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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Why does the Falcon 9 first stage continue to decelerate after its reentry engine burnout?

As you know, Space X streams its missions and the speed and altitude data of the vehicle is shown. After stage separation, stage one gains speed and accelerates in its decent trajectory till reentry ...
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How to design Heading Alignment Cone(HAC)?

I am trying to design a Heading Alignment Cone. Of course, the radius of the circle depends on different parameters like energy, altitude, and aerothermal characteristics of the reentry vehicle and ...
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How do I convert from one local NED frame to another?

A little bit of background in case you are interested. I am running a re-entry simulation, and I am dealing with two different reference frames. The one with the higher fidelity dynamics is in the ...
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1 vote
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How spontaneously can a spacecraft be deorbited [duplicate]

Currently the return of AX-1 has been rescheduled multiple days due to weather concerns in the landing area. How quickly could astronauts on the ISS evacuate to the ground if so required? Scenarios ...
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11 votes
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Mystery balls! Gemini apparently had "thousands of hollow ping-pong-sized balls made of extremely thin aluminum embedded within its walls". What?

This fascinating answer says that "The Gemini capsule floated because it had thousands of hollow balls made of extremely thin aluminum, each composed of two half-spheres welded together, the size ...
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5 votes
1 answer
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How might an "imminent Starlink reentry in your area" alerting script work?

The video below Space debris over Puerto Rico (2/7/2022) SAC seems likely to show one or more reentering Starlink satellites from the 40 "Starlost" lost to atmospheric heating due to a ...
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15 votes
2 answers
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Did any Columbia debris continue orbiting Earth?

For reentry the Space Shuttles lowered their perigee to 28 nautical miles (52 km) above sea level. Shuttle Columbia disintegrated around 60 km altitude, and the first debris fell off as high as 70.5 ...
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8 votes
1 answer
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Would it be feasible to decelerate a crewed vehicle from ~25 km/s only using the atmosphere of Mars (in the context of an "express transit")?

I boldly assumed it would some day be possible to accelerate a crewed vehicle from a refueling station (LEO, GEO, Moon orbit?) to ~35-40 km/s (with several stages) relative to Mars, so it would make ...
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3 votes
1 answer
131 views

Heatshield during re-entry of space vehicles

All the CMs for Apollo, as well as the space shuttles, basically used "Blunt body" technique for re-entry. While Apollo CMs used "ablative" type of heatshield, the space shuttles ...
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11 votes
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Could sheets of stacked graphene be used as part of a heat shield, since its melting point is 3000k to 5000 K

Since graphene material is the strongest manmade material, with "magical" properties, I wonder if it could be considered for use as a heat shield, since its melting point is 3000 to 5000 K ...
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9 votes
2 answers
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Can an ISS module survive reentry?

Nasa is making plans to de-orbit the ISS safely over the pacific ocean, this eventually leads to the question of whether or not an ISS module can survive reentry (survive meaning it is recognizable ...
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13 votes
3 answers
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Has SpaceX chosen to drop the Transpiration cooling of Starship? If so, why?

Earlier, there was news about a proposed concept for Starship to include "transpirational cooling" in its reentry heat shield design. These days there is less news about this and tests so ...
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3 votes
1 answer
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Do reentering capsules always make a(n Earth-shattering ka-)boom and look like a fireball if at night? Time & epicenter predictable w/ public info?

SpaceX enjoys press. So the unexpected events popping up in the news is good for them. March 26, 2021: Fire ball burning over Woodland WA- SpaceX second stage re-entry and burn up. A ‘spectacular’ ...
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4 votes
1 answer
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Dragon re-entry flight profile?

I was looking online for a profile depicting the Dragon re-entry similar to those showing the launch and first stage re-entry (e.g. https://www.elonx.net/wp-content/uploads/...
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14 votes
1 answer
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What is the heat shield refurbishment procedure for a crew Dragon capsule?

How, specifically, is the heat shield replaced or refurbished? More precisely... How do they know it will work for the next mission? :-P
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3 votes
1 answer
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Soyuz: Do you know the coefficient drag and lift to drag ratio are during reentry?

I've been learning Python as a hobby the last two years. I like spaceflight too. Therefore I wrote this code to simulate the reentry of a Soyuz. I'd appreciate some feedback: https://github.com/fra-...
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4 votes
0 answers
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How does a returning Falcon first stage decide when to end its re-entry burn?

