The "Real Aerospace" Thread

[Mjolnir]

Ah, Mjolnir, I see you too are amn of engines :D

Admittedly I was trying to calculate powers of ten at 01.00 AM, so I messed up. The isp is waaaay too high. Muh bad...

In my mind there is a hierarchy of engines: you start with chemical, proceed to solid core NTR (such as NERVA; the only reason we ain't using them right now in space is because of politics),then pulsed NTR (which has an Isp of about 17.000 sec) and the next logical step is nuclear electric. Standard NEP is having a reactor drive an engine and a propellant tank that is separate. The concept I was going for was to have the reactor do double duty, and act as both power source and reaction mass. Though separating the xenon from the salt would still require mass, which may offset any gains I get from saving on reaction mass.

Ah well, it was a nice conversation :) . And I managed to find a source on an theoretical engine that I'd never heard before:
http://www.niac.usra.edu/files/studies/ ... rchese.pdf
As well as revise my info on the pulsed NTR concept (closest thing we have to an actual torchship).
A word of caution though: almost every engine requires radiators. Even the dusty plasma/FFRE (it's only about 50 percent efficient). Only high performance one that does not is the magneto inertial fusion engine:
http://www.projectrho.com/public_html/r ... ial_Fusion

I take my hat off to you, sir!

Well, molten salt reactors aren't the only way to do the job. Zubrin's nuclear saltwater rockets inject the fissile material into a reaction chamber as a salt solution, with the products directly exhausted as high temperature plasma. No xenon extraction required, you just need to build a reaction chamber and nozzle that can handle a continuous torrent of nuclear fire. And keep neutron reflectors away from your propellant tanks. And never ever spring a propellant leak.

As for Blacklight, Mills is a fraud that's been selling his free energy scheme since the early 1990s. Blacklight Power goes by "Brilliant Light Power" these days, probably because Mills had been "about to release commercial products" based on hydrino technology for over 2 decades under the previous name.

[Mr.Tucker]

Oh, I know the man's a fraud. But doctor Marchese's study helped shed light on exactly how they calculate things. Even if said things make no sense physically. Just goes to show ya NASA DOES investigate all manner of claims seriously.

As for doctor Zubrin's... uhmmm...nuclear candle....well, when I first read of it 15 years ago, I thought it was crazy. Today...I still think it is. Doesn't help that the good doctor seems to have a vendetta against VASIMR (which, while not the best, is still the ONLY game in town in terms of plasma propulsion; we really need a serious MPD study...).

OTOH, the research into fusion seems to have taken a turn for the better with the commercial availability of high(er?) temperature superconducting tape:
https://www.youtube.com/watch?v=4ao24BhgBKc
Those superconducting tapes seem to be applicable in many other designs such as ITER (if you could get them to be bolder and stop asking for decades of funding) and even the polywell.
If only the promise came true...

[Mjolnir]

I'd concocted a descendant of the NSWR, the Antimatter-Catalyzed Fusion Boosted Nuclear Saltwater Rocket, which uses small amounts of antimatter to induce fusion as a neutron source to allow subcritical fissile salts to be used, in part as an exercise in stacking letters onto an acronym, and in part to propose a system that aims to improve on the safety and practicality of a NSWR by adding antimatter.

Zubrin seems to suffer from tunnel vision with respect to getting humans to Mars in the particular way he envisions (one-shot missions using Shuttle/ISS-derived expendable vehicles), and his criticism of VASIMR seems to be affected by that. VASIMR can't get humans to Mars faster than chemical propulsion with any power source we can build in the near future, and he seems to think that's the only thing that matters. But it could get bulk cargos there on longer trajectories with far less propellant mass, and it has major speed and endurance advantages when it comes to sending probes out into the belt and outer system.

[Mr.Tucker]

I'd concocted a descendant of the NSWR, the Antimatter-Catalyzed Fusion Boosted Nuclear Saltwater Rocket, which uses small amounts of antimatter to induce fusion as a neutron source to allow subcritical fissile salts to be used, in part as an exercise in stacking letters onto an acronym, and in part to propose a system that aims to improve on the safety and practicality of a NSWR by adding antimatter.

I would ask, if your intent is to use an antimatter catalyzed reaction, why not go straight to fusion? Or, do something similar to H-B inertial catalyzed fusion. Here's a fascinating concept:
http://www.projectrho.com/public_html/r ... nterceptor

[Mjolnir]

I'd concocted a descendant of the NSWR, the Antimatter-Catalyzed Fusion Boosted Nuclear Saltwater Rocket, which uses small amounts of antimatter to induce fusion as a neutron source to allow subcritical fissile salts to be used, in part as an exercise in stacking letters onto an acronym, and in part to propose a system that aims to improve on the safety and practicality of a NSWR by adding antimatter.

I would ask, if your intent is to use an antimatter catalyzed reaction, why not go straight to fusion?

It'd make the acronym shorter.
Note that the above justifications were pretty much an exhaustive list of the design goals.

