All Questions

10,659 questions
48 views

I am having a problem with designing the On Board Data Handling (OBDH) system for our MSI (Multi-Spectral Imager) payload. Our payload will be detached from Orbiter and it will take photos (for ...
58 views

Lambert problem solver needed for custom gravity in Python

I need to solve the Lambert problem, however, I have a custom gravity model. My ODE of motion is: ...
218 views

How tall are Pluto's mountains? Are they the tallest ice features in the Solar System?

The Gizmodo article It Looks Like Pluto Has a Liquid Water Ocean shows a large image of pluto with obliquely lit peaks near both the terminator and the edge of the disk where the topography is really ...
441 views

Why has NASA shunned the worm logo?

I love the NASA "worm" logo. It's a futuristic, stylish rendering of the agency's acronym. But they "retired" it in 1992. WHY??? It was replaced with NASA's original logo, the "meatball": Not be ...
50 views

Another question asks why Spirit and Opportunity weren't launched together. My gut response was that multiple-payload launches were less common then than they are today, but I don't actually know if ...
98 views

Does anyone have pictures of the “lunodrom” that Russia constructed to test the first rover?

Was reading another question involving the Lunokhod missions and then I stumbled across this wikipedia page which stated: In mid-1968, at the facility KIP-10 or NIP-10 (КИП-10 or НИП-10)[3] in the ...
254 views

Why were Spirit and Opportunity separate launches?

In reading this question (Why A=2 and B=1 in the call signs for Spirit and Opportunity?), it prompted me to wonder why Mars probes Spirit and Opportunity were launched separately, even though their ...
35 views

ECI to LVLH transformation [duplicate]

I am working on a transformation of ECI coordinates to LVLH (Local Vertical Local Horizontal) coordinates in order to calculate satellite maneuvers. Does anybody know how should I approach the problem?...
248 views

Would current computer technology have made the Moon landings any easier?

A few days ago a group of us were discussing the Moon landings (specifically the Apollo programme). Whilst this in itself was incredibly impressive we thought it was particularly impressive given the ...
1k views

Have any humans orbited the Earth in anything other than a prograde orbit?

As per the title, have any humans been launched into an orbit around the Earth which is anything other than prograde? E.g. retrograde or polar.
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Is it plausible for a planet that is positioned in the habitable area of a solar system to have little metals? [migrated]

I am big fan of Asimov's Foundation and I am wondering about the plausibility of some of Foundation's imagined words. According to this article Terminus was a special world with little metals: It ...
100 views

Why did Salyut 7 go completely dead when its solar-array-pointing system failed?

According to Wikipedia, when Salyut 7's solar-array-pointing system failed in 1985, its batteries were rendered unable to charge, and the station almost immediately went completely dead: The first ...
5k views

Why A=2 and B=1 in the call signs for Spirit and Opportunity?

The Martian rover Spirit held the call signs MER-A and MER-2. Opportunity was called MER-B and MER-1. The assignment A=2 seems backwards; logic would suggest A=1. Why is this so? Based on comments ...
2k views

Negative impact of having the launch pad away from the Equator

I imagine a satellite meant for reaching a geostationary orbit will benefit most from it, but being near the Equator is surely an advantage to any space launch (right?). However, what's the impact ...
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Which two spacecraft have spent the longest times in libration point orbits? (halo, Lissajous, etc.)

Libration point orbit is a general term including halos, Lissajous', and a whole zoo of others associated with Lagrange points in three-body systems. Which two spacecraft has been in such an orbit ...
1k views

What is the required burn to keep a satellite at a Lagrangian point?

When a satellite reaches a Lagrangian point, it has a non-zero velocity $v_1$ because of the transfer orbit in which it had already been. What burn, say, $\Delta v$, one needs if the satellite is ...
45 views

Is it possible to remove space junk using magnets? [duplicate]

I have heard that the earth is surrounded with tiny bits of "space junk". I was wondering, why not send a large magnet into orbit and collect all the junk? And by time the magnet is covered with ...
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How common are “parallel stages” in a launch vehicle?

I'm being told in this answer and in this comment that the fourth stage of the Farside rocketoon lies in the center of the four "cores" of the third stage. See this answer for several pictures of ...
273 views

Just how pointy does a rocket's nosecone need to be?

There are some beautiful images of the Qu8k rocket launch on this web page and I show a few below. There's a video (below) and the PDF Qu8k Final By Derek Deville, November 27, 2011 The stainless ...
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Why isn't there a rocket to launch a single cubesat?

I find the business model for RocketLab interesting. It is said that they fill a niche in the market by using smaller rockets. And it is true, in comparison to e.g. Falcon 9's payload of 9,500 kg, ...
74 views

Where is Farside's 4th stage?

This answer has a lot of images that I shouldn't need to repost here, and is supplemental to this answer to the question Help me understand what Farside, a ten “stage” rockoon looked like? How was it ...
54 views

Apollo CSM mass, inertia and RCS parameters?

Is there a document specifying the total mass, the 3-by-3 inertia tensor of the Apollo CSM assembly, as well as the geometry of the service module and command module RCS assemblies (in other words, ...
73 views

How did Shuttle computers internally represent time?

How was time represented in the five AP-101 general-purpose computers of the Space Shuttle? How many bits? Encoded as a plain binary count? Split into hours, minutes, seconds, subseconds? Binary-...
98 views

Which one of these Isp's for the Dawn spacecraft is wrong?

