All Questions

1
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0answers
12 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 ...
1
vote
0answers
59 views

Would a Hohmann transfer within LEO be useful?

Hohmann transfer is often used between a lower LEO orbit and MEO, GTO, GEO or beyond. But if the target is a high altitude within LEO, how would a direct ascent compare to ascent to a lower orbit ...
9
votes
1answer
1k views

How does electrical safety system work on ISS?

Is there any possibility that the power consumption is greater than power supply on ISS? What happens (or potentially would happen) if we plug too many electric devices so that ISS couldn't handle it? ...
6
votes
4answers
444 views

Pre-mixing cryogenic fuels and using only one fuel tank

A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single ...
1
vote
1answer
283 views
+50

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?...
-1
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0answers
26 views

Solar heated magnetoplasmadynamic thruster

Can focused sunlight super heat the chamber or gas taking less electricity to change the fuel into plasma?
0
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0answers
47 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,...
2
votes
2answers
125 views

Do horseshoe orbits have anything to do with Lagrange points? Do words fail us here?

I said (2010 SO16 is associated with Lagrange point L3 but wanders so far behind and ahead of it that the orbit is called "horseshoe"... and the comment was made: Not really. L3 is unstable. ...
17
votes
3answers
2k views

How are fuel tanks filled with cryogenic hydrogen?

Cryogenic hydrogen can react with the atmospheric Oxygen to produce an explosion: as well as being cold enough to liquefy (and possibly solidify) atmospheric oxygen, which can be an explosion ...
1
vote
0answers
10 views

How to create a new reactant Ammonium Dinitramide NH4[N(NO2)] in NASA CEA?

Ammonium Dinitramide(ADN) is a compound used as a green propellant for spacecraft propulsion applications. ADN-blends like LMP103S and FLP-106 are currently under development. However, performing a ...
2
votes
0answers
20 views

Why are hexa airfoils used on rockets despite having more drag that diamond airfoils?

I was doing a study on airfoils shape for a rocket. I tested the diamond and the hexagonal airfoil with Missile DatCom, RasAero and the Shock Expansion theory and from my results it seems like the ...
9
votes
1answer
203 views

What is NASA doing to improve the supersonic parachute for the third LDSD test?

Last month, on June 8, 2015, NASA ran the second Low-Density Supersonic Decelerator (LDSD) flight test off the island of Kauai, Hawaii. The inflatable decelerator portion of the test was successful, ...
1
vote
0answers
16 views

Proposed Canso Spaceport

Maritime Launch Services is proposing to build a spaceport facility to launch Ukrainian built Cyclone 4M rockets from Canso into polar and sun synchronous orbit. Knowing very little about the space ...
1
vote
0answers
26 views

Do Mars rovers have irises? How do they safely look at the Sun?

This excellent answer by @MarkAdler to the question Opportunity's last tau was 10.8; what does that mean and how is tau defined and measured? explains that Curiosity uses its PanCam to image the Sun's ...
2
votes
2answers
140 views

What causes those curtain-like hot and cool spots in the 2nd stage nozzle of this Electron ELaNa 19 launch?

Here is a GIF that I made of the recent Electron Launch from frame grabs in the Rocket Lab video ELaNa 19 Launch - 12/16/2018 It is about 4M, so it won't fit in SE's normal image import. Frames are ...
1
vote
0answers
44 views

What is meant by “a high-energy geostationary orbit”? (SpaceX Arabsat 6A)

The Teslarati article SpaceX’s April 7th Falcon Heavy launch a step toward new commercial markets says: While there is some inherent uncertainty surrounding the (once again) fairly new rocket, ...
26
votes
4answers
13k views

Is Nibiru real or totally science fiction?

I have seen lots of YouTube videos stating about Nibiru. They say, that Nibiru is approaching towards earth. Few of the videos claim, that space maps (Google) hide Nibiru with a black patch. Few years ...
1
vote
1answer
224 views

What are these mysterious white star-like dots near MU69 Ultima Thule? Real objects near the asteroid, noise, cosmic rays, or something else?

