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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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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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1answer
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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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1answer
70 views

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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2answers
587 views

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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3answers
367 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 ...
6
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2answers
177 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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3answers
254 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
39 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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2answers
142 views

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
324 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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1answer
172 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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1answer
85 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 ...
6
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1answer
345 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
305 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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1answer
114 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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0answers
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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
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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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1answer
141 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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3answers
505 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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1answer
158 views

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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1answer
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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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2answers
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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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0answers
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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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1answer
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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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1answer
141 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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1answer
83 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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1answer
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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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1answer
210 views

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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0answers
63 views

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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2answers
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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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1answer
306 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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0answers
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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 ...
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2answers
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Drawbacks and advantages of two slidable & rotatable control surfaces for BFS sized spaceships

BFS (SpaceX's Big Falcon Spaceship) is in development and has seen between 2016 and 2018 three major design modifications. January 2018 I asked here how BFS planned to manoever during aerobraking. ...
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2answers
338 views

Why does in-flight mission abort often ends in ballistic high-g reentry?

I am seeing a lot of references to the “ballistic reentry” mode of the crew return vehicle in relation to the abort during the powered ascent stage. In partiulat, the recent crewed Soyuz MS-10 abort ...
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1answer
161 views

What is the likely plan to deorbit the ISS given its size and shape?

The ISS is nearing its final years and this question spurred me to ask a follow up. Let's say that the various countries grab whatever equipment/modules they provided in assembly and the ISS is ...
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1answer
163 views

Satellite retrieval, fix and deploy possible remotely?

Is there any satellites that are designed to come back to Earth for repairs or upgrades and then be deployed again? Would there be any benefits to creating a capsule or inflatable heat shield to go on ...
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2answers
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What eliminates the velocity when occupants return from ISS to earth, and how much?

The ISS has an orbital velocity of ~28000 km/h; the velocity $v$ relative to the landing site of the descent module is probably even higher than that most of the time. Once the occupants have landed, ...
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1answer
429 views

Could I use a satellite as a vehicle for delivering airborne leaflets?

Assuming I have a satellite in a decaying orbit, could I gently release leaflets from my satellite so they were on a near-identical sub-orbital trajectory and have them touch-down safely on the ground ...
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1answer
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What does “Poisson's formula” refer to in this calculation?

I am not entirely sure if this question belongs to this forum, but I don't know where else to ask. I am following a Rocket Propulsion course. There is a section concerned with the Velocity ...
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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 ...
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5answers
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Have Air-breathing Engines ever been used on a reentry vehicle, could they be?

For the purpose of this question I would like to assume there is no risk of life for the astronauts, or that the design would only be used for delivery of a non-ethically-sensitive payload. Looking at ...
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2answers
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Why didn’t the Spacecraft used for the Apollo 11 mission melt in the Earth’s Atmosphere?

My brother has recently been converted to a Flat Earther and is convinced that something that proves his theory is the moon landings being faked by NASA. I have managed to counter argue the majority ...
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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 ...
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2answers
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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 ...
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1answer
466 views

How was/Was Kalam-sat Recovered from the Ocean?

I was reading this article about Kalam-SAT and it states that: "Kalamsat fell into the sea. It will be recovered and NASA will be sending it back to us for decoding the data," [Srimathy Kesan, ...