When a Falcon 9 first stage is returning to Earth to land, it performs a brief re-entry burn in order to slow down. My question is, what criteria does the first stage control software use to decide ...
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22 votes
2 answers
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Space Shuttle Challenger bringing back Salyut-7

We know that on February 11 1985, right after the Soviets lost control of their Salyut-7 station. US Space tracking assets also started noticing that the station was starting to tumble. Kidnapping a ...
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Has there been any bolide-spacecraft near-miss?

Has there been any incident where a reentering spacecraft nearly collided with a meteor?
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Do aeroshells need to be super smooth to survive atmospheric entry?

IIRC, one of the arguments against Shuttle Columbia's hole being repaired was that the repair would not be smooth. Apparently, the heat shielding relied on a sensitive boundary layer. Even a small ...
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2 votes
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Would it have made a difference to the TPS design if the Shuttle used skip reentries?

The Space Shuttle needed silica tiles and carbon-carbon panels to survive the sustained high temperatures of reentry. These materials were fragile and high-maintenance, and this led to the Columbia ...
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1 vote
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What if the Starship fins were fixed?

The body flaps on Starship have the responsibilty of controlling attitude during atmospheric flight. They are also needed to deal with the large moments created by carrying payloads in the nose. ...
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1 vote
2 answers
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How can SpaceX receive data from Starship during re-entry communications blackout

Surviving re-entry will be one of the initial critical aspects of the Starship development program. If there are locations on the vessel where the heat-shield fails, leading to its destruction how ...
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27 votes
2 answers
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Gagarin not ejecting from capsule

I'm currently reading a dutch book about the earlier days of manned spaceflight (Ruimtevaart B. van der Klaauw). Published in 1962 In a chapter about Vostok 1 the book reads as following Translated ...
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2 votes
1 answer
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Into what non-navigable Pacific Ocean area did structural elements of the Progress MS16 cargo ship & Pirs module fall? Are there maps of these areas?

This recent Roscosmos tweet (found in CNET's See astronaut's wild view of a discarded ISS module burning up) says: The non-combustible structural elements of the #ProgressMS16 cargo ship and the #...
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4 votes
1 answer
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Can Mars orbiters be disposed in the atmosphere, as it is done on Earth?

There are a fair number of spacecraft currently orbiting Mars, and each will eventually reach the end of its useful life. Satellites in low Earth orbit are routinely de-orbited at the end of their ...
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1 vote
1 answer
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Could a steel drum perform reentry with a heat shield?

Suppose you have a regular steel drum with an ablative heat shield on the bottom. Theoretically, could this steel drum with heat shield perform a reentry from low earth orbit?
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3 votes
1 answer
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Measurement and estimation of temperature of Space Shuttle nose cone during launch and re-entry

During the launch and re-entry of the Space Shuttle, what are the measured and estimated temperatures (or distribution) of the shuttle nose cone as a function of altitude? How is the temperature ...
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2 votes
1 answer
239 views

What orbits are Starlink satellites now deployed into? How low to do they go on their first perigee?

In my answer to Delta-V of Starlink Satellites I ballpark spherical-cow envelope-back estimated 190 m/s with 2 kg of krypton based on raising only from a 445 km circular orbit to a 550 km circular ...
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2 votes
1 answer
94 views

Change in drag coefficient when Dragon flips over on launch escape?

Consider the Falcon 9. In emergencies, the launch escape system will fire to separate and propel the crew module away from the rocket. After the engine shuts down, the payload trunk will separate ...
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3 votes
0 answers
171 views

Why does the landing trajectory of a blunt body take an S shape in the lower atmosphere?

I coded some Matlab plots of altitude vs time for the re-entry of a point mass (so no aerothermo analysis included). In all the trajectories, there is an S shape closer to the ground. Why? Please ...
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5 votes
1 answer
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If a Space Shuttle tile deorbited on its own, what percentage of it's mass if any would remain in one piece until it reached the surface of the earth?

If a Space Shuttle tile deorbited on its own, what percentage of it's mass if any would still be in one piece if and when it reached the surface of the earth? The question was inspired by one of the ...
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5 votes
2 answers
155 views

How much debris will hit the ground from the Long March 5B compared to the debris from a GTO upper stage?

