Testing times as NASA rattles Mississippi with mighty motor burn NASA has released a video of last week's test burn of an RS-25 motor, which will ultimately power the core stage of the Space Launch System (SLS). The 535-second blast – equivalent to "the amount of time the engines will fire during an actual launch" – took place last Thursday on the A-1 test stand at the Stennis Space …
All respect due to the engineers building and testing the safest vehicle they can, but there has got to be a better way than a bloody great one-shot firework.
You get the distinct feeling that the US Politicians finally woke up to their lack of a launch vehicle, and just told NASA to solve the problem as quick as they could.
See http://www.telegraph.co.uk/news/science/science-news/11805987/Inflatable-space-elevator-invented-by-scientists.html for the latest idea.
Well, instead of riding a tube undergoing a slow explosion, they also tested throwing bombs out the back of a spaceship and surfing the shockwaves from each bomb.
The tests were performed with TNT, but the final plan called for nuclear bombs. It was calculated that you would only need a few ten thousand nukes to get to Alpha Centauri. For some reason they never received permission to procure and detonate even a dozen nukes, and the project was shut down.
>For some reason they never received permission to procure and detonate even a dozen nukes, and the project was shut down.
Funny how quickly all the "peaceful" uses of nuclear weapons disappeared after Strontium 90 started showing up in non trivial amounts in the milk worldwide. Even if you only do it in interstellar space you have to get them up there and make and store them until then all of which are at least mildly frowned upon.
It remains to be seen if humanity can devise a more incremental method of launch, than sitting on a tube full of explosives...!
The whacky ideas of 50 years ago are seeming less extreme with the discovery of new materials. Perhaps more importantly, the computer technology that can *control* many processes with exquisite precision, for any number of incremental steps.
Here's hoping that funky "EM drive" gets either thoroughly explained or a new chapter is added to the *slim* book titled "No more research is needed, we're done".
P.
New technology that gets you away from that rather inefficient stuck-at-the-top-of-a-tube approach?
Check out... Skylon
15 tonnes of payload to ISS orbital height for only around 10 million dollars per flight with a 10-day turnaround between FULLY reusable flights, aboard a single-stage space plane that is due to enter service in 6-7 years...
A revolution in the economics of space flight...
Sorry to have to point it out but a bloody great firework is the only system we have that actually works. Most of the likely (and some amazingly unlikely and down right stupid) fuels have been trialled and the ones remaining (typically kerosene & LOX or LH2 & LOX) are the ones that combine enough specific impulse and scale to get off the ground, while not poisoning us or dissolving the engine.
If, and it is still a big 'if', we see EM drives working it will be a very low force, otherwise we would have seen it before in experiments as a non-trivial effect. So at best an EM drive will be good once you are leaving the Earth's atmosphere and can get low accelerations for months/years based on solar or nuclear generated electrical power.
Edited to add: Yes, the Skylon project is really interesting as you could save a lot of the LOX weight by burning atmospheric O2 up to a decent altitude.
I don't know of any supportive masterminds with volcanic lairs, but one idea that would also help a bit is a massive mountain-side rail-gun style to allow a proportion of the launch momentum to be delivered from ground-based power. Basically you get your main engine & propellent up to say Mach 1 before it even has to burn.
It all comes down to getting more thrust from your fuel. Unlikely, except for a reactor heating the propellent and getting THAT cleared for use is not going to be trivial, and we won't even touch on Project Orion.
Otherwise getting less launch weight and not having to carry the oxidiser (as in Skylon) or by having some ground based propulsion to get you started and a little of the way out of our gravity well.
Re using guns. Its reasonably economically viable to use a supergun to launch supplies into space, if as pointed out you do it up the side of a huge mountain (or mountain range) near the equator. The Andes is probably OK - the odd earthquake might cause the odd problem but the barrel could be relatively cheap and easy to repair if you dont go for silly pressures and accelerations. You could easily get the bits of a much larger rocket up there and then put them together. Fuel would be relatively easy.
"People may be a bit too squishy for the acceleration of a railgun"
It depends on what acceleration you are looking for.
