I only had 15min and had pushed on the issue of non-US commercial resupply services for the International Space Station if the contractors didn’t deliver so I just left the issue when NASA’s ISS programme’s transport office manager, Kathryn Lueders finally said: “The plan is secure all upmass through domestic services;” but the answer perhaps begs more questions?
secure all upmass through domestic services – but the ISS resupply request for proposals letter also has 34,500kg (75,900lb) of downmass required
Of that 8,000kg is downmass that has to be returned. The other 26,500kg can just burn up on reentry. From calendar year 2011 that trash is 5,000kg a year
My theory is that, NASA’s Commercial Orbital Transportation Services/ISS commercial resupply will not deliver in time all the logistical needs of the station, so when will NASA have to look around for replacement up/downmass capability?
For calender year 2010 NASA is expecting a need for 2,700kg of upmass, 500kg of downmass to be returned and 1,500kg of trash. Well an extra Russian Khrunichev Space Center expendable Progress could do this, OK maybe not 2,700kg but almost that much while admittedly it could not transport the 500kg of returned downmass. But then, no ISS commercial resupply with a heatshield and nothing is being returned intact
If I remember correctly there was quite a bit of build up on ISS during the grounding of the Shuttle fleet after the Columbia disaster but that was only for two crew, not six; looks like we’ll see that added storage need onboard again
When I asked Lueders how they calculated the resupply demand that was ISS logistics shortfall she said it was the difference between what was needed and the total capability of the barter agreement supply of European Space Agency Automated Transfer Vehicles (ATV), Japan’s H-II Transfer Vehicles and Progress and Russia’s Soyuz plus the planned purchases for Russia vehicles between now and 2011
But what’s the problem with extra Progress in the first six to possibly 18 months of commercial resupplies planned in-service date – I can’t remember if the Iran Syria noproliferation act waiver NASA has is up to and including 2011?
In 2011 and 2012 the lack of commercial resupply or a limited service is not going to help as “internal” upmass is 4,800kg and external upmass is 1,800kg with returned downmass tripling and trash downmass being 5,000kg in both years
Unless NASA considers ATV or a “last minute” change to Russian Progress cargo vehicle purchases commercial resupply will have to have demonstrated a good capability otherwise that station is going to get very cramped – and realistically both ESA and Roskosmos are going to have to give their industry two-years notice to comfortably deliver an assured service
So I wonder, when in 2009 will NASA know its got a potential problem with its contractors, having placed the contract(s) on 28 November this year?
Thinking through the timing and what I know of space programes’ industrial needs I’d say mid-2009 is going to have to be a decision date for ordering extra Progress at least
Come 2011 the 5,000kg of trash is going to become a lot more problematic. It’s not an amount you can just shovel around the ISS interior
But it is easily disposed of by an ATV, which can carry up to 7,600kg of nicely packaged dry cargo
In my humble opinion while NASA marches on believing it can find commercial resupply domestically it should really begin to think about back-up options and if Russia is too tricky with the US legal situation then western Europe’s ATV, now a proven resupply capability, should be the first port of call – pun intended
Then again, COTS and commercial resupply might go swimmingly well…