General Thread about space related questions

[feanor]

As said, instead of filling development, here you can ask general questions. A better option would be a subforum dedicated to the real life space programs going on.

Fire away ( although I am going to bed, will check it out tomorrow )

[feanor]

I\'ll just copy paste my earlier post

I thought the private sector, particularly SpaceX, was going to take care of these things now? SpaceX Flight Manifest

I\'ll just reply to this discussion once.

We should make a subforum dedicated to real spaceflight.

Anyho; Shuttle hasnt launched full size satellites for a while. only reason they kept it flying after columbia is because the ISS wasnt finished yet. SpaceX won\'t be ready for a while, for the really big satellites. SpaceX is still developing, and does not have the confidence of clients yet (especially DoD ). They have to launch more; so far, spaceX has flown only 2 falcon 9\'s. None of which this year, and it\'s looking mightely like they won\'t launch anything this whole year at all.

Even when they are flying, it isn\'t like USA gets to decide - We\'ll all use spaceX! Certain departments will buy services from them, just like you buy a service from mcdonalds. Others will prefer burger king. ULA will still launch. Energia will still launch. Rockets are still being launched while spaceX doesnt. They have a small fraction of the launch market ( growing, but still ) . Ariane 5 is the biggest sat launcher right now, possibly Proton. These will continue to fly even after spaceX. Space isn\'t the golden bullet for all problems with launching rockets.

Also, price is not everything. Going for a rocket company from your own country really has it\'s own benefit; price becomes less of a concern when most of it flows back into your own economy, and government is quite a big fraction of payloads. Also, retaining of certain skill items, or industrial base.

Who won the space Race?

Depends on where you cut it off. Russians won the early part. NASA did the moon, but Russia did space stations. If you look at capability now, russia wins. If you look in a few years, commercial wins. It\'s better not to see it as a technological race, really. Russia abondened plans for the moon as soon as america got there; imagine if they had eventually developed a system as cheap ( relatively ) as the soyuz for moon travel. But this didnt happen. America did not improve on moon either. Buran was arguably superior to the shuttle, and would be cheaper as well; but, it was still too expensive. Who won that race?

anyway, repeating calls for a forum section dedicated to real space travel. Otherwise, I can redirect you all to Nasaspaceflight.com - Read for a few months before you ask a question, as the people who actually launch rockets get tired of questions like 'how do I make orbit and 'why doesn\'t everyone use SpaceX yet', not to mention people who think real rockets are legos like they are in this excellent game

Maybe I heard wrong, but apparently a lot of the people associated with the Shuttle in NASA were annoyed about having to use Russian rockets... hmmmm.

Human Spaceflight is not all of nasa.

Does their new HLV, the SLS, have Russian parts on it?

no

They\'re going to, the problem is the gap right now; and potentially it\'s a long one;I can\'t even find a date for when Spacex intends to launch their manned capsule-it\'s not on that launch manifest, and it goes to 2015...

manned spaceflight of SpaceX will be around 2014 earliest. spaceX time dilitation factor ( when they announce something and when they actually do it ) is around 2 or so last time I checked, so 2015-2017 is perhaps a better guess. I\'d love to see surprises, but as said, for the last year or so they haven\'t launched anything.

:EDIT: That\'s not supposed to launch manned until 2021-that\'s at least ten years of paying for seats on Soyuz.

The new updated SLS schedule shows first crewed flight ( trip around the moon ) is planned for 2019. Might slip to the left even further. That news item you read was based on a worst case internal schedule. Those worst case conditions didn\'t come true.

Please, let\'s move this to another thread, in general or in unrelated.

repeating calls for new subforum, as it is certainly related.

[sneakeypete]

Had to laugh at someone today on a news outlet suggesting using the X37 space plane to deliver cargo to the ISS. almost as if he was saying, 'yes there\'s Russian and European methods of getting cargo up there... and this carries a fraction of their payload... but its made in the USA!'

Also, to throw a cat amongst the pigeons: will we have a SSTO space plane this century?

[Johno]

Thing is, the Shuttle is a hard act to follow.

Getting 24.4 tonnes to LEO and providing workspace for a large crew is not replaceable. Not at all. Soyuz can get about half the people there, but no cargo; Progress can carry 2.4 tonnes and ATV 7.1 tonnes of cargo, but no people. Nothing manned can carry a large module (though there are other ways of getting them there - e.g. Proton or Delta).

All told, with the Shuttle retired, there\'s just a lot of stuff we can no longer do. Oh, sure, we\'ll get around it; but workaround as we will, there\'s a whole raft of capability that will simply not exist anymore.

