NASA HQ appear to be closing in on a decision to combine the second and third of three planned Commercial Orbital Transportation Services (COTS) demonstration flights (C2 and C3) of SpaceX’s Dragon capsule. Internal schedules, presentations and memos are continuing to point towards a working plan for a preliminary November 30 launch date for the beefed up mission, although challenges remain ahead of approval.
SpaceX COTS:
Buoyed by the success of Dragon’s debut flight, the combination of the next two demonstration flights has been cited as a viable goal for what is key element of NASA’s future aspirations, a roadmap which will eventually hand over the keys of Low Earth Orbit (LEO) to the commercial space flight sector, allowing NASA to refocus the Agency’s attention on Beyond Earth Orbit (BEO) exploration.
While NASA’s flagship launch vehicle for those BEO ambitions – the Space Launch System (SLS) – is expected to be outlined in a definitive plan to lawmakers next month, a temporary role of providing backup to LEO crew and cargo transportation, via what is highly likely to be a Shuttle Derived (SD) Heavy Lift Launch Vehicle (HLV), will not be available prior to 2016.
This in turn leaves the United States’ crew transportation requirements in the hands of the Russians from the second half of 2011, with contracts in place for hundreds of millions of dollars to change hands in return for seats on the Russian Soyuz, along with crew rescue support at the International Space Station (ISS).
So the weight on Dragon’s shoulders is nothing less than huge, with its continued success a potential gap closer between the impending loss of the Space Shuttle and date NASA can stop writing checks to the Russians for hitching a ride on Soyuz, a period where the United States will effectively concede its leadership in space – as much as NASA and the US government claim they will still be number one, despite the lack of a domestic manned launch vehicle.
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Although SpaceX had a shaky start with its opening Falcon I launches, the lessons learned have paid dividends with the opening two successful launches of their Falcon 9 – the latter of which provided Dragon with a smooth test flight ride into space, prior to an issue-free on orbit checkout and an on-target splashdown in the Pacific Ocean.
Launching a human crew on a Dragon is still some time away, not least due to the requirement to test and implement the capsule’s Launch Abort System (LAS), which SpaceX have already began promoting as an integrated system, one which could be potentially used as a land landing system, given it will be embedded into the structure of Dragon.
SpaceX claim they will be ready to launch humans in 2014, thanks in part to the April award of $75m from the Commercial Crew Development (CCDev) initiative to aid development of their integrated escape system, which they class as superior to traditional solid rocket tractor escape towers.
The integrated system appears to be a step up from another alternative to the tower LAS – known as the MLAS (Max Launch Abort System) – which grew out of Constellation Program (CxP) trade study that included other integrated LAS alternatives, such as the Service Module abort motor concept, born out of a hand drawn sketch by former NASA administrator Mike Griffin in 2006.
However, MLAS, which enjoyed a successful pad abort test in 2009, was an alternative LAS that encapsulated – as opposed to being integrated into – the vehicle (in this case Orion), and was intended solely to provide abort capability in the event of a serious failure with its Ares launch vehicle.
A successful launch would have resulted in the Ares/Orion LAS being jettisoned, effectively meaning it was a dead weight to carry uphill.
Cargo runs to the ISS is the first job on the books for Dragon, as contracted by NASA in the Commercial Resupply Services (CRS) contract, worth up to $3.5 billion for SpaceX and fellow commercial winner Orbital.
Initially, SpaceX were tasked with carrying out three test flights – the first of which has been successfully achieved – on a phased test plan which would satisfy NASA and the ISS partners that Dragon would be safe to dock with the orbital outpost.
While Russian media reports have emphasized Roscosmos’ – somewhat obvious – insistence that Dragon proves itself before they’d be happy to sign off on Dragon approaching the ISS, NASA managers have not changed their stance, one which has been consistently positive for most of last year and all of 2011 thus far.
“First formal internal JSC (Johnson Space Center) discussion of the feasibility of combining the two remaining SpaceX demos (COTS 2/3). Managers will go over impacts, work left to do, work that would have to be redone, and launch date estimates based on that,” noted the first memo of 2011 (L2) back in January, referencing the potential of combining both the second and third test flights.
With the Commercial Crew Cargo Project Office noting that the first funding drop was issued to both Orbital and SpaceX in back in December of 2010 – along with the COTS Office added milestones, in tandem with another allocation of NASA funds being distributed this quarter for additional testing – the combination of Dragon’s next two missions began to gain mentions with more frequency.
