Found this interesting: " Antares rocket's more powerful Castor 30XL upper stage motor provided by ATK. The Castor 30XL is a lengthened version of the Antares rocket's flight-proven Castor 30 motor, boosting the launcher's maximum load to the space station by more than 1,000 pounds."Something to be said for the simple design.
Castor 30XL is sort of the performance limit of the solid US. If you look at high energy performance, they use the 121/2, because the Antares first stage has little T/W, and thus the gravity losses of carring the XL are greater than the extra impulse. So, for LEO the XL wins but for escape, the smaller B is a better choice.Remember that the Antares is supposed to be used for small missions. And the "heavy" to LEO was only needed for CRS.BTW, the core has little T/W because the that way you'd need no changes for a better propulsion (like RD-180 or AJ-1E6) to get extra performance. Ditto with a liquid upper stage.
Not having a down mass capability is part of why it has the better up mass.
FWIW, I'd still love to see an ORB/SpaceX demonstrator mission with a ECLSS-equipped Cygnus as a long-duration hab module for low-frills commercial passenger flights. It could neatly pre-empt Bigelow and I bet Space Adventures have enough clients lined up that they'd enjoy having an alternate provider/destination than Soyuz and the ISS. So long as it has a couple of large view-ports and multi-role power/cooling ports for passenger equipment and personal experiments, it should be fine!
Quote from: Ben the Space Brit on 01/17/2014 09:35 amFWIW, I'd still love to see an ORB/SpaceX demonstrator mission with a ECLSS-equipped Cygnus as a long-duration hab module for low-frills commercial passenger flights. It could neatly pre-empt Bigelow and I bet Space Adventures have enough clients lined up that they'd enjoy having an alternate provider/destination than Soyuz and the ISS. So long as it has a couple of large view-ports and multi-role power/cooling ports for passenger equipment and personal experiments, it should be fine!What you will see first is Cygnus flying as a standalone craft, flying experiments in LEO after it's ISS supply mission has completed. There is no rush to perform the destructive re-entry, and there is power and communication to operate as a free-flier for quite a long while. No ECLSS required since no humans are on board.
Quote from: baldusi on 01/16/2014 04:46 pmCastor 30XL is sort of the performance limit of the solid US. If you look at high energy performance, they use the 121/2, because the Antares first stage has little T/W, and thus the gravity losses of carring the XL are greater than the extra impulse. So, for LEO the XL wins but for escape, the smaller B is a better choice.Remember that the Antares is supposed to be used for small missions. And the "heavy" to LEO was only needed for CRS.BTW, the core has little T/W because the that way you'd need no changes for a better propulsion (like RD-180 or AJ-1E6) to get extra performance. Ditto with a liquid upper stage.The Antares User's Guide seems to show that the 130 series boosts more payload to both LEO and escape than the 120 series. The difference between the two does seem to narrow substantially for the higher energy missions. One factor may be that both use the same Star 48BV third stage. - Ed Kyle
132 has more performance than 122 up to about 1500kg where its curve stops. My SWAG is that, with less than 1500kg, second stage acceleration gets too high: see the second image. 122 does well above 6.5g, but only during the Star48 burn.
A question what is Antares its GTO capacity? can you just assume that it can bring the same payload to GTO as it can to a -8.2 km^2/s^2 C3 orbit? Thus being around 1.5t for the 132 version?
Quote from: TrevorMonty on 01/16/2014 01:17 amI wonder if the Antares could handle 6- 7 Merlins.Just launch Cygnus on Falcon 9 if you're going that route. If you're talking just bulky cargo upmass, Cygnus is simply better than Dragon for the same mass.
I wonder if the Antares could handle 6- 7 Merlins.
Quote from: edkyle99 on 01/17/2014 04:36 amQuote from: baldusi on 01/16/2014 04:46 pmCastor 30XL is sort of the performance limit of the solid US. If you look at high energy performance, they use the 121/2, because the Antares first stage has little T/W, and thus the gravity losses of carring the XL are greater than the extra impulse. So, for LEO the XL wins but for escape, the smaller B is a better choice.Remember that the Antares is supposed to be used for small missions. And the "heavy" to LEO was only needed for CRS.BTW, the core has little T/W because the that way you'd need no changes for a better propulsion (like RD-180 or AJ-1E6) to get extra performance. Ditto with a liquid upper stage.The Antares User's Guide seems to show that the 130 series boosts more payload to both LEO and escape than the 120 series. The difference between the two does seem to narrow substantially for the higher energy missions. One factor may be that both use the same Star 48BV third stage. - Ed Kyle132 has more performance than 122 up to about 1500kg where its curve stops. My SWAG is that, with less than 1500kg, second stage acceleration gets too high: see the second image. 122 does well above 6.5g, but only during the Star48 burn.You could add another stage (Star 27H?) if you wanted to send a cubesat to Neptune or something.
Quote from: arachnitect on 01/17/2014 05:12 pmQuote from: edkyle99 on 01/17/2014 04:36 amQuote from: baldusi on 01/16/2014 04:46 pmCastor 30XL is sort of the performance limit of the solid US. If you look at high energy performance, they use the 121/2, because the Antares first stage has little T/W, and thus the gravity losses of carring the XL are greater than the extra impulse. So, for LEO the XL wins but for escape, the smaller B is a better choice.Remember that the Antares is supposed to be used for small missions. And the "heavy" to LEO was only needed for CRS.BTW, the core has little T/W because the that way you'd need no changes for a better propulsion (like RD-180 or AJ-1E6) to get extra performance. Ditto with a liquid upper stage.The Antares User's Guide seems to show that the 130 series boosts more payload to both LEO and escape than the 120 series. The difference between the two does seem to narrow substantially for the higher energy missions. One factor may be that both use the same Star 48BV third stage. - Ed Kyle132 has more performance than 122 up to about 1500kg where its curve stops. My SWAG is that, with less than 1500kg, second stage acceleration gets too high: see the second image. 122 does well above 6.5g, but only during the Star48 burn.You could add another stage (Star 27H?) if you wanted to send a cubesat to Neptune or something.Huh? You posted the 132 and there the 3rd stage (Star 48) did not even get to 4g. the 2nd stage got high g's
132 has more performance than 122 up to about 1500kg where its curve stops. My SWAG is that, with less than 1500kg, second stage acceleration gets too high: see the 132 graph attached to my previous post, where second stage acceleration can be as high as 6.5g. If you look at the corresponding graph for the 122 (attached), you can see that it has higher acceleration -but only during the Star48 burn.
Not sure which thread to ask this in, but this seems close.Orbital have announced their 2013 financial figures and outlook. Interesting enough for an article, but how do I search their past 12 months on their stock price? I want to see if there's been a rise in the price reflecting their successes.
I wonder how come there is no activity here.. with engine needs and what the supply line looks like going forward