209 posts • joined Wednesday 28th May 2008 11:53 GMT
Re: How about a little perspective here?
"But right now both FH and SLS are paper rockets"
Actually the stages for the first Falcon Heavy are mostly assembled. The engine clusters ought to be test fired on the static stand in Texas early in the new year with an actual launch from Vandenberg lightly pencilled in for around April, though that will probably slip.
From today, http://xkcd.com/1297/
Re: 80,000km > 35,786km
Missed the edit window...
The fuel saving is mostly in the plane change manouevre, the higher that is done the less fuel it takes. A launch from Kourou will generally go straight to GEO altitude as it's almost on the Equator anyway. From Cape Canaveral they need to lose 28.5 degrees of inclination so it takes less fuel to go higher, change plane and drop back, and from Baikonour you need to change by about 56 degrees which makes the Lunar fly-by option tempting.
Re: Launch Window?
Partly sun angle in the transfer bit of the orbit, and partly how long the launch team have been working. You do not want a tired ground control team, or have to try and manage a shift change part way through.
Re: 80,000km > 35,786km
It actually takes less fuel that way, although it needs two engine burns to get to the final orbit rather than one. A burn at apogee (the 80,000km point) raises the perigee to GEO altitude, then half an orbit later a second burn drops the apogee and circularises the orbit.
There have been trajectories involving a trip round the moon calculated, although so far the only taker was a Russian launch that had a stage restart failure and used some of its manouvering fuel to do the loop and circularisation. It wasn't carrying enough fuel for a direct insertion. Satellite operators are very conservative and no-one wants to be the first to use a lunar fly-by for real, they all want someone else to demonstrate it works.
"The Five-ish Doctors" that followed on the Red Button (and is no doubt available via other channels by now) is well worth a watch too, and makes me think a lot of the 'news' in the lead up was dis-information...
Re: Let SpaceX launch it!
It's just inside the capability of a Falcon 9 v1.1. Not sure where you're getting the 6,500kg figure from but the SpaceX site gives around 4,850 to GTO for a non-R and you generally get two thirds of that to Mars, and two thirds again for the F9R.
If "Dalek" had been called something like "Last of his kind" (by then we knew there were no other Timelords) and not had the big reveal trailed heavily beforehand, you could have spotted the moment the Dalek spoke its first words on a seismograph as everybody dived over the back of the sofa.
"The Girl In The Fireplace" was helped by David Tennant and Sophia Myles being involved at the time.
In "Human Nature/Family of Blood" there's a nice line where the human Doctor gives his parents names as Sidney and Verity.
But "Blink" is pretty much the perfect time travel story, and bears repeated rewatching for the small details like where Sally Sparrow walks between an Angel and the camera, and the Angel changes position in the fraction of a second while it can't be seen.
In the days of models they were quite often filmed upside down. Turns out the human eye is quite good at spotting strings above a model spacecraft wooshing across the screen, but not when the shot has been inverted so the string appears to be at the bottom.
Re: Cornflakes and beer
Of course not. Breakfast is when the days bottle of scotch gets opened...
Sarah Jane mentioned it to the David Tennant incarnation when they met up in "School Reunion". Her last words at the end of "The Hand of Fear" had been something like "I bet it's not even Croydon".
Re: Poverty and Space Shots
India needs a space programme to help improve conditions in the country. They were one of the first widespread users of satellite direct broadcast TV and make a lot of use of space based communications, weather and earth resources assets. The money spent on any form of space programme doesn't just evaporate, and it is far better for it to be spent via local institutes and manufacturers than for it to be sent abroad to buy services from foreign agencies.
Dropping in an occasional pure research and prestige mission is a very small increment to the overall budget, and almost certainly helps retain the talent required to keep building the applications programmes in the future.
Re: Only 11 actors?
Or Richard Hurndall who even did it in the series...
Or Michael Jayston for that matter...
Re: LOHAN has a STALKER
Hmmm, "Kinetics" instead as it's relating to motion?
Time of Genesis?
Peter Gabriel era or Phil Collins?
Nice silver body with red and yellow vertical surfaces of course.
