Author Topic: ISS Commercial Resupply Services 2 (CRS2) 2017-2030  (Read 473501 times)

Offline JazzFan

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #980 on: 12/25/2015 10:37 pm »
Increased capacity and fewer flights to meet the terms of the contract will make it easier to get the flight and docking scheduling in place.  The number of different vehicles to be launched makes for a more complicated dance of scheduling docking time and work hours required for offload and onloading of cargo. Time saved from these tasks equals more time available for science. With ISS everything has a cause and effect.

Offline meekGee

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #981 on: 12/26/2015 02:10 am »
Dream Chaser is cool, but does it have any advantages beyond lower G reentry, and is that really important?
Much bigger than the lower G reentry, IMHO, is the potential for much lower refurb costs in between flights.
I am not sure that it needs less refurb than the Dragon capsule does. The TPS is rather demanding in this regard. I remember something about 2 weeks for TPS inspection.
That's not too bad, actually.

Yup.

As a believer in VTVL, I really want to see DC fly.  It is the most logical incarnation of a winged design, and so it should get its chance to shine. 

Once both it and DV2 are flying, we compare real-world performances.
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Offline SweetWater

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #982 on: 12/26/2015 02:33 am »
Dream Chaser is cool, but does it have any advantages beyond lower G reentry, and is that really important?
Much bigger than the lower G reentry, IMHO, is the potential for much lower refurb costs in between flights.
I am not sure that it needs less refurb than the Dragon capsule does. The TPS is rather demanding in this regard. I remember something about 2 weeks for TPS inspection.

I apologize if this has been addressed elsewhere, but do we know if NASA would allow Dreamchaser space frames to be reused? I ask because, as I understand it, the Dragon capsules used by SpaceX under the current CRS contract are claimed to be reusable; however, NASA requires a new capsule for each mission.

Offline MP99

Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #983 on: 12/26/2015 02:50 pm »


As a believer in VTVL, I really want to see DC fly.  It is the most logical incarnation of a winged design, and so it should get its chance to shine. 

Nit: VTHL. :-)

Cheers, Martin

Offline meekGee

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #984 on: 12/26/2015 03:20 pm »


As a believer in VTVL, I really want to see DC fly.  It is the most logical incarnation of a winged design, and so it should get its chance to shine. 

Nit: VTHL. :-)

Cheers, Martin
No, no, VTVL...

Still want to see DC fly though...  Give VTHL a sporting chance.

Shuttle was not a good argument against VTHL since it had so many other issues dragging it down.

DC and DV2 would be a fair comparison.
« Last Edit: 12/26/2015 03:20 pm by meekGee »
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Offline RonM

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #985 on: 12/26/2015 04:03 pm »
Dream Chaser is cool, but does it have any advantages beyond lower G reentry, and is that really important?
Much bigger than the lower G reentry, IMHO, is the potential for much lower refurb costs in between flights.
I am not sure that it needs less refurb than the Dragon capsule does. The TPS is rather demanding in this regard. I remember something about 2 weeks for TPS inspection.

I apologize if this has been addressed elsewhere, but do we know if NASA would allow Dreamchaser space frames to be reused? I ask because, as I understand it, the Dragon capsules used by SpaceX under the current CRS contract are claimed to be reusable; however, NASA requires a new capsule for each mission.

NASA told SpaceX to price their bid based on a new Dragon for each mission, but the CRS contract does not require a new Dragon for each flight.

Apparently, it's cheaper for SpaceX to build a new capsule and reuse some of the parts. Dunking Dragon in salt water for landing causes reuse issues. Perhaps propulsive landings on dry land would make reusing Dragon possible.

I am sure NASA is okay with reusing DC. They reused the shuttles. If NASA didn't allow for DC reuse then NASA would have already rejected the DC bid.

Offline Robotbeat

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #986 on: 12/26/2015 04:48 pm »
They are looking to reuse some of the Dragons for CRS.

Heck, I bet some of the previously recovered Dragons are already being processed for specific cargo missions as we speak.

...and yes, of course NASA would allow Dream Chasers to be reused.
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Offline joek

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #987 on: 12/29/2015 04:43 pm »
The 5,000kg payload would only apply if they had the necessary volume. I undestand that the DC internal volume is 14m3, how much do they add with the disposable module?
Let's remember that Enhanced Cygnus can do 3,500kg in 27m3, so you would need something like 38m3 for 5,000kg.
16m^3 for the crew variant if I recall.

It really does hinge on the disposable module which we know almost nothing about. But SNC must think 5,000kg is possible if they selected an Atlas V 542 as a LV. If they were volume constrained they could have gone with a cheaper Atlas.

I recall that was total pressurized volume?  The minimum usable pressurized cargo density is specified in the RFP:
Quote from: CRS2 RFP
2.1.1   A minimum usable pressurized cargo density of 65 Cargo Transfer Bag Equivalents (CTBE) per 1000 kg of pressurized cargo shall be used.  Useable pressurized cargo volume is defined as the volume which can accommodate ISS cargo and payloads types as defined in SSP 50833, paragraph 3.1, Pressurized Volume Area Cargo Requirements.

That is 291 kg/m3 or 19 m3 of usable pressurized cargo volume for the DC claimed maximum of 5500kg up-mass.  However, we don't know if that maximum includes a split between pressurized and unpressurized.

