ISS Commercial Resupply Services 2 (CRS2) 2017-2030

[watermod]

Looking at the 5 rocket/year up-mass ISS delivery specification as an element in a shell game of requirements.     If I was Musk & I am not. I would fly one payload a year on the Falcon Heavy with a 53 mt cylinder full of supplies and launch 4 Falcon 9 rockets empty to be filled up with return products.

[arachnitect]

Interested parties list has been posted:

Aerojet Rocketdyne
Aerospace
Arrow
Astrium
ATDL
ATK
Barrios
Blue Origin
Boeing
Draper Lab
Kistler SS
L-3 Cincinnati
Lockheed Martin
Orbital
Paragon Space Development Corporation
SAS
SNC
SpaceX
Teledyne Brown
United Launch Alliance
UTAS

http://procurement.jsc.nasa.gov/crs2/

Stratolaunch couldn't be bothered to send someone?

[manboy]

The problem, I see with Cygnus is that it does not do downmass. It will be interesting if other parties can beat SpaceX and Dragon in fulfilling of the requirements and in price.

There's been a number of proposals that would give Cygnus a downmass capability.

And how much payload and volume do these cost?

I'm unsure. Orbital's early proposal would have involved replacing the entire PCM with a RCM. More recent proposals involve attaching an expandable heatshield between the PCM and the SM.

[Lar]

Looking at the 5 rocket/year up-mass ISS delivery specification as an element in a shell game of requirements.     If I was Musk & I am not. I would fly one payload a year on the Falcon Heavy with a 53 mt cylinder full of supplies and launch 4 Falcon 9 rockets empty to be filled up with return products.

Can the arm handle something that large and berth it successfully and safely?

Wish there was a use for large pressurized empty cylinders. So it would have to be deorbited? This is OT for the thread though.

[Jim]

Looking at the 5 rocket/year up-mass ISS delivery specification as an element in a shell game of requirements.     If I was Musk & I am not. I would fly one payload a year on the Falcon Heavy with a 53 mt cylinder full of supplies and launch 4 Falcon 9 rockets empty to be filled up with return products.

NASA doesn't want that and would disqualify any proposal like that.
a.  They don't know the whole year's logistics requirements
b.  There are perishable items for the crew that needs to go up regularly
c.  There are experiments that needs regular trips
d. there are last minute additions.

[jongoff]

Looking at the 5 rocket/year up-mass ISS delivery specification as an element in a shell game of requirements.     If I was Musk & I am not. I would fly one payload a year on the Falcon Heavy with a 53 mt cylinder full of supplies and launch 4 Falcon 9 rockets empty to be filled up with return products.

NASA doesn't want that and would disqualify any proposal like that.
a.  They don't know the whole year's logistics requirements
b.  There are perishable items for the crew that needs to go up regularly
c.  There are experiments that needs regular trips
d. there are last minute additions.

This is the same reason why the idea of continuing to fly shuttle to solve all the ISS's needs didn't actually make sense. While there are definitely some low value (Tang and TP) logistics requirements that might be forecastable in advance, most of the useful things happening on station are just not something you can fly in one big chunk. On the other hand, while it would be great to receive frequent smaller shipments, with the current way cargo handling is done, the overhead per delivery makes them want to go with a small but frequent number of deliveries.

~Jon

[jongoff]

The problem, I see with Cygnus is that it does not do downmass. It will be interesting if other parties can beat SpaceX and Dragon in fulfilling of the requirements and in price.

There's been a number of proposals that would give Cygnus a downmass capability.

And how much payload and volume do these cost?

I'm unsure. Orbital's early proposal would have involved replacing the entire PCM with a RCM. More recent proposals involve attaching an expandable heatshield between the PCM and the SM.

However the fact that Cygnus doesn't do downmass isn't necessarily a bad thing. There's plenty of trash that needs disposal, and it turns out there are plenty of interesting things you can do with a spacecraft like Cygnus that doesn't need to make it back down to Earth in a hurry after leaving ISS.

~Jon

[Elmar Moelzer]

Hmm, this looks pretty awful.
Btw, maybe I saw that wrong, but this would use a Taurus2 not an Antares...

[NovaSilisko]

Hmm, this looks pretty awful.
Btw, maybe I saw that wrong, but this would use a Taurus2 not an Antares...

Antares was known during development as Taurus II.

[Elmar Moelzer]

Hmm, this looks pretty awful.
Btw, maybe I saw that wrong, but this would use a Taurus2 not an Antares...

Antares was known during development as Taurus II.

Ahh, I started to suspect something like that, but was not sure. Thanks for clarification.

[Jim]

On the other hand, while it would be great to receive frequent smaller shipments, with the current way cargo handling is done, the overhead per delivery makes them want to go with a small but frequent number of deliveries.

~Jon

But not too frequent as to interrupt the crew schedule and microgravity qualitiy

[baldusi]

On the other hand, while it would be great to receive frequent smaller shipments, with the current way cargo handling is done, the overhead per delivery makes them want to go with a small but frequent number of deliveries.