I hope some commentards will check, but I figure that if you had a 2km rail gun on some suitable mountain and were running at 3g sustained acceleration your meat-sacks would survive fine and you would be doing about Mach 1 at the exit point where (hopefully!) the chemical rockets take over 11 seconds or so in to the whole process.
Also I was thinking of a mag-lav rail and electrically powered linear motor, not a "supergun" and explosive charge.
True, (or close enough: v = root(2*20*2000) = root(80000) so maybe you need nearer 3km or 3g) but Mach 1 is about 4% of the momentum you need and consequently about 0.16% of the kinetic energy.
Exercises for the reader: Is it true that if Earth was a bit larger, it would be flat-out impossible for any self-contained chemical rocket to get to low orbit? If so, is that another term for the Drake equation that is usually left out?
Exercises for the reader: Is it true that if Earth was a bit larger, it would be flat-out impossible for any self-contained chemical rocket to get to low orbit? If so, is that another term for the Drake equation that is usually left out?
AFAIK the Drake equation is about whether intelligent life exists *on* other planets, not whether they are able to get *off* said planets.
>AFAIK the Drake equation is about whether intelligent life exists *on* other planets, not whether they are able to get *off* said planets.
The Drake equation contains this factor:
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
If a civilisation that cannot reach orbit, the absence of communication satellites might affect the nature of ERM that they emit.
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"I hope some commentards will check, but I figure that if you had a 2km rail gun on some suitable mountain and were running at 3g sustained acceleration your meat-sacks would survive fine and you would be doing about Mach 1 at the exit point where (hopefully!) the chemical rockets take over 11 seconds or so in to the whole process."
I don't know if this is either feasible or useful but one could launch a vehicle via this method without a crew, and then send the crew up separately in a roman-candle type rocket or whatever other mode of conveyance won't necessarily kill them. Doing so would allow the rail-gun launched vehicle to be optimized for the strengths and survivability of the hardware as opposed to the weaknesses and survivability of the flesh and blood crew, who would rendezvous with their vehicle in space. This might enable the launch of larger vehicles and cargoes although economies of scale (budgetary and/or engineering) might or might apply.
Of course there would be a need to engineer the rail-launched vehicle for the launch itself as opposed to being engineered for space-travel proper - two profoundly different sets of engineering requirements. But as a cargo carrier to get materials into space to build a large space-faring ship, it might be useful.
I don't know if this is either feasible or useful but one could launch a vehicle via this method without a crew, and then send the crew up separately in a roman-candle type rocket or whatever other mode of conveyance won't necessarily kill them... ...Of course there would be a need to engineer the rail-launched vehicle for the launch itself as opposed to being engineered for space-travel proper - two profoundly different sets of engineering requirements. But as a cargo carrier to get materials into space to build a large space-faring ship, it might be useful.
A rail gun would certainly be a way to get a large tank full of fuel into orbit. It can then be used fuel-up any spaceship you've managed to get up there by other means.
I think the big problem with a rail gun is you have to impart all the momentum right at the start. It turns out you really *don't* want to accelerate too fast in the lower atmosphere if you can avoid it, because you end up losing a lot of energy to air friction.
...one idea that would also help a bit is a massive mountain-side rail-gun style to allow a proportion of the launch momentum to be delivered from ground-based power.
There are a number of possibilities that have been explored in this regard such as firing a laser at the bottom of the craft to superheat the air beneath it. That's pretty nifty, but my favorite is the space gun which would be capable of literally firing objects into space (much as the name implies). The US Navy has a railgun project that is coming close to being able to do this with small objects, but these are meant to come back down. Still, if the research put into that could be further developed to launch things with a reasonable amount of acceleration (without turning people into paste), we might have a winner.
For purposes of comparison, escape velocity is about 11.2 kps (81 bnps) and the USN railgun will fire projectiles at about 2.5-3.5 kps (18-25 bnps) while the fastest bullet train taps out at around .17 kps (1.2 bnps).
> ... the only system we have that actually works.
Apart from that it has to be appreciated that an enormous amount of money and engineering is spent on an event where lots of scientists are watching, for more than 500 seconds and with straight faces, to the world's largest fire fart simulation.