[Iskierka]

24.4 tonnes to LEO is an unnecessarily high amount, however. Ariane 5 doesn\'t achieve that, and it rarely doesn\'t have to wait for double launches to get a launch greenlit, since few people are willing to pay the cost of a single launch.

Then the shuttle was so damn expensive. Maybe it was something that could do most things, but it did nothing well and everything inefficiently. Given a lot of the problem was a result of the vehicle being inherently man-rated, AND so large, it will probably work out better to have personnel and cargo launch separately now.

I probably mention it a little often, but Skylon could act as a replacement. Easily 24 people to orbit on a dedicated mission, with a couple tonnes of cargo, or up to 30-40 people. Alternatively, up to 9.5 tonnes to the ISS on the C1 variant; likely closer to 11-12 on C2 and more on D1. Its absolute LEO capability is 15-16 tonnes in the C2, meaning it\'s not far behind the shuttle, though I can\'t find exacting figures on what the shuttle\'s payloads are according to desired orbit.

[feanor]

Thing is, the Shuttle is a hard act to follow.

Getting 24.4 tonnes to LEO and providing workspace for a large crew is not replaceable. Not at all. Soyuz can get about half the people there, but no cargo; Progress can carry 2.4 tonnes and ATV 7.1 tonnes of cargo, but no people. Nothing manned can carry a large module (though there are other ways of getting them there - e.g. Proton or Delta).

All told, with the Shuttle retired, there\'s just a lot of stuff we can no longer do. Oh, sure, we\'ll get around it; but workaround as we will, there\'s a whole raft of capability that will simply not exist anymore.

Actually, it\'s not really hard to follow. You can vastly improve on that. IF ( and this is a big if ) you get the same budget for it.

Also, it\'s not actually efficient to try to copy all the capabilities the shuttle has; some parts are simply not needed, or can simply be improved. (no solar panels, non spherical leaking cabin, limited delta-V, large amount of wasted upmass/downmass instead of cargo, etc )

But, you can things the shuttle could theoretically do, like crew transfer, way cheaper.

Launching 24.4 tonnes to leo is easy as well. - but not at the same time. Both of these combined will still cost vastly less then the shuttle - and can be finetuned way way easier.

Workspace is not needed; copy ATV\'s or HTV\'s payload cannister ( or a cygnus module ) and fly it up there.

It was a great vehicle, but had flaws.

Had to laugh at someone today on a news outlet suggesting using the X37 space plane to deliver cargo to the ISS. almost as if he was saying, 'yes there\'s Russian and European methods of getting cargo up there... and this carries a fraction of their payload... but its made in the USA!'

Also, to throw a cat amongst the pigeons: will we have a SSTO space plane this century?

Actually, there was a press release to use the X-37 for this purpose from boeing. But it\'s rightly seen as PR, because their CST-100 is way, way further ahead, easier, cheaper, and doesn\'t have problems like pressurized space, payload capabilty, airframe stress, etc etc.

SSTO spaceplane? no. SSTO, possibly. Think early atlas mass produced, something like that. TSTO spaceplane, possibly.

[Iskierka]

SSTO isn\'t that useful. Main purpose of SSTO would be with a reusable vehicle, would vastly simplify and cheapen turnaround. If you\'re making something expendable, multiple stages aren\'t too significant, so they may as well be used.

Just quickly in reply to the SSTO spaceplane possibility, here is a paper on the technical feasibility, and here is a paper on economic feasibility, with a comparison to a TSTO vertical launch spaceplane NASA proposed.

The economic paper repeats a fair bit, but there is a decent amount of info in there.

[feanor]

SSTO isn\'t that useful. Main purpose of SSTO would be with a reusable vehicle, would vastly simplify and cheapen turnaround. If you\'re making something expendable, multiple stages aren\'t too significant, so they may as well be used.

Just quickly in reply to the SSTO spaceplane possibility, here is a paper on the technical feasibility, and here is a paper on economic feasibility, with a comparison to a TSTO vertical launch spaceplane NASA proposed.

The economic paper repeats a fair bit, but there is a decent amount of info in there.

Skylon is nice and all, and if it ever gets flying it\'ll be a true game changer, but really, don\'t believe everything they say.

There are still very significant issues which need to be resolved before it can fly. And when I say 'significant issues' I mean that it might not be possible at all.

And then there are the HUGE developmet costs. That can very easily fall through.

Again, if it\'ll work then it\'ll be a game changer. But remember; it might not work.

[Johno]

Feanor: There is ONE item in your list which can\'t be copied by any vehicle that is currently extant, and that\'s downmass.

