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#940
by
CameronD
on 22 May, 2017 00:52
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I'm excited by this project. And virtually in my backyard, no less! Well... A four hour drive from my backyard 
Though when it comes to N.Z. media coverage of it; there is a non-charming, naive and parochial attitude to Space industry and Space Exploration in Kiwi media. Some, like Duncan Garner on 'The A.M. Show' is reasonably upbeat and excited by it. But if you listen to Talkback Radio in this country - the producers seem to let on air more than the usual share of ''Oh; but isn't all a waste of money when there are people living in cardboard boxes in this country, and Earthquake damaged Cathedrals still to rebuild". They seem to be blissfully unaware of the existence of Commercial Space Ventures - regardless of large or small Government subsidies...
And I even heard one R-word (you know the one) pipe up with "I see that New Zealand is going to join the 'Fake Space club' like the Yanks and the Russkies with their model rockets and computer effects..."
There are people in my country who are very, very punchable w4nkers indeed... 
Well.. look on the bright side. You'll be able to drive to a viewing platform of your selection, totally unmolested by crowds of anything other than sheep (maybe deer if you're really unlucky), sit peacefully in the sunshine beer in hand and (hopefully) watch a rocket lift-off from the top of the Mahia Peninsula.
Now
that's something you can't do in the United States!
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#941
by
ArbitraryConstant
on 22 May, 2017 00:57
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The reason isp is popular in the US (whereas exhaust velocity is more popular in Europe/Russia) is because non-metric people prefer to talk in terms of mass-force.
When you can't convert between units easily, every industry ends up making its own weirdo units...
The weight of the batteries should still be many times higher than the amount of fuel spent by the gas generator in a comparable gg cycle engine, AND the full mass of the batteries is in the craft during full duration of the flight, unlike the fuel used by gas generator which is leaving the vehicle.
I think this is perhaps not framing the tradeoff in the most useful terms. You're right that the dry mass impact hurts performance compared to gas generator, but launchers in this class frequently end up using pressure fed (FireFly) or solid (Pegasus) and that's even worse. If gas generator was never an option due to the engineering and business realities, then electric pumped is an improvement over what would have otherwise been used, and it's a genuinely welcome addition to the pantheon of rocket cycles.
There's a bunch of other applications that have occurred to me where it would be potentially quite useful and outperform the existing options. For example, for lunar missions the baseline propulsion is pressure fed hypergols. NASA has considered pressure fed methalox. This would easily outperform both of those without the development costs of advanced cycles. Another application would be as a kick stage, which are frequently solids now, and solids on top of a Centaur is a travesty.
So this really seems to be to be top notch work by Rocket Lab that will be influential beyond this one launcher.
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#942
by
MATTBLAK
on 22 May, 2017 01:08
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#943
by
savuporo
on 22 May, 2017 01:19
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There's a bunch of other applications that have occurred to me where it would be potentially quite useful and outperform the existing options. For example, for lunar missions the baseline propulsion is pressure fed hypergols. NASA has considered pressure fed methalox. This would easily outperform both of those without the development costs of advanced cycles. ..
There's been a discussion of this above, too. Integrated into a spacecraft with solar power, batteries can be recharged, and a relatively large battery bank could potentially serve other mission goals as well.
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#944
by
LouScheffer
on 22 May, 2017 01:46
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Well, ISP tells how many seconds an engine can support a mass against gravity, using the same mass of fuel. So a bigger number is better in a way that is very relevant for rockets.
I don't think that is correct. From the rocket equation [...]
Using the rocket equation makes sense if the mass being lifted is the fuel being consumed, and then ISP does not give the number of seconds, as you correctly point out.
ISP is more of a test-stand metric, where the fuel is not the mass being lifted. It's how long, using X kg of fuel, you can generate X kg-force (enough to support X kg). It's independent of X or the units of X, since they cancel. So if you put your engine on a test stand, and require it to generate 1 (tonne, kg, lb)-force of thrust, how long can it do this using 1 (tonne, kg, or lb) of fuel.