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"I don't know what would be more scary - being in space or sitting atop such a contraption beforehand."
To quote John Glenn (veteran Space Shuttle & Mercury programme astronaut), I would guess it's the latter...
I guess the question I'm asked the most often is: "When you were sitting in that capsule listening to the count-down, how did you feel?" Well, the answer to that one is easy. I felt exactly how you would feel if you were getting ready to launch and knew you were sitting on top of two million parts -- all built by the lowest bidder on a government contract.
I can't help feeling that the whole launch a completed satellite into space thing is getting a bit silly and perhaps it's time we started to seriously explore at least partial in space construction. The current method relies on everything going perfectly every time. Even a slight failure of the launch system results in total failure and the loss of 70 tons of very expensive equipment.
The alternative would be multiple much small launches, lets say 100 1 ton launches. Chances are one would fail but over all I think it could still work out cheaper. One obvious potential advantaged would be the possibility of using exotic launch systems (e.g. mass drivers) for parts that are robust and able to handle the g-forces. Additionally once we have in space construction sorted out we can start building big things in space, imagine being able to build the thirty meter telescope in orbit!
Actually, I think larger launchers are more cost-effective. For every launch you are paying to launch both vehicle and payload so the economics of scale apply.
This doesn't preclude assembling stuff in space but, as the ISS is testament to, this is far from easy: gravity and radiation shields in the form of an atmosphere have their advantages. I suspect this is why the moon is so attractive as a half-way house: possible to build large facilities reasonably easy and low enough gravity to make really large launches possible.
I don't think the moon is that useful as a staging ground, unfortunately. It has most of the disadvantages of building in orbit -- no radiation shielding, no atmosphere -- and 1/6 g is still quite a deep gravity well to get something out of. It negates one of the biggest potential benefits of building in orbit, which is you can build a lot lighter if your vehicle never has to support itself against gravity.
Losing a payload in a launch incident isn't that much cost.
Hundreds of prototypes are built to make sure everything will work and the incremental cost of building a backup is tiny so there's always a backup.
The major expense is R&D and all that cost is counted as part of the launch price.
It's a bit easier with cookie-cutter systems such as geostationary comms birds and that's reflected in their vastly lower per-launch cost, but even then no two are the same.
This is 21st century craftsmanship producing one-offs at least as wonderful as one of Fabergé's eggs.
@Stevie, Yes I know, it's not about the engine. Water is used with every launch. It's not only smoke in the video but a hell of a lot of steam from the water. To explain why water cuts the sound and the vibration will require the Wikipedia, apart from that, water is needed to save the launch pad. I just wonder how much water, like gallons per second.
For the Pad 39 Space Shuttle launches the peak flow is apparently 900,000 US gallons per minute for the Sound Suppression Water System.
http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-lc39.html#sts-lc39-ssws
But it must vary as they only store 300,000 US gallons for the launch. Must have been much more for this static test where the motor doesn't shoot off.
I was wondering what that steam plume would do to the already humidity laden Mississippi air.
I was also wondering what all those people were staring at for 9 minutes. Once you've seen 10 seconds of that video, you've seen it all.
70 tonnes is the rocket payload to low earth orbit.
I expect that means that they are planning a vehicle and fuel load to achieve that.
The Saturn V weighed nearly 3000 tonnes on the pad, and its payload to LEO was 120 tonnes.
Still unsurpassed, nothing getting anywhere near it.
This SLS development is planned to go to 130 tonnes, this first block plan is to 70, block 1b to 100 and then block 2 eventually to 130 tonnes.
back in 1990. Driving along the I10, from Louisiana to Florida. We saw a "NASA Rocket Test facility" sign, and decided to check it out. This was December, so hardly peak tourist. We had a guided tour, with the observation that if we had been a day earlier, the facility would have been closed to visitors, due to a "special" test (go figure).
Can highly recommend it. These guys were geek major.
Saw the test platform from about 3 miles away :)
On the same trip, we visited Blackwater park in Mississippi - we were the only visitors that week.
I drive by there frequently as I have family in the area. The visitor center (where you catch the shuttle bus to Stennis) is right off the I-10. First eastbound (or last westbound) exit in Mississippi. They recently opened the new Infinity Science Center adjacent to the visitor center. Haven't been in the Infinity addition yet but looks pretty awesome from what I can see passing by and from their website.
