All Questions

1
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0answers
15 views

Why are JPL using this expression to emulate Schwarzschild orbits?

From the documentation ”Formulation for Observed and Computed Values of Deep Space Network Data Types for Navigation ” expression 4-61 on page 4-42 it can be seen that JPL uses the following ...
5
votes
1answer
379 views

Where did Heinlein say “Once you get to Earth orbit, you're halfway to anywhere in the Solar System”?

I know what it means. I've seen delta-V charts. But I don't know if Robert Heinlein wrote this down, or simply said it off-the-cuff to somebody. Variations include: "Reach low orbit, and your ...
2
votes
0answers
48 views

How is this engine put together? [duplicate]

I'm going through How to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES and am confused how their sample engine is physically built together. This is a picture of their assembly where the ...
11
votes
3answers
761 views

How can Trident be so inexpensive? Will it orbit Triton or just do a (slow) flyby?

The recent NY Times article Neptune’s Moon Triton Is Destination of Proposed NASA Mission says (in part): HOUSTON — Is it time to go back to Neptune? Scientists representing NASA’s Jet ...
2
votes
1answer
78 views

Would a mouse trap snap faster or slower in space than on Earth?

Would a spring loaded mechanism outside a spacecraft activate a lever faster or slower in space with no atmosphere and gravity than on Earth? Basically this is in reference to mechanical instruments ...
0
votes
1answer
41 views

Why would different Shuttle orbits have different mission directors?

The Wikipedia page for NASA Flight director Holly Ridings contains a portrait with two other STS-117 mission flight directors. The caption there says: Flight directors for the STS-117 mission in ...
0
votes
1answer
40 views

How are satellites made “demisable” and what else do recent FAA documents tell us about SpaceX's plans for StarLink satellites?

Comments in chat mention that recent FAA documents show that there have been design changes in the StarLink satellites that make future builds "demisable". This sounds interesting but I don't really ...
0
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2answers
76 views

Why would an 8-minute burn result in a 6-month delay?

The Ars Technica article Vice President may tell NASA to accelerate lunar landings ends with: And on Thursday, NASASpaceFlight.com reported that the agency is considering skipping a critical test ...
-2
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0answers
48 views

Do all US vice presidents get cool jackets?

The Ars Technica article Vice President may tell NASA to accelerate lunar landings starts with "We're tired of generating PowerPoint journeys that don't go anywhere." and explains that one or ...
2
votes
0answers
44 views

Why do countries or companies still bother sending landers/probes to the moon?

Countries like Israel, South Korea, or China most recently and companies like ispace have plans to send landers to the lunar surface. At least according to this list. Is it because there is little ...
2
votes
1answer
33 views

Rendezvouses in halo or lissajous orbits

If a spacecraft was in an EM-L2 halo/lissajous orbit, and another craft would was going to approach EM-L2 a few days later, could they rendezvous immediately or is there a limitation when the second ...
2
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0answers
71 views

How does a turbopump work

I am a kid pursuing a career in propulsion, and I was wondering, "how does a turbopump work?" I would really appreciate a detailed explanation. Thanks!
1
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1answer
55 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 ...
2
votes
0answers
20 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 ...
3
votes
0answers
49 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 ...
19
votes
7answers
3k 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 ...
2
votes
0answers
32 views

Proposed Canso Spaceport, challenges to commercial viability of a private 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
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0answers
43 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 ...
1
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0answers
62 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, ...
12
votes
1answer
2k 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? ...
1
vote
0answers
74 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 ...
2
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0answers
62 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 ...
3
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0answers
69 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). ...
0
votes
0answers
67 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
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0answers
130 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
2answers
114 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, ...
7
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0answers
102 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 ...
0
votes
0answers
10 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
1answer
111 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.
2
votes
2answers
130 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 ...
1
vote
1answer
100 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 ...
11
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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 ...
8
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1answer
296 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 ...
2
votes
1answer
52 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 ...
3
votes
1answer
56 views

Could OneWeb's satellites be launched on Electron rockets?

OneWeb's satellites weigh about 150 kg each, which is within the range of the Electron rocket. However I am not sure about the target orbit(s). Technically speaking, could OneWeb launch its satellite ...
1
vote
0answers
48 views

GPS PPS stable signal [on hold]

My question concerns the GPS NMEA reading data about PPS signal. Is there any way to know via software using NMEA that the GPS PPS signal provided by its outport is already synchronized with the one ...
0
votes
1answer
47 views

What is considered a good SNR for satellites?

When performing a link budget for satellite communications, a key component is defining an acceptable signal-to-noise-ratio in order to obtain the necessary bit-rate. How does one determine what the ...
2
votes
1answer
262 views

Help me understand what Farside, a ten “stage” rockoon looked like? How was it configured?

@OrganicMarble's answer links to NASA Sounding Rockets, 1958-1968, A Historical Summary and in Appendix A starting on page 79 it lists: Farside: A type of rockoon developed by Aeronutronics ...
2
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0answers
78 views

Could a fat rocket be used on Mars?

Since Mars' atmosphere is around 2% the density of Earth's then could a much wider rocket achieve orbit? Could the rocket be in the shape of a capsule or an optimal shape for reentry on Earth?
1
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0answers
34 views

How effective is the Orion radiation protection plan?

This article gives a basic overview of the procedure for astronauts on deep space missions who need to take shelter from energetic events such as solar flares. The shelter area strongly resembles a ...
3
votes
1answer
75 views

Would high altitude native populations make better astronauts for a Mars mission?

High altitude populations in Tibet, the Andes, and Ethiopia have genetic adaptations that allow them to better handle low oxygen levels. They are also used to colder and drier climates. And lastly ...
-1
votes
0answers
64 views

Solar preheated magnetoplasmadynamic thruster fuel [on hold]

Can focused sunlight super heat the gas in a MPD thruster reducing the electricity needed to work? From comments: http://www.projectrho.com/public_html/rocket/enginelist.php#id--Beamed_Power--...
1
vote
0answers
80 views

A lander/SSTO and a “transport stage” that remains in orbit

Would be a good idea to have a lander/SSTO and a "transport stage" that remains in orbit for interplanetary travel to connect with spacecraft in LEO to and provide extra thrust from more efficient ...
3
votes
0answers
37 views

What rocket uses the largest percentage of Fuel/Oxidizer before liftoff?

inspired by this question: How much propellant is used up until liftoff? which asks how much propellant (fuel/oxidizer) a typical rocket uses before liftoff. What has been or is the most non-typical ...
2
votes
1answer
69 views

Identify this astronaut and shuttle mission

After about 02:00 in the Kinematic video SpaceX Delivers Critical Docking Adapter for NASA to the ISS the astronaut says: You know the Space Shuttle’s been with ...
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 ...
4
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2answers
205 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 ...
8
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1answer
979 views

How much propellant is used up until liftoff?

How much of the total propellant mass (fuel+oxidizer) of the first stage/boosters is usually burnt between ignition and liftoff?
3
votes
0answers
86 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 ...
3
votes
3answers
1k views

When was the first strap-on booster used in spaceflight?

The first use of the term "strap-on" in Google Ngram viewer is in 1930 and presumably that wasn't about a booster being attached to a rocket for additional thrust at lift-off. When was a strap-on ...

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