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#945
by
QuantumG
on 22 May, 2017 01:59
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ISP is more of a test-stand metric, where the fuel is not the mass being lifted. It's how long, using X kg of fuel, you can generate X kg-force (enough to support X kg). It's independent of X or the units of X, since they cancel. So if you put your engine on a test stand, and require it to generate 1 (tonne, kg, lb)-force of thrust, how long can it do this using 1 (tonne, kg, or lb) of fuel.
... and importantly for a test stand, you can easily measure mass-force and time, therefore deriving ISP.
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#946
by
QuantumG
on 22 May, 2017 02:01
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I think this is perhaps not framing the tradeoff in the most useful terms. You're right that the dry mass impact hurts performance compared to gas generator, but launchers in this class frequently end up using pressure fed (FireFly) or solid (Pegasus) and that's even worse. If gas generator was never an option due to the engineering and business realities, then electric pumped is an improvement over what would have otherwise been used, and it's a genuinely welcome addition to the pantheon of rocket cycles.
Indeed. Really small gas generators is a hard problem that was identified as one of those "minimum gauge" problems back when people first started looking at small boosters. The typical solution was to go with pressure fed or solids.
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#947
by
Steven Pietrobon
on 22 May, 2017 05:08
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I'm excited by this project. And virtually in my backyard, no less! Well... A four hour drive from my backyard
Any chance of driving there and live streaming from your mobile phone? The closest point seems to be the road that goes down along the beach. That is 11.3 km away, which should be close enough to get a good view.
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#948
by
Steven Pietrobon
on 22 May, 2017 05:24
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Just checked the 3G mobile phone map at link below. The east side of Mahia peninsula has very poor coverage. The west side is much better, so you're better off driving down the west side.
https://www.vodafone.co.nz/network/coverage/Distance is a little further at 11.5 km. You might be able to go further South, but mobile phone coverage might be limited. The land is also flatter compared to the east site, so you should be able to see it rise over land a little earlier.
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#949
by
MATTBLAK
on 22 May, 2017 05:26
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No, I'm afraid not
I've just returned from a cross country trip to the other side of the Island yesterday. I've crunched the numbers and it's a 5 or 6 hour drive from here in Auckland. If I left at midnight, I'd make it there by dawn and liftoff is tentatively set for 9:00am. However, since it's a less than 40,000lb thrust rocket, viewing it from more than 10kms away would be a bit uninspiring. Even a Shuttle launch from that distance wouldn't look very flash...
I tried awhile ago to get Press Credentials for this launch, but to no avail. At the time, there was no solidly announced launch window to make plans to attend. And security is very tight for this - some might even call it anal...
EDIT: When the launch goes ahead, I'll try to put in a link to footage of it on this page.
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#950
by
MATTBLAK
on 22 May, 2017 05:30
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...Also, when I buy my new Galaxy phone in a couple of weeks, I'll install a map app then! I'm still using a Galaxy 1.
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#951
by
Steven Pietrobon
on 22 May, 2017 05:35
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If I left at midnight, I'd make it there by dawn and liftoff is tentatively set for 9:00am.
That was the old time. The NOTAMs indicate that the window opens at 12:30 pm local! Getting up at 6:30 am gets you there one hour before launch.
However, since it's a less than 40,000lb thrust rocket, viewing it from more than 10kms away would be a bit uninspiring.
You'll be seeing history! That has to be inspiring.
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#952
by
MATTBLAK
on 22 May, 2017 05:38
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You're getting better news of it than I can see in the mainstream media here!! Are you linked to Rocketlab's page or something?! The last launch time I heard was 9:00am!
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#953
by
Steven Pietrobon
on 22 May, 2017 05:45
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You're getting better news of it than I can see in the mainstream media here!! Are you linked to Rocketlab's page or something?! The last launch time I heard was 9:00am!
Mainstream media don't have a clue. Check out the NOTAMs for yourself. Go to
https://pilotweb.nas.faa.gov/PilotWeb/Under NOTAM retrieval, select:
Report Format Type: ICAO
Locations: NZZO
View Notams
There are two NOTAMS B2339/17 and B2338/17. They list the times as
23 MAY 00:30 2017 UNTIL 23 MAY 05:30 2017
The time 00:30 is UTC, which is 12:30 pm your time.