NOTE: I think either possibility suggested below is possible, I'm not looking for arguments why one of them would be your favorite like this answer. Instead, I'm looking for a fairly conclusive answer;...
1
vote
0answers
56 views

Can something float on top of the atmosphere? [duplicate]

So this is more of a thought experiment similar to the idea of a space elevator, but bear with me... Can we put something that "floats" on top of the atmosphere? A few ideas A pressure regulating ...
2
votes
1answer
90 views

How high could a weather balloon be used on Mars without rupturing?

How high could a weather balloon be used on Mars without rupturing? Assume that the balloon is adapted for Mars' atmosphere and gravity from standard high altitude balloons used on Earth.
4
votes
1answer
70 views

Approximate Amount of Debris in LEO?

Considering the amount of satellites and rockets launched with second stages or other parts floating in space, approximately how many pieces of space debris would there be in low earth orbit (counting ...
13
votes
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....
3
votes
0answers
51 views

Falcon 9 Landing Speed

I wanted to know what the fastest speed is that a Falcon 9 can land at and thus the max force the landing legs can withstand. I assumed the mass when landed is 26,000 kg (I once heard that somewhere). ...
6
votes
1answer
172 views

Does prolonged space flight have any effect on the physical traits of the human body?

Can a variable of physical traits like height, weight, complexion be changed in outer space? Maybe by gravity or by something else that determines these traits (like the UV rays of the sun that ...
17
votes
3answers
762 views

Is there any money in space?

Currently everything used by astronauts in space gets there via a state/government sponsored lift. Astronauts can also bring a few personal supplies, but I imagine that most if not all financial ...
11
votes
4answers
4k views

Are satellites able to stream real-time videos about certain parts of Earth's surface?

Are surface-scanning satellites able to show certain parts of Earth's surface real-time? For example, to follow a person who's escaping. Somewhere I heard that these satellites are able to make ...
1
vote
0answers
71 views

Does this rocket engine test run look healthy?

The new Ariane 6's upper stage engine "Vinci" is expected to challenge the RL-10C, which is currently the most efficient chemical rocket engine on the market. The European aerospace conglomerate aims ...
3
votes
1answer
53 views

Maximum height for a Mars Ballon?

The altitude record for an unmanned balloon is 53.0 kilometers. wikipedia If we use this Earth based record for an estimate of the maximum possible height of a balloon started from Mars surface, ...
4
votes
1answer
161 views

Most recent launch of a nuclear reactor, and current barriers to launching the next one?

This question about Kilopower nuclear reactors got me thinking. Answer(s) to How many nuclear fission reactors have been launched into space? How many are still there? suggest that most nuclear ...
8
votes
1answer
181 views

Fastest orbit transfer constrained by maximum g-force magnitude

Let's consider an imaginary constant 1g rocket from Earth to Mars. What is the fastest possible trajectory? Intuitively it seems that the fastest travel time is achieved with the "radial" trajectory (...
13
votes
2answers
1k views

Ordering of the Lagrange points

Is there any basis for the ordering of the L-points? Specifically, is there any particular reason for choosing L1 as the first L-point?
13
votes
3answers
5k views

Have any astronauts/cosmonauts died in space?

After some casual reading around on the internet I got to the accidents that have occurred over the years in space exploration. I got to wondering that while I know that astronauts have died during ...
8
votes
1answer
288 views

Does a high staging number have diminishing returns? Is there a way to address that mathematically?

I was reading this question: Help me understand what Farside, a ten "stage" rockoon looked like? How was it configured? Comments link to Highest stage counts in actual launchers? but here ...
48
votes
2answers
15k views

Why don't the Space Shuttle's tires explode in the vacuum of space?

According to this NASA article the tires are inflated to 340 psi (main gear) and 300 psi (nose gear). At landing, there is significant strain, but what about in space? Are the tires exposed to vacuum ...
4
votes
2answers
199 views

How was the 18 December 2018 Bering Sea Fireball detected and characterized? Was it a serendipity or a weather satellite?