But yeah, we could send up lots of different spacecraft to copy much of the shuttle\'s capability. And you\'re right, it could be cheaper. And yes indeed, budget is the issue. Frankly, if NASA had been given enough budget to develop a next-generation shuttle follow-on, they\'d have produced a vehicle which would have learned a lot of the lessons taught by Challenger and Columbia (and other non-catastrophic but highly irritating failures that never made the newspapers). Not just NASA, either - if the Russians had had the budget to complete a couple of Burans and the Energia rockets to lift them, it would have been (probably) a better vehicle, having incorporated those lessons.

Iskierka: Re - Skylon: Preaching to the choir, my friend. However, I suspect it will run into the same budgetary problems that have killed future Shuttle developments in the USA and Russia. It will probably be downscaled, downgraded and eventually cancelled.

I hope it doesn\'t; I\'d be as excited to see it fly as any Pom would be. But experience shows me that these things seldom come to fruition. :\'(

[Iskierka]

Yes, it might not work. However, I\'ve looked through what is probably the majority of material available on Skylon by this point, and found few 'significant issues'. Neither did the ESA with their own investigation. While there are high development costs, they\'re not actually more than your typical airliner, and the final product is cheaper to produce also.

Granted, yes, it might not work. In preparing tests for the precooler earlier this year, they ran into some manufacturing problems and ended up some three months behind schedule. However, due to extremely promising early results, they\'re still well on track to complete testing by their deadline.

REL, from what\'s shown so far (STERN/STRICT turned out better results than their assumptions of what to expect, and vehicle projections were made on assumptions of the projects failing completely; the precooler modules performed far in excess of what\'s necessary in lab tests, and are performing still better than assumed in full tests, etc.) seem to be one of few companies who actually make pessimistic projections. More should, it makes you look much better when your ideas work far better than they need to.

If Skylon fails, I agree it\'ll probably be budget. It\'s promising though that they already have $350 million for a proper engine demonstrator, assuming the precoolers work. (and being the most-tested part, they certainly seem to) And since the engine is the key component, once it gets that far ...

[feanor]

Feanor: There is ONE item in your list which can\'t be copied by any vehicle that is currently extant, and that\'s downmass.

True. I don\'t think that it is quite a serious issue, though. Afaik, falcon 9 / cst 100 would provide enough downmass for people ( heh ) and (cooled) experiments. Modules like the pump module that failed - true. I wonder how usefull ( or rather, needed ) that is.

That capabilty is lost, but I see all previous missions except for shuttle / ISS, and it wasn\'t needed there. And space station building was possible before ( Mir ).

If you want to return satellites the first requirement is that it\'s cheaper then launching a new one. For that, you\'ll probably need a cheap RLV ( possibly even completely reusable ) - and when you can develop that, launch costs will go down aswell, making return even less attractive.

So, meh. it\'s got it\'s pros, and it\'ll be hard to return large objects - but I think the value of that is doubtfull.

A SpaceX dragon with 4 passengers ( as is currently the proposed version to fly to the ISS ? ) will have quite some downmass cargo place and mass left..

[icefire]

The hubble telescope would have been taken back to earth with a shuttle, so that we could marvel in all its glory at a museum at the end of its service life. Now all that awaits it is a rendezvous with the atmosphere

[feanor]

The hubble telescope would have been taken back to earth with a shuttle, so that we could marvel in all its glory at a museum at the end of its service life. Now all that awaits it is a rendezvous with the atmosphere

You know that for each of the shuttle missions to repair / upgrade hubble, you could have launched a new, improved one?

Hubble missions were a cool idea and something you can nicely show to the public, but they where a waste.

RE my issues with skylon:

General rocket equation / payload SSTO fraction

Structural low weight needed to make it work.

The funding question is hard. Quite hard.

Of course, they passed quite some reviews, and their plans look good.

As said, I wish them all the best. Even if they do not make their goals, add a SRB or 2 to it, or make a small upper stage, and you still very well could be cheaper.

But please, do not yet accept them as a given ( ie - it\'ll be developed. So, when do we build the space hotel with skylon? )

and then - 2019, at the soonest. that\'s quite a while away for spaceX and the like...

[Johno]

Feanor: I have a friend who was involved in Hubble. We actually discussed this issue, and he said that there was more to that one than met the eye.

Sure, in cost terms you\'d be right. But that\'s not all there is to it. For example, the process of grinding Hubble\'s mirror was incredibly time-consuming and exacting[1]. And there were other assemblies and parts that were similarly difficult to craft.

All up, it took 10 years to design and build the Hubble as it was. You could certainly buy a new instrument for the cost of the missions to service it. What you COULDN\'T do is actually build those new instruments in the time allotted.

[1] Indeed, it was that led to its early problems - a worn gauge meant that the grinding was just ever so slightly out of position. Fortunately, because it was done with a gauge with a known amount of wear, computer software could compensate for it, so in the long run no harm was done.