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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How is retropropulsion by the Falcon 9 first stage being used to design retropropulsion entry on Mars?

Much has been made of how the reentry burns of Falcon 9 first stages occur at an altitude where the atmosphere is similar in density to the atmosphere of Mars, and so they demonstrate that supersonic ...
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What is the speed of crew Dragon upon splashdown?

After reentry, what is the speed of the Dragon 2 capsule right before splashdown? What g-force is received upon splashdown? At the time of writing, this answer gives such information for many other ...
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Could SpaceX's Starship's landing and restart process work on Titan?

Gravity on Saturn's moon Titan is much weaker and the atmosphere is far denser than either Earth's or Mars's, which Starship seems to have been designed for. Could an unmanned starship do an Earth-...
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What (the heck) is 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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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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What is the maximum velocity for feathered reentry systems?

I gather that the Virgin Galactic planes use feathered reentry systems with a maximum velocity of about 1.4 Mach, or about .5 km/s. I understand this won't work from full orbital speed, 7km/s, because ...
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How long would a plasma trail last during a lander's Mars atmospheric entry?

In this video of the Orion reenty, ᴴᴰ Full Onboard Re-entry into Earth’s Atmosphere ● New NASA Spacecraft, the plasma trail appears to last about 90 seconds. Screenshot from video Considering how ...
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491 views

Tiangong-1 reentry

I’m trying to understand what could happen when the Tiangong-1 will reenter the atmosphere (probably on march 2018). Starting from an initial state obtained from a TLE, I integrate the position and ...
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Has any (additional) debris from Mir de-orbiting been found?

After reading the answers from this question and reading the excellent article here that goes through the de-orbiting in detail, I wondered if any debris had been found after it plunged into the ocean?...
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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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31 views

Why did Mars Pathfinder have such a high atmospheric entry velocity?

I was wondering what the highest atmospheric entry velocity of any lander was at Mars, for direct-entry landers (as opposed to those released from an orbiter), the atmospheric entry velocity tends to ...
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SpaceX Dragon Maximum Return Payload

For one of my university courses, we were asked to assess the viability of an asteroid exploitation mission. Assuming that we can somehow mine and refine the material (platinum in this case), we still ...
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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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209 views

Apollo re-entry guidance

I am referencing chapter 7 of the book "Spacecraft Navigation and Guidance" by Maxwell Noton. Can anyone tell me how to determine control gains C1 and C2 in equation 7.58 and 7.59 in respective ...
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503 views

How does the entry angle of a meteor affect the straight line distance traveled?

I'm trying to help a student solve the following problem: A 15 meter in diameter asteroid with a mass of approximately 10,000 metric tons going 20 km/s. The entry and time for disintegration was 28 ...
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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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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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56 views

How large can heatshield holes be?

The tiles on the underside of the STS Orbiter had gaps between them to allow for the frame underneath to shift slightly. However, if the gaps were too large fillers were used. What controls the ...
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Starship surface heating on Mars landing

Mars atmosphere is much thiner than Earth's And then how much will Starship heat on a Mars landing comparing to a landing on Earth?
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Seeking Book about Aerodynamic Design of the Space Shuttle

a few years ago I found a book written by an engineer working on the aerodynamics of the shuttle during design, ALT, and early STS. I have since forgotten the title and author's name. Does that ...
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67 views

Is there a rule of thumb for the mass of thermal protection systems?

A lot of discussions of SSTOs and the potential for making upper stages re-usable hinge on the fact that thermal protection systems for reentry from full orbital velocity are pretty heavy (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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67 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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Atmospheric Entry Vehicle: Wind frame representation and Visualization

I am looking at entry dynamics for a convex blunt aeroshell. We use Heading angle, bank angle and flight path angle for description of attitude from local horizon axes system. While it is sufficiently ...
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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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Could an electrically pumped rocket stage position its batteries to enable it to re-enter stably nose-first?