Offline baldusi

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #988 on: 12/29/2015 05:12 pm »
Now that I see the MPLM average density, it was, in fact, 331kg/m³. So, I guess it could be doable with DC and an Atlas V 5xx. And the if the disposable module is a 3m (diameter) x 2m (length) cylinder, it could add 14m³ which should enable 5,000gk at 167gk/m³ (which seems realistic).

Online rcoppola

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #989 on: 01/09/2016 05:52 pm »
I think it would be fair to say that neither the Cygnus or DC in their current proposed configurations could accommodate delivery of unpressurized payloads such as BEAM and the Docking adapters...?

Also...Any word on the contract awards?
« Last Edit: 01/09/2016 05:56 pm by rcoppola »
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Offline arachnitect

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #990 on: 01/09/2016 06:34 pm »
I think it would be fair to say that neither the Cygnus or DC in their current proposed configurations could accommodate delivery of unpressurized payloads such as BEAM and the Docking adapters...?

Also...Any word on the contract awards?

Orbital was going to take their unpressurized logistics module through CDR during COTS, I don't know how far they got.

Offline ncb1397

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #991 on: 01/09/2016 06:41 pm »
I think it would be fair to say that neither the Cygnus or DC in their current proposed configurations could accommodate delivery of unpressurized payloads such as BEAM and the Docking adapters...?

Also...Any word on the contract awards?
Would it be really that hard to mount something to the Cygnus or DC inside the payload fairing? For companies that do rocket science, that doesn't sound like rocket science.
« Last Edit: 01/09/2016 06:42 pm by ncb1397 »

Online rcoppola

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #992 on: 01/10/2016 03:07 am »
I think it would be fair to say that neither the Cygnus or DC in their current proposed configurations could accommodate delivery of unpressurized payloads such as BEAM and the Docking adapters...?

Also...Any word on the contract awards?
Would it be really that hard to mount something to the Cygnus or DC inside the payload fairing? For companies that do rocket science, that doesn't sound like rocket science.
That's really not the question though, since I clearly included the discriminator of "current proposals" not what is theoretically possible. As for it not being rocket science...actually that's exactly what it is. Where exactly would you attach the BEAM in the current DC configuration?
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Offline rayleighscatter

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #993 on: 01/10/2016 01:47 pm »

That's really not the question though, since I clearly included the discriminator of "current proposals" not what is theoretically possible.
NASA isn't currently proposing anymore payloads like BEAM or IDA though, so it is theoretical.

Offline ncb1397

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #994 on: 01/11/2016 12:28 pm »
I think it would be fair to say that neither the Cygnus or DC in their current proposed configurations could accommodate delivery of unpressurized payloads such as BEAM and the Docking adapters...?

Also...Any word on the contract awards?
Would it be really that hard to mount something to the Cygnus or DC inside the payload fairing? For companies that do rocket science, that doesn't sound like rocket science.
That's really not the question though, since I clearly included the discriminator of "current proposals" not what is theoretically possible. As for it not being rocket science...actually that's exactly what it is. Where exactly would you attach the BEAM in the current DC configuration?

Actually, the DC proposal is for up to 500 kg of unpressurized cargo. IDA masses 526 kg. So, technically no, it couldn't accommodate IDA because it is 5.2% over weight. How hard it would be to uprate the vehicle is anyone's guess. BEAM is too heavy and bulky, but there are other ways to test inflatable modules in space. If it wasn't logistically possible to do BEAM at ISS, it wouldn't be a huge deal. BEAM was sized to fit the logistics capacity of cargo suppliers. If it was sized for SLS, would we be saying that SLS is required capability? We don't know much about orbital's CRS 2 proposal, but mounting external cargo should be even easier than DC.
« Last Edit: 01/11/2016 12:29 pm by ncb1397 »

Offline TrevorMonty

Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #995 on: 01/11/2016 02:37 pm »
I think it would be fair to say that neither the Cygnus or DC in their current proposed configurations could accommodate delivery of unpressurized payloads such as BEAM and the Docking adapters...?

Also...Any word on the contract awards?
Would it be really that hard to mount something to the Cygnus or DC inside the payload fairing? For companies that do rocket science, that doesn't sound like rocket science.
There is no need to duplicate each vehicles capabilities, just accept some jobs can only be done with specific vehicles.
Dragons has trunk.
Cygnus can do additional missions after leaving ISS and carry very bulky cargo.
DC can land its cargo at an airport and has low reentry Gs.


Offline guckyfan

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #996 on: 01/11/2016 04:43 pm »
Cygnus can do additional missions after leaving ISS and carry very bulky cargo.

Can it? I recall it was mentioned that the opening of the berthing port is much smaller for Cygnus than for Dragon. That would limit them for diameter. They can carry a lot though.

Offline ncb1397

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #997 on: 01/11/2016 04:50 pm »


Cygnus can do additional missions after leaving ISS and carry very bulky cargo.

Can it? I recall it was mentioned that the opening of the berthing port is much smaller for Cygnus than for Dragon. That would limit them for diameter. They can carry a lot though.

I think he means it can carry high density and low density cargo. Each individual item of low density cargo could be any size diameter.

Offline Kryten

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #998 on: 01/11/2016 08:21 pm »
Quote
Charles A. Lurio
‏@TheLurioReport
Some in DC saying very likely that the winners of the second set of ISS cargo supply contracts to be announced Thursday (CRS-2).

Offline Star One

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Re: ISS Commercial Resupply Services 2 (CRS2) 2017-2024
« Reply #999 on: 01/11/2016 09:42 pm »
I hope that's correct been eager to hear if DC gets a piece of the pie.

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