The Wikipedia article NASA Solar Technology Application Readiness says: The ions are accelerated through two fine grids with roughly a 1300 V difference between them for 2.3 kW operation, with a ...
1k views

Why “strap-on” boosters, and how do other people say it?

This came up for me in the context of translating something into German. Everybody throws around terms like "strap-on boosters", although they aren't actually held on by straps. It's not even meant ...
205 views

Determine the “nearest” orbit

There are 100 circular orbits with different radii, inclinations and RAAN. The nearest orbit by definition is the one, which requires less $\Delta V$ for a transfer. Assumed that 2 impulsive ...
163 views

Why we don't use cyclotron for ion thrusters?

We know that the advantage of thruster is high efficiency and 'everlasting' propulsion. Which It can not provide a sudden huge propulsion during launch like chemical fuel is its biggest problem. I ...
731 views

Is there a realtime, uncut video of Saturn V ignition through tower clear?

"Hi, I'm Organic Marble and I'm bad at searching Youtube." Inspired by this question What event determined the transfer of control from Kennedy Space Center to Houston?, I'd like to watch a 1:1 (...
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How does the centre of mass of a spacecraft vary in a trajectory?

We all know that rockets have thrust along with a large mass flow, meaning that their mass is constantly depleted. For ground launcher rockets, the propellants form a large part of the mass and this ...
614 views

Why was Houston selected as the location for the Manned Spacecraft Center?

NASA's Manned Spacecraft Center in located in Houston, Texas. What were the site selection criteria, and what contenders were there other than Houston? The center is named for Lyndon B. Johnson. He ...
79 views

Can LOX containing hydrogen peroxide be used as an oxidizer for a liquid fueled rocket?

While searching the internet for designs on liquid fueled rocket engines, I noticed that some bottles of liquid oxygen say they contain some percentage of hydrogen peroxide. Could that be used as an ...
45 views

Does a deep space network benefit by having a diversity of latitudes?

When placing ground stations for a deep space communications network, there is a well-established benefit to spreading out the stations by longitude. In particular, having at least three stations ...
177 views

Could a chemically propelled craft travel directly between Earth and Mars spaceports?

If in the near future we manage to build out some infrastructure in space--including robotic asteroid mining so that we can get water without pushing it up a gravity well--are LOX/LH2 rockets powerful ...
525 views

Why could the Lunar Ascent Engine be used only once?

The Lunar Ascent Engine was used during the Apollo missions to ascent from the lunar surface back to the Command and Service Module. There was one risky aspect of that engine: it was not possible to ...
221 views

What event determined the transfer of control from Kennedy Space Center to Houston?

Launches at Kennedy Space Center in Florida were managed by the on-site launch control center. At some point in the mission, authority was transferred to the mission control center in Houston, Texas. ...
54 views

Delay-Doppler maps in space science

Maybe this question might be more physics related, but I've read about mostly in context of space science: What is a delay-doppler map (DDM)? I can find it in exploration of asteroids (e.g. (...
96 views

Is the vestibular system ever useful in spaceflight?

The Vintage Space video Eleven Deaf Men Helped NASA Leave Earth describes a number of different NASA experiments done on human subjects who had damaged vestibular systems due to childhood illness. ...
34 views

How does the inter-propellant seal works in kerosene/LOX and UDMH/NTO rockets?

I get that the inter-propellant seal on the SSME LOX HP pump is simply a series of cascading regular seals trying to eliminate bleed-through by venting and letting boil at each stage, so that when ...
4k views

What were the “pills” that were added to solid waste in Apollo 7?

In the BBC News Worldservice podcast 10, 9, 8, 7: The dramatic missions that made the Moon landing possible told by retired astronaut Nicole Stott (Expeditions 20, 21, STS-128 and STS-133) after ...
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What is the current status of Stirling engine-based radioisotope generator technology?

@Heopps' cool answer to the question Any proposed missions to explore the black liquid on Titan? Technical challenges? has an interesting line: ASRG generator was planned as compact energy source ...
69 views

Are new precision gyroscopes used in spaceflight pretty much all optical?

Gyroscopes are used in spaceflight as parts of inertial systems to monitor spacecraft attitude. They are not absolute, they will drift slowly over time and so need occasional calibration via other ...
350 views

What performance specification would be lower for Krypton than for Xenon in Hall effect thrusters?

The Ars Technica article SpaceX scrubs first attempt to launch 60 Internet satellites [Updated] (found here) discusses the use of Krypton rather than Xenon in the Starlink Hall effect ion thrusters: ...
58 views

Why did the nozzles on the SRB's igniter initiator point toward the grain of the main igniter while the main igniter's nozzle pointed straight down?

How did the shuttle designers make those decisions? What made it a better decision to point the exhaust of the igniter initiator toward the main igniter's grain at an angle? What made it a better ...
43 views

How much more hardware is needed in a cross-fed CBC rocket than a non-cross-fed one?

Is it just a matter of adding a multi-in fuel manifold?
143 views

How to come back from a Venus cloud station?

I heard of the idea of having a manned station floating in the atmosphere of Venus, where the pressure is roughly equal to earth sea level. The idea is exciting, but what I don't understand is how ...
122 views

Why did the number of recovery ships decrease with time?

This NASA page names the various ocean ships that have helped recover NASA spacecraft. There is a general trend that later missions used fewer ships. Read the link for details, but here are some ...
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Does engine purging cause dry run of turbo pump in a liquid rocket engine? If it occurs, what is the implication?

Does engine purging in a liquid rocket engine cause dry run of the turbopump? If so, does that have any implication for the design, health, maintenance, or operation of the pump? How do we calculate ...
273 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 ...