~Jon

But not too frequent as to interrupt the crew schedule and microgravity qualitiy

I thought that berthing VV had no influence in microgravity quality.
On a different not, aren't was to automatize and simplify VV berthing so it doesn't requires so many crew hours? I assumed that whatever the next station is, a lot of thought have to go on logistics. Berthing should be a strictly a robotic operation. This way of doing things is simply too expensive.

[manboy]

Hmm, this looks pretty awful.

Can you elaborate?

On the other hand, while it would be great to receive frequent smaller shipments, with the current way cargo handling is done, the overhead per delivery makes them want to go with a small but frequent number of deliveries.

~Jon

But not too frequent as to interrupt the crew schedule and microgravity qualitiy

Berthing should be a strictly a robotic operation.

I've thought the same thing many times. Apparently from a hardware standpoint the arm isn't capable of autonomously grappling free-flying payloads (or at least that is what I believe Jim has said in the past). It would be interesting to see if NASA could launch a modified end effector that would add that capability.

[jongoff]

On the other hand, while it would be great to receive frequent smaller shipments, with the current way cargo handling is done, the overhead per delivery makes them want to go with a small but frequent number of deliveries.

~Jon

But not too frequent as to interrupt the crew schedule and microgravity quality

That's what I was trying to get at with the second part of my run-on sentence. It's a trade-off with the desire for faster logistics reaction time pushing towards more flights, and the desire to minimize the cargo logistics impact on crew time and microgravity pushing to fewer, bigger flights.

Is that run-on any better?

~Jon

[jongoff]

On the other hand, while it would be great to receive frequent smaller shipments, with the current way cargo handling is done, the overhead per delivery makes them want to go with a small but frequent number of deliveries.

~Jon

But not too frequent as to interrupt the crew schedule and microgravity qualitiy

I thought that berthing VV had no influence in microgravity quality.
On a different not, aren't was to automatize and simplify VV berthing so it doesn't requires so many crew hours? I assumed that whatever the next station is, a lot of thought have to go on logistics. Berthing should be a strictly a robotic operation. This way of doing things is simply too expensive.

Microgravity degradation is due at least to the initial berthing maneuver (there's a bump involved, though not as big a one as for docking), and also possibly due to the bumps from crew unloading and securing the cargo. The crew time hit is more for cargo unloading and trash reloading than it is for just the berthing operations itself, though those are also crew-time consuming.

Could there be ways of dealing at least with the crew time burdens? I'm pretty sure there are. We've proposed some telerobotic options to NASA for reducing crew time burdens due to cargo logistics, but haven't had much luck. And some of the worst of the microgravity issues could be dealt with by using man-tended free flyers for the most sensitive experiments. There are ways of solving these problems, but they require significant changes to how NASA does things currently, and while NASA does seem able to adapt, patience is necessary (though you do sometimes get surprised when they get you a good answer in three months when you had been expecting six).

~Jon

[Jim]

I thought that berthing VV had no influence in microgravity quality.
On a different not, aren't was to automatize and simplify VV berthing so it doesn't requires so many crew hours? I assumed that whatever the next station is, a lot of thought have to go on logistics. Berthing should be a strictly a robotic operation. This way of doing things is simply too expensive.

I believe the  ISS has to maintain specific attitudes for rendezvous and berthing

[baldusi]

I concur that a free flyer would seem a very interesting solution to the microgravity problem. Specially when you already have Cygnus. I'm pretty sure that a 4.2m Cygnus wouldn't be very expensive, since Thales had to reduce the pressurized module from that size. And I thought that the station had multiple attitude changes, for example to minimize the solar panels drag. And they have the reboosts and DAM that are much worse.
Does the crew movement for loading and unloading really affect to much? Moving a few tens of kilos in a 400 tonnes station shouldn't have such an impact. I would guess that the gravity gradient and attitude control per orbit would be much worse offenders.
I have to admit, that I'm still pondering what should be the lessons for the next space laboratory. I believe the fully autonomous rendezvous, capture and berthing should be a must. Or at the very least handled by the ground crew. I love the idea of a free flyer. Not only for the microgravity reasons but for the potential for dangerous experiments that would be unacceptable on a crewed situation. If I had to work on space I would like to develop the business and technical plan for a commercial continuation of the ISS.

[Elmar Moelzer]

Hmm, this looks pretty awful.

Can you elaborate?

Well unless I misunderstood, this is meant as a means to return pressurized cargo to earth. The thing is quite fast when it hits the ocean. There are no parachutes to further brake the fall. It just does not look very nice.

[arachnitect]

Hmm, this looks pretty awful.

Can you elaborate?

Well unless I misunderstood, this is meant as a means to return pressurized cargo to earth. The thing is quite fast when it hits the ocean. There are no parachutes to further brake the fall. It just does not look very nice.

My understanding is HEART is a tech demo for inflatable heatshields (Mars landing), not a model for an operational cargo return system.

[Elmar Moelzer]

My understanding is HEART is a tech demo for inflatable heatshields (Mars landing), not a model for an operational cargo return system.

Then why is it attached to a Cygnus returning from the ISS?