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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74 views

Expansive ablative heat shield

Are there studies about using expansive foam such as polyurethane, so that it provides high volume & high cross section heatshielding, instead of inflatable ones, or in combination with inflatable ...
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Minimal heating a realistic reentry vehicle could achieve?

In this question, I asked whether it would be possible to make a reentry vehicle that could slow down from orbit and glide to the ground entirely passively. The answers and comments point out several ...
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1answer
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Why does the Apollo reentry trajectory show a few climbs?

In this answer the following graph is displayed: It shows two slight increases in altitude (after 1st peak g and at the end of the blackout). For me, it looks like zoom climbs (trading kinetic ...
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What's this purple donut in the video of the Falcon 9 fairing's atmospheric reentry?

This SpaceX tweet (found in CNET's SpaceX camera captures incredible view of rocket part returning to Earth) shows a video taken by a camera in one half of the fairing on the recent STP-2 mission and ...
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Are there examples of cargo being damaged during re-entry?

Are there examples of items being brought to or returned to Earth that were damaged in the re-entry process? For example, lunar samples during Apollo, or something being returned in the Shuttle ...
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1answer
83 views

Did the heat shield of the Vostok 1 capsule ablate during reentry?

This Wikipedia article (in german) has some information about the heat shield of Vostok 1. The heat shield was made from asbestos, its thickness was increased from 3 cm to up to 18 cm. The weight of ...
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1answer
204 views

Why don't the hottest temperatures of a re-entering spacecraft occur near the “bottom”?

The paintings of the Apollo command module and space shuttle below portray the heating effects of re-entry. The whitest parts of the spacecraft get the hottest, with cooler parts in red and darker ...
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47 views

What is the longest manned re-entry from Low Earth Orbit ever recorded?

What is the record for the longest amount of time that a manned spacecraft has taken to re-enter from low Earth orbit (LEO)? I would prefer the duration between the beginning of the re-entry burn ...
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1answer
91 views

How do I calculate re-entry velocity when decaying from a circular orbit?

I am trying to find the velocity of an object during re-entry so that I can calculate the peak heat flux but I'm a bit stuck. I know how to find the velocity of the original, circular orbit (300km) ...
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351 views

What does this SpaceX tweeted photo show and what causes the pure red and blue color?

This May 4, 2019 SpaceX tweet says More photos from Falcon 9’s 40th successful launch from Pad 40 in Florida and 39th first stage rocket booster landing to date → http://flickr.com/spacex and ...
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At what altitude does a spacecraft slow down?

So as far as i understand at 100km atmosphere exists although very faint. Could someone aproximate the speed of a sphere at 50km altitude after re-entry from a high orbit? It might sound as a wierd ...
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Two stage reentry from Moon/Mars

There are a number of questions addressing the desirability and/or feasibility of a slower reentry from Earth orbit in order to reduce thermal load. At least most of them run into the problem that ...
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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 ...
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What is the point in which metal turns white hot during launch or reentry called?

This is a slow motion film of the Sprint missle. There is a point where to skin goes white hot like a light switch. What is that called? What metal gets white hot while keeping its shape?
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Do owners of reentering spacecraft notify the countries' whose airspace they are likely to violate and seek permission?

@PearsonArtPhoto's answer contemplates: Any object that is below 100 km now is considered an aircraft, and technically needs the permission of the country over which it is flying to enter that air ...
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Why not increase contact surface when reentering the atmosphere?

If a craft were to increase the surface area where contact is made with air during reentry, I imagine the heat quantity per area unit would decrease, making the use of (heavy) heat shields less of a ...
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how is the g-load for an atmospheric re-entry vehicle measured? and why is it relevant?

Out of curiosity, I always heard about g-loads regarding entry vehicles and in aviation, I understand the relevance of the concept when humans are involved, and for unmanned missions I gather that due ...
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Sharp nose or Blunt nose vehicle for higher rentry speeds?

Hypersonic Technology Vehicle 2 (HTV-2) is a crewless, experimental hypersonic glide vehicle rocket glider developed as part of the DARPA Falcon Project capable of flying at 13,000 mph (Mach 17.53, 21,...
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What is the orbit and expected lifetime of Crew Dragon trunk?

Per the timeline mentioned in the webcast the Crew Dragon separated from its trunk before the deorbit burn. I suppose that happens so clean separation can be confirmed before committing to deorbit as ...
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397 views

Nose cone of Dragon 2 closes only after deorbit burn

The Dragon v2 capsule opens its nose cone right after it separated from the Falcon's second stage. It is then open for the whole flight until after the deorbit burn. So there appears to be a good ...
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2answers
190 views

Is there a practical maximum size for a space capsule returning to Earth?

Assuming I need to get a large cargo or a lot of people safely to Earth's surface in one go in a single-use capsule of the Apollo CM / Soyuz descent type but larger, and assuming that the capsule is ...
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378 views

How do orbital spacecraft calculate reentry?

For a given spacecraft, in a given LEO orbit, assuming you have all the required data, how do you choose the needed burnout speed and timing (or position in orbit), in order to reach a certain point ...
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1answer
46 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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Titan vs Mars for colonization

This question is along the same vein as Venus vs Mars for colonization but without the person at the table. Is Mars better than Titan which to me seems a more realistic option for colonization? With ...
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1answer
334 views

Will SpaceX vehicles orbit Mars before they enter the atmosphere?