“At the SpaceX quarterly it was reported that they are looking at combining the next two flights and they feel they can get to ISS soon,” added the COTS office. “The recommendation as to how to proceed is forthcoming.”
By February, ISS long-range (all vehicle) manifests (L2) were still listing separate missions, with C2 (or D2) launching on July 15, followed by C3 (or D3) on October 8, prior to spending October 10 to November 4 on Station. However, a caveat was also listed, citing the “potential that D2 and D3 could be combined”.
Based on the separate C2 and C3 missions, C2 would be tasked with mission objectives up to allowing Dragon to approach the Station to within 10 kilometers, use its radio cross-link to allow the ISS crew to receive telemetry from the capsule and send commands, prior to ending the five day mission with a splashdown in the Pacific Ocean. C3 would then carry out a full unmanned mission, docking with the ISS.
Interestingly, the aforementioned manifest also shows both the first operational mission of Dragon (CRS-1) and Orbital’s Cygnus opening Demo flight would launch within a week of each other in mid-December, with Dragon being relocated on Station to make room for its commercial cousin.
With Soyuz and Progress activity also scheduled for December, the February ISS manifest was giving an insight into one of the busiest months of traffic ever to be seen by the ISS. However, as with all manifests, slips, realignments and planning changes rarely result in a manifest 10 months ahead becoming the reality.
By March, additional milestones for SpaceX were sent to the NASA Associate Administrator (Mr Doug Cooke) for his signature, prior to a Joint Program Review (JPR) with the ISS Program management. Memos which followed in April ramped up the positivity that the next two Dragon missions would be combined.
First, Mission Operations notes cited the Flight Operations Review (FOR) for the combined mission is targeting sometime in August, before becoming part of the regular ISS status presentations, which outlined that a Dragon C3 rendezvous simulation was carried out on March 23, followed by a Technical Interchange Meeting (TIM) for Dragon Ops at SpaceX’s HQ in Hawthorne, California.
The presentation, dated April 20, notes the pending decision from NASA HQ to combine the two missions and confirms an internal work-to date of November 30 for the C2/C3 flight – as much as (MOD) Mission Operations Directorate would be able to support a mission in early October.
“Dragon Status: Dragon is waiting on official direction from HQ to combine the C2 and C3 missions and fly at the end of November. MOD to allow us to work a combined mission launching October 8, SpaceX working towards November 30 date,” noted the ISS ISE Systems presentation – one of a regular group of presentations which provide status on the Station for MOD (L2).
Also listed are some of the current challenges, such as the need for workarounds relating to the S-Band omnidirectional antenna – a system which radiates power uniformly in all directions in one plane, with the radiated power decreasing with elevation angle above or below the plane, dropping to zero on the antenna’s axis, and “realism” of the ISS modeling during the SpaceX sims using SimCity.
“S-Band Omni system design currently violates NTIA (National Telecommunications and Information Administration) power flux density restrictions – assessing if we can fly mission with no omni antennas (VERY limited insight during free flight- burn in the blind) or if design changes can fix this issue,” added the presentation on the challenges.
“Simulations in SimCity do not allow modeling of most of ISS – limited realism during joint sims. Will mitigate issues such as PV (Pilot Viewpoint) as much as possible through detailed Stage Testing and End-to-End Testing in August.”
NASA and ISS partners also need to design a mission profile which would allow Dragon to combine the C2 objective of executing a flight to within 10km of the ISS, with the C3 objective of actually approaching and docking with the ISS.
Analytical validation will provide some confidence, while it is likely Dragon will carry out some on orbit operations, prior to a final Go/No Go review to either end the mission ahead of the C3 objectives, or gain approval for the vehicle to proceed with rendezvous and docking.
A decision on the combined missions was expected in May, however, the latest internal notes published on Monday appear to point to a late June decision point, based on a comment from the Commercial Cargo department, cited as saying “SpaceX meeting end of June to discuss combining missions with launch hopefully before end of year.”
More information is expected from the Dragon Special Topics meetings, which includes a Phase III – part 1 – review. The first meeting took place on May 3, with another meeting scheduled for May 11, prior to a two day discussion scheduled for May 16-17. Flight Readiness Reviews (FRRs) are expected mid-summer.
A list of general questions were sent – and accepted – by SpaceX early last month. However, no response has yet been received.
(Images via SpaceX and L2 documentation. Follow SpaceX updates via the SpaceX open forum section and L2’s specific SpaceX and ISS Sections – the latter of which containins the information used in this article and is updated continually – all linked above).