It was commented that there are currently 22 SpaceX upper stages in orbit that will eventually reenter in an uncontrolled fashion. PcMan pointed that out when I asked Why the Long March 5B wasn't ...
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4 votes
1 answer
256 views

Why couldn't China's space agency do a controlled deorbit burn for the Long March 5B?

China has succeeded in launching the main module of its future space station, Tian He. Cool! The Long March 5B core that launched it is now in an uncontrolled decaying orbit. It's estimated it will ...
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1 vote
2 answers
172 views

Deorbit first stage?

I have read the answers about deorbiting second/upper stage. But since the lastest launch of Long March 5B raised concern about its uncontrolled reentry (yeah, too big). Unlike SpaceX's Falcon, other ...
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7 votes
1 answer
370 views

Nighttime reentry of occupied spacecraft?

In looking at details of the tomorrow early morning (Sunday, May 2, 2021) reentry of the crewed SpaceX Dragon capsule, I see that it's reentry plan is for a nighttime splashdown in the Gulf of Mexico. ...
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6 votes
1 answer
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Is there a very light material that could deorbit without burning up?

Is there a very light material that could deorbit without burning up? I am thinking of a very light, strong, heat resistant thread, rope, net, or sheet that sheds heat so fast as it deorbits that it ...
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2 votes
2 answers
1k views

Minimum reentry velocity ideal for a spacecraft returning to Earth

During the return trip from Mars or Moon, SpaceX starship can refuel it's propellant tanks before reentry. It can use these propellants for reverse thrust to bring the spacecraft velocity to near idle ...
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3 votes
0 answers
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Falcon 9: transonic attitude control on reentry

Attitude control on the falcon 9 is done with engine thrust vectoring, cold gas thrusters, and grid fins. After the reentry burn, when the rocket stage is in the atmosphere, there is a short period ...
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3 votes
2 answers
374 views

Would it be possible to avoid the heat-from-friction problem when re-entering the atmosphere by performing (vertical) "U-turns"?

If you lift a swing at a children's playground and release it will swing back and forth for a while, losing some altitude in each swing, mostly (?) due to drag. Eventually it has lost all energy and ...
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1 vote
1 answer
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State vector update on reentry

The integration errors from IMU state measurements would seem very problematic when you're coming in for a landing, where error tolerances would probably be as small as they could get. This must mean ...
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2 votes
1 answer
89 views

Help understanding vectors in diagram from "Magnetohydrodynamic flow control during reentry" and the actual goal of this research

A link to the ESA Advanced Concepts Team page Magnetohydrodynamic flow control during reentry was recently shared under Re-entry Heat Shield Alternative. It says: During the reentry phase, spacecraft ...
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5 votes
1 answer
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ISS battery "de-orbit" burnup?

In reading these two questions: How many kilograms of nickel particles will be dispersed in Earth's atmosphere by dumping old ISS batteries overboard? and Why does it take so long for ISS garbage ...
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5 votes
3 answers
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Why does it take so long for ISS garbage to fall out of orbit?

The ISS recently jettison some garbage and expects it to take 2-4 years to de-orbit and burn up. From Gizmodo's ISS Ditches 2.9-Ton Pallet of Batteries, Creating Its Most Massive Piece of Space Trash: ...
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3 votes
0 answers
271 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 ...
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9 votes
1 answer
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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 ...
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5 votes
1 answer
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Regulations for cubesats designed to survive reentry and be retrieved?

I'm currently thinking about the potential of manufacturing certain items (ZBLAN, Semiconductors, Organs, Drugs, etc.) in LEO and I want to know whether it would be possible/legal to design a cubesat ...
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4 votes
0 answers
91 views

During space shuttle reentry, why was the sign of GALR based on mach number rather than directly on alpha?

(My apologies if this should go in Aviation.SE instead - I'm not quite certain where questions regarding the behaviour of the shuttle's flight controls during reentry should go.) For flight in ...
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2 votes
1 answer
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How fast was NASA Perseverance flying at when it hit Mars' atmosphere?

Do we know how fast Perseverance was flying at relative to Mars when it hit its atmosphere? The closest figure I could get to was "over 12,000mph" according to this article: https://www....
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2 votes
1 answer
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During reentry, does the flux stay laminar? Should become turbulent the capsule could not mantain attitude

This a thing that, instinctively, I find it hard to grasp. The capsules are designed with a centre of gravity slightly to the direction of the thermal shield, this assures the right attitude, but how ...
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