When SpaceX starts sending vehicles to Mars, how will they handle landing on Mars? Will the Starship (Upper Stage, transit vehicle) slow down enough to capture into orbit of Mars before entering the ...
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323 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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105 views

Heat Shielding Material for Reusable Craft

I'm a bit new to all this and have a quick question about heat shielding. My research tells me that for reusable craft (i.e. Space Shuttles) they used to use a plastic-based shields that would burn ...
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390 views

The aerodynamic stability of the truncated cone shape

Can someone explicate the stability of the truncated cone shape of the reentry vehicle of a spaceship when moving in the atmosphere with its bottom facing forward? It seems counterintuitive that it ...
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1answer
313 views

Is a ballistic blimp entry possible on this way?

Could the entry of Mars with balloons work by inflating to equalize with the atmospheric air pressure, while establishing buoyancy before meeting the ground? Would a balloon pop if dropped from space?...
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116 views

Could a spacecraft produce lift using sublimating material?

Following this question, could a spacecraft approaching upper atmosphere from very low circular Earth orbit, produce lift to soar propulsively, bleeding speed at constant apoapsis, by sublimating ...
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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 ...
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1answer
131 views

What's the minimium velocity for re-entry flames to start?

Considering a space shuttle re-entering Earth, what's the minimum velocity that would cause the vehicle to start burning? Is there an equation to calculate that? I presume it varies according to the ...
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164 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 ...
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563 views

How much does the rotation of the Earth affect re-entry and could we go against it?

I was thinking about how many things are affected by the Earth's rotation, and was wondering how much more difficult a retrograde re-entry would be (where the Earth's rotation direction is assumed ...
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What is typical lifetime of GTO rocket stages before reentry?

Most of geostationary satellites are launched at geostationary transfer orbit (GTO) first by rocket's upper stage. Than satellites separate and circularize the orbit by own propulsion. The upper ...
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Can a Soyuz-MS still propel itself back to earth if all its Hydrogen Peroxide decomposed?

In this answer it is stated that: If the fuel fully decomposes then return to Earth is still possible but only via ballistic descent I find it a little bit surprising, but maybe there is enough Δv ...
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Was splashing down on the USSR-controlled territory a possibility for Apollo missions?

From what I understand, the planned landing areas for Apollo command modules were pre-programmed beforehand and happened in the South Pacific. Was there any remote possibility of an emergency ...
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What was the nature of the visible part of the viscous wake trailing the Apollo CM during reentry?

This diagram suggests a helix in the wake, was it a single-helix, a multiple helix, or a superhelix? Is there any other part of the wake that would be visible?
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Orion reentry plasma

Below are two screen shots from the video of the Orion reentry, Astronaut’s-Eye View of NASA’s Orion Spacecraft Re-entry, and a diagram. Is the plasma contained, or primarily within the viscous wake, ...
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Did the Apollo astronauts ever describe reentry deceleration?

Did the Apollo astronauts describe any differences in how it felt in the CM as it passed between the hypersonic, supersonic, transonic and the subsonic zone? Did the CM shake more or less in ...
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143 views

What would happen if air hitting heatshield was ignited?

During Earth's atmospheric entry of an Apollo-like capsule, what would happen if oxygen hitting heatshield was mixed with fuel injected through heatshield, and ignited? Edit & addendum : During ...
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Apollo recovery zone(s)

For the Apollo missions that left Earth orbit, were there multiple recovery zones for each splashdown? How big was each zone?
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97 views

Atmospheric re-entry speed

What would be the difference in atmospheric re-entry speeds from LEO and GEO, assuming a Hohmman transfer orbit from GEO to re-entry? If I am getting the transfer orbit concept correct?
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Hypersonic Inflatable Aerodynamic Decelerator entry to Mars' atmosphere

Is it known whether or not a Hypersonic Inflatable Aerodynamic Decelerator inflation and entry into Mars' atmosphere would produce more violent vibrations and lateral movements than was experienced by ...
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What is the circular item that fell off of the returning booster during the CRS-16 mission?

During reentry of the first stage booster on the Dragon Resupply Mission (CRS-16), there was a ring-looking item that floated away from the booster. I would imagine it is some sort of ice debris, but ...
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Are there any advantages to being a smaller spacecraft for reentry?

Could a ship drop its cargo or shed weight before reentry to lessen the strain on the ship during reentry? Would a ship breaking down to smaller parts before reentry have any advantages over being one ...
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1answer
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Slipstream re-entry. Is it possible in theory?

Slip-streaming in cycle races saves a lot of energy by shielding the follower from a head wind. A sacrificial meteoroid precedes the re-entering spacecraft. It directs the hot plasma away from it. As ...
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How do the dynamic pressure evolves during reentry?

During launcher ascent, dynamic pressure evolution is describe in this answer for the Saturn V. I suppose this is comparable from one launcher to another. Given the protections designed for reentry, ...
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345 views

How does falcon-9 engine survive while re-entry burn without chilling ?

I've often seen that in launch sequence, "engine chilldown". I've learnt that chilling is done to avoid thermal cracking in plumbing lines and also to avoid cavitation. While re-entry, do they ...
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What are the three peaks in this Apollo reentry heating plot?

The question Challenging Karman line from above includes the following plots and cites an answer in Quora by Robert Frost, Instructor and Flight Controller at NASA who has provided many authoritative ...