Or, do something similar to H-B inertial catalyzed fusion. Here's a fascinating concept:
http://www.projectrho.com/public_html/r ... nterceptor

Funny you specifically linked that, I've discussed the ACFBNSWR with Elukka before, and the rather more serious microfission/fusion pulse drive proposals that inspired it.

[Mr.Tucker]

Check this out Mjolnir: https://www.centauri-dreams.org/2012/08 ... -a-review/
Seems like an Isp of 50,000 would be the limit on ion drives.

[Krulle]

Edit: forgot to add source. XKcD was recognisable, but the link is https://xkcd.com/2074/. Just to be complete.[/edit]

[Zorg56]

Time to invent interdimensional transport.

[Krulle]

funtional interplantery travel would be nice too.
Let's go for that first, since it seems more reachable with current physics knowhow....

[Zorg56]

It is possible with nuclear engines since, i think, 80s.
USSSR is no more around to invest billions in project that wont make any money, so...

[icekatze]

hi hi

I'd also accept a laser sail to another star system.

[GeoModder]

hi hi

I'd also accept a laser sail to another star system.

Slowpoke!

[Krulle]

It is possible with nuclear engines since, i think, 80s.

Butnotbeing done. So...

[Zarya]

Timelapse eyecandy made by ESA astronaut Alexander Gerst, currently on board of the ISS.
He captured the Progress MS-10 cargo launch on 16 Nov. 2018 at 18:14 GMT from the Baikonur Cosmodrome in Kazakhstan:



00:07 1st stage booster separation
00:19 Core stage separation
00:34:05 discarded stage reenters atmosphere
00:34:19 Progress separates from upper stage

I am intrigued by the puffs caused by staging, or even better, by the RCS thrusters that help mission hardware to make a controlled descend. Like 50 seconds into this clip, the return of a Falcon 9 first stage after the SAOCOM 1A launch from Vandenberg on 7 October 2018:



Another one. Filmed from LA. The entire video is cool but RCS manoeuvring starts ~3 minutes in:



One more, Soyuz 51S docking with the International Space Station on July 28, 2017:

https://mobile.twitter.com/astrokomrade ... 71328?s=21

[Arioch]

I remember seeing a video shot from either Mir or the ISS where a backlit Progress was approaching to dock, and you could clearly see the maneuvering thrusters fire. It was pretty cool.

I was watching the InSight Mars landing today, and they mentioned that New Horizons (the spacecraft that did the Pluto flyby) is scheduled to reach its next target (Kuiper Belt object 2014MU69 or "Ultima Thule") in January 2019. It's already almost there.



http://pluto.jhuapl.edu/Mission/Where-i ... /index.php

It's hard to believe that the Pluto flyby was three and half years ago.

They also have an image where New Horizons is trying to detect Ultima Thule visually. It's a reminder of how difficult it can be to detect objects in space against the background starfield, despite the lack of "stealth in space", even when you know exactly what you're looking for and exactly where to look.



http://pluto.jhuapl.edu/News-Center/New ... e=20180828

[Zarya]

There may be a lack of ‘stealth in space’, it is also vast.

Indeed hard to believe New Horizons fly through is already three and half years ago.
Almost looks it was a source of inspiration

(Closest Approach to Pluto was on Tuesday July 14 2015 at 7:49 AM EDT)

Fun fact: the spacecraft is communicating with us over 3.5 billion miles (5.6 billion km) using only 4 watts

[Zarya]

I was watching the InSight Mars landing today, and they mentioned that New Horizons (the spacecraft that did the Pluto flyby) is scheduled to reach its next target (Kuiper Belt object 2014MU69 or "Ultima Thule") in January 2019. It's already almost there.

Just to note that the Johns Hopkins University Applied Physics Laboratory updated the New Horizons website design... and that the flyby will be on January 1st, 2019

[Mjolnir]

I was watching the InSight Mars landing today, and they mentioned that New Horizons (the spacecraft that did the Pluto flyby) is scheduled to reach its next target (Kuiper Belt object 2014MU69 or "Ultima Thule") in January 2019. It's already almost there.

Just to note that the Johns Hopkins University Applied Physics Laboratory updated the New Horizons website design... and that the flyby will be on January 1st, 2019

Further update, the flyby was a complete success, and the highest-resolution images were received yesterday:
http://pluto.jhuapl.edu/News-Center/New ... e=20190222

[Zarya]

Further update, the flyby was a complete success, and the highest-resolution images were received yesterday:
http://pluto.jhuapl.edu/News-Center/New ... e=20190222

The data rate at which the spacecraft communicates with us is currently lower than 5kb/sec. The high-res material will have arrived in a slow trickle, perhaps as a progressive download. When checking yesterday, NHPC signals were received in Canberra at a data rate of 2 kb/sec.

This is caused by a modest transmission power (4 watt), the limited size of the spacecraft’s parabolic dish and the distance ~4.13 billion miles (~6.64 billion kilometers). It currently takes New Horizon’s radio signals six hours and ten minutes to reach us.

[Arioch]

I believe they said it will take 20 months to receive the entire data set.