As in http://www.davidsissonmodels.co.uk/GAOthers/XL5title.jpg
(From http://www.davidsissonmodels.co.uk/xl5.htm )
They've been selling it for 69 quid, but knocking a tenner off the price brings it down to just under 50?
I'll swap you this slightly crumpled ten pound note for the change you got from your 69 pounds...
Re: A bit late to the party arent they?
Random off-topic snippet. Compared to the date the old ten bob note was withdrawn, a current fiver has the equivalent buying power of about 7/6...
Nah, "Colr" is a web 2.0 site. And the "r" is red...
Hmmm, security patrols?
In a former workplace the overnight security guards were supposed to take a walk round the building every so often. Dotted round the place were some sort of tags, and when they did their rounds they carried a reader with them that recorded the time each tag was visited. NFC could replace the daily or weekly download with realtime, and result in a call ("Do you need an alarm clock or assistance?") or visit in case of missed.
Also geo-caching without suspicious looking boxes in public areas.
Maplin include the VAT, RapidNFC don't, so it's nearer a fourpence difference when you account for that.
Re: Ok what have I missed
Simples. You've used two different time units. 8600 km per *hour* and 9.82 m per *second*^2. You did the multiplying by 1000 to change the km to m, but skipped the 3600 to change seconds to hours or vice versa.
Is there a link
To an online donation page for the matching funds that could be included in the article? http://www.tnmoc.org/support maybe?
Baron Silas Greenbacks henchcrow Stiletto who had to be revoiced as a dodgy Londoner for US distribution.
Re: Can some boffin explain how it works
It's a combination of light pressure and solar wind acting on the various stuff evaporating from the comet. The small gas and dust particles are affected more than the main body of the comet so start lagging behind.
When a comet picks up a large sideways component to its velocity you quite often get multiple tails as different size gas molecules and dust particles are sorted by the acceleration they pick up from the light.
Re: Dirty Snowball
Put that hammer down Lucifer...
Re: Who really owns these?
And salvage law does not apply to any government owned vessel.
“We despise the French, we are mortally afraid of the Soviets, we do not believe the British can afford us." - German Rocket Scientists after the war.
Re: A pedantic ex-BBC VT engineer points out...
And the quick sample I've just looked at all show the classic signs of FR, soft, vignetting around the edge and, as someone mentioned in another comment, things crawling across the screen.
A pedantic ex-BBC VT engineer points out...
In 1953 the BBC was still five years away from having any kind of magnetic video recorder. VERA arrived in 1958 and used spools of wire. Most programmes were done live, and a film recording (Cine camera pointing at a monitor with a long persistence phosphor) would only be made if there was a chance of an overseas sale.
One advantage of hypergolic fuels is that they self ignite as soon as they mix so you don't get much of an explosion. The American Titan II used the same sort of fuel which led to the Gemini launch escape system being ejector seats instead of the solid rockets used on Mercury and Apollo.
Re: There are other issues
"the concern as to whether the pad would survive holding down an SRB for two minutes"
Ooh! An easy one! It wouldn't. Once the SRB lit it was going somewhere, the question was how much else of the stack went with it. If both lit at the same time then everything was fine, if only one lit then the external tank was going to rip in half. The hold down bolts were triggered by the same signal that fired the SRBs anyway.
There were a couple of cases where the explosive nuts on hold down bolts failed to fire. Either the bolt would stretch and snap (it was actually designed to do that) or the whole thing would pull through the skirt of the SRB.
Re: If you're going into deep space you'll be using nuclear power
Voyager type RTGs won't do the job. At launch they only produce 470W from three units massing about 38kg each. Back of an envelope gives about 250kg for 1kW so a couple of tonnes to get the 8kW needed. A Russian TOPAZ gets closer, 300-1000kg for 5kW but at the low end there's no (or very minimal) shielding so you'd not want to put it on a long duration flight.
The cut-over between solar and nuclear power for payload operations is generally the asteroid belt, although the Juno mission currently on its way to Jupiter is solar powered due in part to there not being enough of the relevant Plutonium isotope to build the RTGs needed. The Curiosity rover had first call on it and even then there wasn't quite enough and a couple of instruments got dropped. There's a second Curiosity type rover due to go to Mars in a few years time, it looks like that will have to use solar panels as Spirit and Opportunity did.
