of the International Space Station, NASA astronaut Ron Garan, Expedition 28 flight ...
7
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1answer
377 views

What will Max Q for descent be? [duplicate]

I've seen lots of flight profiles that give Max Q during ascent. Around 33 to 35 kilopascals, if memory serves. But I have been having a hard time finding Max Q during descent. With the recent reuse ...
6
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0answers
219 views

Could ablative material sublimation slow down a spacecraft?

Thought experiment illustrated below: Suppose a weird spacecraft entering Earth's atmosphere from low Earth orbit, payload first. Behind it there is an inverted nozzle shaped structure, attached with ...
5
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3answers
558 views

When I see the SpaceX reentry vidos I see no flaming ionizaton

When I see the SpaceX reentry videos I see no flaming ionization from the time the reentry starts. I realize things must be getting hot at some point but its not the ball of fire I imagined . Where ...
20
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1answer
2k views

Why is it that during reentry phase a capsule cannot communicate with mission control?

During reentry phase into the Earth's atmosphere the heat produced by air friction does not allow any communication with the surface. Why does the heat interfere with electronic frequencies and ...
16
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2answers
1k views

Do we have any idea when Tiangong-1 will deorbit?

In March 2016 China's Manned Space Engineering Office announced that all Tiangong-1 telemetry had failed leaving no ability to safely control the space station's decent. With what we know about the ...
14
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5answers
4k views

When does an aerobraking space craft create a sonic boom?

There are a lot of variables with the speed of sound, a sonic boom is created when all of those variables meet. the speed of sound, a critical speed known as Mach 1, and is approximately 1,225 km/h ...
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3answers
1k views

Has any spacecraft had a way for the crew to escape during reentry?

All manned spacecraft to date have come back to Earth eventually, and when they do it's through a flaming ball of plasma. It seems too probable that this plasma would have a way of breaking things ...
14
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1answer
1k views

Any imagery from Shuttle Columbia's SILTS pod on the internet?

(Inspired by this question) One of the distinguishing features of Shuttle Columbia was its Shuttle Infrared Leeside Temperature Sensing (SILTS) pod. This was an experiment that took infrared imagery ...
12
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1answer
1k views

Could the Shuttle boosters crash into each other?

I watched a few videos "from the boosters" of their suborbital flight with the Shuttle, and what I noticed is that after the boosters were jettisoned there was a phase of flight that was quite chaotic ...
10
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1answer
2k views

Have liquid cooling systems been tested for reentry surfaces?

A tough exterior of heat-dissipating material is generally used for reentry modules. I am wondering if there have been any attempts or experiments at using liquid cooling systems as thermal protection ...
10
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2answers
4k views

Why will the Orion system land on water, while the Soyuz lands on land?

I wonder why the Orion Multi-Purpose Crew Vehicle will only allow ocean landings while the Soyuz spacecraft is capable of landing on land? Also, what mode of landings does the Chinese space program ...
9
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2answers
737 views

How long does trash jettisoned by hand from the ISS fall before burning up on reentry?

NASA proposed a policy for the jettison of trash from the ISS space station. This article notes that a recent ISS space station spacewalk by Russian cosmonauts involved one man jettisoning by hand a ...