CCDev to CCiCAP to CCtCAP Discussion Thread

[Robotbeat]

Should I have said it was off an STS stockpile 4 seg RMSRV with a dummy US going suborbital? If that's what you're getting at it does not change my point.

Yeah, it does. It had very little to do with Ares I. Unless SpaceX uses left-over solid rockets for its abort tests (and doesn't plan on using them for actual operational aborts), the comparison is ridiculous.

[Elmar Moelzer]

Ares-I had an actual test flight in Ares-X, so I don't think the ability to put hardware in the air should be the sole indicator of progress.

Ares-X has almost nothing in common with Ares-I. The rocket motor was different (4 segment instead of 5), there was no upper stage. The 4 and 5 segment boosters might look similar on the outside, but from what I understand the internal geometry of the solid propellant has to be very different.

[newpylong]

You literally just said exactly what I wrote.

My point was putting any hardware up, whether its hobbled together test vehicles or pad abort tests are not indicative of progress by themselves.

[Robotbeat]

Well, Ares I-x /was/ still much better than just more powerpoints and CAD drawings, although it was ridiculously expensive for being just cobbled together parts.

[Elmar Moelzer]

Well, Ares I-x /was/ still much better than just more powerpoints and CAD drawings, although it was ridiculously expensive for being just cobbled together parts.

It was a pointless waste of money.

[Hauerg]

Yes it was. But to the public it looked like progress.

[clongton]

Ares-I was cancelled but to NOT fly Ares-X would have cost more money in contract termination fees than just flying the thing. That's why they went ahead with the launch.

[Galactic Penguin SST]

Well the above discussion may have no linkage to the thread title anyway, seeing that none of the CCiCAP bidders are doing an Ares-I-X style flight.....

.....so back to the topic, shall we? 

[yg1968]

Bolden blogs about the importance of fully funding commercial crew for FY 2015:
http://blogs.nasa.gov/bolden/2014/03/25/bringing-space-launches-back-to-america/

[yg1968]

NASA has named Kathy Lueders Commercial Crew Program manager; no longer "interim." She replaced Ed Mango.

https://twitter.com/flatoday_jdean/status/458245608709836800
http://www.nasa.gov/content/nasa-selects-commercial-crew-program-manager/

[yg1968]

Commercial crew return on investment report:
http://www.nasa.gov/sites/default/files/files/NASA_ROI_Report_April2014.pdf

[USFdon]

On page 2 of that report, is it just me or does that Dream Chaser on top of the Atlas V in the wind tunnel have a SRB attached? I though they were big on having no solids or could this be verifying that they could add them for higher energy missions for the distant future?

[Lars_J]

On page 2 of that report, is it just me or does that Dream Chaser on top of the Atlas V in the wind tunnel have a SRB attached? I though they were big on having no solids or could this be verifying that they could add them for higher energy missions for the distant future?

Good catch - I extracted the image from the PDF:

[BuzzumFrog]

On page 2 of that report, is it just me or does that Dream Chaser on top of the Atlas V in the wind tunnel have a SRB attached? I though they were big on having no solids or could this be verifying that they could add them for higher energy missions for the distant future?

Good catch - I extracted the image from the PDF:

I've been lurking around for a few months, but I couldn't resist chiming in here.  At the Spacecraft Technology Expo in Long Beach last month, ULA's booth had models of both the Boeing CST-100 and the Dreamchaser mounted on the Atlas 5.  The single SRB was present on the Dreamchaser model in the same position as in this photo.  I can't recall the configuration for the CST-100, but I think it was two SRBs.

Why would they have just 1?  Would it be to oppose and cancel out the Dreamchaser's lifting force in the lower atmosphere?

[Lars_J]

On page 2 of that report, is it just me or does that Dream Chaser on top of the Atlas V in the wind tunnel have a SRB attached? I though they were big on having no solids or could this be verifying that they could add them for higher energy missions for the distant future?

Good catch - I extracted the image from the PDF:

I've been lurking around for a few months, but I couldn't resist chiming in here.  At the Spacecraft Technology Expo in Long Beach last month, ULA's booth had models of both the Boeing CST-100 and the Dreamchaser mounted on the Atlas 5.  The single SRB was present on the Dreamchaser model in the same position as in this photo.  I can't recall the configuration for the CST-100, but I think it was two SRBs.

Why would they have just 1?  Would it be to oppose and cancel out the Dreamchaser's lifting force in the lower atmosphere?

Atlas V has launched three times with 1 SRB before, so it would be because it is needed to lift DC to orbit.

[Space Ghost 1962]

Why would they have just 1?  Would it be to oppose and cancel out the Dreamchaser's lifting force in the lower atmosphere?

Atlas flight control system can deal with asymmetric / unbalanced thrusts from non-symmetrically disposed SRBs.

Key issue with flying an unshrouded payload is to "null" out aerodynamic forces/loads to prevent bending/deviation. You could do that in different ways, but you don't want to add new dynamic inputs to flight dynamics. So as long as it has a constant effect like with the asymmetric SRB, and it doesn't have too great an aeroload vector/bending, then the flight dynamics can work.

[Elmar Moelzer]

Wonder how much the SRBs will drive up the cost for launching the DC...

[baldusi]

From the CCiCAP selection statement, I remember that DC was considered as having a chance of using no solids. But CST-100 was at least a solid and any performance grows would risk the need for two. So my guess is that both went over their reserves and needed an extra solid. My calculation is that performance to an 51.6deg 300km circular orbit (normal insertion), is around 10.5tonne for 402; 12.5tonnes for 412; and 14.3tonnes for a 422. A Falcon 9 v1.1 is 15.3 tonnes. All numbers according to NLS II site.
Thus, it would seem that at least for this, SpaceX has more mass margin than CST-100 and DC.

[vt_hokie]

Wonder how much the SRBs will drive up the cost for launching the DC...

I wonder if (a) maybe it's only for the unmanned OTV test flight and (b) if it's for the operational version too, what are the implications not only for cost but also safety?

[baldusi]

Wonder how much the SRBs will drive up the cost for launching the DC...

I wonder if (a) maybe it's only for the unmanned OTV test flight and (b) if it's for the operational version too, what are the implications not only for cost but also safety?

I don't believe that it's too much issue. In no time during the SRB duration, by itself, would have a T/W>1 for the single version. I don't remember the numbers for two. But easy to run away from in any case. The most delicate issue would be asymmetric thrust. But clearly, while not ideal, NASA deems them acceptable. And then you have to compare Atlas V flight history with Falcon 9 v1.1. As a fan, I don't might li. But if minimum risk should be the measure, Probably CST-100 on Atlas V is the choice. At least it has the strongest companies behind. Of course you might believe that is better to give chance to the yound boys. And I might concur. But lowest ex ante risk is that combo.