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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32
votes
7answers
13k 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 ...
6
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3answers
1k 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 ...
8
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2answers
1k views

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 ...
16
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1answer
1k 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....
14
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2answers
2k views

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'. ...
23
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5answers
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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 ...
56
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2answers
26k 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 ...
13
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3answers
3k views

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 ...
17
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3answers
8k 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 ...
7
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2answers
699 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 ...
16
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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 ...
10
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2answers
900 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 ...
3
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0answers
207 views

How many kilograms of nickel particles will be dispersed in Earth's atmosphere by dumping old ISS batteries overboard?

Weighing 2.9 tons... this heap of old batteries is now the heaviest single piece of garbage to be jettisoned from the International Space Station. begins Gizmodo's ISS Ditches 2.9-Ton Pallet of ...
22
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3answers
15k 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 (...
15
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5answers
35k 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, ...
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 ...
14
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1answer
3k views

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 ...
12
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3answers
1k 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 ...
3
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3answers
633 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 ...
3
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3answers
952 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 ...
51
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4answers
8k views

What impact will the deorbiting of thousands of satellites have on the atmosphere?

With the creation of mega satellite constellations like Starlink, there are several thousand satellites being launched each year. This means that as these satellites go out of order in a few years, ...
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 ...
30
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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 ...
22
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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 ...
13
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2answers
3k 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?
13
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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: ...
5
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3answers
330 views

Would plasma sheathes from reentry heating block optical/UV communications as well as radio?

During reentry, it's routine for the ionized atmosphere surrounding the spacecraft to cut off radio communications for a certain period. As far as I know, this can't be avoided, except perhaps by ...
36
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3answers
5k 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 ...
14
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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 ...
10
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1answer
558 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
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1answer
2k views

This ISS trash deployment looks more like 2 feet than 2 inches per second, was it too fast or are these articles incorrect?

Digital Trends' Watch a NASA astronaut jettison part of the ISS into space which was linked in says: Writing in Air & Space last year about the process of jettisoning objects, veteran NASA ...
8
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1answer
288 views

Nature of "the silky black 'highly flame-resistant felt'" on Block 5 Falcon 9's, and its intended functions?

The Teslarati article SpaceX Falcon 9 Block 5 rocket’s drone ship return captured in stunning detail [gallery] and accompanying photo spread shows many interesting details of "SpaceX’s first West ...
7
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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
20k 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 ...
11
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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, ...
10
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5answers
5k views

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: ...
31
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6answers
6k 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 ...
19
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4answers
4k views

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 ...
19
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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 ...
18
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3answers
5k views

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 ...
15
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2answers
2k views

Tiangong-1 reentry impact place probabilities

Following all the news concerning Tiangong-1, I have seen the following plot made by the Aerospace Corporation where Blue area: null probability of impact Yellow area: high probability of impact ...
10
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1answer
1k 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 ...
43
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2answers
11k views

Why didn't the Space Shuttle bounce back into space as many times as possible so as to lose a lot of kinetic energy up there?

From this video, I got know that Space Shuttle did reentry around 5000 miles away from landing site. It's angle of attack is maintained around 40 degrees during re-entry. If it is more than that, it ...
14
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1answer
3k views

How is the periscope port on Soyuz spacecraft secured for the atmospheric reentry?

Soyuz Backup Periscope (ВСК-4) is used in Soyuz spacecraft to align itself for orbital corrections, deorbit burn, and rendezvous with the International Space Station. Here is a cute closeup photograph ...
12
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2answers
731 views

What are the requirements differences between Escape Suit and EVA Suit?

I read up articles on both types - EVA suits meant for spacewalks, and Escape Suits used in launch and reentry - but other than bright orange color for ACES making it easy to find and the fact that ...
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, ...
10
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2answers
5k views

What is the outside of the Soyuz capsule covered in?

When you look at a Soyuz, it seems like the descent and orbital modules are covered in some kind of fabric-like material. You can see wrinkles and it does not look like traditional metal as you might ...
9
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1answer
324 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 ...
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 ...