Comments on: NuSTAR launches into orbit!

By: Terry Baker

Terry Baker — Thu, 05 Jul 2012 19:23:25 +0000

Congrats NuStar Team!! With such past, it is good to see that NuStar is finally launched into its orbit.

By: Jonathan McDowell

Jonathan McDowell — Sat, 16 Jun 2012 01:16:37 +0000

Was Nancy Roman ever PI of a mission? She was in charge of all NASA astronomy for a long time especially during the OAO period…

By: Joseph G

Joseph G — Fri, 15 Jun 2012 18:19:37 +0000

@31 Boingo: IIRC, the leading original plan for the Shuttle had it carried aloft by a hypersonic “mothership” that dropped it off at high speed at the edge of the atmosphere. This meant that the entire system was reusable. Unfortunately, they (not sure if it was NASA or some budget committee) decided that designing TWO ground-breaking new vehicles would be too expensive, so they settled on the booster and external tank design (which caused both Shuttle losses). Bummer. If they’d stuck with the original plan, initial expense notwithstanding, the Shuttle might have actually been as cost-effective per launch as was initially advertised.
On the other hand, hypersonic mothership/daughtership separation (or heck, just a hypersonic aircraft, period) isn’t exactly a well-traveled field, so it may well have been just as risky as the Shuttle design we’re all familiar with. We may never know…

By: Paul

Paul — Fri, 15 Jun 2012 17:57:43 +0000

A recent paper found a much higher than expected index of refraction at gamma ray energies. So, it may be possible to design a gamma ray telescope with refractive optics.

http://phys.org/news/2012-05-gamma-ray-optics-viable-tool.html

(on arxiv: http://arxiv.org/abs/1111.3608 )

By: Paul

Paul — Fri, 15 Jun 2012 17:53:22 +0000

One (minor) advantage of air launch is that the first stage engine can have a larger nozzle, and higher expansion ratio. This improves its specific impulse.

The expansion ratio of a first stage engine is limited by the need for the pressure of the exhaust at the exit plane to not be too low. If it is too much less than ambient pressure, flow separation can occur, with unpredictable (or bad) results. At launch altitude, air pressure is maybe 1/3 of sea level, allowing the nozzle to be longer.

By: Gary Ansorge

Gary Ansorge — Fri, 15 Jun 2012 13:56:14 +0000

Just a note about the European Extremely Large Telescope.. Looks like it will get built…

http://physicsworld.com/blog/2012/06/one_step_closer_towards_europe.html

…and that’s way cool too…

Gary 7

By: Boingo

Boingo — Fri, 15 Jun 2012 10:44:31 +0000

I like the launch method. I have long thought that it is a better idea to have a vehicle launch from an aeroplane like first stage.

I first came across the concept in 1986 when I saw a drawing of a German plan for such a launch vehicle in a series of potential shuttle replacement plans in an issue of Popular Science. A few days later on the morning of January 28th I was discussing the concept with a friend of mine at school as a better idea than the shuttle. I said it was a much better idea than using boosters and a big external tank. Less than an hour later came the news that the Challenger had exploded.

Creepy.

By: Brian Too

Brian Too — Thu, 14 Jun 2012 23:14:04 +0000

Very interesting info on imaging in the X-Ray band.

By: puppygod

puppygod — Thu, 14 Jun 2012 20:34:34 +0000

Wow, it’s first time I heard about Stratolaunch – and it seems to be pretty neat. This is one of the reasons why I think we should go about commercial space travel. Synergy. When it’s one big government-funded agency, then either they do something or fail. If it is dozen or so smaller entities, each one competing, cooperating and innovating, then even if some fail, other will learn from the mistakes and just a little different approach might succeed. Best luck to them.

By: Calli Arcale

Calli Arcale — Thu, 14 Jun 2012 17:21:36 +0000

@ Pete Jackson:

Yes, I think Kevin and I both know that airlaunch doesn’t buy you a whole lot in energetics. Some, but not a lot. He was asking why it is not more used, and I explained that this is because it can only launch smaller payloads, and for commercial operators in that size range, it usually makes more sense to go for a bulk deal on a bigger rocket. It may also be pushing the limits of Orbital’s manufacturing capabilities — I don’t know what their max flight rate is to begin with, and they’ve launched 42 times since their first flight 1990 (including three failures).

So while I’m not sure what you were responding to with that, you are correct — the main advantage in launching from the aircraft is that you have a much simpler ground support arrangement, and it’s entirely portable to any launch site on Earth that’s within range of a decent-sized airport (one large enough to accommodate widebody airliners).

You mentioned that a really big air-launched rocket would need a much bigger airplane. That makes me want to plug Stratolaunch, which is aiming to do exactly that. They’re building this monstrous carrier aircraft out of two use 747s. It’ll be this huge twin-boom aircraft (built by Scaled Composites, naturally; they seem to excel at twin-booms) with a Falcon 9 rocket slung in between. It will be rather more limited in where it can operate from, given the size of that aircraft and the use of liquid prop instead of solids, but it’s the same basic concept, scaled up.