Are the batteries in existing or planned electrically pumped rocket stages massive enough to change the centre of mass of the empty stage such that new re-entry strategies are available? e.g. Could ...
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Which deorbit trajectory minimizes reentry heating?

Atmospheric reentry, as I understand it, is a balancing act between minimizing delta-v needed and not burning up or breaking up in the atmosphere. The higher the velocity on reentry, the greater the ...
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69 views

Is there an official flight profile of the reentry of the Dragon spacecraft?

I wonder whether there's an official plan of the reentry and landing of either the former Dragon spacecraft or the Dragon V2/Crew Dragon, with details like altitudes, velocities, burn length and ...
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48 views

What is the splash down speed of the manned dragon capsule?

What's the rated speed of the crewed dragon capsule? Do we have any data on the actual measurement for the demo mission? I'd also appreciate any info on speed for Soyuz, other soviet manned, Apollo, ...
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77 views

How hard would it be to get some comms during reentry?

As I type, a Crew Dragon is out of touch while it reenters. While I see how the plasma around the spaceship would make it very hard to communicate, I'm surprised that it is really impossible. How hard ...
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How long was Sputnik 1's second stage rocket body in orbit? Are there TLEs for it?

Early artificial satellites were tracked by radio and visually by amateurs, scientists and military personnel for various reasons including fun and improving the understanding of orbital dynamics ...
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77 views

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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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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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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338 views

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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Looking for atmospheric density models of various planets and moons

Looking for atmospheric density models of various planets and moons, any sort of data/resources/database of this information would be extremely useful as I am working on recreating these models for ...
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128 views

What happens with re-entry at different angles?

I was reading the article on J002E3, and it mentions that most other S-IVB have entered the atmosphere and mostly burned until reduced to relatively small pieces. They did, however, enter the ...
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Does the airburst effect of a meteor depend on the chemical composition of the atmosphere?

Does the magnitude and character of an airbursting meteor depend substantially on whether it hits an atmosphere with much O2, N2 or CO2? Does the oxygen in Earth's atmosphere affect meteors? Assume ...
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Falcon 9 landing speed estimate?

How fast is a Falcon 9 stage 1 going when it touches ground? Rough estimates are OK. An upper limit would be helpful too. I'm getting 5.5 m/s (12 mph) in simulation and wondering how reasonable this ...
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33 views

Falcon 9 Reentry Burn Duration?

The videos and simulations I've seen suggest the reentry burn lasts 30 seconds. This is followed by the final landing burn and it may be preceded by a boostback burn. I'm interested only in the ...
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50 views

How is PICA different from other heat shielding materials?

What are the differences and why did SpaceX prefer to use PICA?
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g-forces entering and leaving atmospheres, how would they vary from one body to another?

I was wondering how launching from and returning into atmospheres of other bodies such as Mars, Venus, Titan, etc. would differ from Earth's. Specifically, I am wondering how many g's would be ...
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What was the leeward surface temperature of the Apollo Command Module during reentry?

From the Apollo Experience Report: Thermal Protection System, there is a diagram that shows the surface temperatures of the Command Module at various points (image was obtained from this answer). It ...
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Have studies / worked examples, including mass figures, been published for these reentry methods for reusable upper stages?

(Related: is there a general rule of thumb for thermal protection systems?) For a fully-reusable launch vehicle to be developed, we need a lightweight thermal protection system and method for (...
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Defining overshoot and undershoot boundary of entry corridor

I have been reading up on the mathematic of atmospheric entry. I have found different methods to theoretically calculate the corridor width but I don't understand how to define the overshoot and ...
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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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Has the answer to PopSci's question “How Many Years Does The Space Station Have Left?” been published?

This answer to the question Why does the ISS have to be destroyed? begins It doesn't, not really, but there will come a time when it will simply not be worth keeping it up. and mentions a study, ...
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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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How will SpaceX land its rockets on the unleveled surface of Mars?

SpaceX plans to send the Starship to Mars and to land it there, tail first in a vertical position. Unlike the Perseverance rover, which seems to be able to land on uneven terrain without the need for ...
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176 views

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,...