It's a jobs program. As all new NASA launchers, especially manned ones, it'll get 90% to flight and be canceled. Remember Venturestar (aka X-33)? Remember the Constellation program? Remember Ares I (which actually got one test launch) and Ares V? All canceled after tons of money was spent.
I give it about 15% chance of a flight, and no chance of a second flight.
Congress is trying hard to cancel the commercial crew capsules as well, but they've got Elon Musk to deal with, so it won't be the usual stroke of a pen.
Skylon as a flying craft is still vapour-rub.
NASA using the most reliable rocket engine - modified and power boosted - so potentially as reliable as sticking a turbo on a Fergie tractor engine then.
SpaceX ... getting close but still not there.
Diamond elevators? Not in my lifetime.
For reasonable economics and safety my money is still on the Iron Chicken from the Clangers ... if she just let down a rope we could climb up ... it is a documentary isn't it?
Steam launchers.
Spray water vapor into an expansion chamber at the back of the rocket, pulse a laser up it and the expansion of the steam provides thrust.
Power storage on the ground to run the laser is a challenge, but recent progress in military lasers (US Navy) is quite promising.
Oh yeah, you also have to have a really good aiming system, although you need that for zapping incoming hypersonic missiles too.
Wikipedia has the numbers for a Saturn V ( https://en.wikipedia.org/wiki/Saturn_V ). There's a rather nice graph of g-force against time and (a real gem here) the text notes that they actually had to *turn off* one of the 1st stage engines in-flight to avoid squishing the payload. :)
Apollo was abso-fucking-lutely awesome.
Think they reckoned it was doing 100mph by the time it cleared the tower.
No matter. Numbers will never do a Saturn V justice.
It's like trying to describe say a Ferrari.
I remember well watching launches as a kid. Mind numbing. Awe inspiring. I was 'there' when they stepped on the moon. I felt I held hands with the planet during Apollo 13. Amazing times.
I think it was Michael Collins who when asked what it was like to ride one said something like
"Imagine being strapped to the top of the biggest firework man ever built, they lit the blue touch paper, and then watched from the safety of their bunkers...."
Damn. Come on. Do it again....
"Imagine being strapped to the top of the biggest firework man ever built, they lit the blue touch paper, and then watched from the safety of their bunkers...."
Ah, bunkers. That's yet another thing they learned the hard way. The Apollo 4 launch was so loud it damaged the press building about a mile(?) away. Later Apollos had some sort of sound suppressors.
https://www.youtube.com/watch?v=1uoVfZpx5dY
The last upgrade (from a proprietary ISA processor with plated wire memory) was to a pair of M68000, however it turned out that to keep them in close enough synchronization they had to be on the same chip.
A project killer for most projects but not NASA.
Who simply asked Motorola to run off a special batch of twin 68k's.
The new design presumably won't need that design "feature" this time round.
While the running engine is quite well behaved something like 13 power heads (the parts around the drive turbines) were destroyed working out the start sequence. You might say the turbines are "bump started" by a series of "burps" as the LH2 flash boils when first flowing into t pump impellers (IOW the pump impellers start the turbines, not the other way round, before ignition).
The process is delicate. One head got blown up because the sensor reading the valve open angle was off by one degree.
In theory since the SLS engines (RS25D) will be short life they can be made lighter and simpler by simplifying all the bearing packages and deleting the GHE purge gas tanks, each about 300lb
Wheather this will be done is another matte.
That's not a rocket. That's Hotblack Desiato testing a smoke machine for the next Disaster Area concert.
"See http://www.telegraph.co.uk/news/science/science-news/11805987/Inflatable-space-elevator-invented-by-scientists.htm"
I knew they were remaking Thunderbirds with CGI actors and real sets but I didn't realise the sets were going to be full-scale. Let me guess - the tower springs a leak and the blast of expelled air blows the World President's jet off course into the jungle while the tower looks like it'll fall on Lady Penelope who is trapped in her car and Scott has to prioritise personal feelings against civic duty?
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