Re: Mass of NEXT and power source ?
Worth noting that when you get to your destination you've effectively got a 'free' power source to drive your science payload and communications gear, with chemical engines you still need a power supply for the instruments but the mass has to come out of the payload.
And for comparison, the Dawn spacecraft currently travelling between Vesta and Ceres runs its ion engine from a solar array that produced 10kW around Earth and about 1300W in the asteroid belt.
Re: Low earth orbit question ....
Makes the antenna tracking more difficult. For an equatorial orbit the satellites will only ever move along a single line across the sky, for an inclined orbit not only will that line appear to move as the earth rotates underneath it but the ground station will also need to switch to the next plane of satellites as the line vanishes below the horizon.
Re: Wibbly wobbly pebbles!
No, it's not raining...
I think you imagine wrong. Number plates fall under the Construction and Use Regulations which apply to vehicles on land customarily used by the public, car parks included, as well as on the public highway.
Re: I want to . . .
Bring back Motorail. Drive your electric car to the station and on to the train, plug it in to the wagon which is tapping a bit extra from the overhead, drive your electric car off again at the other end with a nice recharge.
Your robot self driving electric car could even drop you off by the ticket office, park itself on the wagon and hook up to the charger and be waiting outside the exit at the far end...
Re: 1 MW Electric - What about the Batterys
You'll probably need to run the main engine for a few minutes to charge the lift-off/landing batteries before you go. Two electric motors and some batteries are likely to be lighter to carry round when they're not needed than two IC engines capable of lifting the thing. It's like Formula 1 KERS for aircraft.
Re: American jobs
Alenia made the Columbus lab, most of the nodes, the three MPLMs and now the pressurised cargo section of the ATVs. They came up with a kit of parts with plain ring, ring with 4 CBM ports, plain endcap, endcap with CBM and endcap with Russian docking port. Pick two endcaps and however many rings you need and there's your module.
There was actually a problem with tankers for V2s turning up with less fuel on board than they'd started out with.
The percentage of water was down to ease of manufacture and handling in the engine, the fuel was used for cooling the engine chamber before being burned and getting 75% abv probably only needed a single distillation. The V2 did use peroxide, but for driving pumps, not for propulsion.
Re: Commercial power generation potential?
Usable power for power generation is a very different thing to usable power for propulsion. I would expect this engine to actually produce more energy than was used to trigger it, but it won't be in a form that can be siphoned off to trigger the next bang.
"I do wonder what it will take to loft this 150-ton system into orbit"
The article says about a third of that is payload and the rest could probably be split into two, say the engine itself in one load and the rest of the structure in another. That puts you in range of three Falcon Heavy launches to get everything to Earth orbit, or you could use the ISS type assembly process and launch empty units and fit them out internally via multiple small launches. The engine itself is likely to be the heaviest component and the one you don't want to split further, ideally it goes up in one lump and has labels for "Insert fuel hose here" and the like.
"We Find Ghoulish Humour Helps"
Sounds like it should be the name of an ROU.
For this sort of thing the drone will almost certainly have an auto-pilot (eg ArduCopter) that will let it follow a pre-programmed course. It's more likely to be the limited flight time (10-15 minutes) of a hexacopter will restrict them. There's a reason that entrants to http://www.theregister.co.uk/2012/10/07/uav_challenge_canberra_win/ tend to have fixed wings instead of rotary.
Re: With a little help from my friends (FTFY)
Launch costs can be difficult to determine. Russia markets the Proton to the West through a US company, International Launch Services, who tend to quote prices a bit under those of Ariane and Atlas 5/Delta 5 launches. There's good reason to believe that a Proton is built by around 50 people in a bit under a year, putting the basic unit cost at around 10 million. The Soviet Union put in a lot of effort up front at reducing the manufacturing costs of its launchers and making them easy to check out prior to launch, Soyuz and Proton were both designed as ICBMs so the plan was to have lots of them and to be able to launch them at short notice. SpaceX have learned those lessons and should be able to reduce their costs as the Falcon designs settle down.
Re: It's all very well giving the location
Given the location you're unlikely to be far out if you assume sea-level and go for an airburst at a couple of hundred feet.
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