The map at Fireball and Bolide Data is reproduced in the BBC News article US detects huge meteor explosion with the 2013 Chelyabinsk event and the recent 18-Dec0281 Bering Sea event annotated. The ...
7
votes
0answers
93 views

28V vs. 124V on the ISS

Apparently the US segment of the ISS runs on 124v DC, while the Russian segment is on 28v DC. Why the difference? I understand it is often safer to have several different voltages rather than one, but ...
24
votes
6answers
7k views

Why no recent information about or photos of Ultima Thule?

It's been two weeks since New Horizons flew past Ultima Thule but the most recent news on the Johns Hopkins site is dated the fourth of January The image gallery has had no new pictures since the ...
3
votes
0answers
83 views

Suggestion for software which allows orbit data generation under different conditions (such as J2, ATM drag etc)

I am an amateur astrophysics enthusiast trying to generate orbit data. What I want to achieve: I want to be able to generate orbits while only considering effects of (J2, J3, atm drag, solar ...
0
votes
0answers
8 views

How exactly is asteroid composition determined using spectral data from key regions not observable through Earth’s atmosphere?

@LocalFluff's answer to the question How does one spacecraft best visit multiple asteroids? mentions the proposed CASTAway Asteroid Spectroscopic Survey mission proposal and links to the conference ...
3
votes
4answers
311 views

near space vacuum balloon

OK we know that due to air pressure a vacuum balloon would not be possible on earth. But would it be possible to create one that floated near space with almost no air pressure? If so how much ...
2
votes
2answers
122 views

Has anything like the Luna 2 “Flag Grenade” been done since?

I read this week's XKCD and learned a fun new fact about the first contact with the moon. A replica of the ball that they mention in the comic is shown below: Gratis the wiki page on Luna 2. Source ...
8
votes
1answer
862 views

Is the Asteroid Belt in a plane that intersects Earth and Jupiter?

Is the Asteroid Belt in the same plane as Earth and Jupiter or they are in different planes?
2
votes
1answer
45 views

What is OneWeb's constellation's “progressive pitch” and how does it avoid interference with Ku-band satellites in GEO everywhere on Earth?

The Wikipedia article section OneWeb satellite constellation; Design characteristics tells us: The satellites will operate in the Ku band, communicating in the microwave range of frequencies in the ...
0
votes
1answer
52 views
+50

Maximum size for a Ion thruster solar array

In other questions I have asked about using a solar sail to double as a reflective mirror to provide light to an ion engine. What would be the maximum size or surface area of a parabolic sail where ...
1
vote
1answer
94 views

Astrophysics on “The Martian”

In the movie the martian what was the purpose of the hermes crew in blasting a part of the ship? Was that explosion on the front or back of the ship? After the explosion what happened to the speed ...
6
votes
2answers
594 views

What is the most number of stages, including fractional stages?

Falcon 9 clearly has two stages, but the smaller two-stage Electron has a "kick-stage" so some might call that 2.5. The question Quantitative benefits of Atlas II's engine-dropping or 1.5 staging? and ...
11
votes
2answers
1k views

Highest stage count that are used one right after the other?

Two questions inspired this question: Highest stage counts in actual launchers? Answer: Saturn V six stages to the Moon Does a high staging number have diminishing returns? Is there a way to address ...
4
votes
1answer
1k views

Difference in communication delay on ISS

What cause the difference in communication delay, about 11 seconds in this video: and apparently almost no delay on this one: ...
33
votes
2answers
7k views

How do ISS astronauts “get their stripes”?

This answer shows two astronauts on a spacewalk outside the ISS. The caption reads: Rick Mastracchio as EV1 (red stripes) and Mike Hopkins as EV2 (no stripes) leaving the airlock during US EVA-24 (...
5
votes
1answer
910 views

formula linking RAAN and LTAN

I just want to ask if someone does possess the formula linking the local hour to the right ascension of the ascending node (RAAN). I will try to explain myself: I know that I want my satellite to be ...

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