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#954
by
Steven Pietrobon
on 22 May, 2017 05:52
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#955
by
MATTBLAK
on 22 May, 2017 06:26
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The Galaxy Note 5 can directly livestream to Youtube. Can you beg, borrow or steal one for tomorrow? :-)
http://www.tomsguide.com/us/samsung-galaxy-youtube-stream-how-to,news-21673.html
The other way to live stream is to hookup your camera or phone to a computer which is plugged into a 3G wireless internet USB stick.
**Thanks for the weblinks, Steve - I knew nothing about them, being the relatively uninformed creature that I am. And No, I'm afraid I can't go near the place tomorrow or anyday soon - it's not just a simple drive down the road. The unpredictability of closed roads in central, rural N.Z. could make my trip a waste of time - it's snow and ice season there. And I also don't feel like paying illegal 'tolls' to some of the local yokels there. Yes; that is a thing here...
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#956
by
TrevorMonty
on 22 May, 2017 09:13
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I read something about sight seeing being restricted to tour operators, once commercial launches start. Would be case off closing roads and paying for bus ride to viewing site.
Given narrow roads and next to no roadside parking it does make sense. Also injects s bit revenue into local community. I don't mind if the price is reasonable <$25.
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#957
by
Proponent
on 22 May, 2017 12:09
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Thrust in metric should be in Newtons (N) or kilo Newtons (kN).
To be pedantic, I'll point out that the organisation which defines SI units would prefer "newton" or "kilonewton", without capitals or embedded spaces:
Unit names are normally printed in roman (upright) type, and they are treated like ordinary nouns. In English, the names of units start with a lower-case letter (even when the symbol for the unit begins with a capital letter), except at the beginning of a sentence or in capitalized material such as a title....
When the name of a unit is combined with the name of a multiple or sub-multiple prefix, no space or hyphen is used between the prefix name and the unit name. The combination of prefix name plus unit name is a single word.
See the 39th page of the first attached PDF.
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#958
by
ringsider
on 22 May, 2017 12:26
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#959
by
MATTBLAK
on 22 May, 2017 12:44
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I hate to be negative - but unless they've already got something planned and 'up their sleeves', I've heard of no live broadcast of the first launch attempt.
When STS-1 launched on April 12th, 1981: pretty much every country in the civilized world had live coverage of the launch - except New Zealand. When there was the first return to flight after Shuttle 'Challenger' - no mainstream coverage here, despite my old organisations' attempts to get them to notice. And the John Glenn Shuttle mission?! Nada!! When there was STS-114; the return to flight after 'Columbia' - no mainstream coverage here. Although, I personally campaigned hard to get live coverage of this launch. I was told it was going to happen - but at the last minute; they inexplicably changed their mind.
In March 1986 there was live coverage of the Giotto/Halley's Comet encounter... But that was 31 years ago. And now that N.Z. is about to launch their own space rocket? I am unaware of any publicity by TVNZ or 'Three' (TV3) that they intend to cover the launch. In fact - talkback radio today had some comment about 'what a waste of money while people are living in boxes under a bridge'...
I've combated this ignorance in my country for more than 30 years. You are more likely to get live coverage here of the relaunch of 'American Idol'...
Though when it comes to N.Z. media coverage of it; there is a non-charming, naive and parochial attitude to Space industry and Space Exploration in Kiwi media. Some, like Duncan Garner on 'The A.M. Show' is reasonably upbeat and excited by it. But if you listen to Talkback Radio in this country - the producers seem to let on air more than the usual share of ''Oh; but isn't all a waste of money when there are people living in cardboard boxes in this country, and Earthquake damaged Cathedrals still to rebuild". They seem to be blissfully unaware of the existence of Commercial Space Ventures - regardless of large or small Government subsidies...
I've just returned from a cross country trip to the other side of the Island yesterday. I've crunched the numbers and it's a 5 or 6 hour drive from here in Auckland. If I left at midnight, I'd make it there by dawn and liftoff is tentatively set for 9:00am. However, since it's a less than 40,000lb thrust rocket, viewing it from more than 10kms away would be a bit uninspiring. Even a Shuttle launch from that distance wouldn't look very flash...