Archive for the ‘ESA’ Category

Or The Space Game, by ESA.

The Space Game Screenshot

Minimize delta vee by moving the planets around (this changes the probe's arrival time at the planet). This shows my best solution so far, with some playing one evening, about 13 km/s

This is a nice javascript webpage where a probe is shot from Earth to Jupiter with gravity assists at Venus (twice), Earth and Mars. You try to achieve the lowest propulsive delta vee. You decide when the spacecraft arrives at each encounter and the program basically calculates the rest. It’s quite a nifty little piece of Javascript, the future of web applications is like this. It works fine with Chrome on Linux at least. Probably IE will have problems but who uses that anyway?

I’m ranked at #39 at 12.74 km/s… Far behind the gurus who get below 10 km/s readings! There are apparently some prizes for the top three, but I think people are in it for the fun of it.

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Rand Simberg talks about impedance matching. So I’d like to make a post of my comment there (I’ve always wondered why this obvious alternative gets mentioned so little…)

What to do when you arrive at Mars or Earth with your solar electric propelled vessel?

So, the problem with most low fuel demand velocity change schemes is that they only give slow accelerations. Low fuel high velocity change means solar or nuclear electric propulsion and aerocapture mainly.

High delta vee aerobraking is hard to do in one pass – it gets dangerous because of atmospheric variability and potentially other reasons.

Simple: detach a small capsule with the humans that goes directly to the surface (with only days of life support) and leave the untended craft to do multi-pass aerobraking. Hitting van Allen belts a few more times or taking a long time doesn’t matter that much with no humans onboard.

You could also potentially ultimately leave the long distance craft at some Lagrange point instead of LEO. (Cue some clever and complex maneuvers to save fuel – maneuvers that take long.)

Something similar could also be done when a long distance stack is assembled in LEO: send the humans there only after it’s through the belts. They can go with a smallish capsule again. Potentially at some Lagrange point, or in space without any fixed reference, just along the way. It could be dangerous though if the capsule doesn’t have much life support.

Many of these things have potential delta vee penalties as well as timing inflexibilities, but they could have enough other benefits that they should be considered.

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At the Science and Society picture library. Note the many small independently hinging peroxide/kerosene Gamma chambers, the large but cancelled Larch engine, the washing machine / musical box guidance computer with a rotary drum that has bumps, and many other things.

The British seem to be very engaged in nostalgia and “only if” in the aerospace sector. The country was bankrupted by two very heavy wars, and its empire was being dismantled at the end of the latter war. Some of its launcher technologies were quite good but somehow it could not transform into the more modern European capability that would then come through the French, mainly, after some abortive efforts by many parties and their joint ventures. Part of this was the promise by the Americans to launch European payloads on Deltas. Except when said payloads then started competing commercially with American ones…

I’ve seen and touched the Europa launcher at Oberschleissheim, Munich. It’s not as big as one would think. It also seemed complex and fragile with all the truss work, wires and pipes going everywhere. Corrugations and spot welds. Still very advanced compared to the V-2 chamber standing next to it, but otherwise it seemed somewhat anachronistic.

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The Man. On Space Review. [EDIT: About a month ago, but I only just read it.] This is just excellent. So many things I agree with, that go against the stupid myths of spaceflight and space policy. If you read one space policy interview this year, this should be it!

“NASA is an organization that is dominated by fixed costs. In business terms everything is in the overhead,” he said. The committee found, with some effort, that the fixed cost of NASA’s human spaceflight program is $6–7 billion a year. “The bottom line is that they can’t afford to keep the doors open with they money they’ve got, let alone do anything with it.”

However, he said, if you’re trying to minimize costs, it makes more sense to use a smaller launch vehicle that flies more frequently and has other users and applications. The key to making that work for exploration architectures that require large amounts of propellant—and hence have driven the planning for heavy-lift vehicles like the Ares 5—is the use of propellant depots and in-space propellant transfer. “If you use in-space propellant transfer, it’s no longer true that you have to have a really big piece,” he said.

He said that while he had his own opinions on the right selection of launch vehicles, he didn’t have any insights on what direction the White House and Congress would go. “It’s really up to policymakers whether we have a space program or a jobs program.”

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Jeff Greason is a rational person who simply gets it. It is mind boggling how completely opposite from someone like Mike Griffin he is.

See Jeff’s presentation with the Augustine Panel.

Paraphrasing, “we could go to Mars with Ares V but we shouldn’t – cause we couldn’t stay anyway”. Exactly. That’s the problem with NASA. (or the major one)

I bet he will be ignored completely.

Also, I would like to work for that guy. Too bad because of ITAR I couldn’t work in the USA.

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Nice video explanation of the SABRE engine by Richard Varvill.

In a sense, it boils down to the problem of changing the hot fast low pressure intake air flow to a cold slow high pressure flow.

In the Sabre engine, techniques somewhat similar to liquid air plants are used: there is a compressor, that is coupled to an expander, the expander runs from the “waste” heat of the compressor. This is efficient, but it is heavy. In Sabre the compressor is the shock cone (the jet engine style compressor only compresses the cooled air).

The heat exchangers are critical, and I wonder how reliable and expensive they will get with the vast temperature envelopes, ice and thin wall problems of the huge number of tubes there are. On the other hand, such heat exchangers could have uses in many other places as well. (Power generation.) The helium in the tubes is especially leak prone.

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Note, this text was originally posted as a comment on Rob Coppinger’s Hyperbola blog at flight international.

I hope there was more expansion in the “third way” for space journalism, at the moment it’s more like the big professional publications relaying NASA and ESA etc PAOs and company press releases, while blogs and forums are pushing snark and rumors (mostly false, but there are technical people there that help checking that at least some).

Not being entirely fair here, but it’s easier to describe it so briefly without nuances.

There are sources that are not official that can still be used, which if reasonably verified (signed documents, court evidence class are the ultimate of course, but there are lesser things) are much better than rumors. That’s the job of the journalist to investigate and not just propagate press releases. Watergate happened because of strong journalists driving for the truth to be uncovered. Aviation Week wasn’t used to be called Aviation Leak for nothing etc etc… I don’t mean you’re not doing investigations, just that there should be much more of it, and more resources being put into it too.

There are more things besides Ares or human-rated EELV:s.

What about the Galileo satnav farce? (And I don’t mean the traditional US vs EU stance taken.) How could EADS buy SSTL? There are probably tons of people inside the program, both on the industry and on the government side, just wanting to get their stuff known. Incompetence, corruption, shameless narrow self interest driving, etc. there is that like in every industry… Once again, a journalist gatekeeper with a good sense of the problem needs to make this all heard, otherwise it just goes into either silence or an anonymous rumor mill, loads of unverifiable claims and mud slinging. For democracy to work, the media is extremely important. Government and EU procuring is a very obscure process to the voters.

Mainstream space journalism is too kind. On the other hand, many forums and blogs are too snarky and amateurish.

There needs to be enough investigation to uncover the dirty secrets and there needs to be technical competence to understand what the issues are. That’s the third way for space journalism. Real investigation and criticism to the point.

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